| Patent application number | Description | Published |
|---|
| 20080225560 | SWITCHING CONTROLLER FOR PARALLEL POWER CONVERTERS - A switching controller for parallel power converters is disclosed. The switching controller includes an input circuit coupled to an input terminal of the switching controller to receive an input signal. An integration circuit is coupled to the input circuit to generate an integration signal in response to the pulse width of the input signal. A control circuit generates a switching signal for switching the power converters. The switching signal is enabled in response to the enabling of the input signal. A programmable delay time is generated between the input signal and the switching signal. The pulse width of the switching signal is determined in response to the integration signal. | 09-18-2008 |
| 20080232018 | Control Circuit with Short-circuit Protection for Current Sense Terminal of Power Converters - A control circuit includes a detection circuit to detect the short-circuited of a current sense terminal of the power converter. It includes a comparator, a verification circuit and a timer circuit. The comparator receives an input signal for generating a sense signal. The input signal represents the switching current of a power switch. The sense signal is enabled when the input signal is lower than a threshold. The verification circuit generates a protection signal in response to the sense signal or/and -a delay signal. The protection signal is generated when the current sense terminal is short-circuited, in which the power switch and the sense signal are enabled after the time delay of the delay signal. The protection signal turns off the power switch for the protection. | 09-25-2008 |
| 20080232138 | Switching drive circuit for soft switching - A switching drive circuit for soft switching is disclosed. It includes an input circuit to receive an input signal. A first delay circuit generates a first delay time in response to the enable of the input signal. A second delay circuit generates a second delay time in response to the disable of the input signal. A switching signal generator generates switching signals. The pulse width of the high-side switching signal is generated in proportional to the pulse width of the input signal. The high-side switching signal is enabled after the first delay time once the input signal is enabled. The low-side switching signal is disabled in response to the enable of the input signal. The low-side switching signal is enabled after the second delay time once the high-side switching signal is disabled. | 09-25-2008 |
| 20080232142 | OUTPUT CURRENT CONTROL CIRCUIT FOR POWER CONVERTER WITH A CHANGEABLE SWITCHING FREQUENCY - A control circuit controls the output current of the power converter at the primary side of the transformer. The control circuit includes a current-detection circuit for generating a primary-current signal in response to the switching current of the transformer. A voltage-detection circuit is coupled to the transformer to generate a period signal and a discharge-time signal in response to the reflected voltage of the transformer. A signal-process circuit is utilized to generate a current signal in response to the primary-current signal, the period signal and the discharge-time signal. The period signal is correlated to the switching period of the switching signal of the power converter. The discharge-time signal is correlated to the duty cycle of switching current at the secondary-side of the transformer. The current signal is correlated to the output current of the power converter. | 09-25-2008 |
| 20080232147 | RESONANT INVERTER - The present invention provides a low-cost resonant inverter circuit for ballast. The resonant circuit includes a transformer connected in series with a lamp to operate the lamp. A first transistor and a second transistor are coupled to switch the resonant inverter circuit. A second winding and a third winding of the transformer are used for generating control signals in response to a switching current of the resonant inverter circuit. The transistor is turned on once the control signal is higher than a high-threshold. Next, the transistor is turned off once the control signal is lower than a low-threshold. Therefore, soft switching operation for the first transistor and the second transistor is achieved. | 09-25-2008 |
| 20080290410 | Mosfet With Isolation Structure and Fabrication Method Thereof - A MOSFET with an isolation structure is provided. An N-type MOSFET includes a first N-type buried layer and a P-type epitaxial layer disposed in a P-type substrate. A P-type FET includes a second N-type buried layer and the P-type epitaxial layer disposed in the P-type substrate. The first, second N-type buried layers and the P-type epitaxial layer provide isolation between FETs. In addition, a plurality of separated P-type regions disposed in the P-type epitaxial layer further provides an isolation effect. A first gap exists between a first thick field oxide layer and a first P-type region, for raising a breakdown voltage of the N-type FET. A second gap exists between a second thick field oxide layer and a second N-well, for raising a breakdown voltage of the P-type FET. | 11-27-2008 |
| 20080309256 | INTEGRATED CIRCUIT CONTROLLER FOR BALLAST - The present invention provides an integrated circuit controller for ballast with preheat/repreheat filament and ignition time control. A charge/discharge circuit is connected to a capacitor to provide the charge/discharge path for the capacitor. It charges when integrated circuit controller without errors and discharges when error occurred during lamp operation or power tripped. A control circuit is coupled to the charge/discharge circuit to control the charge/discharge circuit to charge or discharge the capacitor. A compare circuit is coupled to the charge/discharge circuit to compare a voltage signal on the capacitor from the charge/discharge circuit with threshold voltages for timing control and providing a preheat signal and an ignition signal. A control logic circuit is coupled to the control circuit to control the control circuit and coupled to the compare circuit to receive the preheat signal and the ignition signal for preheating the filament and igniting the lamp. The control logic circuit further receives a feedback voltage for over voltage protect. Once the feedback voltage is over its threshold voltage in the control logic circuit, the control logic circuit controls the control circuit for discharging the capacitor. | 12-18-2008 |
| 20080309380 | METHOD AND APPARATUS FOR DETECTING SWITCHING CURRENT OF MAGNETIC DEVICE OPERATED IN CONTINUOUS CURRENT MODE - The present invention provides a method and apparatus for detecting a continuous current of a switching current. A current signal is produced in response to a switching current of the magnetic device. By sampling the waveform of the current signal in response to the enabling of a switching signal, a first current signal and a second current signal are generated. A continuous current signal is produced according to the first current signal and the second current signal. The continuous current signal is corrected to the continuous current of the switching current. | 12-18-2008 |
| 20080310203 | METHOD AND APPARATUS TO PROVIDE SYNCHRONOUS RECTIFYING CIRCUIT FOR OFFLINE POWER CONVERTERS - A synchronous rectifying circuit is provided for power converter. A pulse signal generator is utilized to generate a pulse signal in response to the leading edge and the trailing edge of a switching signal. The switching signal is used for switching the transformer of the power converter. An isolation device such as pulse transformer or small capacitors is coupled to the pulse signal generator for transferring the pulse signal through an isolation barrier of a transformer. A synchronous rectifier includes a power switch and a control circuit. The power switch is equipped in between the secondary side of the transformer and the output of the power converter for the rectifying. The control circuit having a latch is operated to receive the pulse signal for turning on/off the power switch. | 12-18-2008 |
| 20090027926 | METHOD AND APPARATUS TO PROVIDE SYNCHRONOUS RECTIFYING CIRCUIT FOR FLYBACK POWER CONVERTERS - A synchronous rectifying circuit is provided for flyback power converter. A pulse generator is utilized to generate a pulse signal in response to a leading edge and a trailing edge of a switching signal. The switching signal is used for switching the transformer of the power converter. An isolation device such as pulse transformer or small capacitors is coupled to the pulse generator for transferring the pulse signal through an isolation barrier of a transformer. A synchronous rectifier includes a power switch and a control circuit. The power switch is connected in between the secondary side of the transformer and the output of the power converter for the rectifying operation. The control circuit having a latch is operated to receive the pulse signal for controlling the power switch. | 01-29-2009 |
| 20090033244 | INTEGRATED CIRCUIT WITH A PREHEAT CONTROL FOR A BALLAST - The present invention provides a ballast with preheat function for fluorescent or compact fluorescent lamps. The lamp is connected in series with an inductor and a capacitor to form a resonant circuit. A first switch and a second switch controlled by control circuit are coupled to the resonant circuit for switching the resonant circuit. A RC circuit is composed of a first resistor and a second resistor connected in series to form a voltage divider, and a capacitor is connected in parallel with second resistor. Switching frequency is voltage dependent. | 02-05-2009 |
| 20090040792 | SYNCHRONOUS RECTIFYING CIRCUIT FOR RESONANT POWER CONVERTERS - A synchronous rectifying circuit is provided for resonant power converter. An integrated synchronous rectifier comprises a rectifying terminal, a ground terminal a first input terminal and a second input terminal. The rectifying terminal is coupled to the secondary side of a power transformer. The ground terminal is coupled to the output of the power converter. A power transistor is connected between the rectifying terminal and the ground terminal. The first input terminal and the second input terminal are coupled to receive a pulse signal for turning on/off the power transistor. A pulse-signal generation circuit includes an input circuit coupled to receive the switching signal for switching the power transformer of the power converter. | 02-12-2009 |
| 20090050962 | MOSFET WITH ISOLATION STRUCTURE FOR MONOLITHIC INTEGRATION AND FABRICATION METHOD THEREOF - A MOSFET device with an isolation structure for a monolithic integration is provided. A P-type MOSFET includes a first N-well disposed in a P-type substrate, a first P-type region disposed in the first N-well, a P+ drain region disposed in the first P-type region, a first source electrode formed with a P+ source region and an N+ contact region. The first N-well surrounds the P+ source region and the N+ contact region. An N-type MOSFET includes a second N-well disposed in a P-type substrate, a second P-type region disposed in the second N-well, an N+drain region disposed in the second N-well, a second source electrode formed with an N+ source region and a P+ contact region. The second P-type region surrounds the N+ source region and the P+ contact region. A plurality of separated P-type regions is disposed in the P-type substrate to provide isolation for transistors. | 02-26-2009 |
| 20090058389 | CONTROL CIRCUIT FOR MEASURING AND REGULATING OUTPUT CURRENT OF CCM POWER CONVERTER - A switching control circuit is provided for measuring and regulating an output current of a power converter. The power converter is operated under continuous current mode. A detection circuit generates a continuous-current signal and a peak-current signal by detecting a switching current of an inductive device. An integration circuit generates an average-current signal in response to the continuous-current signal, the peak-current signal and an off time of a switching signal. The switching control circuit generates the switching signal in response to the average-current signal. The switching signal is coupled to switch the inductive device and regulate the output current of the power converter. A time constant of the integration circuit is correlated to the switching period of the switching signal, therefore the average-current signal will be proportional to the output current. | 03-05-2009 |
| 20090091304 | CONTROL CIRCUIT FOR MULTI-PHASE, MULTI-CHANNELS PFC CONVERTER WITH VARIABLE SWITCHING FREQUENCY - A switching control circuit for multi-phases PFC converters is provided. It includes a PFC-control circuit coupled to receive a first-inductor signal and a feedback signal for generating a first-switching signal. The first-switching signal is utilized to switch the first inductor for power factor correction. A phase-detection circuit detects the first-switching signal and a second-inductor signal for generating a start signal and a phase-lock signal. The start signal is developed to enable a second-switching signal. The second-switching signal is coupled to switch a second inductor. An on-time-adjust circuit is coupled to adjust the on time of the second-switching signal in accordance with the phase-lock signal. The phase-lock signal is correlated to the period between the end of the second-inductor signal and the start of the second-switching signal. | 04-09-2009 |
| 20090091951 | CONTROL CIRCUIT FOR SYNCHRONOUS RECTIFYING AND SOFT SWITCHING OF POWER CONVERTERS - A control circuit for soft switching and synchronous rectifying is provided for power converter. A switching-signal circuit is used for generating drive signals and a pulse signal in response to a leading edge and a trailing edge of a switching signal. The switching signal is developed for regulating the power converter. Drive signals are coupled to switch the power transformer. A propagation delay is developed between drive signals to achieve soft switching of the power converter. An isolation device is coupled to transfer the pulse signal from a primary side of a power transformer to a secondary side of the power transformer. A controller of the integrated synchronous rectifier is coupled to the secondary side of the power transformer for the rectifying operation. The controller is operated to receive the pulse signal for switching on/off the power transistor. The pulse signal is to set or reset a latch circuit of the controller for controlling the power transistor. | 04-09-2009 |
| 20090091960 | METHOD AND APPARATUS FOR SYNCHRONOUS RECTIFYING OF SOFT SWITCHING POWER CONVERTERS - An apparatus for synchronous rectifying of a soft switching power converter is provided. An integrated synchronous rectifier includes a power transistor coupled between a transformer and the output of the soft switching power converter, and a controller receiving a pulse signal to switch on/off the power transistor. A switching control circuit generates the pulse signal in response to a current signal, and generates drive signals to switch the transformer in response to a switching signal. An isolation device is coupled to transfer the pulse signal between the switching control circuit and the integrated synchronous rectifier. The switching signal is used for regulating the power converter and the current signal is correlated to the switching current of the transformer. | 04-09-2009 |
| 20090109715 | SYNCHRONOUS RECTIFYING FOR SOFT SWITCHING POWER CONVERTERS - An synchronous rectifying apparatus or synchronous rectifying circuit of a soft switching power converter is provided to improve the efficiency. The integrated synchronous rectifying circuit includes: a power transistor connected from a transformer to the output of the power converter for rectifying; a controller having a latch circuit generates a drive signal to control the power transistor in response to a switching signal generated by a winding of the transformer in response to the switching of the transformer. The controller turns off the power transistor when the switching signal is lower than a low-threshold. The power transistor is turned on when the switching signal is higher than a high-threshold. Furthermore, a maximum-on-time circuit provided in the controller is applied to generate a maximum-on-time signal for limiting the maximum on time of the power transistor. | 04-30-2009 |
| 20090110129 | SYNCHRONOUS RECTIFYING CIRCUIT FOR OFFLINE POWER CONVERTER - A synchronous rectifying circuit is provided for power converter. An integrated synchronous rectifier has a rectifying terminal, a ground terminal a first input terminal and a second input terminal. The rectifying terminal is coupled to secondary side of a transformer. The ground terminal coupled to output of the power converter. A power transistor is connected between the rectifying terminal and the ground terminal. The first input terminal and the second input terminal are coupled to receive a pulse signal for turning on/off the power transistor. A pulse-signal generation circuit includes an input terminal coupled to receive the switching signal for switching the transformer of the power converter. A first output terminal and a second output terminal of the pulse-signal generation circuit generate the pulse signal. An isolation device is coupled between the first input terminal and the second input terminal, and the first output terminal and the second output terminal. | 04-30-2009 |
| 20090129125 | SYNCHRONOUS REGULATION CIRCUIT - A primary-side switching circuit generates switching signals for switching a transformer. A secondary-side switching circuit is coupled to an output of the power converter to generate pulse signals in response to the switching signals and an output voltage of the power converter. Pulse signals are generated to rectify and regulate the power converter. A synchronous switch includes a power-switch set and a control circuit. The control circuit receives the pulse signals via capacitors for turning on/off the power-switch set. The power-switch set is connected in between the transformer and the output of the power converter. Furthermore, a flyback switch is operated to freewheel the inductor current of the power converter. The flyback switch is turned on in response to the off state of the power-switch set. The on time of the flyback switch is programmable and correlated to the on time of the power-switch set. | 05-21-2009 |
| 20090135631 | Method and apparatus of providing synchronous rectifying and regulation for power converters - A synchronous regulation circuit is provided to improve the efficiency of the power converter. A primary-side switching circuit generates a synchronous signal and a switching signal. The switching signal is used for soft switching a transformer. A secondary-side switching circuit is coupled to the output of the power converter to generate a pulse signal in response to the synchronous signal and the output voltage of the power converter. The pulse signal is a differential signal generated for the rectifying and the regulation of the power converter. A synchronous switch includes a power switch and a control circuit. The control circuit receives the pulse signal for turning on/off the power switch. The power switch is connected in between the transformer and the output of the power converter. Furthermore, a flyback switch is operated as a synchronous rectifier to freewheel the inductor current of the power converter. The flyback switch is turned on in response to the off of the power switch. The on time of flyback switch is programmable and correlated to the on time of the power switch. | 05-28-2009 |
| 20090174344 | OFFLINE CONTROL CIRCUIT OF LED DRIVER TO CONTROL THE MAXIMUM VOLTAGE AND THE MAXIMUM CURRENT OF LEDS - An offline control circuit of LED driver controls the maximum voltage and the maximum current of a plurality of LEDs. A switching circuit generates a plurality of LED currents through a transformer. A voltage-feedback circuit generates a voltage loop signal in response to the voltage across the LEDs. A current-feedback circuit senses a plurality of LED currents for generating a current loop signal in response the maximum current of the LEDs. A buffer circuit generates a feedback signal in accordance with the voltage loop signal and the current loop signal. The feedback signal is coupled to the switching circuit through an optical-coupler for controlling the maximum voltage and the maximum current of the LEDs. | 07-09-2009 |
| 20090195183 | CONTROLLER OF LED LIGHTING TO CONTROL THE MAXIMUM VOLTAGE OF LEDS AND THE MAXIMUM VOLTAGE ACROSS CURRENT SOURCES - Controller of LED lighting to control the maximum voltage of LEDs and the maximum voltage across current sources is provided. A voltage-feedback circuit is coupled to the LEDs to sense a voltage-feedback signal for generating a voltage loop signal. Current sources are coupled to the LEDs to control the LED currents. A detection circuit senses the voltages of the current sources for generating a clamp signal in response to a maximum voltage of the current sources. Furthermore, a buffer circuit generates a feedback signal in accordance with the voltage loop signal and the clamp signal. The feedback signal controls the maximum voltage of the LEDs and the maximum voltage across the current sources. | 08-06-2009 |
| 20090200997 | SWITCHING CONTROLLER HAVING PROGRAMMABLE FEEDBACK CIRCUIT FOR POWER CONVERTERS - A switching controller for a boost power converter includes a switching-control circuit and a programmable feedback circuit. The programmable feedback circuit is coupled to an output of the boost power converter via a voltage divider. The programmable feedback circuit includes a current source coupled to a switch. On a light-load condition, a power-saving signal turns on the switch. The switch will conduct a programming current supplied by the current source toward the voltage divider. Furthermore, the voltage divider is externally adjustable for programming a determined level of an output voltage of the boost power converter on the light-load condition. Additionally the present invention increases system design flexibility to meet practical power-saving requirements without adding circuitries and increasing cost. | 08-13-2009 |
| 20090213623 | METHOD AND APPARATUS OF PROVIDING SYNCHRONOUS REGULATION CIRCUIT FOR OFFLINE POWER CONVERTER - A synchronous regulation circuit is provided. A secondary-side switching circuit is coupled to the output of the power converter to generate a synchronous signal and a pulse signal in response to an oscillation signal and a feedback signal. An isolation device transfers the synchronous signal from the secondary side to the primary side of the power converter. A primary-side switching circuit receives the synchronous signal to generate a switching signal for soft switching a transformer. The pulse signal is utilized to control a synchronous switch for rectifying and regulating the power converter. The synchronous switch includes a power switch and a control circuit. The control circuit receives the pulse signal for turning on or off the power switch. The power switch is connected between the transformer and the output of the power converter. A flyback switch is operated as a synchronous rectifier to freewheel the inductor current of the power converter. The flyback switch is turned on in response to the off state of the power switch. The turn-on period of flyback switch is correlated to the turn-on period of the power switch. | 08-27-2009 |
| 20090213626 | SWITCHING CONTROLLER CAPABLE OF REDUCING ACOUSTIC NOISE FOR POWER CONVERTERS - The present invention provides a switching controller capable of reducing acoustic noise of a transformer for a power converter. The switching controller includes a switching circuit, a comparison circuit, an activation circuit, and an acoustic-noise eliminating circuit. The acoustic-noise eliminating circuit comprises a first-check circuit, a second-check circuit, a pulse-shrinking circuit, and a limit circuit. The first-check circuit receives a switching-current signal which is correlated to a switching current of the power converter and a PWM signal to generate a trigger signal. The second-check circuit receives the trigger signal to generate a control signal. When the frequency of the trigger signal falls into audio band, the control signal will be enabled to limit the switching current. Therefore, the acoustic noise of the transformer can be eliminated. | 08-27-2009 |
| 20090213628 | OFFLINE SYNCHRONOUS RECTIFYING CIRCUIT WITH CURRENT TRANSFORMER FOR SOFT SWITCHING POWER CONVERTERS - A synchronous rectifying circuit of soft switching power converter is provided to improve the efficiency. The integrated synchronous rectifier includes a power transistor connected from a transformer to the output of the power converter for rectifying. A controller having a latch circuit generates a drive signal to control the power transistor in response to a switching-current signal. A current transformer generates the switching-current signal in response to the switching current of the transformer. The controller turns off the power transistor when the switching-current signal is lower than a second threshold. The power transistor is turned on once the switching-current signal is higher than a first threshold. Furthermore, a pulse-width detection circuit generates a pulse signal coupled to disable the drive signal and turn off the power transistor. | 08-27-2009 |
| 20090219003 | OFFLINE SYNCHRONOUS SWITCHING REGULATOR - An offline synchronous switching regulator is proposed for improving the efficiency thereof. Switches are coupled to switch a transformer and generate a switching signal at a secondary side of the transformer. A switching circuit is coupled to an output of the regulator to generate pulse signals in response to the switching signal and a feedback signal. Pulse signals are utilized to control a synchronous switch for rectifying and regulating the regulator. The synchronous switch includes a power-switch set and a control circuit. The control circuit receives pulse signals for turning on/off the power-switch set. The power-switch set is connected in between the transformer and the output of the regulator. A flyback switch freewheels an inductor current and can be turned on in response to the off state of the power-switch set whose on-time is correlated to the on-time of the power-switch set. | 09-03-2009 |
| 20090309526 | CONTROL CIRCUIT WITH DUAL PROGRAMMABLE FEEDBACK LOOPS FOR BLDC MOTORS - A BLDC (brushless direct current) motor system of the present invention includes a control circuit, a sequencer, a driving circuit, and a BLDC motor. The control circuit comprises a speed-feedback loop and a torque-feedback loop to control the maximum speed and the maximum torque of the BLDC motor in parallel configuration. The speed-feedback loop generates a speed-control signal. The torque-feedback loop generates a torque-control signal. A PWM circuit receives the speed-control signal and the torque-control signal to generate a PWM signal. A pulse width of the PWM signal is correlated to the level of the speed-control signal and/or the level of the torque-control signal. | 12-17-2009 |
| 20090310388 | METHOD AND APPARATUS FOR MEASURING THE SWITCHING CURRENT OF POWER CONVERTER OPERATED AT CONTINUOUS CURRENT MODE - An apparatus for detecting a switching current of the power converter, wherein the apparatus includes a signal generation circuit, a sample-and-hold circuit, and a calculating circuit. The signal generation circuit generates a sample signal in accordance with the pulse width of a switching signal. The sample-and-hold circuit is coupled to receive the sample signal and switching current signal for generating a first current signal and a second current signal. The calculating circuit is coupled to receive the first current signal and the second current signal for generating output signals. The switching signal is used for switching the magnetic device of the power converter, and the switching current signal is correlated to the switching current of the power converter; the output signals are correlated to the value of the switching current of the power converter. | 12-17-2009 |
| 20090316451 | APPARATUS PROVIDING PROTECTION FOR POWER CONVERTER - A switching circuit for a power converter includes an oscillation circuit, a first circuit, and a first comparator. The oscillation circuit generates a switching signal for regulating an output of the power converter. The first circuit generates a threshold signal. The first comparator is coupled to receive a signal representative of a current through a power switch. Besides, the first comparator generates a control signal in response to the signal and the threshold signal. A frequency of the switching signal is increased in response to the enabling of the control signal. | 12-24-2009 |
| 20100007295 | OVER-TORQUE CONTROL CIRCUIT FOR BLDC MOTORS - A BLDC (brushless direct current) motor system of the present invention includes a control circuit, a sequencer, a driving circuit, and a BLDC motor. The control circuit determines the maximum torque and the maximum speed of the BLDC motor. The control circuit includes an over-current detection circuit to generate a reset signal in response to a switching current of the BLDC motor. The reset signal is generated when the switching current of the BLDC motor exceeds a threshold. A pulse width of the PWM signal is correlated to the level of a speed-control signal and the level of the torque-control signal. The pulse width of the PWM signal is also controlled by the reset signal generated by the over-current detection circuit. | 01-14-2010 |
| 20100007317 | BUCK-BOOST PFC CONVERTERS - A buck-boost PFC converter is provided and includes an inductor, first and second transistors, a first diode, and a control circuit. The inductor has a first terminal and a second terminal. The first transistor is coupled to a positive-power rail and the first terminal of the inductor. The second transistor is coupled to the second terminal of the inductor and a negative-power rail. The first diode is connected from the second terminal of the inductor to an output of the buck-boost PFC converter. The control circuit generates a first signal and a second signal coupled to control the first transistor and the second transistor respectively. The first signal is utilized to turn on the first transistor for conducting the positive-power rail to the inductor. The second signal is utilized to turn on the second transistor for conducting the inductor to the negative-power rail. | 01-14-2010 |
| 20100007394 | METHOD AND APPARATUS OF PROVIDING A BIASED CURRENT LIMIT FOR LIMITING MAXIMUM OUTPUT POWER OF POWER CONVERTERS - A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal. A waveform generator generates a waveform signal in response to a switching signal and a second-sampling signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a first-sampling signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to the second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal. | 01-14-2010 |
| 20100014324 | OFFLINE SYNCHRONOUS RECTIFYING CIRCUIT WITH SENSE TRANSISTOR FOR RESONANT SWITCHING POWER CONVERTER - A synchronous rectifying circuit of a resonant switching power converter is provided to improve the efficiency. The synchronous rectifying circuit includes a power transistor and a diode connected to a transformer and an output ground of the power converter for rectifying. A sense transistor is coupled to the power transistor for generating a mirror current correlated to a current of the power transistor. A controller generates a driving signal to control the power transistor in response to a switching-current signal. A current-sense device is coupled to the sense transistor for generating the switching-current signal in response to the mirror current. The controller enables the driving signal to turn on the power transistor once the diode is forwardly biased. The controller generates a reset signal to disable the driving signal and turn off the power transistor once the switching-current signal is lower than a threshold. | 01-21-2010 |
| 20100033991 | SWITCHING CONTROLLER HAVING SWITCHING FREQUENCY HOPPING FOR POWER CONVERTER - A switching controller having switching frequency hopping for a power converter includes a first oscillator generating a pulse signal and a maximum duty-cycle signal for determining a switching frequency of a switching signal, a pattern generator having a second oscillator and generating a digital pattern code in response to a clock signal, a programmable capacitor coupled to the pattern generator and the first oscillator for modulating the switching frequency of the switching signal in response to the digital pattern code, and a PWM circuit coupled to the first oscillator for generating the switching signal in accordance with the maximum duty-cycle signal. A maximum on-time of the switching signal is limited by the maximum duty-cycle signal. The switching signal is utilized to switch a transformer of the power converter. | 02-11-2010 |
| 20100039088 | INTERLEAVED SLAVE SWITCHING CIRCUIT FOR DISCONTINUOUS MODE PFC CONVERTER - A slave switching circuit for a master-slave PFC converter is disclosed. The slave switching circuit includes a phase-detection circuit coupled to detect a master-switching signal and a slave-inductor signal for generating a start signal and a phase-lock signal. The start signal is coupled to enable a slave-switching signal. The slave-switching signal is coupled to switch a slave inductor. An on-time-adjust circuit is used to adjust the on-time of the slave-switching signal in accordance with the phase-lock signal. The slave-inductor signal is correlated to the demagnetization of the slave inductor. The phase-lock signal is coupled to minimize the period between the disablement of the slave-inductor signal and the enablement of the start signal. | 02-18-2010 |
| 20100097104 | CONTROL CIRCUIT HAVING OFF-TIME MODULATION TO OPERATE POWER CONVERTER AT QUASI-RESONANCE AND IN CONTINUOUS CURRENT MODE - A control circuit is developed to adaptively operate a power converter at quasi-resonance (QR) and in a continuous current mode (CCM) to achieve high efficiency. The control circuit includes a PWM circuit generating a switching signal coupled to switch a transformer. A signal generation circuit generates a ramp signal and a pulse signal. The pulse signal is generated in response to the ramp signal for switching on the switching signal. A feedback circuit produces a feedback signal according to an output load of the power converter. The feedback signal is coupled to switch off the switching signal. A detection circuit is coupled to the transformer for generating a valley signal in response to the waveform of the transformer. The valley signal is further coupled to generate the pulse signal when the ramp signal is lower than a threshold. The level of the threshold is correlated to the feedback signal. | 04-22-2010 |
| 20100123449 | WALL CONTROL INTERFACE WITH PHASE MODULATION AND DETECTION FOR POWER MANAGEMENT - A wall control interface for power management includes a transmitting circuit that generates a switching signal to control a switch and achieve a phase modulation to a power line signal in response to a transmitting-data. A receiving circuit is coupled to detect the phase of the power line signal for generating a data signal and a receiving-data in response to the phase of the power line signal. The receiving circuit further generates a control signal to control power of a load in accordance with the data signal or the receiving-data. The phase modulation is achieved by controlling a turn-on angle of the power line signal. The switch remains in a turn-on state during the normal condition, which achieves good power and low current harmonic. The phase modulation is only performed during the communication of the power management. | 05-20-2010 |
| 20100123563 | POWER MANAGEMENT INTERFACE - A power management interface is provided and includes a switch, a transmitting circuit, and a receiving circuit. The switch is coupled to an AC power line for controlling a power line signal to a load. The transmitting circuit generates a switching signal to control the switch and achieve a phase modulation to the power line signal in response to a transmitting-data. The receiving circuit is coupled to receive the power line signal for detecting a phase of the power line signal and generating a receiving-data to control power of the load. The receiving-data is generated in accordance with the phase detection of the power line signal and correlated to the transmitting-data. | 05-20-2010 |
| 20100124079 | OFFLINE SYNCHRONOUS RECTIFIER WITH CAUSAL CIRCUIT FOR RESONANT SWITCHING POWER CONVERTER - A synchronous rectifier of a resonant switching power converter is provided to improve efficiency. The synchronous rectifier includes a power transistor and a diode connected to a transformer and an output of the resonant switching power converter for ratifications. A controller generates a drive signal to control the power transistor in response to an on signal and an off signal. A causal circuit is developed to generate the off signal in accordance with the on signal. The on signal is enabled once the diode is forward biased. The on signal is coupled to enable the drive signal for switching on the power transistor. The off signal is coupled to disable the drive signal for switching off the power transistor. The off signal is enabled before the on signal is disabled. | 05-20-2010 |
| 20100141307 | Frequency multiplier and method for frequency multiplying - A frequency multiplier according to the present invention comprises a period-to-voltage converter that generates a control signal in response to the period of an input signal. An oscillator generates an output signal in accordance with the control signal. The level of the control signal is corrected to the frequency of the input signal. The control signal is coupled to determine the frequency of the output signal. | 06-10-2010 |
| 20100172156 | OFFLINE SYNCHRONOUS RECTIFIER CIRCUIT WITH TURNED-ON ARBITER AND PHASE-LOCK FOR SWITCHING POWER CONVERTERS - A synchronous rectifier circuit of a switching power converter is provided and includes first and second power transistors and first and second diodes connected to a transformer and an output of the power converter for rectifying. An arbiter circuit generates a lock signal to prevent the second power transistor from being turned on when the first diode the first power transistor is turned on. A controller generates a drive signal to control the first power transistor according to an on signal and an off signal. A phase-lock circuit generates the off signal according to the on signal. The on signal is enabled once the first diode is forward biased. The one signal enables the drive signal for turning on the first power transistor. The off signal disables the drive signal for turning off the first power transistor. The off signal is enabled before the disabling of the on signal. | 07-08-2010 |
| 20100182804 | SWITCHING CIRCUIT FOR PRIMARY-SIDE REGULATED RESONANT POWER CONVERTERS - The present invention provides a switching circuit to regulate an output voltage and a maximum output current at the primary side of a resonant power converter. The switching circuit includes a pair of switching devices and a controller. The controller is coupled to a transformer to sample a voltage signal thereof and generates switching signals to control the switching devices. The switching frequency of the switching signals is increased in response to the decrease of the output voltage. The increase of the switching frequency of the switching signals decreases the power delivered to the output of the resonant power converter. The output current is therefore regulated. | 07-22-2010 |
| 20100201334 | SYNCHRONOUS RECTIFIER HAVING PHASE LOCK CIRCUIT COUPLED TO FEEDBACK LOOP FOR RESONANT POWER CONVERTERS - A synchronous rectifier for a switching power converter is provided and includes a power transistor, a diode, and a control circuit. The power transistor and the diode are coupled to a transformer and an output of the power converter for the rectification. The control circuit generates a drive signal to switch on the power transistor once the diode is forward biased. The control circuit includes a phase-lock circuit. The phase-lock circuit generates an off signal to switch off the power transistor in response to a pulse width of the drive signal. The pulse width of the drive signal is shorter than a turned-on period of the diode. The phase-lock circuit further reduces the pulse width of the drive signal in response to a feedback signal. The feedback signal is correlated to an output load of the power converter. | 08-12-2010 |
| 20100202162 | ASYMMETRICAL RESONANT POWER CONVERTERS - A resonant power converter is provided and includes a capacitor, an inductive device, a first transistor, a second transistor, and a control circuit. The capacitor and the inductive device develop a resonant tank. The first transistor and the second transistor are coupled to switch the resonant tank. The control circuit generates a first signal and a second signal to control the first transistor and the second transistor respectively. Frequencies of the first signal and the second signal are changed for regulating output of the resonant power converter. The control circuit is further coupled to detect an input voltage of the resonant power converter. A pulse width of the second signal is modulated in response to change of the input voltage. | 08-12-2010 |
| 20100202163 | FLYBACK POWER CONVERTERS - A dual-switch flyback power converter includes a control circuit to generate a switching signal. A high-side driving circuit includes a pulse generation circuit. The pulse generation circuit generates a pulse-on signal and a pulse-off signal to control two transistors in response to the switching signal. The two transistors further respectively provide a level-shift-on signal and a level-shift-off signal to a comparison circuit to enable/disable a high-side driving signal. Without using a charge pump circuit to power the high-side driving circuit, a floating winding of a transformer is utilized to provide a floating voltage to power the high-side driving circuit, which reduces the cost of the dual-switch flyback power converter and ensures a sufficient high-side driving capability of the high-side driving circuit. | 08-12-2010 |
| 20100202167 | SOFT SWITCHING POWER CONVERTER WITH A VARIABLE SWITCHING FREQUENCY FOR IMPROVING OPERATION AND EFFICIENCY - A power converter according to the present invention comprises a resonant tank. The resonant tank is switched by a plurality of transistors. A control circuit generates a plurality of switching signals to control the transistors. The pulse widths of the switching signals are modulated for regulating an output voltage of the power converter. The control circuit is coupled to detect an input voltage of the power converter. The frequency of the switching signals is changed in response to the change of the input voltage or/and an output load of the power converter. | 08-12-2010 |
| 20100232182 | DUAL-SWITCHES FLYBACK POWER CONVERTER WITH SELF-EXCITED SUPPLY TO POWER THE HIGH-SIDE DRIVER - An exemplary embodiment of a flyback power converter includes a transformer for power transfer, a high-side transistor, a low-side transistor, two diodes, a control circuit, and a high-side drive circuit. The high-side transistor and the low-side transistor are coupled to switch the transformer. The two diodes are coupled to said transformer to circulate energy of leakage inductance of the transformer to an input power rail of the power converter. The control circuit generates a switching signal coupled to control the high-side transistor and the low-side transistor. The high-side drive circuit is coupled to receive the switching signal for driving the high-side transistor. The transformer has an auxiliary winding generating a floating power to provide power supply for said high-side drive circuit. | 09-16-2010 |
| 20100232183 | CONTROL CIRCUIT OF RESONANT POWER CONVERTER WITH ASYMMETRICAL PHASE SHIFT TO IMPROVE THE OPERATION - A control circuit of the resonant power converter according to the present invention comprises a frequency modulation circuit modulating a switching frequency of a switching signal in response to a feedback signal in a first operation range. A phase-shift circuit performs a phase-shift modulation to the switching signal in response to the feedback signal in a second operation range. A burst circuit performs a burst modulation to the switching signal in response to the feedback signal in a third operation range. The control circuit is operated in the first operation range when the feedback signal is higher than a first threshold. The control circuit is operated in the second operation range when the feedback signal is lower than the first threshold and higher than a second threshold. The control circuit is operated in the third operation range when the feedback signal is lower than the second threshold. | 09-16-2010 |
| 20100232187 | OUTPUT VOLTAGE CONTROL CIRCUIT OF POWER CONVERTER FOR LIGHT-LOAD POWER SAVING - A control circuit of a power converter for light-load power saving according to the present invention comprises a first feedback circuit coupled to an output voltage of the power converter to receive a first feedback signal. A second feedback circuit is coupled to the output voltage to receive a second feedback signal. A control circuit generates a switching signal for switching a transformer of the power converter and regulating the output voltage of the power converter in response to the first feedback signal and the second feedback signal. The switching signal is generated in accordance with the first feedback signal when an output load is high. The switching signal is generated in accordance with the second feedback signal during a light-load condition. | 09-16-2010 |
| 20110037443 | PARALLEL CONNECTED PFC CONVERTER - A parallel PFC converter comprises a first PFC circuit, a second PFC circuit, and a voltage divider. The second PFC circuit is connected in parallel with the first PFC circuit for generating an output voltage of the parallel PFC converter. The voltage divider is coupled to receive the output voltage for generating a first feedback signal and a second feedback signal. The first feedback signal is higher than the second feedback signal. The first PFC circuit and the second PFC circuit respectively comprises a first switching control circuit and a second switching control circuit for regulating the output voltage. It is an object of the present invention to reduce the power loss for improving the efficiency of the PFC converter. | 02-17-2011 |
| 20110038180 | RESONANT POWER CONVERTER WITH HALF BRIDGE AND FULL BRIDGE OPERATIONS AND METHOD FOR CONTROL THEREOF - A resonant power converter with half bridge and full bridge operations and a method for control thereof are provided. The resonant power converter includes a full bridge circuit, a control circuit and a PFC circuit. The full bridge circuit switches a power transformer in response to switching signals. The control circuit coupled to receive a feedback signal and an input signal generates switching signals. The feedback signal is correlated to the output of the power converter and the input signal is correlated to the input voltage of the full bridge circuit, where the full bridge circuit is operated as a full bridge switching when the input signal is lower than a threshold, and the full bridge circuit is operated as a half bridge switching when the input signal is higher than the threshold. The PFC circuit generates the input voltage of the full bridge circuit. | 02-17-2011 |
| 20110038183 | SWITCHING REGULATOR HAVING TERMINAL FOR FEEDBACK SIGNAL INPUTTING AND PEAK SWITCHING CURRENT PROGRAMMING - A switching regulator of a power converter is provided and includes a feedback-input circuit, a programming circuit, and a peak-current-threshold circuit. The feedback-input circuit is coupled to a terminal of the switching regulator for receiving a feedback signal. The feedback-input circuit is operated in a first range of a terminal signal. The programming circuit is coupled to the terminal for generating a programming signal. The programming signal is operated in a second range of the feedback signal. The peak-current-threshold circuit generates a threshold signal in accordance with the programming signal. The feedback signal is coupled to regulate the output of the power converter, and the threshold signal is coupled to limit a peak switching current of the power converter. | 02-17-2011 |
| 20110062876 | OFFLINE LED DRIVING CIRCUITS - An offline LED driving circuit includes a controller, a shunt regulator, an opto-coupler, and a dimming circuit. The controller generates a switching signal to switch a transformer for providing an output voltage and an output current. The shunt regulator is coupled to an output terminal of the LED driving circuit for providing a feedback signal to the controller via the opto-coupler. The dimming circuit coupled to the shunt regulator modulates the feedback signal at a first feedback level and a second feedback level in response to a dimming signal. The output voltage is respectively regulated at a first output level and a second output level in response to the first feedback level and the second feedback level of the feedback signal. The duty cycle of the switching signal will be varied in a soft-start manner when the feedback signal changes from the second feedback level to the first feedback level. | 03-17-2011 |
| 20110062877 | OFFLINE LED LIGHTING CIRCUIT WITH DIMMING CONTROL - An offline LED lighting circuit comprises a controller and a dimming circuit. The controller generates a switching signal to switch a transformer for generating an output voltage and an output current at an output terminal of the offline LED lighting circuit to drive LEDs. The dimming circuit is coupled to the controller to modulate the switching signal in response to a dimming signal. A first reference voltage and a second reference voltage of the controller are generated in response to the dimming signal. The switching signal is modulated by the first reference voltage and the second reference voltage. The controller regulates the output voltage at a first output level and a second output level in response to both the first reference voltage and the second reference voltage. The second output level is lower than the first output level. | 03-17-2011 |
| 20110063877 | Synchronous rectifying circuit with primary-side swithching current detection for offline power converters - A synchronous rectifying circuit is provided for offline power converter. A pulse signal generator is utilized to generate a pulse signal in response to a switching current of the power transformer. An isolation device is coupled to the pulse signal generator for transferring the pulse signal through an isolation barrier of the power transformer. A synchronous rectifier includes a power switch and a control circuit. The power switch is coupled between the secondary side of the power transformer and the output of the power converter for the rectifying. The control circuit is operated to receive the pulse signal for turning on/off the power switch. The pulse signal is generated to turn on the power switch once the switching current is higher than a threshold. | 03-17-2011 |
| 20110080109 | HIGH EFFICIENCY LED DRIVER WITH CURRENT SOURCE REGULATIONS - The present invention provides a control circuit for LED driver. A voltage-feedback circuit is coupled to LEDs to sense a voltage-feedback signal for generating a voltage loop signal. Current sources are coupled to the LEDs to control LED currents. A detection circuit is connected to sense voltages of current sources for generating a current-source loop signal in response to a minimum voltage of the current sources. Furthermore, a buffer circuit generates a feedback signal in accordance with the voltage loop signal and the current-source loop signal. The feedback signal is coupled to limit a maximum voltage of the LEDs and regulate the minimum voltage across the current sources. | 04-07-2011 |
| 20110116287 | SWITCHING CONTROLLER HAVING SWITCHING FREQUENCY HOPPING FOR POWER CONVERTER - A switching controller having switching frequency hopping for a power converter includes an oscillator generating a pulse signal for determining a switching frequency of a switching signal, a maximum duty-cycle circuit generating a maximum duty-cycle signal in response to the switching signal for determining the switching frequency of the switching signal, a pattern generator generating a digital pattern code in response to a clock signal, a programmable capacitor coupled to the pattern generator and the oscillator for modulating the switching frequency of the switching signal in response to the digital pattern code, and a PWM circuit coupled to the oscillator and the maximum duty-cycle circuit for generating the switching signal in accordance with the pulse signal and the maximum duty-cycle signal. A maximum on-time of the switching signal is limited by the maximum duty-cycle signal. The switching signal is utilized to switch a transformer of the power converter. | 05-19-2011 |
| 20110169418 | LED DRIVE CIRCUIT WITH A PROGRAMMABLE INPUT FOR LED LIGHTING - A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal. | 07-14-2011 |
| 20110254498 | Constant-Speed Control Circuit for BLDC Motors - A speed-control circuit for a BLDC motor is provided. The speed-control circuit includes a pulse generator, a current source circuit, a filter circuit, an error amplification circuit and a PWM circuit. The pulse generator detects a speed signal of the BLDC motor to generate a pulse signal. The filter circuit is coupled to the current source circuit to generate an average signal. The error amplification circuit receives the average signal and a speed-reference signal for generating a speed-control signal. The PWM circuit generates a switching signal to drive the BLDC motor in response to the speed-control signal. A pulse width of the switching signal is determined by the speed-control signal. | 10-20-2011 |
| 20110254537 | Method and Apparatus for Detecting CCM Operation of a Magnetic Device - A method and an apparatus for detecting a CCM operation of a magnetic device are developed. The method generates a current signal in accordance with a switching current of the magnetic device and generates a first current signal and a second current signal by sampling the current signal. A mode signal is further generated according to the first current signal and the second current signal. The mode signal indicates the magnetic device is operated in CCM or DCM. The apparatus comprises a first sample circuit, a second sample circuit, and an arbiter. The first sample circuit samples the current signal to generate the first current signal. The second sample circuit samples the current signal to generate the second current signal. The arbiter generates the mode signal according to the first current signal and the second current signal for indicating the magnetic device is operated in CCM or DCM. | 10-20-2011 |
| 20110255309 | High-Speed Reflected Signal Detection for Primary-Side Controlled Power Converters - A controller for a power converter includes a clamping circuit, a switching circuit and a pulse generator. The clamping circuit is coupled to an input terminal of the controller for detecting a detection signal from a transformer. The switching circuit generates a switching signal to switch the transformer in response to the detection signal for regulating the power converter. A maximum level of the detection signal is clamped to be under a level of a threshold voltage during an off-period of the switching signal. Since the maximum level of the detection signal is clamped and the oscillating energy of the reflected signal is discharged, the speed of detecting the detection signal is increased. Therefore, the regulation of the primary-side controlled power converter can be improved accordingly. | 10-20-2011 |
| 20110305048 | ACTIVE-CLAMP CIRCUIT FOR QUASI-RESONANT FLYBACK POWER CONVERTER - An active clamp circuit for a QR flyback power converter according to the present invention comprises an active-clamper connected to a primary winding of a power transformer of the QR flyback power converter in parallel. A high-side transistor driver is coupled to drive the active-damper. A charge-pump circuit is coupled to the high-side transistor driver to provide a power supply to the high-side transistor driver in accordance with a voltage source. A control circuit generates a control signal coupled to control the high-side transistor driver. The control signal is generated in response to a PWM signal and an input voltage of the QR flyback power converter. | 12-15-2011 |
| 20110305051 | START-UP CIRCUIT WITH LOW STANDBY POWER LOSS FOR POWER CONVERTERS - A start-up circuit with low standby power loss for power converters according to present invention comprises a first diode and a second diode coupled to an input voltage of the power converter. A start-up resistor is coupled to the join of the first diode and the second diode. A high-voltage switch is coupled to the start-up resistor to generate a power source. A control circuit generates a switching signal for switching a transformer. A detection circuit generates a disable signal in response to the input voltage to disable the switching signal. A winding of the transformer is coupled to the power source to generate the power for the power source. The high-voltage switch is turned off to cut off the start-up resistor for saving the power loss once the voltage of the power source is higher than a threshold. | 12-15-2011 |
| 20110317454 | DUAL SWITCHES FLYBACK POWER CONVERTER WITH WIDE INPUT VOLTAGE RANGE - A dual switches Flyback power converter with a wide input voltage range according to the present invention comprises an input diode and an energy-store capacitor. The input diode can prevent the reflected voltage from the power transformer of the power converter to charge the electrolytic capacitor of the power converter. The energy-store capacitor will store the reflected voltage and the energy of the leakage inductor of the power transformer. The energy stored in the energy-store capacitor will be recycled to the output voltage of the power converter. Further, the input diode can be replaced by an input transistor to prevent the reflected voltage from the power transformer to charge the electrolytic capacitor. | 12-29-2011 |
| 20120001600 | CONTROL CIRCUIT OF INTERLEAVED PFC POWER CONVERTER - A control circuit of an interleaved PFC power converter according to the present invention comprises a master switching control circuit, a slave switching control circuit, and a slave reference signal generator. The master switching control circuit generates a control signal and a first switching signal in response to an input voltage and a feedback signal. The first switching signal is utilized to control a first switch of the PFC power converter. The slave reference signal generator generates a slave control signal in response to a load condition of the PFC power converter and the control signal. The slave switching control circuit generates a second switching signal in response to the slave control signal. The slave control signal is utilized to control a second switch of the PFC power converter. The slave reference signal generator adjusts the control signal in response to the load condition for generating the slave control signal correspondingly. The slave control signal drives the slave switching control circuit to adjust the switching frequency of the second switch for reducing the switching loss. | 01-05-2012 |
| 20120008352 | METHOD AND APPARATUS OF PROVIDING A BIASED CURRENT LIMIT FOR LIMITING MAXIMUM OUTPUT POWER OF POWER CONVERTERS - A biased current-limit circuit for limiting a maximum output power of a power converter includes an oscillator for generating a pulse signal and an oscillation signal. A waveform generator generates a waveform signal in response to the oscillation signal. A sample-hold circuit is used to sample the waveform signal to generate a hold signal in response to a switching signal. The sample-hold circuit further samples the hold signal to generate a current-limit threshold in response to a second-sampling signal. A current comparator is utilized to compare a current-sensing signal with the current-limit threshold to limit a maximum on-time of the switching signal. | 01-12-2012 |
| 20120057375 | METHOD AND APPARATUS FOR A FLYBACK POWER CONVERTER PROVIDING OUTPUT VOLTAGE AND CURRENT REGULATION WITHOUT INPUT CAPACITOR - A control circuit of a power converter according to the present invention comprises an output circuit, at least one input circuit and an input-voltage detection circuit. The output circuit generates a switching signal for regulating an output of the power converter in response to at least one feedback signal. The switching signal is coupled to switch a transformer of the power converter. The input circuit samples at least one input signal for generating the feedback signal. The input signal is correlated to the output of the power converter. The input-voltage detection circuit generates an input-voltage signal in response to the level of the an input voltage of the power converter. The input circuit will not sample the input signal when the input-voltage signal is lower than a threshold. The control circuit can eliminate the need of the input capacitor for improving the reliability of the power converter. | 03-08-2012 |
| 20120069611 | Correction Circuit of a Switching-Current Sample for Power Converters in Both CCM and DCM Operation - The present invention provides a correction circuit for a power converter. The correction circuit includes a sampling circuit, a demagnetizing-time circuit, a duty circuit, and a compensation circuit. The sampling circuit generates an average-current signal in response to a switching current of the power converter. The demagnetizing-time circuit generates a discharging-time signal in response to a switching signal and an input-voltage signal. The duty circuit generates a duty signal in response to the discharging-time signal, an on-time of the switching signal, and a switching period of the switching signal. The compensation circuit is coupled to receive the average-current signal and the duty signal for generating a corrected signal. The switching signal is utilized to switch a magnetic device for regulating an output voltage of the power converter. The corrected signal is coupled to generate the switching signal. | 03-22-2012 |
| 20120081039 | METHOD AND APPARATUS FOR A LED DRIVER WITH HIGH POWER FACTOR - A control circuit of a LED driver according to the present invention comprises an output circuit, an input circuit and an input-voltage detection circuit. The output circuit generates a switching signal to produce an output current for driving at least one LED in response to a feedback signal. The switching signal is coupled to switch a transformer. The input circuit samples an input signal for generating the feedback signal. The input signal is correlated to the output current of the LED driver. The input-voltage detection circuit generates an input-voltage signal in response to an input voltage of the LED driver. The input circuit will not sample the input signal when the input-voltage signal is lower than a threshold. The control circuit can eliminate the need of the input capacitor for improving the reliability of the LED driver. | 04-05-2012 |
| 20120170321 | FEEDBACK CIRCUIT WITH REMOTE ON/OFF CONTROL FOR POWER SUPPLY - A feedback circuit of power supply according to the present invention comprises a switching controller, an optocoupler, an error amplifier and a timer. The switching controller generates a switching signal in accordance with a feedback signal for regulating an output voltage of the power supply. The optocoupler generates the feedback signal. The error amplifier is coupled to the output voltage of the power supply for generating an amplified signal. The amplified signal is connected to an input of the optocoupler. A remote on/off signal is further coupled to the input of the optocoupler. The timer generates a control signal to disable the switching signal in response to the feedback signal. The control signal is generated after a delay time when the feedback signal is lower than a threshold. | 07-05-2012 |
| 20120170330 | SINGLE-STAGE PFC CONVERTER WITH CONSTANT VOLTAGE AND CONSTANT CURRENT - An exemplary embodiment of a power converter is provided. The power converter includes a transformer, a power device, a switching controller, and a capacitor. The power device is coupled to the transformer for switching the transformer to product output of the power converter. The switching controller receives a feedback signal for generating a switching signal coupled to drive the power device. An input circuit of the switching controller is coupled to the transformer to sample an input signal for generating the feedback signal, and the input signal is correlated to the output of the power converter. The capacitor is coupled to the switching controller to provide frequency compensation for a feedback loop of the power converter. Input of the power converter is without an electrolytic capacitor, and a maximum output current of the power converter is a constant current. | 07-05-2012 |
| 20120206117 | MULTI-FUNCTION TERMINAL OF POWER SUPPLY CONTROLLER FOR FEEDBACK SIGNAL INPUT AND OVER-TEMPERATURE PROTECTION - The present invention provides a control circuit having a multi-function terminal. The control circuit comprises a switching circuit, a sample-and-hold circuit, a detection circuit, and a comparator. The sample-and-hold circuit is coupled to the multi-function terminal for generating a sample voltage by sampling the feedback signal during a first period. The detection circuit is coupled to the multi-function terminal during a second period for generating a detection voltage. The comparator compares the detection voltage and the sample voltage for generating an over-temperature signal, wherein the over-temperature signal is couple to disable the switching signal. | 08-16-2012 |
| 20120206944 | CONTROL CIRCUIT FOR BURST SWITCHING OF POWER CONVERTER AND METHOD THEREOF - This invention provides a control circuit for burst switching of a power converter comprising: an adaptive circuit generating an adaptive threshold in response to a feedback signal correlated to an output load of the power converter; and a switching circuit generating a switching signal to switch a transformer of the power converter in accordance with the adaptive threshold and the feedback signal for regulating an output of the power converter. | 08-16-2012 |
| 20120281434 | METHOD AND APPARATUS FOR CONTROLLING RESONANT POWER CONVERTER - A control circuit of a resonant power converter is disclosed. The control circuit comprises a first transistor and a second transistor for switching a transformer and a resonant tank comprising a capacitor and an inductor. A controller is configured to receive a feedback signal correlated to the output of the power converter for generating a first switching signal and a second switching signal to drive the first transistor and the second transistor, respectively. A diode coupled to the first transistor and the resonant tank for detecting the state of the first transistor and generating a detection signal for the controller. The detection signal indicates if the transistors are in a zero voltage switching (ZVS) state. If the transistors are not in the ZVS state, the switching frequency of the transistors will be increased. | 11-08-2012 |
| 20120300503 | CONTROL CIRCUIT WITH ZVS-LOCK AND ASYMMETRICAL PWM FOR RESONANT POWER CONVERTER - A control circuit for a resonant power converter and a control method thereof are disclosed. The control circuit comprises a first transistor and a second transistor switching a transformer through a resonant tank. A controller receives a feedback signal for generating a first switching signal and a second switching signal coupled to drive the first transistor and the second transistor respectively. The feedback signal is correlated to an output of the resonant power converter. A diode is coupled to the second transistor for detecting the state of the second transistor for the controller. The first switching signal and the second switching signal are modulated to achieve a zero voltage switching (ZVS) for the second transistor. | 11-29-2012 |
| 20130027987 | REGULATION CIRCUIT ASSOCIATED WITH SYNCHRONOUS RECTIFIER PROVIDING CABLE COMPENSATION FOR THE POWER CONVERTER AND METHOD THEREOF - A regulation circuit of a power converter for cable compensation according to the present invention comprises a signal generator generating a compensation signal in accordance with a synchronous rectifying signal. An error amplifier has a reference signal for generating a feedback signal in accordance with an output voltage of the power converter. The compensation signal is coupled to program the reference signal. The feedback signal is coupled to generate a switching signal for regulating an output of the power converter. The regulation circuit of the present invention compensates the output voltage without a shunt resistor to sense the output current of the power converter for reducing power loss. | 01-31-2013 |
| 20130051098 | ADAPTIVE SLOPE COMPENSATION PROGRAMMABLE BY INPUT VOLTAGE OF POWER CONVERTER - A method for controlling a power converter is provided. The method includes the following steps. A switching signal coupled to switch a transformer for regulating the output of the power converter is generated in accordance with a feedback signal and a ramp signal. The ramp signal is generated in accordance with a switching current signal and a slope compensation signal. The slope compensation signal is generated in response to an input voltage signal. The input voltage signal is generated in response to the level of the input voltage of the power converter. The feedback signal is generated in accordance with the output of the power converter, and the switching current signal is correlated with a switching current of the transformer. | 02-28-2013 |
| 20130063112 | CONTROLLER AND POWER CONVERTER USING THE SAME FOR CLAMPING MAXIMUM SWITCHING CURRENT OF POWER CONVERTER - A controller of a power converter is provided. The controller includes a feedback circuit, an output circuit, and a clamping circuit. The feedback circuit generates a feedback signal in accordance with output of the power converter. The output circuit generates a switching signal in accordance with the feedback signal for regulating the output of the power converter. The clamping circuit limits the feedback signal under a first level for a first load condition and limits the feedback signal under a second level for a second load condition. The clamping circuit includes a timer circuit. The timer circuit determines a slew rate of the feedback signal for increasing the feedback signal from the first level to the second level, and the second level is higher than the first level. | 03-14-2013 |
| 20130063986 | CONTROL CIRCUIT FOR CONTROLLING THE MAXIMUM OUTPUT CURRENT OF POWER CONVERTER AND METHOD THEREOF - A control circuit of the power converter according to the present invention comprises a feedback circuit, an output circuit and an adaptive clamping circuit. The feedback circuit generates a feedback signal in accordance with an output of the power converter. The output circuit generates a switching signal in accordance with the feedback signal for regulating the output of the power converter. The adaptive clamping circuit limits the level of the feedback signal under a first level for a first load condition. The feedback circuit determines a slew rate of the feedback signal for increasing the level of the feedback signal from the first level to a second level. The adaptive clamping circuit is disabled and the level of the feedback signal can be increased to the second level for a second load condition. | 03-14-2013 |
| 20130063990 | PROTECTION CIRCUIT FOR POWER CONVERTER - A protection circuit of a power converter without an input capacitor is disclosed. The protection circuit comprises a high voltage switch, a detection circuit and a control circuit. The switch senses an input voltage of the power converter via a resistor for generating a first signal. The detection circuit coupled to a transformer senses the input voltage of the power converter for generating a second signal. The control circuit controls a switching signal in response to the first signal and the second signal. The switching signal is utilized to switching the transformer for regulating the power converter; and the level of the first signal and the second signal is correlated a level of the input voltage of the power converter. | 03-14-2013 |
| 20130094253 | Control Circuit for Offline Power Converter without Input Capacitor - The present invention provides a control circuit for a power converter. The control circuit includes a switching circuit, an input-voltage detection circuit and a current-limit threshold. The switching circuit generates a switching signal coupled to switch a transformer of the power converter for regulating an output of the power converter in response to a feedback signal. The input-voltage detection circuit generates a control signal when an input voltage of the power converter is lower than a low-input threshold. The feedback signal is generated in response to the output of the power converter. A maximum duty of the switching signal is increased in response to the control signal. The current-limit threshold is for limiting a maximum value of a switching current flowing through the transformer. The current-limit threshold is increased in response to the control signal. An input of the power converter doesn't connect with electrolytic bulk capacitors. | 04-18-2013 |
| 20130106488 | SUCCESSIVE APPROXIMATION MULTIPLIER-DIVIDER FOR SIGNAL PROCESS AND METHOD FOR SIGNAL PROCESS | 05-02-2013 |
| 20130127510 | ISOLATION INTERFACE CIRCUIT FOR POWER MANAGEMENT - An isolation interface circuit is disclosed. The isolation interface circuit comprising a transmitting circuit and a receiving circuit. The transmitting circuit configured to receive a first serial interface signal and a second serial interface signal for generating a differential polarity pulse signal. The receiving circuit configured to receive the differential polarity pulse signal for generating the first serial interface signal and the second serial interface signal. The differential polarity pulse signal are generated in response to the first serial interface signal and the second serial interface signal. The first serial interface signal and the second serial interface signal are generated in accordance with the differential polarity pulse signal. In a period, only one of the transmitting circuit and the receiving circuit can be enabled. | 05-23-2013 |
| 20130147452 | SWITCHING CURRENT SYNTHESIS CIRCUIT FOR POWER CONVERTER - A control circuit of a power converter is provided. The control circuit comprises a PWM circuit, a sample circuit, and emulation circuit. The PWM circuit generates a switching signal for switching an inductor and generating a switching current of the inductor in response to a current feedback signal. The sample circuit is coupled to sample a switching current signal into a capacitor during an on time of the switching signal. The emulation circuit generates a discharge current couple to discharge the capacitor during an off time of the switching signal for generating the current feedback signal. The switching current signal is correlated to the switching current of the inductor, and the discharge current is generated in response to an input voltage of the inductor, an output voltage of the power converter, and the on time of the switching signal. | 06-13-2013 |
| 20130182476 | ADAPTIVE SAMPLING CIRCUIT FOR DETECTING THE DEMAGNETIZED VOLTAGE OF THE TRANSFORMER - An adaptive sampling circuit of the power converter according to the present invention comprises a sample-and-hold unit and a signal-generation circuit. The sample-and-hold unit is coupled to a transformer to generate a feedback signal by sampling a demagnetized voltage of the transformer in response to a sample signal. The signal-generation circuit generates the sample signal in response to a magnetized voltage of the transformer, the demagnetized voltage of the transformer, a switching signal and a code. The sample signal is used for sampling the demagnetized voltage. The feedback signal is correlated to an output voltage of the power converter. The switching signal is generated in response to the feedback signal for switching the transformer and regulating the output of the power converter. The adaptive sampling circuit is used to precisely measure the demagnetized voltage of the transformer without the limitation of the transformer design. | 07-18-2013 |
| 20130214601 | INTERFACE CIRCUITS FOR CASCADE AND SERIES BATTERY MANAGEMENT AND METHODS THEREOF - An interface circuit for cascade battery management and an interface circuit for series battery management are provided. The interface circuit for cascade battery management comprises a master microcontroller, a slave microcontroller, a receiving opto-coupler, and transmitting opto-coupler. The master microcontroller is coupled to a first battery block. The slave microcontroller is coupled to a second battery block. The receiving opto-coupler has an input terminal coupled to an output terminal of the master microcontroller, and the receiving opto-coupler has an output terminal coupled to an input terminal of the slave microcontroller. The transmitting opto-coupler has an input terminal coupled to an output terminal of the slave microcontroller, and the transmitting opto-coupler has an output terminal coupled to an input terminal of the master microcontroller. The master microcontroller communicates with the slave microcontroller using the pulse-width-modulation (PWM) through the transmitting opto-coupler and the receiving opto-coupler. | 08-22-2013 |
| 20130223111 | DIGITAL CONTROL CIRCUIT FOR RESONANT POWER CONVERTERS - A resonant control circuit for a power converter is provided. The resonant control circuit includes a microcontroller, a switching-signal timer, a first PWM timer, and a signal detection circuit. The microcontroller has a memory circuit, and the memory circuit includes a program memory and a data memory. The switching-signal timer generates a first switching signal coupled to switch a transformer. The first PWM timer generates a PWM signal coupled to control a synchronous rectifying transistor of the power converter for synchronous rectifying. The signal detection circuit is coupled to an output of the power converter for generating a feedback data from a feedback signal. The microcontroller controls the first switching signal by programming the switching-signal timer in accordance with the feedback data. The microcontroller controls the first PWM signal by programming the first PWM timer in response to the first switching signal. | 08-29-2013 |
| 20130249601 | SAMPLING CIRCUIT FOR MEASURING REFLECTED VOLTAGE OF TRANSFORMER FOR POWER CONVERTER OPERATED IN DCM AND CCM - A sampling circuit of the power converter according to the present invention comprises an amplifier circuit receiving a reflected voltage for generating a first signal. A first switch and a first capacitor are utilized to generate a second signal in response to the reflected voltage. A sample-signal circuit generates a sample signal in response to the disable of a switching signal. The switching signal is generated in accordance with a feedback signal for regulating an output of the power converter. The feedback signal is generated in accordance with the second signal. The sample signal is utilized to control the first switch for sampling the reflected voltage. The sample signal is disabled once the first signal is lower than the second signal. The sampling circuit precisely samples the reflected voltage of the transformer of the power converter for regulating the output of the power converter. | 09-26-2013 |
| 20130250639 | DIGITAL CONTROLLED POWER CONVERTER WITH EMBEDDED MICROCONTROLLER - The present invention provides a digital controller for a power converter. The digital controller includes a microcontroller, an analog-to-digital converter, a signal generator, a protection circuit, and a PWM circuit. The analog-to-digital converter is coupled to an output of the power converter for generating a digital feedback signal for the microcontroller. The signal generator is controlled by the microcontroller for generating a switching signal coupled to switch a transformer. The protection circuit generates a reset signal to disable the switching signal. The microcontroller controls the switching signal to regulate the output of the power converter. The protection circuit is further coupled to detect a switching current of the transformer for controlling the reset signal if the switching current of the transformer exceeds a second threshold. The PWM circuit generates a PWM signal coupled to control a synchronous rectifying transistor for synchronous rectifying operation. | 09-26-2013 |
| 20130271271 | RECEIVING CONTROL CIRCUIT FOR A WALL CONTROL INTERFACE WITH PHASE MODULATION AND DETECTION FOR POWER MANAGEMENT - A wall control interface for power management includes a transmitting circuit that generates a switching signal to control a switch and achieve a phase modulation to a power line signal in response to a transmitting-data. A receiving circuit is coupled to detect the phase of the power line signal for generating a data signal and a receiving-data in response to the phase of the power line signal. The receiving circuit further generates a control signal to control power of a load in accordance with the data signal or the receiving-data. The phase modulation is achieved by controlling a turn-on angle of the power line signal. The switch remains in a turn-on state during the normal condition, which achieves good power and low current harmonic. The phase modulation is only performed during the communication of the power management. | 10-17-2013 |
| 20130279206 | CONTROL CIRCUIT FOR AN INVERTER WITH SMALL INPUT CAPACITOR - A control circuit for an inverter according to the present invention comprises a PWM circuit and a controller. The PWM circuit generates switching signals in accordance with a PWM control signal. The switching signals are coupled to switch a transformer through transistors for generating an output of the inverter. The controller is coupled to receive a command signal and an input signal for generating the PWM control signal. The input signal is correlated to an input voltage waveform of the inverter. The command signal is utilized to determine a power level of the output of the inverter. The advantages of the control circuit are lower cost, small size, good power factor and higher reliability. | 10-24-2013 |
| 20130329464 | DIGITAL POWER CONTROL CIRCUIT FOR POWER CONVERTER AND CONTROL CIRCUIT FOR POWER CONVERTER - A control circuit for a power converter and a digital power control circuit for a power converter are provided. The control circuit comprises a microcontroller, an oscillation circuit, an analog-to-digital converter and a signal generator. The microcontroller comprises a flash memory. The oscillation circuit comprises a phase lock loop for generating a clock signal. The analog-to-digital converter generates a digital feedback signal for the microcontroller corresponding to an output of the power converter. The signal generator is configured to receive the clock signal and data of the microcontroller for generating a switching signal. The switching signal is configured to switch a transformer for regulating the output of the power converter corresponding to the output of the microcontroller. | 12-12-2013 |
| 20130329468 | SWITCHING CONTROLLER WITH CLAMP CIRCUIT FOR CAPACITOR-LESS POWER SUPPLIES - A control circuit of a power converter according to the present invention comprises a switching circuit and a sample circuit. The switching circuit generates a switching signal in accordance with a feedback signal and a sampled signal. The switching signal is coupled to switch a transformer of the power converter for regulating an output of the power converter. The feedback signal is generated in accordance with the output of the power converter. The sample circuit generates the sampled signal by sampling a signal of the transformer. The sampled signal is correlated to an output voltage of the power converter. | 12-12-2013 |
| 20140001992 | Control Circuit with Frequency Hopping for Permanent Magnet Motor Control | 01-02-2014 |
| 20140016374 | REGULATION CIRCUIT HAVING OUTPUT CABLE COMPENSATION FOR POWER CONVERTERS AND METHOD THEREOF - A regulation circuit with the output cable compensation is developed for a power converter. It includes an error amplifier for generating a feedback signal in accordance with an output of the power converter. A compensation circuit is coupled to a transformer of the power converter for generating a compensation signal in response to a transformer signal generated by the transformer. The feedback signal is applied to generate a switching signal for switching the transformer and regulating the output of the power converter. The compensation signal is coupled to modulate the feedback signal for compensating a voltage drop of the output cable of the power converter. | 01-16-2014 |
| 20140036548 | CONTROL CIRCUIT WITH FAST DYNAMIC RESPONSE FOR POWER CONVERTERS - A control circuit of a power converter is provided. It comprises a voltage detection circuit detecting a reflected signal for generating a voltage-loop signal. A current detection circuit detects a current of a transformer for generating a current-loop signal. An oscillator generates an oscillation signal in accordance with an output load of the power converter. A PWM circuit generates a switching signal according to the voltage-loop signal, the current-loop signal and the oscillation signal for regulating an output of the power converter. A load detection circuit receives a detection signal through an signal-transfer device for increasing a switching frequency of the switching signal. The detection signal is generated once the output is lower than a low-voltage threshold. The oscillation signal determines the switching frequency of the switching signal. The control circuit reduces the voltage drop of the output when the output load is changed. | 02-06-2014 |
| 20140092645 | CONTROL CIRCUIT AND TERMINAL FOR CABLE COMPENSATION AND WAKE-UP OF PRIMARY-SIDE REGULATED POWER CONVERTER - A control circuit of a power converter is provided. It comprises a signal generation circuit generating an oscillation signal in accordance with an output load. A PWM circuit generates a switching signal according to a voltage-loop signal, a current-loop signal and the oscillation signal for regulating an output of the power converter. A regulation circuit receives a compensation signal for an output cable compensation and a wake-up. The compensation signal is coupled to increase a switching frequency of the switching signal once the output of the power converter is lower than a low-voltage threshold. The control circuit reduces the voltage drop of the output when the output load is changed. | 04-03-2014 |
| 20140118039 | CHARGE PUMP CIRCUITS HAVING FREQUENCY SYNCHRONIZATION WITH SWITCHING FREQUENCY OF POWER CONVERTERS - A control circuit of a power converter is provided. The control circuit includes a switching circuit and a charge pump circuit. The switching circuit generates a switching signal for controlling the power converter. The charge pump circuit includes an oscillator for generating an oscillation signal synchronized with the switching signal. The oscillation signal is coupled to control a switch of the charge pump circuit for generating a voltage source. | 05-01-2014 |
| 20140126250 | CONTROL CIRCUIT OF POWER CONVERTER WITH TEMPERATURE CONTROL AND METHOD FOR CONTROLLING POWER CONVERTER - A control circuit of a power converter and a method for controlling the power converter are provided. The control circuit of the power converter comprises a switching circuit and a temperature-sensing device. The switching circuit generates a switching signal in response to a feedback signal, and the switching circuit generates a current-sensing signal for regulating an output of the power converter. The temperature-sensing device generates a temperature signal in response to temperature of the temperature-sensing device. | 05-08-2014 |
| 20140146576 | DUAL GATE DRIVE CIRCUIT FOR REDUCING EMI OF POWER CONVERTERS AND CONTROL METHOD THEREOF - A dual gate drive circuit for a power converter and a control method are provided for reducing EMI of the power converter. The dual gate drive circuit comprises a switch and a switching control circuit. The switch is coupled to a transformer of the power converter to switch the transformer for regulating an output of the power converter. The switching control circuit generates a first switching signal and a second switching signal in response to a feedback signal to switch the switch for switching the transformer. The feedback signal is correlated to the output of the power converter. The second switching signal is enabled after a time delay once the first switching signal is enabled. | 05-29-2014 |
| 20140146579 | TRANSISTOR GATE DRIVER WITH CHARGE PUMP CIRCUIT FOR OFFLINE POWER CONVERTERS - A controller of the power converter according to the present invention comprises a gate driver. The gate driver generates a gate-drive signal. The gate-drive signal is coupled to drive a power transistor to switch a transformer of the power converter for regulating an output of the power converter. The gate driver has a charge-pump circuit for charging pump a voltage level of the gate-drive signal. Therefore, the gate-drive signal can fully turn on the power transistor. | 05-29-2014 |
| 20140176095 | METHOD AND APPARATUS FOR CONTROLLING PROGRAMMABLE POWER CONVERTER - The present invention provides a circuit for controlling a programmable power converter. The circuit includes a micro-controller, a controller, and a timer. The controller includes a voltage error amplifier. The micro-controller has a program memory and a data memory. The controller generates switching signals in response to a voltage-feedback signal for regulating an output voltage of the programmable power converter. The voltage error amplifier generates the voltage-feedback signal according to a voltage reference signal and the output voltage of the programmable power converter. A gain of the voltage error amplifier and a value of the reference signal are programmed by the micro-controller. | 06-26-2014 |
| 20140185333 | ACTIVE CLAMP CIRCUITS FOR FLYBACK POWER CONVERTERS - An active clamp circuit for a flyback power converter is provided. The active clamp circuit includes a power transistor, a capacitor, a high-side transistor driver, a charge-pump circuit, and a controller. The power transistor is coupled in series with a capacitor to develop an active-clamper. The active-damper is coupled in parallel with a primary winding of a transformer of the flyback power converter. The high-side transistor driver is coupled to drive the power transistor. The charge-pump circuit is coupled to a voltage source and the high-side transistor driver to provide a power supply to the high-side transistor driver. The controller generates a control signal coupled to control the high-side transistor driver. The control signal is generated in response to a demagnetizing time of the transformer. | 07-03-2014 |
| 20140192566 | PRIMARY-SIDE CONTROLLED PROGRAMMABLE POWER CONVERTER - A circuit for controlling a programmable power converter is provided. The circuit comprises a control circuit, a switching controller, and a first opto-coupler. The control circuit generates a programmable voltage-reference signal for regulating an output voltage of the programmable power converter. A feedback circuit of the control circuit detects the output voltage for generating a feedback signal in response to the programmable voltage-reference signal and the output voltage. The switching controller detects a switching current of a transformer for generating a switching signal coupled to switch the transformer for generating the output voltage and an output current in response to the feedback signal and the switching current of the transformer. The first opto-coupler transfers the feedback signal from the control circuit to the switching controller. The control circuit is at the secondary side of the transformer and the switching controller is at the primary side of the transformer. | 07-10-2014 |
| 20140195065 | CONTROL CIRCUIT FOR PROGRAMMABLE POWER SUPPLY - A control circuit for a programmable power supply is provided. It comprises a reference generation circuit generating a voltage-reference signal and a current-reference signal for regulating an output voltage and an output current of the power supply. A feedback circuit detects the output voltage and the output current for generating a feedback signal in accordance with the voltage-reference signal and the current-reference signal. A switching controller generates a switching signal coupled to switch a transformer for generating the output voltage and the output current in accordance with the feedback signal. A micro-controller controls the reference generation circuit. The micro-controller, the reference generation circuit, and the feedback circuit are equipped in the secondary side of the transformer. The switching controller is equipped in the primary side of the transformer. The control circuit can achieve good performance for the programmable power supply. | 07-10-2014 |
| 20140198535 | METHOD AND APPARATUS FOR CONTROLLING PROGRAMMABLE POWER CONVERTER WITH LOW STANDBY POWER LOSS - Method and apparatus for controlling a programmable power converter are provided. The method and apparatus generate a first power source and a second power source. The voltage level of the second power source is lower than the voltage level of the first power source. The first power source and the second power source provide a power supply for a control circuit. The control circuit will use the first power source as its power supply when the first power source is low. The control circuit will use the second power source as its power supply for saving the power when the first power source is high. | 07-17-2014 |
| 20140232284 | LED DRIVE CIRCUIT WITH A PROGRAMMABLE INPUT FOR LED LIGHTING - A LED drive circuit according to the present invention comprises a controller and a programmable signal. The controller generates a switching signal coupled to switch a magnetic device for generating an output current to drive a plurality of LEDs. The programmable signal is coupled to regulate a current-control signal of the controller. The switching signal is modulated in response to the current-control signal for regulating the output current, and the level of the output current is correlated to the current-control signal. | 08-21-2014 |
| 20140233275 | ADAPTIVE ACTIVE CLAMP OF FLYBACK POWER CONVERTER WITH HIGH EFFICIENCY FOR HEAVY LOAD AND LIGHT LOAD - A control circuit of a flyback power converter according to the present invention comprises a low-side transistor, an active-damper, a high-side drive circuit, and a controller. The low-side transistor is coupled to switch a transformer. The active-damper is coupled in parallel with the transformer. The high-side drive circuit is coupled to drive the active-clamper. The controller generates a switching signal and an active-clamp signal. The switching signal is coupled to drive the low-side transistor. The switching signal is generated in accordance with a feedback signal for regulating an output of the flyback power converter. The active-clamp signal is coupled to control the high-side drive circuit and the active-damper. The active-clamp signal is generated in response to a demagnetizing time of the transformer. The pulse number of the active-clamp signal is less than the pulse number of the switching signal in a light load condition. | 08-21-2014 |
| 20140239882 | APPARATUS FOR CHARGING BATTERY THROUGH PROGRAMMABLE POWER ADAPTER - An apparatus for charging a battery is provided and includes a power adaptor and a controller. The power adaptor has a communication interface coupled to a cable of the power adapter for receiving command-data and generates a DC voltage and a DC current according to the command-data. The controller is coupled to the battery for detecting a battery voltage of the battery and generates the command-data according to the battery voltage. The DC voltage and the DC current are coupled to the cable and programmable according to the command-data. The command-data is coupled the cable through a communication circuit of the controller. | 08-28-2014 |
| 20140239885 | CONTROL CIRCUIT FOR CHARGING BATTERY THROUGH PROGRAMMABLE POWER SUPPLIER - A charging circuit for charging a battery is provided. A power supplier has a communication interface coupled to a cable for receiving command-data and generates a DC voltage and a DC current in accordance with the command-data. A controller is coupled to the battery for detecting a battery-voltage and generates the command-data in accordance with the battery-voltage. A switch is coupled to the cable for receiving the DC voltage and the DC current through a connector. The DC voltage and the DC current generated by the power supply are coupled to the cable, and the DC voltage and the DC current are programmable in accordance with the command-data. The command-data generated by the controller is coupled the cable through a communication circuit of the controller. The controller is coupled the connector for detecting a connector-voltage and control an on/off state of the switch in response to the connector-voltage. | 08-28-2014 |
| 20140289540 | PROGRAMMABLE POWER SUPPLY - The present invention provides a method of programming a programmable power supply. In the method, a requesting signal is generated in a device, and the requesting signal is received in the programmable power supply. Then, an output voltage of the programmable power supply is determined in accordance with a frequency of the requesting signal. The output voltage of the programmable power supply is coupled to power a load of the device. A de-bounce operation is further provided for filtering noises of the requesting signal. The requesting signal comprises a high-state period and a low-state period. The high-state period is defined during which a level of the requesting signal is higher than a threshold. The low-state period is defined during which the level of the requesting signal is lower than the threshold. The output voltage of the programmable power supply is further determined by a period of the requesting signal. | 09-25-2014 |
| 20140306548 | METHOD AND APPARATUS FOR CONTROLLING WIRELESS INDUCTION POWER SUPPLY - The present invention provides a method and an apparatus for controlling the wireless induction power supply. The apparatus comprises a transmitter control circuit and a receiver control circuit. The method comprises generating a plurality of switching signals for switching a transmitter winding and generating a power; detecting a level of a transmitter signal from the transmitter winding; and controlling a switch to deliver the power from a receiver winding to a load. The receiver winding is coupled to receive the power from the transmitter winding. The switching signals will be disabled if the level of the transmitter signal is not higher than a threshold over a first period or the level of the transmitter signal is higher than a high-threshold over a second period. Accordingly, the method and the apparatus according to the present invention have the foreign object detection (FOD) function for the safety. | 10-16-2014 |
| 20140307484 | CONTROL CIRCUIT FOR ACTIVE CLAMP FLYBACK POWER CONVERTER WITH PREDICTED TIMING CONTROL - A control circuit of a flyback power converter according to the present invention comprises a low-side transistor, an active-clamper, a high-side drive circuit, and a controller. The low-side transistor is coupled to switch a transformer. The active-clamper is coupled in parallel with the transformer. The high-side drive circuit is coupled to drive the active-damper. The controller generates a switching signal and an active-clamp signal. The switching signal is coupled to drive the low-side transistor. The switching signal is generated in accordance with a feedback signal for regulating an output voltage of the flyback power converter. The active-clamp signal is coupled to control the high-side drive circuit and the active-clamper. The active-clamp signal is generated in response to a predicted time of the transformer. The predicted time is determined in accordance with an input voltage, the output voltage and an on time of the switching signal. | 10-16-2014 |
| 20140362608 | METHOD FOR PROGRAMMABLE PRIMARY-SIDE-REGULATED POWER CONVERTER - The invention discloses a method for controlling a programmable primary-side-regulated power converter. The method includes the following steps. A light load situation is enabled for a first time period at a secondary side of a transformer. A transmit-code is generated at the secondary side of the transformer. A current pulse signal is generated at the secondary side of the transformer according to the transmit-code after the first time period. The light load situation is detected at a primary side of the transformer for the first time period. A current signal is detected by detecting a primary side switching current of the transformer. A receive-code is generated according to the current signal. An output current and/or an output voltage of the power converter is generated in accordance with the receive-code. The transmit-code and the receive-code are correlated. The current pulse signal and the current signal are correlated. | 12-11-2014 |
| 20140372776 | METHOD AND APPARATUS FOR SELECTING THE OUTPUT OF PROGRAMMABLE POWER ADAPTER - An apparatus of programming an output of a programmable power adapter according to the present invention comprises a control circuit. The method according to the present invention sends a signal to a device. A resistor is coupled to the signal to determine the level of the signal. The resistor is installed in the device. The method according to the present invention checks the level of the signal in the programmable power adapter and determines an output voltage of the programmable power adapter in accordance with the level of the signal. The output voltage of the programmable power adapter is coupled to the device to provide a power for a load of the device. | 12-18-2014 |
| 20150036394 | METHOD AND APPARATUS OF FREQUENCY MODULATION FOR POWER SAVING OF ADAPTIVE POWER CONVERTER - The present invention proposes a method for controlling an adaptive power converter. The method comprises: generating an output-sense signal by sampling a reflected voltage of a transformer; receiving a feedback signal related to an output power of the adaptive power converter; generating a clock signal in response to the feedback signal and the output-sense signal; generating a switching signal for switching the transformer and regulating an output voltage of the adaptive power converter. The reflected voltage is correlated to the output voltage of the adaptive power converter. The switching signal is generated in response to the feedback signal. The frequency of the switching signal is determined by the clock signal. The frequency of the switching signal is decreased in response to a decrement of the feedback signal. | 02-05-2015 |
| 20150042303 | CONTROL CIRCUIT OF POWER CONVERTER AND METHOD THEREFORE - A control circuit of a power converter and a method therefore are provided. The control circuit comprises an input circuit, an amplifier, a PWM circuit, and a power management circuit. The input circuit is coupled to a transformer to generate a sensing signal related to an output voltage of the power converter. The amplifier generates a feedback signal according to the sensing signal and a reference signal. The PWM circuit generates a switching signal according to the feedback signal for switching the transformer and regulating the output voltage of the power converter. The power management circuit controls the reference signal according to the feedback signal. The power management circuit includes a timer for determining a period, and the output voltage of the power converter decreases while an output power of the power converter is lower than a light-load threshold. A method for controlling the control circuit is also disclosed. | 02-12-2015 |
| 20150049523 | METHOD FOR CONTROLLING SYNCHRONOUS RECTIFIER OF POWER CONVERTER AND CONTROL CIRCUIT USING THE SAME - The invention discloses a method for controlling a synchronous rectifier of a power converter and a control circuit using the same. The method includes the following steps. A control signal is generated to control a synchronous rectification transistor in response to an on-time of a switching signal, a level of a transformer voltage and an output voltage of the power converter. The switching signal is used for switching a transformer. The control signal is generated once the switching signal is turned off. A transformer signal is related to an input voltage of the power converter. The control signal is generated when the on-time of the switching signal is longer than a first time threshold. | 02-19-2015 |
| 20150061566 | CONTROL CIRCUIT FOR DRIVING MOTOR AND METHOD FOR CONTROLLING SPEED OF MOTOR - A control circuit for driving a motor and a method for controlling a speed of a motor are provided. The control circuit comprises a microcontroller and a drive circuit. The microcontroller has a memory. The drive circuit is configured to drive the BLDC motor according to a control of the microcontroller. The memory include a RPM table, and the microcontroller sends a duty signal to the drive circuit to change a speed of the motor according to the RPM table. | 03-05-2015 |
| 20150062972 | SYNCHRONOUS RECTIFIER CONTROL CIRCUITS OF POWER CONVERTERS - A synchronous rectifying control circuit of a power converter is provided. The synchronous rectifying control circuit comprises a synchronous rectifying driver, a charge pump capacitor, and a capacitor. The synchronous rectifying driver is coupled to a transformer for generating a control signal to switch a transistor. The charge pump capacitor is coupled to a power source for generating a charge pump voltage. The capacitor is coupled to store the charge pump voltage. The transistor is coupled to the transformer and operated as a synchronous rectifier. The charge pump voltage is coupled to guarantee a sufficient driving capability for the control signal. | 03-05-2015 |
