Patent application number | Description | Published |
20090045873 | CLOSE-LOOP CLASS-D AUDIO AMPLIFIER AND CONTROL METHOD THEREOF - The present invention discloses a Class-D power amplifier and control method thereof. In one embodiment, the amplifier feeds back the signal at the output node to the inverting input of the comparator, and provides a high frequency triangular wave signal to the non-inverting input of the comparator. In addition, the non-inverting input of the comparator may be coupled to an offset voltage, while the inverting input of the comparator may be coupled to a fixed-frequency rectangular wave signal, a feedback signal which is derived from the output stage and an input signal. In use, the switching frequency may be at least substantially fixed, so as to reduce the influence on the system caused by electromagnetic interruption (EMI). Further, the control circuit is simple, and some devices can be integrated. | 02-19-2009 |
20090140655 | SIMPLE PROTECTION CIRCUIT AND ADAPTIVE FREQUENCY SWEEPING METHOD FOR CCFL INVERTER - A CCFL inverter circuit integrates a feedback circuit and protection circuit together. For both in-phase and out-of-phase applications, sensed lamp voltages can be used for open lamp and short lamp detection and sensed currents can be used for open lamp detection. The driving circuit adjusts the open lamp frequency by using a duty cycle control signal so that the driving circuit can always achieve the desired lamp voltage gain. | 06-04-2009 |
20090273951 | SMART DRIVING METHOD FOR SYNCHRONOUS RECTIFIER AND ITS APPARATUS THEREOF - The present invention discloses a smart driving method for a secondary synchronous rectifier of an isolated converter and its apparatus thereof. The apparatus comprises: a main circuit having a secondary synchronous rectifier Q | 11-05-2009 |
20090284163 | METHOD AND APPARATUS FOR DRIVING MULTIPLE PARALLEL DISCHARGE LAMPS - The present invention provides a method and apparatus for driving multiple parallel discharge lamps, which increases the switching frequency once the open lamp condition is detected to provide an output voltage that is high enough to ignite the lamp again. | 11-19-2009 |
20100072906 | METHODS AND APPARATUS FOR DRIVING DISCHARGE LAMPS - Methods and apparatus for driving discharge lamps are disclosed herein. In one embodiment, a method for driving a discharge lamp includes generating a switching signal to drive a discharge lamp, monitoring a working status of the discharge lamp, and determining whether the discharge lamp is operating abnormally based at least in part on the monitored working status. The method also includes decreasing a duty cycle of the switching signal when the discharge lamp is determined to operate abnormally. | 03-25-2010 |
20100201335 | OFF TIME CONTROL METHOD FOR SWITCHING REGULATOR - The present invention provides an off time control method and switching regulator using it. The current flowing through a switch is compared with a current threshold, and the switch is turned off if the current flowing through the switch is larger than the current threshold. The off time of the switch is determined by the load. The current threshold is variable at light load to prevent generating the audible noise and improve the whole efficiency. | 08-12-2010 |
20100264985 | CLOSE-LOOP CLASS-D AUDIO AMPLIFIER AND CONTROL METHOD THEREOF - The present invention discloses a Class-D power amplifier and control method thereof. In one embodiment, the amplifier feeds back the signal at the output node to the inverting input of the comparator, and provides a high frequency triangular wave signal to the non-inverting input of the comparator. In addition, the non-inverting input of the comparator may be coupled to an offset voltage, while the inverting input of the comparator may be coupled to a fixed-frequency rectangular wave signal, a feedback signal which is derived from the output stage and an input signal. In use, the switching frequency may be at least substantially fixed, so as to reduce the influence on the system caused by electromagnetic interruption (EMI). Further, the control circuit is simple, and some devices can be integrated. | 10-21-2010 |
20100265742 | SWITCHING REGULATOR WITH FREQUENCY LIMITATION AND METHOD THEREOF - The present invention provides a switching regulator with frequency limitation and method thereof. The switching frequency of the switching regulator is limited through setting of a minimum off time, so as to improve the efficiency and EMI distribution of the switching regulator. | 10-21-2010 |
20100270937 | CIRCUIT AND METHOD FOR STRIKING CCFL - A circuit for controlling the switch frequency of an inverter that strikes and drives fluorescent lamps is disclosed. The circuit comprises a frequency generator and an offset circuit. The offset circuit provides a current signal in response to the lamp status. The frequency generator provides a frequency control signal in respond to the current signal so as to control the switch frequency of the inverter. When the lamp is open, the switch frequency of the inverter is higher; when the lamp is lighted, the switch frequency of the inverter is lower. | 10-28-2010 |
20100302288 | DUAL ENDED DRIVER CIRCUIT FOR LCD BACKLIGHT AND THE METHOD THEREOF - A dual ended driver circuit for a LCD backlight is disclosed. The circuit comprises a master board and a slave board, which provides a first output drive signal and a second output drive signal to either end of a lamp set, respectively. The circuit only uses one control chip to synchronize and make symmetrical the first output drive signal and the second output drive signal. | 12-02-2010 |
20100302815 | SWITCHING MODE POWER SUPPLY WITH A MULTI-MODE CONTROLLER - A switching mode power supply with a multi-mode controller is provided. The switching mode power supply may include a transformer having a primary winding and a secondary winding to supply power to a load. A feedback circuit may be included to generate a feedback signal that varies in relation to the load on the secondary winding. The multi-mode controller may include a switching circuit, a frequency control circuit and a current limiting circuit. The switching circuit may be coupled to the primary winding to control current flow through the primary winding. The frequency control circuit may control a switching frequency of the switching circuit based on the feedback signal. The current limiting circuit may limit current flow through the primary winding by causing the switching circuit to suspend current flow through the primary winding when the current reaches a peak current limit that is set based on the feedback signal. | 12-02-2010 |
20100302816 | SWITCHING MODE POWER SUPPLY WITH A SPECTRUM SHAPING CIRCUIT - In accordance with the teachings described herein, systems and methods are provided for a switching mode power supply. In one example, the switching mode power supply may include a transformer, a switching circuit and a switching control circuit. The transformer receives a DC input voltage on a primary winding and generates a DC output voltage on a secondary winding. The switching circuit, which may include a MOSFET switch, is coupled to the transformer and is configured to switch the transformer on and off. The switching control circuit generates a switching control signal to control the switching circuit in order to regulate the DC output voltage of the transformer. The switching control circuit is configured to generate the switching control signal as a function of a timing signal having a varying frequency, wherein the varying frequency of the timing signal causes a switching frequency of the switching circuit to vary over a period of time in order to reduce electromagnetic interference caused by the switching circuit. | 12-02-2010 |
20110002068 | SWITCHING REGULATOR WITH FAULT PROTECTION AND METHOD THEREOF - A switching regulator with fault protection and method thereof. The switching regulator comprises a switching circuit, a control circuit, a fault detection circuit and a fault timer. The fault detection circuit is electrically coupled to the switching circuit to detect whether a fault condition exists and generate a fault signal accordingly. The fault timer starts to time once the fault signal becomes valid, and is reset when the fault signal becomes invalid. If the fault time reaches a first time threshold, the control circuit is disabled, and the switch in the switching circuit is turned off. | 01-06-2011 |
20110006706 | LATCH-OFF OF REAL TIME SYNCHRONOUS RECTIFICATION FOR LIGHT LOAD CONTROL - The present invention discloses a light load control circuit and the method accordingly where the synchronous rectification is latched off selectively according to the gate voltage of the synchronous rectifier. | 01-13-2011 |
20110007526 | FREQUENCY LIMITATION METHOD WITH TIME HYSTERESIS USED IN QUASI-RESONANT CONTROL - A frequency limitation method used in quasi-resonant control of a switching regulator is disclosed. The switching frequency is limited through setting a minimum time limit, such as a minimum switching period or a minimum OFF time. The minimum time limit may be a first time limit or a second time limit. The minimum time limit is changed into another value if the minimum voltage point approaches the minimum time limit point, so as to eliminate the audible noise. | 01-13-2011 |
20110012538 | LATCH-OFF OF SYNCHRONOUS RECTIFICATION FOR LIGHT LOAD CONTROL - Disclosed is a light load control circuit and the method accordingly where the synchronous rectification is latched off when the light load condition is detected for several successive cycles. | 01-20-2011 |
20110051470 | SWITCHING MODE POWER SUPPLIES AND ASSOCIATED METHODS OF CONTROL - Switching mode power supplies and associated methods of control are disclosed herein. In one embodiment, a method for controlling a switching mode power supply includes determining whether the switching mode power supply is in a burst mode. If the switching mode power supply is in the burst mode, the method includes recording a switching time with and without switching pulses to obtain a current value of an equivalent frequency and generating a peak current limit that decreases as a load becomes lighter based on the equivalent frequency, thereby maintaining the equivalent frequency at the current value above an audible range. If the switching mode power supply is not in the burst mode, the method includes continuing to monitor whether the switching mode power supply is in the burst mode. | 03-03-2011 |
20110084677 | POWER SUPPLIES AND ASSOCIATED METHODS OF CONTROL - Switching mode power supplies (SMPS) that can operate in a control mode for a normal load condition and operate with a burst-mode controller for a light load condition are disclosed herein. In one embodiment, a method for controlling the switching mode power supply includes when the load is in a light load condition, the switching mode power supply is controlled by a burst-mode controller. | 04-14-2011 |
20110110123 | SWITCHING MODE POWER SUPPLY SPECTRUM SHAPING AND THE METHOD THEREOF - Embodiments of circuits and methods for a switching mode power supply are described in detail herein. In one embodiment, a switching mode power supply includes a transformer having a primary winding and a secondary winding to supply power to a load, a feedback circuit that generates a feedback signal that varies in relation to the load on the secondary winding, a switching circuit coupled to the primary winding to control current flow through the primary winding, and a control circuit coupled to the switching circuit to control the on/off status of switching circuit in response to the feedback signal and the current flow through the primary winding. The control circuit comprises a spectrum shaping circuit configured to generate a spectrum shaping signal in response to the feedback signal. The spectrum shaping signal can then be used to regulate the switching frequency and the spectrum shaping range. | 05-12-2011 |
20110182095 | PACKAGE FOR SYNCHRONOUS RECTIFIER MODULE - The present technology discloses a package for a synchronous rectifier module, and also discloses synchronous rectification circuits and power supply adapters. The synchronous rectification circuit co-packages the synchronous rectifier and the driver into one single package. The single package simplifies the external circuitry and reduces potential electromagnetic interferences. | 07-28-2011 |
20110199793 | SWITCHING MODE POWER SUPPLY WITH PRIMARY SIDE CONTROL - The present technology are directed to switching mode power supplies with primary side control. In one embodiment, the switching mode power supply provides an equivalent current signal which represents a load current. The equivalent current signal is then used to control a switching circuit in the switching mode power supply. | 08-18-2011 |
20110227492 | DRIVER SYSTEMS FOR DRIVING LIGHT EMITTING DIODES AND ASSOCIATED DRIVING METHODS - LED driver systems and associated methods of control are disclosed herein. In one embodiment, the LED driver system comprises a converter and a controller. The controller is responsive to the LED current feedback signal and a dimming signal, and operable to generate a continuous gate drive signal to control the primary side switch of the converter. Thus, the controller regulates the output current of the converter. | 09-22-2011 |
20110227493 | LIGHT EMITTING DIODE DRIVER SYSTEMS AND ASSOCIATED METHODS OF CONTROL - Light emitting diode (LED) dimming and driver systems and associated methods of control are disclosed herein. In one embodiment, a system comprises a PFC stage and an LED driver stage. The LED driver stage comprises an isolated converter and a controller responsive to a dimming signal to dim LED strings for backlight. The controller also regulates an output current of the isolated converter. | 09-22-2011 |
20110227497 | POWER SYSTEMS FOR DRIVING LIGHT EMITTING DIODES AND ASSOCIATED METHODS OF CONTROL - Embodiments of LED driver circuits and the associated methods are disclosed herein. In one embodiment, the LED driver circuit comprises a switch-mode converter, a controller, a feedback circuit, and a gating circuit. The feedback circuit includes a current balance circuit. The gating circuit is responsive to both a current feedback signal and a voltage feedback signal and is configured to select one of them as the feedback signal. | 09-22-2011 |
20110228570 | SWITCHING MODE POWER SUPPLIES WITH PRIMARY SIDE CONTROL AND ASSOCIATED METHODS OF CONTROL - Switching mode power supplies with primary side control and associated methods of control are disclosed. In one embodiment, a signal with input voltage information and a signal with both input voltage information and output voltage information are provided to a subtracter to generate a feedback signal that is indicative of the output voltage. The feedback signal is then used to control the switching mode power supply. | 09-22-2011 |
20110285301 | TRIAC DIMMER COMPATIBLE SWITCHING MODE POWER SUPPLY AND METHOD THEREOF - Triac dimmer compatible switching mode power supplies used as LED drivers are disclosed herein. A PFC controller is configured in the switching mode power supplies. With the PFC controller, the current keeping the triac in the on-state is supplied by the DC/DC converter, and the LC resonance is reduced. | 11-24-2011 |
20120013187 | METHOD AND CIRCUIT FOR CURRENT BALANCE - This disclosure presents method and circuit for current balance. An AC signal or a DC signal is applied to a circuit to source current to loads. A capacitor is configured to balance the current in loads. By matching the charging time and the discharging time of the balance capacitor in every cycle, the current balance of the loads is achieved. | 01-19-2012 |
20120112795 | Peak Current Control Circuit for Switching Mode Power Supply and Method Thereof - A switching mode power supply with improved peak current control is disclosed. A varying reference signal is adopted to limit the peak current in the energy storage component. The varying reference signal is an exponential function of a time period when a power switch is ON, wherein the power switch is coupled to the energy storage component. The varying reference signal may be generated by a circuit comprising a RC circuit and one or several voltage sources. | 05-10-2012 |
20120113684 | Compensation Circuit for Constant Current Regulation of Power Supply and Method Thereof - A compensation circuit and method for constant current regulation of switching mode power supply are disclosed. The ringing waveform of a feedback signal, indicative of the output current of the power supply, causes error. To eliminate the error, a current source charges a capacitor in response to a demagnetizing oscillation signal indicative of the error caused by the ringing waveform of the feedback signal. The voltage across the capacitor is compared to a reference signal to generate a more accurate signal indicative of the conductive time of a secondary diode in a secondary winding of the switching mode power supply. This more accurate signal is inputted to a logic circuit to generate a constant current control signal to control a power switch of the power supply. | 05-10-2012 |
20120139505 | Bridgeless PFC Converter and the Method Thereof - A bridgeless PFC (power factor correction) converter with improved efficiency is disclosed. The bridgeless PFC converter comprises: a first input terminal and a second input terminal configured to receive an input AC signal; an output terminal; an inductor set comprising N inductors, wherein a first terminal of each inductor is coupled to the first input terminal; and an output stage comprising (N+1) switching circuits coupled between the output terminal and a ground node. | 06-07-2012 |
20120248984 | BALLAST AND ASSOCIATED CONTROL CIRCUIT - The embodiments of the present invention disclose a ballast and associated control circuit wherein the control circuit comprises a multi function pin, a preheat cut-off circuit and an over-voltage protection circuit, wherein the multi function pin is coupled to the preheat cut-off circuit and a first switch configured to turn on the first switch at a preheat state of the ballast and to turn off the first switch at the end of the preheat state, and wherein the multi function pin is further coupled to the over-voltage protection circuit and a voltage sense circuit configured to receive a sensed output voltage signal and to stop the ballast after the preheat state when the sensed output voltage is larger than a first threshold. Compared with prior art, the present invention may reduce the volume and lower down the cost of circuit. | 10-04-2012 |
20120293141 | BRIDGELESS PFC CONVERTER AND THE METHOD THEREOF - A bridgeless PFC (power factor correction) converter with improved efficiency is disclosed. The bridgeless PFC converter comprises: input terminals configured to receive an input AC power supply; an output terminal configured to provide power supply; a high frequency bridge arm comprising a first switch and a third switch coupled between the output terminal and a ground node; a low frequency bridge arm comprising a second switch and a fourth switch coupled between the output terminal and the ground node; an inductor coupled between the input AC power supply and the high frequency bridge arm; and a control circuit configured to control the switching of switches in the high frequency bridge arm and the low frequency bridge arm. | 11-22-2012 |
20130300384 | ISOLATED SWITCHING MODE POWER SUPPLY AND THE METHOD THEREOF - An isolated switching mode power supply, having: a transformer having a primary winding, a secondary winding and a third winding; a current limit comparator configured to provide a current limit signal based on the current sense signal and the peak current signal; a logic circuit configured to provide a logic control signal based on the frequency control signal and the current limit signal; a startup control circuit configured to generate a startup control signal based on the current sense signal; a load detecting circuit configured to provide a load detecting signal based on the second feedback signal and the switching signal; and a selector configured to provide the logic control signal or the startup control signal based on the load detecting signal. | 11-14-2013 |
20130301310 | ISOLATED SWITCHING MODE POWER SUPPLY AND THE METHOD THEREOF - An isolated switching mode power supply, having: an input terminal; an output terminal; a transformer having a primary winding and a secondary winding; a primary power switch coupled to the primary winding; a secondary power switch coupled between the secondary winding and the output terminal of the power supply; a secondary controller configured to generate a frequency modulation signal based on the output voltage and the first feedback signal; a coupled device configured to provide a frequency control signal based on the output voltage and the frequency modulation signal; and a primary controller configured to provide a switching signal to control the primary power switch based on the current sense signal and the frequency control signal. | 11-14-2013 |
20130301311 | SWITCHING MODE POWER SUPPLY AND THE METHOD THEREOF - A switching mode power supply, having: an input port; an output port; an energy storage component and a pair of power switches coupled between input port and the output port; an error amplifier configured to generate an amplified error signal based on the feedback signal and the reference signal; an error comparator configured to generate a frequency control signal based on the amplified error signal and the first sawtooth signal; a peak current generator configured to generate a peak current signal based on the frequency control signal; a peak current comparator configured to generate a current limit signal based on the peak current signal and the current sense signal; and a logic circuit configured to generate a switching signal to control the power switches based on the frequency control signal and the current limit signal. | 11-14-2013 |
20130308349 | SWITCHING REGULATOR, THE CONTROL CIRCUIT AND THE METHOD THEREOF - A switching regulator that decreases power loss and resolves thermal issues by jumping its switching frequency to a maximum frequency when its load reaches a peak load. | 11-21-2013 |
20140153301 | AC SIGNAL DETECTOR AND THE METHOD THEREOF - An AC signal detector having: a rectify circuit having a first input terminal and a second input terminal configured to receive an AC signal, and an output terminal configured to provide a rectified signal based on the AC signal; a detecting circuit having an input terminal coupled to the output terminal of the rectify circuit to receive the rectified signal, and an output terminal configured to provide a square signal based on the rectified signal; and an unplug indicate circuit having an input terminal coupled to the detecting circuit to receive the square signal, and an output terminal configured to provide an unplug indicate signal based on the square signal. | 06-05-2014 |
20140177290 | SWITCH MODE POWER SUPPLY, CONTROL CIRCUIT AND ASSOCIATED CONTROL METHOD - A switch mode power supply having an output terminal configured to provide an output voltage, the switch mode power supply has a first switch and a control circuit. The control circuit is configured to provide a switching control signal to control the first switch. The control circuit is configured to provide the switching control signal based on a first pulse signal having a first frequency and a second frequency for a light load condition, and the control circuit is configured to provide the switching control signal based on a second pulse signal for a non-light load condition. | 06-26-2014 |
20140285163 | HIGHLY EFFICIENT PFC CIRCUIT AND CONTROL METHOD THEREOF - A PFC circuit includes: a switching circuit having a power switch; an on time control circuit for controlling an on time period of the power switch; a first off time control circuit; a second off time control circuit; and a logic circuit selectively controls the power switch working under CCM or DCM; when working under CCM, the first off time control circuit controls an off time period of the power switch and when working under DCM, the second off time control circuit controls the off time period of the power switch. | 09-25-2014 |
20150016154 | PEAK SAMPLE CIRCUIT FOR AC VOLTAGE AND METHOD THEREOF - A peak sample circuit for AC voltage, including: a rectifier coupled to receive an AC voltage and to rectify the AC voltage to generate a rectified signal; a delay circuit coupled to receive the rectified signal and to delay the rectified signal to generate a delayed rectified signal; a comparison circuit coupled to receive the delayed rectified signal and to generate a square signal based on the comparison of the rectified signal and the delayed rectified signal; and a sample output circuit coupled to receive the rectified signal, wherein the sample output circuit samples the rectified signal under the control of the square signal and provides a peak sample signal representative of the peak value of the AC voltage. | 01-15-2015 |
20150028923 | HIGH EFFICIENCY GATE DRIVE CIRCUIT FOR POWER TRANSISTORS - An improved gate drive circuit is provided for a power device, such as a transistor. The gate driver circuit may include: a current control circuit; a first secondary current source that is used to control the switching transient during turn off of the power transistor and a second secondary current source that is used to control the switching transient during turn on of the power transistor. In operation, the current control circuit operates, during turn on of the power transistor, to source a gate drive current to a control node of the power transistor and, during turn off of the power transistor, to sink a gate drive current from the control node of the power transistor. The first and second secondary current sources adjust the gate drive current to control the voltage or current rate of change and thereby the overshoot during the switching transient. | 01-29-2015 |