Patent application number | Description | Published |
20080218001 | METHOD AND APPARATUS FOR MODE SELECTION FOR HIGH VOLTAGE INTEGRATED CIRCUITS - A method is disclosed to add functionality to a terminal of a high voltage integrated circuit without the penalty of additional high voltage circuitry. The benefit is that alternative modes of operation can be selected for testing, trimming parameters of the integrated circuit, or any other purpose without the cost of an additional terminal. In one embodiment, ordinary low voltage circuitry monitors the voltage on the terminal that normally is exposed to high voltage. The configuration of a simple voltage detector and an ordinary latch allows easy entry into the test and trimming mode when the integrated circuit is not in the intended application, but prohibits entry into the test and trimming mode when the integrated circuit operates in the intended application. | 09-11-2008 |
20080218138 | METHOD AND APPARATUS FOR REDUCING AUDIO NOISE IN A SWITCHING REGULATOR - A switching regulator utilizing on/off control that reduces audio noise at light loads by adjusting the current limit of the switching regulator. In one embodiment, a switching regulator includes a state machine that adjusts the current limit of the switching regulator based on a pattern of feedback signal values from the output of the power supply for a preceding N cycles of the drive signal. The state machine adjusts the current limit lower at light loads such that cycles are not skipped to reduce the operating frequency of the switching regulator into the audio frequency range until the flux density through the transformer is sufficiently low to reduce the generation of audio noise. | 09-11-2008 |
20080239609 | METHOD AND APPARATUS PROVIDING FINAL TEST AND TRIMMING FOR A POWER SUPPLY CONTROLLER - A power supply controller having final test and trim circuitry. In one embodiment, a power supply controller for switched mode power supply includes a selector circuit, a trim circuit, a shutdown circuit and a disable circuit. The trim circuit includes a programmable circuit connection that can be selected by the selector circuit by toggling a voltage on an external terminal such as for example a power supply terminal, a control terminal or a function terminal of the power supply controller. The programmable circuit connection in the trim circuit can be programmed by applying a programming voltage to the external terminal. The shutdown circuit shuts down the power supply controller if the temperature rises above an over temperature threshold voltage. The shutdown circuit includes adjustment circuitry that can be used to test the shutdown circuit. The adjustment circuitry can adjust and reduce the over temperature threshold of the power supply controller. Thus, the power supply controller can be tested without having to actually heat the part. The disable circuit includes a programmable circuit connection, which when programmed prevents further trimming of power supply controller and prevents adjustment of the shutdown circuit over temperature threshold. | 10-02-2008 |
20080246446 | METHOD AND APPARATUS FOR ON/OFF CONTROL OF A POWER CONVERTER - A power converter control method and apparatus is disclosed. An example power converter controller according to aspects of the present invention includes feedback sampling circuitry to be coupled to an output of a power converter. The feedback sampling circuitry is to generate feedback signal samples after a conduction of a power switch is terminated during enabled switching cycles. Switch conduction control circuitry is coupled to the feedback sampling circuitry. The switch conduction circuitry includes switch conduction enable circuitry that is coupled to enable or disable the conduction of the power switch during a switching cycle in response to the feedback signal samples. The power switch is caused to conduct during at least a portion of an enabled switching cycle and prevented from conducting during an entirety of a disabled switching cycle. Switch conduction termination circuitry is also optionally included in the switch conduction circuitry and is coupled to terminate the conduction of the power switch during enabled switching cycles in response to the current through the power switch. Switch conduction scheduling circuitry is also included in the switch conduction circuitry and is coupled to determine a varying number of future enabled and disabled switching cycles in response to the feedback signal samples from a present switching cycle and one or more past switching cycles. | 10-09-2008 |
20080246447 | METHOD AND APPARATUS FOR INTEGRATED CABLE DROP COMPENSATION OF A POWER CONVERTER - An integrated circuit controller for a power converter to be coupled to a distribution network is disclosed. An example integrated circuit controller according to aspects of the present invention includes a switching control circuit that outputs a drive signal to control switching of a switch to regulate an output of the power converter. The integrated circuit controller also includes a cable drop compensator that outputs a compensated reference voltage signal to the switching control circuit in response to a switching signal. The switching signal is responsive to the drive signal. The compensated reference voltage signal is representative of a voltage value that is responsive to a distribution voltage across the distribution network and a load voltage across a load to be coupled to the distribution network. The switching of the switch is responsive to the compensated reference voltage signal and a feedback signal. | 10-09-2008 |
20080246456 | METHOD AND APPARATUS FOR CONTROLLING THE MAXIMUM OUTPUT POWER OF A POWER CONVERTER - A controller for a power converter is disclosed. An example circuit controller according to aspects of the present invention includes an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter. A current sensor is also included and is to be coupled to sense a current flowing in a power switch. A drive signal generator is to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period. The controller is coupled to adjust a switching cycle period of the power switch to be proportional to a value of the input signal multiplied by a time period. The time period is the time it takes for the current flowing in the power switch to change between two current values when the power switch is in the on state. | 10-09-2008 |
20080247199 | METHOD AND APPARATUS FOR POWER CONVERTER FAULT CONDITION DETECTION - An example controller includes a fault detector and a control. The fault detector is to be coupled to a feedback circuit of a power converter to detect a fault condition in the power converter in response to an input voltage of the power converter. The control is coupled to the fault detector and is to be coupled to control the switching of a power switch to regulate an output of the power converter. The control is coupled to inhibit the switching of the power switch in response to the fault detector detecting the fault condition during the switching of the power switch. | 10-09-2008 |
20080247202 | METHOD AND APPARATUS FOR SENSING MULTIPLE VOLTAGE VALUES FROM A SINGLE TERMINAL OF A POWER CONVERTER CONTROLLER - An example controller for a power converter according to aspects of the present invention includes a switching control that switches a power switch to regulate an output of a power converter. The controller also includes a sensor coupled to receive a signal from a single terminal of the controller. The signal from the single terminal is representative of a line input voltage of the power converter during at least a portion of an on time of the power switch. The signal from the single terminal is also representative of an output voltage of the power converter during at least a portion of an off time of the power switch. The switching control is responsive to the sensor. | 10-09-2008 |
20080259653 | METHOD AND APPARATUS FOR CONDITIONAL RESPONSE TO A FAULT CONDITION IN A SWITCHING POWER SUPPLY - Techniques are disclosed to regulate an output of a power converter. One example power converter controller circuit includes a line sense input to be coupled to receive a signal representative of an input voltage of a power converter. A feedback input to be coupled to receive a feedback signal representative of an output of the power converter is also included. A drive signal generator is also included to generate a drive signal coupled to control switching of a switch to provide a regulated output parameter at the output of the power converter in response to the feedback signal. The drive signal generator is coupled to receive a plurality of inputs including the line sense input and the feedback input. The drive signal generator is coupled to latch the power converter into an off state in response to a detection of a fault condition in the power converter as detected by the plurality of inputs if the power converter input voltage is above a first threshold level. The drive signal generator to be unresponsive to the signal representative of the power converter input voltage while the controller is regulating the output parameter at the output of the power converter. | 10-23-2008 |
20090021298 | METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A TIME MEASUREMENT - Techniques are disclosed to select functional parameters and/or operating modes of a circuit based on a time measurement are disclosed. One example integrated circuit includes a threshold detection and timing circuit that is coupled to measure a signal during an initialization period of the integrated circuit from a multifunction capacitor that is to be coupled to a first terminal of the integrated circuit. A selection circuit is coupled to the threshold detection and timing circuit to select a parameter/mode of the integrated circuit in response to the measured signal from the multifunction capacitor during the initialization period of the integrated circuit. The multifunction capacitor is coupled to provide an additional function for the integrated circuit after the initialization period of the integrated circuit is complete. | 01-22-2009 |
20090040795 | METHOD AND APPARATUS FOR INCREASING THE POWER CAPABILITY OF A POWER SUPPLY - Techniques are disclosed to extend an on time period of switch to regulate a transfer of energy from an input of a power supply to an output of a power supply. One example integrated circuit includes an energy transfer element coupled between an input and an output of the power supply. A switch is coupled to the input of the energy transfer element. A controller is coupled to the switch to control switching of the switch to regulate a transfer of energy from the input of the power supply to the output of the power supply in response to a feedback signal received from the output of the power supply. The controller is coupled to limit a maximum on time period of the switch a first maximum on time period in response to a first range of power supply operating conditions and to a second maximum on time period for a second range of power supply operating conditions. | 02-12-2009 |
20090091309 | OFF-LINE CONVERTER WITH DIGITAL CONTROL - A regulation circuit for use in DC to DC converter is disclosed. One such regulation circuit includes a feedback circuit to be coupled an energy transfer element output to receive a feedback signal to indicate whether the energy transfer element output is above or below a threshold level. A control circuit is included that is to be coupled to a switch that is coupled to an energy transfer element input. The control circuit is further coupled to the feedback circuit to generate a drive signal to control the switch to regulate the energy transfer element output to approximately the threshold level. The control circuit is to maintain an on-time of a current cycle of the drive signal and not allow an on-time of a next cycle of the drive signal in response to the energy transfer element output rising above the threshold level. | 04-09-2009 |
20090189682 | METHOD AND APPARATUS FOR MODE SELECTION FOR HIGH VOLTAGE INTEGRATED CIRCUITS - A method is disclosed to add functionality to a terminal of a high voltage integrated circuit without the penalty of additional high voltage circuitry. The benefit is that alternative modes of operation can be selected for testing, trimming parameters of the integrated circuit, or any other purpose without the cost of an additional terminal. In one embodiment, ordinary low voltage circuitry monitors the voltage on the terminal that normally is exposed to high voltage. The configuration of a simple voltage detector and an ordinary latch allows easy entry into the test and trimming mode when the integrated circuit is not in the intended application, but prohibits entry into the test and trimming mode when the integrated circuit operates in the intended application. | 07-30-2009 |
20090195229 | METHOD AND APPARATUS FOR REDUCING AUDIO NOISE IN A SWITCHING REGULATOR - A switching regulator utilizing on/off control that reduces audio noise at light loads by adjusting the current limit of the switching regulator. In one embodiment, a switching regulator includes a state machine that adjusts the current limit of the switching regulator based on a pattern of feedback signal values from the output of the power supply for a preceding N cycles of the drive signal. The state machine adjusts the current limit lower at light loads such that cycles are not skipped to reduce the operating frequency of the switching regulator into the audio frequency range until the flux density through the transformer is sufficiently low to reduce the generation of audio noise. | 08-06-2009 |
20090251121 | METHOD AND APPARATUS PROVIDING FINAL TEST AND TRIMMING FOR A POWER SUPPLY CONTROLLER - A power supply controller having final test and trim circuitry. In one embodiment, a power supply controller for switched mode power supply includes a selector circuit, a trim circuit, a shutdown circuit and a disable circuit. The trim circuit includes a programmable circuit connection that can be selected by the selector circuit by toggling a voltage on an external terminal such as for example a power supply terminal, a control terminal or a function terminal of the power supply controller. The programmable circuit connection in the trim circuit can be programmed by applying a programming voltage to the external terminal. The shutdown circuit shuts down the power supply controller if the temperature rises above an over temperature threshold voltage. The shutdown circuit includes adjustment circuitry that can be used to test the shutdown circuit. The adjustment circuitry can adjust and reduce the over temperature threshold of the power supply controller. Thus, the power supply controller can be tested without having to actually heat the part. The disable circuit includes a programmable circuit connection, which when programmed prevents further trimming of power supply controller and prevents adjustment of the shutdown circuit over temperature threshold. | 10-08-2009 |
20090251931 | METHOD AND APPARATUS FOR CONDITIONAL RESPONSE TO A FAULT CONDITION IN A SWITCHING POWER SUPPLY - Techniques are disclosed to regulate an output of a power converter. One example power converter controller circuit includes a line sense input to be coupled to receive a signal representative of an input voltage of a power converter. A feedback input to be coupled to receive a feedback signal representative of an output of the power converter is also included. A drive signal generator is also included to generate a drive signal coupled to control switching of a switch to provide a regulated output parameter at the output of the power converter in response to the feedback signal. The drive signal generator is coupled to receive a plurality of inputs including the line sense input and the feedback input. The drive signal generator is coupled to latch the power converter into an off state in response to a detection of a fault condition in the power converter as detected by the plurality of inputs if the power converter input voltage is above a first threshold level. The drive signal generator to be unresponsive to the signal representative of the power converter input voltage while the controller is regulating the output parameter at the output of the power converter. | 10-08-2009 |
20090256544 | METHOD AND APPARATUS TO LIMIT OUTPUT POWER IN A SWITCHING POWER SUPPLY - Techniques are disclosed to adjust a current limit in a switching regulator. One example switching regulator includes a comparator having first and second inputs and an output. The first input of the comparator is adapted to sense a current flow through a switch and the second input of the comparator is adapted to sense a variable current limit value. A controller is coupled to the output of the comparator and to the switch to control switching of the switch to regulate an output of a power supply in response a feedback signal. The controller disables the switch if the sensed current flow through the switch is greater than the sensed variable current limit value. The variable current limit value is set to a first variable current limit value by the controller in response to an input line voltage of the power supply if there is not an over current condition during a first switching cycle that occurs after a skipped switching cycle of the switch. The variable current limit value is set to a second variable current limit value by the controller in response to the input line voltage if there is the over current condition during the first switching cycle that occurs after the skipped switching cycle. | 10-15-2009 |
20090296427 | METHOD AND APPARATUS TO LIMIT MAXIMUM SWITCH CURRENT IN A SWITCHING POWER SUPPLY - Techniques are disclosed to limit the current in a switch of a switching power supply. An example switching regulator circuit includes a power switch to be coupled to an energy transfer element of a power supply. A controller to generate a drive signal is coupled to be received by the power switch to control the switching of the power switch. A short on time detector is included in the controller. The short on time detector is to detect an occurrence of a threshold number of one or more consecutive short on times of the switch. A frequency adjuster is also included in the controller and coupled to the short on time detector. The frequency adjuster is to adjust an oscillating frequency of an oscillator included in the controller in response to the short on time detector. | 12-03-2009 |
20090303766 | METHOD AND APPARATUS FOR INCREASING THE POWER CAPABILITY OF A POWER SUPPLY - Techniques are disclosed to extend an on time period of switch to regulate a transfer of energy from an input of a power supply to an output of a power supply. One example integrated circuit includes an energy transfer element coupled between an input and an output of the power supply. A switch is coupled to the input of the energy transfer element. A controller is coupled to the switch to control switching of the switch to regulate a transfer of energy from the input of the power supply to the output of the power supply in response to a feedback signal received from the output of the power supply. The controller is coupled to limit a maximum on time period of the switch a first maximum on time period in response to a first range of power supply operating conditions and to a second maximum on time period for a second range of power supply operating conditions. | 12-10-2009 |
20090310389 | METHOD AND APPARATUS PROVIDING A MULTI-FUNCTION TERMINAL FOR A POWER SUPPLY CONTROLLER - A method for controlling a power supply is disclosed. An example method includes deactivating the power supply in response to a first current through a first terminal of a power supply controller falling below a first threshold value. The power supply is activated in response to the first current through the first terminal rising above a second threshold value. Deactivating the power comprises causing a power switch coupled to a primary winding of the power supply not to receive a switching waveform for more than one cycle until the power supply is activated. | 12-17-2009 |
20100073041 | METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A MEASUREMENT DURING AN INITIALIZATION PERIOD - Techniques are disclosed to select functional parameters and/or operating modes of a circuit based on a measurement during an initialization period. In one aspect an integrated circuit includes a threshold detection circuit coupled to measure during an initialization period of the integrated circuit a signal from a first external circuit comprising one or more components coupled to a first external terminal of the integrated circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the signal from the first external circuit during the initialization period of the integrated circuit. The first external terminal is further coupled to one or more additional external circuits, each of which comprising one or more components. The one or more additional external circuits are coupled to provide one or more signals at the first external terminal to be used by the integrated circuit during normal operation at times other than the initialization period to provide at least one additional function for the integrated circuit after the initialization period of the integrated circuit is complete. | 03-25-2010 |
20100194198 | METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH AN EVENT COUNTER IN A POWER CONVERTER - A control circuit for use in a power converter with an unregulated dormant mode of operation includes a drive signal generator coupled to generate a drive signal to control switching of a power switch to be coupled to the control circuit to regulate a flow of energy to a power converter output in response to an energy requirement of one or more loads to be coupled to the power converter output. An unregulated dormant mode control circuit is included and is coupled to render dormant the drive signal generator thereby ceasing the regulation of the flow of energy to the power converter output by the drive signal generator when the energy requirement of the one or more loads falls below a threshold for more than a first period of time. The drive signal generator is coupled to be unresponsive to changes in the energy requirements of the one or more loads when dormant. The unregulated dormant mode control circuit is coupled to power up the drive signal generator after a second period of time has elapsed. The drive signal generator is coupled to again be responsive to changes in the energy requirement of the one or more loads after the period of time has elapsed. | 08-05-2010 |
20100194367 | METHOD AND APPARATUS TO REGULATE AN OUTPUT VOLTAGE OF A POWER CONVERTER AT LIGHT/NO LOAD CONDITIONS - An example apparatus to regulate an output voltage of a power converter at light/no load conditions includes a driver circuit, a feedback circuit, and an adjustable voltage reference circuit. The driver circuit is coupled to output a drive signal to switch a power switch between an ON state and an OFF state to regulate an output of the power converter. The feedback circuit is coupled to the driver circuit and is further coupled to output an enable signal to switch the power switch to an ON state in response to an output voltage signal. The adjustable voltage reference circuit is coupled to adjust a voltage reference such that a bias winding voltage of the power converter is adjusted nonlinearly in response to a load that is to be coupled to the output of the power converter. | 08-05-2010 |
20100194445 | POWER SUPPLY CONTROLLER WITH INPUT VOLTAGE COMPENSATION FOR EFFICIENCY AND MAXIMUM POWER OUTPUT - A controller for a power supply includes a logic block and a time-to-frequency converter. The logic block is to generate a drive signal in response to a clock signal. The drive signal is to be coupled to control switching of a power switch of the power supply to regulate an output of the power supply. The time-to-frequency converter is coupled to the logic block and generates the clock signal having a frequency responsive to a time period of the drive signal. | 08-05-2010 |
20100220503 | METHOD AND APPARATUS FOR CONTROLLING THE MAXIMUM OUTPUT POWER OF A POWER CONVERTER - A controller for a power converter is disclosed. An example circuit controller according to aspects of the present invention includes an input voltage sensor to be coupled to receive an input signal representative of an input voltage of the power converter. A current sensor is also included and is to be coupled to sense a current flowing in a power switch. A drive signal generator is to be coupled to drive the power switch into an on state for an on time period and an off state for an off time period. The controller is coupled to adjust a duty cycle of the power switch in response to a difference between a time it takes the current flowing in the power switch to change between two current values when the power switch is in the on state and a control time period. | 09-02-2010 |
20100246222 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - Various techniques directed to the digital control of a switching regulator are disclosed. In one aspect, a power supply regulator includes a compare circuit to be coupled to receive a feedback signal representative of an output level of a power supply. This causes a feedback state signal to be generated having a first feedback state that represents an output level of the power supply that is above a threshold level and a second feedback state that represents an output level of the power supply that is below the threshold level. An adjustment circuit is coupled to the compare circuit to adjust the feedback state signal in response to at least one of adjusting the threshold level or adjusting the feedback signal. The adjustment to the feedback state signal tends to cause the feedback state signal to revert from a state at the time of adjustment to a state immediately preceding the adjustment. A control circuit is to be coupled to a power switch and is to be coupled to receive an oscillating signal and the feedback state signal. The control circuit is to control switching of the power switch in response to the oscillating signal and the feedback state signal to regulate the output level of the power supply. | 09-30-2010 |
20100254166 | METHOD AND APPARATUS FOR ON/OFF CONTROL OF A POWER CONVERTER - A power converter control method and apparatus is disclosed. An example power converter controller according to aspects of the present invention includes a feedback sampling circuit coupled to receive a feedback signal representative of an output of a power converter to generate feedback signal samples during enabled switching cycles. The power converter controller also includes a switch conduction control circuit coupled to the feedback sampling circuit. The switch conduction control circuit includes switch conduction enable circuitry coupled to enable or disable the conduction of a power switch during a switching cycle in response to the feedback signal samples. The switch conduction control circuit also includes switch conduction scheduling circuitry coupled to determine a varying number of future enabled and disabled switching cycles in response to the feedback signal samples from a present switching cycle and one or more past switching cycles. | 10-07-2010 |
20100321039 | METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A TIME MEASUREMENT - An example integrated control circuit includes a regulator, a first comparator, a second comparator, and a counter. The regulator is to charge, during a time period, a capacitor. The first comparator is to provide an output indicating when a voltage on the capacitor reaches a first threshold voltage. The second comparator is coupled to provide an output indicating when the voltage on the capacitor reaches a second threshold voltage. The counter is coupled to begin counting in response to the first threshold voltage being reached and is coupled to stop counting in response to the second threshold voltage being reached. The counter is coupled to provide an output representative of the capacitance value of the capacitor during the time period and the integrated control circuit receives a bias current at the terminal from the capacitor to provide power to operate the integrated control circuit after the time period has ended. | 12-23-2010 |
20110019441 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - In one aspect, a power supply regulator includes a feedback terminal, a node, a control circuit, a first current source, and a second current source. The node is coupled to the feedback terminal to provide a feedback state signal in response to a feedback current through the feedback terminal. The feedback state signal has feedback states that represent an output of the power supply. The control circuit is to be coupled to a power switch and to receive the feedback state signal to regulate the output of the power supply. The first current source is coupled to the node to provide a first current to the node. The second current source is coupled to the node to selectively remove a second current from the node to modulate the feedback current and to alter the feedback state of the feedback state signal. | 01-27-2011 |
20110025288 | METHOD AND APPARATUS FOR MAINTAINING A CONSTANT LOAD CURRENT WITH LINE VOLTAGE IN A SWITCH MODE POWER SUPPLY - A power supply regulator including a variable current limit threshold that increases during an on time of a switch. In one aspect, a power supply regulator includes a comparator coupled to receive a signal representative of a current through a switch during an on time of the switch. The comparator is further coupled to receive a variable current limit threshold that increases during the on time of the switch. The power supply regulator also includes a feedback circuit coupled to receive a feedback signal representative of an output of a power supply. A control circuit is also included and is coupled to the switch, to an output of the comparator, and to an output of the feedback circuit. The control circuit is coupled to control a switching of the switch in response the output of the comparator and the output of the feedback circuit to regulate the output of the power supply. | 02-03-2011 |
20110084679 | METHOD AND APPARATUS PROVIDING FINAL TEST AND TRIMMING FOR A POWER SUPPLY CONTROLLER - A power supply controller having final test and trim circuitry. In one embodiment, a power supply controller for switched mode power supply includes a selector circuit, a trim circuit, a shutdown circuit and a disable circuit. The trim circuit includes a programmable circuit connection that can be selected by the selector circuit by toggling a voltage on an external terminal such as for example a power supply terminal, a control terminal or a function terminal of the power supply controller. The programmable circuit connection in the trim circuit can be programmed by applying a programming voltage to the external terminal. The shutdown circuit shuts down the power supply controller if the temperature rises above an over temperature threshold voltage. The shutdown circuit includes adjustment circuitry that can be used to test the shutdown circuit. The adjustment circuitry can adjust and reduce the over temperature threshold of the power supply controller. Thus, the power supply controller can be tested without having to actually heat the part. The disable circuit includes a programmable circuit connection, which when programmed prevents further trimming of power supply controller and prevents adjustment of the shutdown circuit over temperature threshold. | 04-14-2011 |
20110085360 | METHOD AND APPARATUS PROVIDING A MULTI-FUNCTION TERMINAL FOR A POWER SUPPLY CONTROLLER - A power supply controller circuit is disclosed. An example power supply controller circuit includes a control circuit coupled to generate a switching waveform to be used to regulate an output of a power supply. A current input circuit is coupled to receive a current representative of an input of the power supply. The current input circuit is to generate a sense signal in response to the current representative of the input of the power supply. A first comparator is coupled to the current input circuit to receive the sense signal. The first comparator coupled to generate a first signal in response to the sense signal being above a first threshold. An enable/disable logic circuit is coupled to the first comparator. The enable/disable logic circuit is coupled to deactivate the control circuit in response to the first signal. | 04-14-2011 |
20110110125 | METHOD AND APPARATUS TO LIMIT MAXIMUM SWITCH CURRENT IN A SWITCHING POWER SUPPLY - An example integrated circuit for use in a power supply includes a switch, a terminal and a controller. The controller is coupled to control switching of the switch to regulate the output of the power supply in response to a feedback signal received at the terminal. The controller includes a comparator and an oscillator. The comparator is coupled to detect when a switch current through the switch exceeds a current limit and the oscillator is coupled to extend an off time of the switch in response to the comparator detecting that the switch current exceeds a current limit and if an on time of the switch is substantially equal to a sum of a leading edge blanking period and a current limit delay time period. The oscillator extends the off time of the switch independent of the feedback signal. | 05-12-2011 |
20110228568 | OFF-LINE CONVERTER WITH DIGITAL CONTROL - A circuit for regulating the level at a power converter output is disclosed. An example circuit includes an input for receiving a feedback signal. The feedback signal has a first feedback state that represents a level that is above a threshold level and a second feedback state that represents a level that is below the threshold level. An oscillator is included that provides an oscillation signal that cycles between two states. A switch having a first terminal, a second terminal and a control terminal are also included. The switch is operable to couple or decouple the first terminal and the second terminal in response to a control signal received at the control terminal. The control signal is responsive to the oscillation signal and to the first and second feedback states. | 09-22-2011 |
20110255310 | METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH AN EVENT COUNTER IN A POWER CONVERTER - A method for controlling an output of a power converter includes generating a drive signal with a control circuit, entering a dormant mode of operation that includes powering down the control circuit if a flow of energy to an output of the power converter is less than a threshold value for more than a first period of time, and powering up the control circuit after it is in the dormant mode of operation for a second period of time. | 10-20-2011 |
20110267843 | METHOD AND APPARATUS TO LIMIT OUTPUT POWER IN A SWITCHING POWER SUPPLY - An example integrated circuit controller for a power supply includes a modulator, a drive signal generator, a comparator, and a variable current limit generator. The modulator generates an enable signal having logic states responsive to a feedback signal. The drive signal generator either enables or skips enabling a switch of the power supply during a switching period in response to the logic state of the enable signal. The comparator asserts an over current signal to disable the switch if current flowing through the switch exceeds a variable current limit. The variable current limit generator sets the variable current limit to a first current limit in response to one logic state of the enable signal during a switching period and sets the variable current limit to a second current limit if the enable signal transitions logic states and the over current signal is asserted during the switching period. | 11-03-2011 |
20110267846 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A controller for use in a power converter providing sensing of an isolated output is disclosed. An example controller includes a current controller to be coupled to an energy transfer element and an input of the power converter. A control circuit is included that generates a mode select signal coupled to be received by the current controller. A first, second or third current is enabled in the current controller in response to a selection of a first, second or third mode of operation, respectively, of the current controller by the control circuit. The first current is substantially zero, the second current is greater than the third current and the third current is greater than the first current. A first feedback circuit is coupled to the control circuit and is coupled to generate a first feedback signal representative of an output of the power converter during the first mode of operation after a period of operation of the second mode of operation of the current controller. A second feedback circuit is coupled to the control circuit and is coupled to generate a second feedback signal representative of the output of the power converter during the first mode of operation after a period of operation of the third mode of operation of the current controller. The control circuit is coupled to control selections of the first, second or third modes of operation in response to the first and second feedback signals to control a transfer of energy from the input of the power converter to the output of the power converter. | 11-03-2011 |
20110267847 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A controller for use in a power converter to detect changes in output voltage. An example controller includes a drive circuit to generate a switching signal. The switching signal is coupled to be received by a power switch to be coupled to an energy transfer element and an input of the power converter to control a transfer of energy from the input of the power converter to an output of the power converter. An output voltage sensor is coupled to the drive circuit and coupled to receive a feedback signal representative of the output of the power converter. The output voltage sensor includes first and second pulse sampler circuits. The first pulse sampler circuit is coupled to capture a first peak voltage representative of a second peak of a ringing voltage of the feedback signal at a first time in the feedback signal. The second pulse sampler circuit is coupled to capture a second peak voltage representative of the second peak of the ringing voltage of the feedback signal at a second time in the feedback signal. The output voltage sensor is coupled to output a change signal to the drive circuit in response to the first and second peak voltages. | 11-03-2011 |
20110285374 | METHOD AND APPARATUS FOR MAINTAINING A CONSTANT LOAD CURRENT WITH LINE VOLTAGE IN A SWITCH MODE POWER SUPPLY - A method and apparatus of reducing peak current variation with changing input line voltage in a switch mode power supply is disclosed. An example method includes sensing a current through a switching device of the switch mode power supply. A variable current limit threshold is generated, which increases from a first level to a second level during an on time of the switching device. The current is compared to the variable current limit threshold. A feedback signal representative of an output voltage of the switch mode power supply is sensed. The switching device is controlled in response to the feedback signal and said comparing the current to the variable current limit threshold. | 11-24-2011 |
20120002448 | METHOD AND APPARATUS FOR ON/OFF CONTROL OF A POWER CONVERTER - A power converter is disclosed. An example power converter includes an energy transfer element coupled between a power converter input and a power converter output. A power switch is coupled to the energy transfer element and the power converter input. A feedback sampling circuit is coupled to receive a feedback signal representative of the power converter output to generate feedback signal samples during switching cycles. A switch conduction scheduling circuit is coupled to determine enabling and disabling of the power switch in future switching cycles in response to the feedback signal samples from a present switching cycle and one or more past switching cycles. A switch conduction control circuit is coupled to enable or disable conduction of the power switch during a switching cycle to control an amount of energy transferred from the power converter input to the power converter output. | 01-05-2012 |
20120002451 | METHOD AND APPARATUS FOR INTEGRATED CABLE DROP COMPENSATION OF A POWER CONVERTER - An integrated circuit controller for a power converter to be coupled to a distribution network is disclosed. An example integrated circuit controller according to aspects of the present invention includes a switching control circuit that outputs a drive signal to control switching of a switch to regulate an output of the power converter. The integrated circuit controller also includes a cable drop compensator that outputs a compensated reference voltage signal to the switching control circuit in response to a switching signal. The switching signal is responsive to the drive signal. The compensated reference voltage signal is representative of a voltage value that is responsive to a distribution voltage across the distribution network and a load voltage across a load to be coupled to the distribution network. The switching of the switch is responsive to the compensated reference voltage signal and a feedback signal. | 01-05-2012 |
20120007575 | METHOD AND APPARATUS FOR CONTROLLING THE MAXIMUM OUPUT POWER OF A POWER CONVERTER - An example controller for a power converter includes an input voltage sensor, a current sensor, an oscillator, a timing and multiplier circuit, and a drive signal generator. The input voltage sensor receives an input signal representative of an input voltage and the current sensor senses a current in a power switch. The oscillator generates a signal having a switching frequency and the timing and multiplier circuit adjusts the switching frequency of the signal to be proportional to a value that is the input voltage multiplied by a time it takes the current in the power switch to change between two current values. The drive signal generator drives the power switch into the on state for an on time period and an off state for an off time period in response to the current in the power switch and in response to the signal having the switching frequency. | 01-12-2012 |
20120039097 | METHOD AND APPARATUS FOR SENSING MULTIPLE VOLTAGE VALUES FROM A SINGLE TERMINAL OF A POWER CONVERTER CONTROLLER - An example controller for a power converter includes a switching control coupled to switch a power switch of the power converter to control a transfer of energy from an input of the power converter to an output of the power converter. A sensor is coupled to sample a single terminal of the controller during a portion of an off time of the power switch to output a signal representative of an output voltage of the power converter. The sensor is further coupled to sample the single terminal during a portion of an on time of the power switch to output a signal representative of a line input voltage of the power converter. The switching control is responsive to the sensor. | 02-16-2012 |
20120081930 | METHOD AND APPARATUS TO LIMIT MAXIMUM SWITCH CURRENT IN A SWITCHING POWER SUPPLY - An integrated circuit for use in a power supply includes a drive signal generator, a short on time detector, and an oscillator. The drive signal generator generates a drive signal in response to a clock signal. The short on time detector provides an output indicating that consecutive on times of the drive signal are short on times. An on time of the drive signal is a short on time if a switch current of the switch exceeds a current limit after a leading edge blanking period and if the on time of the switch is less than or equal to a sum of the leading edge blanking period and a current limit delay time period. The oscillator generates the clock signal and changes a frequency of the clock signal from a first frequency to a lower second frequency in response to the output of the short on time detector. | 04-05-2012 |
20120099350 | METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A MEASUREMENT DURING AN INITIALIZATION PERIOD - An integrated circuit includes a threshold detection circuit that is coupled to measure a signal from a first resistive external circuit coupled between a fourth external terminal of the integrated circuit and a first external terminal of the integrated circuit during a duration of an initialization period after the fourth external terminal has been charged to a supply threshold value. A regulator circuit is coupled to charge the fourth external terminal to the supply threshold value during the initialization period of the integrated circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the signal measured from the first resistive external circuit during the duration of the initialization period after the fourth external terminal has been charged to the supply threshold value. | 04-26-2012 |
20120147632 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A controller for use in a power converter includes a control circuit to be coupled to a current controller coupled to an energy transfer element. A first, second or third current is enabled in the current controller in response to the control circuit. The first current is substantially zero, the second current is greater than the third current, and the third current is greater than the first current. The third current only partially discharges a capacitance coupled to a terminal coupled between the energy transfer element and the current controller. A first feedback circuit coupled to the control circuit generates a first feedback signal after a full discharge pulse of current through the current controller. A second feedback circuit coupled to the control circuit generates a second feedback signal after a partial discharge pulse of current through the current controller. | 06-14-2012 |
20120155129 | METHOD AND APPARATUS TO LIMIT OUTPUT POWER IN A SWITCHING POWER SUPPLY - An example power supply includes an energy transfer element, a switch, and a controller. The controller includes a modulator, a drive signal generator, a comparator, and a variable current limit generator. The modulator generates an enable signal having logic states responsive to a feedback signal. The drive signal generator either enables or skips enabling a switch of the power supply during a switching period in response to the logic state of the enable signal. The comparator asserts an over current signal to disable the switch if the switch current exceeds a variable current limit. The variable current limit generator sets the variable current limit to a first current limit in response to one logic state of the enable signal and sets the variable current limit to a second current limit if the enable signal transitions logic states and the over current signal is asserted during the switching period. | 06-21-2012 |
20120163043 | METHOD AND APPARATUS TO REGULATE AN OUTPUT VOLTAGE OF A POWER CONVERTER AT LIGHT/NO LOAD CONDITIONS - An example controller for a primary side control power converter includes a feedback circuit, a driver circuit, and an adjustable voltage reference circuit. The feedback circuit is coupled to compare a feedback signal representative of a bias winding voltage of the power converter with a voltage reference. The driver circuit is coupled to output a switching signal to control a switch of the power converter to regulate an output of the power converter in response the feedback circuit. The adjustable voltage reference circuit is coupled to adjust the voltage reference such that the bias winding voltage is adjusted nonlinearly in response to a load condition at the output of the power converter. The adjustable voltage reference circuit is further coupled to detect the load condition in response to the switching signal. | 06-28-2012 |
20120170327 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - An output voltage sensor for use in a power converter controller includes a first pulse sampler circuit coupled to receive a feedback signal representative of an output of a power converter. The first pulse sampler circuit is coupled to capture a first peak voltage representative of a second peak of a ringing voltage of the feedback signal at a first time in the feedback signal. A second pulse sampler circuit is coupled to receive the feedback signal representative of the output of the power converter. The second pulse sampler circuit is coupled to capture a second peak voltage representative of the second peak of the ringing voltage of the feedback signal at a second time in the feedback signal. The output voltage sensor is coupled to output a change signal to a drive circuit of the power converter controller in response to the first and second peak voltages. | 07-05-2012 |
20120188799 | METHOD AND APPARATUS FOR INCREASING THE POWER CAPABILITY OF A POWER SUPPLY - One example controller for a power supply includes an oscillator, a drive signal generator, and a restart circuit. The oscillator generates a clock signal and the drive signal generator controls switching of a switch to regulate an output of the power supply in response to the clock signal. The restart circuit generates a restart signal in response to a current through the switch and in response to an absolute maximum on time period. The oscillator generates the clock signal to have a fixed maximum frequency in response to the restart signal indicating that the current through the switch reaches a current limit threshold within the absolute maximum on time period. The oscillator also generates the clock signal to have a variable minimum frequency in response to the restart signal indicating that the current through the switch has not reached the current limit threshold within the maximum on time period. | 07-26-2012 |
20120218786 | METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH AN EVENT COUNTER IN A POWER CONVERTER - An example power converter includes an energy transfer element, a switch, and a control circuit. The control circuit includes a drive signal generator and an unregulated dormant mode control circuit. The unregulated dormant mode control circuit renders dormant the drive signal generator thereby ceasing the regulation of the output by the drive signal generator when the energy requirement of the one or more loads falls below a threshold for more than a first period of time. The drive signal generator is unresponsive to changes in the energy requirements of the one or more loads when dormant. The unregulated dormant mode control circuit powers up the drive signal generator after a second period of time has elapsed, such that the drive signal generator is again responsive to changes in the energy requirement of the one or more loads after the second period of time has elapsed. | 08-30-2012 |
20120218788 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - In one aspect, a power supply includes an energy transfer element, a switch, a feedback circuit, a comparator, a state machine, and a control circuit. The feedback circuit generates a feedback signal representative of an output level of the power supply. The comparator provides a feedback state signal having a first feedback state that represents the output level of the power supply being above a threshold level and a second feedback state that represents the output level being below the threshold level. The state machine selectively modulates a first signal in response to the feedback state signal, where the first signal is the feedback signal or the threshold value signal. The control circuit is coupled to control switching of the switch to regulate the output level of the power supply in response to the feedback state signal. | 08-30-2012 |
20120250368 | POWER SUPPLY CONTROLLER WITH INPUT VOLTAGE COMPENSATION FOR EFFICIENCY AND MAXIMUM POWER OUTPUT - A controller for regulating an output of a power supply includes a logic block and an oscillator. The logic block generates the drive signal to control switching of a power switch in response to a clock signal. The clock signal has a frequency that decreases responsive to a time period of the drive signal, where a decrease in the time period of the drive signal represents an increase in an input voltage of the power supply. The oscillator is coupled to generate the clock signal in response to a waveform having an amplitude swing. The oscillator alters the waveform in response to the time period of the drive signal. | 10-04-2012 |
20120280670 | OFF-LINE CONVERTER WITH DIGITAL CONTROL - A power converter includes an input and an output. A regulation circuit is coupled between the power converter input and the power converter output. The regulation circuit is coupled to receive a feedback signal representative of the power converter output. The feedback signal has a first feedback state that represents a level at the power converter output that is above a threshold level and a second feedback state that represents a level at the power converter output that is below the threshold level. An oscillator is included in the regulation circuit that provides an oscillation signal that cycles between two states. The regulation circuit is coupled to be responsive to the oscillation signal and to a change between the first and second feedback states to enable or disable a flow of energy from the power converter input to the power converter output. | 11-08-2012 |
20120320639 | METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A MEASUREMENT DURING AN INITIALIZATION PERIOD - A power supply includes an energy transfer element coupled between an input and an output. A switch is coupled to an input of the energy transfer element. A threshold detection circuit includes in an integrated circuit coupled to measure a signal from a resistive external circuit coupled between fourth and first external terminals of the integrated circuit during an initialization period after the fourth external terminal has been charged to a supply threshold value. A regulator circuit is coupled between second and fourth external terminals of the integrated circuit. The regulator circuit is coupled to charge the fourth external terminal to the supply threshold value during the initialization period. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode of the integrated circuit in response to the measured signal. | 12-20-2012 |
20130058138 | METHOD AND APPARATUS TO LIMIT MAXIMUM SWITCH CURRENT IN A SWITCHING POWER SUPPLY - An integrated circuit for use in a power supply includes a drive signal generator, a first delay, a second delay, a comparator, a first logic, a first short on time detector, and a second logic. The drive signal generator generates a drive signal to control a switch in response to a clock signal. The short on time detector sets the first latch indicating that an on time of the switch is a short on time. The second logic is coupled to detect long pulses of the drive signal to reset the first latch indicating that the on time of the switch is not a short on time. An on time of the drive signal is a short on time if a switch current of the switch exceeds a current limit after a sum of a leading edge blanking period and a current limit delay time period. | 03-07-2013 |
20130077355 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A power converter controller includes a drive circuit coupled to control switching of a power switch coupled to an energy transfer element and an input of the power converter. An output voltage sensor including first and second pulse sampler circuits is coupled to capture first and second peak voltages, respectively, that are representative of a second peak of a ringing voltage of a feedback signal representative of an output of the power converter. The first pulse sampler circuit is coupled to capture the first peak voltage at a first time in the feedback signal. The second pulse sampler circuit is coupled to capture the second peak voltage at a second time in the feedback signal. The drive circuit is coupled to receive a change signal from the output voltage sensor in response to the first and second peak voltages. | 03-28-2013 |
20130121040 | METHOD AND APPARATUS TO REGULATE AN OUTPUT VOLTAGE OF A POWER CONVERTER AT LIGHT/NO LOAD CONDITIONS - An example controller for a primary side control power converter includes a feedback circuit, a driver circuit, and an adjustable voltage reference circuit. The feedback circuit compares a feedback signal representative of a bias winding voltage of the power converter with a voltage reference. The driver circuit outputs a switching signal having a switching period to control a switch to regulate an output of the power converter in response to the feedback signal and enables or disables a switching period based on the output of the feedback circuit. The adjustable voltage reference circuit adjusts the voltage reference by a first amount in response to a first number of disabled switching periods indicating a first load condition at the output of the power converter and by a second amount in response to a second number of disabled switching periods indicating a second load condition at the output of the power converter. | 05-16-2013 |
20130128625 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A power converter includes a current controller coupled to an energy transfer element to selectively enable a first, second or third current in the current controller. The first current is substantially zero, the second current is greater than the third current, and the third current is greater than the first current. The third current only partially discharges a capacitance coupled to the energy transfer element and the current controller. A control circuit is to be coupled to the current controller to selectively enable the first, second or third current in the current controller. A first feedback circuit is coupled to generate a first feedback signal while the first current is enabled by the current controller after a full discharge pulse. A second feedback circuit is coupled to generate a second feedback signal while the first current is enabled in the controller after a partial discharge pulse. | 05-23-2013 |
20130170251 | METHOD AND APPARATUS FOR SENSING MULTIPLE VOLTAGE VALUES FROM A SINGLE TERMINAL OF A POWER CONVERTER CONTROLLER - A controller for use in a power converter includes a sensor coupled to receive a signal from a single terminal of the controller. The signal from the single terminal represents an output voltage of the power converter during at least a portion of an off time of a power switch and a line input voltage during a portion of an on time of the power switch. A switching control is to be coupled to switch the power switch to regulate the output of the power converter in response to the sensor. A power limiter is coupled to the sensor to output a power limit signal to the switching control in response to the line input voltage of the power converter. The switching control is further coupled to switch the power switch to regulate the output of the power converter in response to the power limit signal. | 07-04-2013 |
20130232358 | METHOD AND APPARATUS FOR INCREASING THE POWER CAPABILITY OF A POWER SUPPLY - One controller for a power supply includes an oscillator, a first circuit, a counter, and a pause circuit. The first circuit generates a drive signal to control switching of a switch to regulate an output of the power supply. The first circuit initiates an on time period of the switch in response to both a clock signal of the oscillator and an enable signal that is generated in response to a feedback signal of the power supply. The counter receives the enable signal and generates an output signal when the counter reaches a count value indicating that the enable signal has been idle for an amount of time. The pause circuit generates a pause signal in response to the output signal of the counter. The oscillator is paused in response to the pause signal and a maximum on time period of the switch is extended while the oscillator is paused. | 09-05-2013 |
20130294117 | METHOD AND APPARATUS FOR CONTROLLING THE MAXIMUM OUPUT POWER OF A POWER CONVERTER - An example control circuit for use in a power converter includes an input voltage sensor, a current sensor, and a drive signal generator. The input voltage sensor generates a first signal representative of an input voltage (Vin) of the power converter. The current sensor generates a second signal representative of a switch current through a power switch of the power converter. The drive signal generator generates a drive signal to control switching of the power switch in response to the first and second signals. The drive signal generator sets a switching frequency of the drive signal based on a product K×Vin×t to control a maximum output power of the power converter, where K is a fixed number and t is a time it takes the second signal to change between two values of the switch current when the power switch is in an on state. | 11-07-2013 |
20140022825 | METHOD AND APPARATUS TO SELECT A PARAMETER/MODE BASED ON A MEASUREMENT DURING AN INITIALIZATION PERIOD - A power supply control circuit includes a threshold detection circuit coupled to a first terminal to measure a signal at the first terminal during a duration of an initialization period after a fourth terminal has been charged to a supply threshold value. A regulator circuit is coupled between a second terminal and the fourth terminal to charge the fourth terminal to the supply threshold value during the initialization period of the power supply control circuit. A selection circuit is coupled to the threshold detection circuit to select a parameter/mode in response to the signal measured at the first terminal. The first terminal is further coupled to receive one or more additional signals during normal operation at times other than the initialization period to provide at least one additional function for the power supply control circuit after the initialization period is complete. | 01-23-2014 |
20140036551 | METHOD AND APPARATUS FOR ON/OFF CONTROL OF A POWER CONVERTER - A power converter includes an energy transfer element coupled between a power converter input and a power converter output. A power switch is coupled to the energy transfer element and the power converter input. A feedback sampling circuit is coupled to receive a feedback signal representative of the power converter output to generate at least one feedback signal sample during each switching cycle. A switch conduction scheduling circuit is coupled to set a number of enabled cycles and a number of disabled cycles of the power switch in a plurality of future switching cycles in response to the feedback signal samples for each present switching cycle and one or more past switching cycles. A switch conduction control circuit is coupled to enable or disable conduction of the power switch during a switching cycle to control an amount of energy transferred from the power converter input to the power converter output. | 02-06-2014 |
20140063867 | APPARATUS AND METHOD FOR SENSING OF ISOLATED OUTPUT - A switched-mode power supply includes an energy transfer element coupled between a primary side and a secondary side. A first main terminal of a switch is coupled to the energy transfer element and a second main terminal of the switch is coupled to an input of the primary side. A driver circuit is coupled to drive the switch to be open at a first one of a plurality of levels and closed at a second one of the plurality of levels. The driver circuit is coupled to drive the switch to be substantially independent of a voltage between the first and second main terminals at a third one of the plurality of levels. A current conducted between the first and second main terminals at the third one of the plurality of levels is sufficient to only partially discharge a capacitance that is coupled to the first main terminal. | 03-06-2014 |
20140126246 | METHOD AND APPARATUS FOR DIGITAL CONTROL OF A SWITCHING REGULATOR - An on/off controller device includes a control circuit to generate a control signal to switch a power switch between an on state and an off state to transfer energy from a primary side to a secondary side of a switched mode power supply. A comparator is coupled to generate an enable signal that enables and disables the switching of the power switch by the control circuit. The comparator compares a feedback signal with a variable threshold and switches the enable signal between enabling and disabling the switching of the power switch. The variable threshold is modulated to increase a fundamental frequency of the switching of the power switch by the control circuit. The variable threshold is modulated with a fixed amplitude pulse that is combined with a second threshold to modulate the variable threshold between a first higher value and a second lower value. | 05-08-2014 |
20140133194 | APPARATUS AND METHOD FOR DETECTING A CHANGE IN OUTPUT VOLTAGE OF AN ISOLATED POWER CONVERTER - A power converter controller includes a drive circuit coupled to control switching of a power switch to control a transfer of energy from an input of the power converter to an output of the power converter. A voltage sensor is coupled to the drive circuit to receive a feedback signal. The voltage sensor includes pulse sampler circuitry coupled to sample a first voltage representative of one of the peaks other than a first peak of ringing of the feedback signal in a first enabled switching cycle, sample a second voltage representative of the same peak of ringing of the feedback signal in a subsequent enabled switching cycle, and compare the sample of the first voltage with the sample of the second voltage and output a change signal based on the comparison. The drive circuit is further coupled to control switching of the power switch in response to the change signal. | 05-15-2014 |
20140153297 | POWER SUPPLY CONTROLLER WITH INPUT VOLTAGE COMPENSATION FOR EFFICIENCY AND MAXIMUM POWER OUTPUT - An apparatus includes an ON/OFF controller for regulating an output of a switched mode power supply by selectively enabling current conduction by a power switch within enabled switching cycles and disabling current conduction by the power switch within disabled switching cycles. The controller includes a logic block and a time-to-frequency converter. The logic block generates a drive signal that enables the current conduction by the power switch within respective enabled switching cycles and disables the current conduction by the power switch within respective disabled switching cycles. The time-to-frequency converter generates a variable-frequency clock signal that defines durations of the switching cycles, where the time-to-frequency converter increases a duration of a switching cycle in response to a decrease in duration of current conduction by the power switch in a previously enabled switching cycle. | 06-05-2014 |
20140204623 | CHARGING CIRCUIT FOR A POWER CONVERTER CONTROLLER - A controller includes a first controller terminal, a second controller terminal, a first p-channel metal-oxide-semiconductor field-effect transistor, and a second pMOS transistor. The first controller terminal is to be coupled to a bypass capacitor coupled to a secondary side of an isolated power converter. The second controller terminal to be coupled to an output node of the secondary side. The first pMOS transistor includes a first source terminal coupled to the second controller terminal, a first drain terminal, and a first body diode. The second pMOS transistor includes a second source terminal coupled to the first controller terminal, a second drain terminal coupled to the first drain terminal, and a second body diode. A cathode of the second body diode is coupled to the second source terminal. An anode of the second body diode is coupled to the second drain terminal. | 07-24-2014 |
20140204624 | POWER CONVERTER CONTROLLER WITH MULTIPLE POWER SOURCES - A controller includes a bypass terminal, a first power circuit, a second power circuit, and a charging control circuit. The bypass terminal is to be coupled to a bypass capacitor coupled to a secondary side of an isolated power converter. The first power circuit is coupled to the bypass terminal and a first terminal to be coupled to a first node of the secondary side. The first power circuit transfers charge from the first terminal to the bypass terminal for storage on the bypass capacitor. The second power circuit is coupled to the bypass terminal and a second terminal to be coupled to a second node of the secondary side. The second power circuit transfers charge from the second terminal to the bypass terminal for storage on the bypass capacitor. The charging control circuit controls which of the first and second power circuits transfers charge to the bypass terminal. | 07-24-2014 |
20140204625 | SECONDARY CONTROLLER FOR USE IN SYNCHRONOUS FLYBACK CONVERTER - A secondary controller for use in a synchronous flyback converter includes a comparator, a drive circuit, and logic circuitry. The comparator is coupled to generate a compare signal in response to a comparison of a threshold to an input signal representative of a secondary winding voltage of the synchronous flyback converter. The drive circuit is coupled to generate a drive signal to control a first switch to be coupled to a primary side of the synchronous flyback converter. The drive signal is coupled to be generated by the drive circuit in response to a feedback signal representative of an output of the synchronous flyback converter. The logic circuitry is coupled to the drive circuit and coupled to the comparator. The logic circuitry is also coupled to generate a control signal to control a second switch in response to the drive signal and in response to the compare signal. | 07-24-2014 |
20140204626 | RECEIVE CIRCUIT FOR USE IN A POWER CONVERTER - A receive circuit for use in a power converter controller includes a first amplifier coupled to receive an input pulse. A second amplifier is coupled to a first output of the first amplifier. The first output is coupled to be responsive to the input pulse and to a second output of the second amplifier. An output circuit is coupled to generate an output signal in response to the second output. | 07-24-2014 |
20140247628 | METHOD AND APPARATUS FOR POWER CONVERTER FAULT CONDITION DETECTION - A controller includes a control, a sensor, and a fault detector. The control is configured to control a switch to regulate an output of the power converter. The sensor receives a signal from a terminal of the controller that is representative of an input voltage during an ON state of the switch and is representative of an output voltage during an OFF state of the switch. The sensor is configured to sample the signal from the terminal during the ON state to generate a first sample signal and to sample the signal from the terminal during the OFF state to generate a second sample signal. The fault detector detects a fault condition in response to either the first or the second sample signals. The control inhibits the switching of the switch to reduce a power output level of the power converter in response to the fault condition. | 09-04-2014 |
20140254202 | LOW THRESHOLD VOLTAGE COMPARATOR - A voltage comparator includes an amplifier coupled to receive an input signal at an amplifier input and generate an output signal at an amplifier output in response to the input signal. The amplifier includes a current generation circuit coupled to generate a first current flowing through a first branch and a second current flowing through a second branch. A first transistor has a first terminal coupled to the amplifier input and a second terminal coupled to the first branch. A second transistor has a third terminal coupled to the second branch, a fourth terminal coupled to a reference voltage. A second control terminal of the second transistor is coupled to the first control terminal. An output circuit is coupled to the amplifier output to generate a comparator output signal in response to the output signal. The amplifier output is coupled to the second branch. | 09-11-2014 |
20140254213 | POWER CONVERTER OUTPUT VOLTAGE CLAMP AND SUPPLY TERMINAL - A secondary control circuit includes a voltage regulator circuit to be coupled to an output of a power converter to provide a regulated power supply. One or more switched loads is coupled between a first terminal to be coupled to the output of the power converter and an output ground terminal. One or more comparator circuits is coupled to a second terminal coupled to receive an output sense signal. Each one of the one or more comparator circuits is coupled to receive a respective one of one or more reference signals. Each respective one of the one or more reference signals is a scaled representation of a first one of the one or more reference signals. Each one of the one or more switched loads is coupled to be switched in response to an output of a respective one of the one or more comparator circuits. | 09-11-2014 |
20140254214 | TECHNIQUES FOR CONTROLLING A POWER CONVERTER USING MULTIPLE CONTROLLERS - A power converter controller includes a primary controller that is galvanically isolated from a secondary controller. The primary controller controls a state of a power switch during a first mode of operation according to a switching pattern defined by the primary controller. During a second mode of operation, the primary controller controls the state of the power switch in response to control signals received via a communication link. The secondary controller operates in a powered down state during the first mode of operation. The secondary controller initiates a transition operation with the primary controller that transitions the primary controller and the secondary controller from the first mode of operation to the second mode of operation. In the second mode of operation, the secondary controller transmit the control signals to the primary controller via the communication link. | 09-11-2014 |
20140307479 | METHOD AND APPARATUS FOR SENSING MULTIPLE VOLTAGE VALUES FROM A SINGLE TERMINAL OF A POWER CONVERTER CONTROLLER - A controller for use in a power converter includes a switching control and a sensor. The switching control generates a first signal to control switching of a power switch between a first state and a second state. The sensor receives a second signal from a single terminal of the controller during at least a portion of the time that the power switch is in the first state and during at least a portion of the time that the power switch is in the second state. The second signal is representative of a line input voltage during at least the portion of time that the power switch is in the first state and is representative of an output voltage during at least the portion of time that the power switch is in the second state. The sensor is coupled to be responsive to the first signal. | 10-16-2014 |
20150062980 | METHOD AND APPARATUS FOR IMPLEMENTING AN UNREGULATED DORMANT MODE WITH AN EVENT COUNTER IN A POWER CONVERTER - A control circuit for use in a power converter includes a drive signal generator coupled to generate a drive signal to control switching of a switch to regulate an output of the power converter. An event detection circuit is coupled to the drive signal generator to indicate if a switching period of one switching cycle of the drive signal exceeds a threshold switching period. An event counter circuit is coupled to the event detection circuit to render dormant the drive signal generator if the event detection circuit indicates a period of a switching cycle of the drive signal exceeds the threshold switching period for a threshold consecutive number of switching cycles. | 03-05-2015 |