| Patent application number | Description | Published |
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| 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 |
