Abstract: A secondary controller for use in a power converter includes a drive circuit coupled to a secondary side of the power converter. The drive circuit is configured to generate a first signal to enable a first switch coupled to a primary side of the primary converter. The first signal is generated in response to a feedback signal representative of an output of the power converter. A control circuit is coupled to receive the first signal and an input signal representative of a secondary winding voltage of the power converter. The control circuit is configured to generate a second signal to control a second switch coupled to the secondary side of the power converter. The control circuit is configured to generate the second signal in response to the first signal and a compare signal, and in response to an output of a latch.

Abstract: A controller for use with a power converter and a power switch comprising a primary controller and a secondary controller. The primary controller to control the power switch to transfer energy from the input side to the output side of the power converter. The secondary controller to transmit a control signal to the primary controller through a communication link, and to initiate a transition operation with the primary controller through the communication link. The secondary controller comprises a secondary switch control circuit configured to output the control signal in response to an output of the power converter, a charging circuit coupled to an energy storage element for providing power to the secondary control circuit, and a voltage detection circuit coupled to the energy storage element, wherein the voltage detection circuit is configured to indicate to the secondary switch control circuit when to initiate the transition operation.

Abstract: A secondary controller for use in a power converter includes a drive circuit coupled to a secondary side of the power converter. The drive circuit is configured to generate a first signal to enable a first switch coupled to a primary side of the primary converter. The first signal is generated in response to a feedback signal representative of an output of the power converter. A control circuit is coupled to receive the first signal and an input signal representative of a secondary winding voltage of the power converter. The control circuit is configured to generate a second signal to control a second switch coupled to the secondary side of the power converter. The control circuit is configured to generate the second signal in response to the first signal and a compare signal, and in response to an output of a latch.

Abstract: A controller for use in a power converter for transferring energy between an input and an output, the controller comprising a second controller to generate a request event and a request signal in response to a feedback signal and a switching window signal, the second controller to transmit the request event during a switching window of the switching window signal. The second controller comprising an extremum locator switching window generator to generate the switching window corresponding with an extremum in the winding signal and a measurement enable circuit to output an enable signal to enable the extremum locator switching window generator to measure a duration of a half cycle to generate the switching window. The measurement enable circuit to enable the extremum locator switching window generator in response to the feedback signal reaching a percentage of a target reference and output a quiet signal to prevent transmitting the request event.

Abstract: A secondary controller for use in a power converter includes a drive circuit coupled to a secondary side of the power converter. The drive circuit is coupled to generate a first signal to enable a first switch coupled to a primary side of the primary converter. The first signal is generated in response to a feedback signal representative of an output of the power converter. A control circuit is coupled to receive the first signal and an input signal representative of a secondary winding voltage of the power converter. The control circuit is coupled to generate a second signal to control a second switch coupled to the secondary side of the power converter in response to the first signal and the input signal.

Abstract: A controller for use in a power converter for transferring energy between an input and an output, the controller comprising a second controller to generate a request event and a request signal in response to a feedback signal and a switching window signal, the second controller to transmit the request event during a switching window of the switching window signal. The second controller comprising an extremum locator switching window generator to generate the switching window corresponding with an extremum in the winding signal and a measurement enable circuit to output an enable signal to enable the extremum locator switching window generator to measure a duration of a half cycle to generate the switching window. The measurement enable circuit to enable the extremum locator switching window generator in response to the feedback signal reaching a percentage of a target reference and output a quiet signal to prevent transmitting the request event.

Abstract: A controller for use with a power converter and a power switch comprising a primary controller and a secondary controller. The primary controller to control the power switch to transfer energy from the input side to the output side of the power converter. The secondary controller to transmit a control signal to the primary controller through a communication link, and to initiate a transition operation with the primary controller through the communication link. The secondary controller comprises a secondary switch control circuit configured to output the control signal in response to an output of the power converter, a charging circuit coupled to an energy storage element for providing power to the secondary control circuit, and a voltage detection circuit coupled to the energy storage element, wherein the voltage detection circuit is configured to indicate to the secondary switch control circuit when to initiate the transition operation.

Abstract: A controller configured for use with a power converter and a power switch comprising a primary controller coupled to the power converter and configured to provide a switch drive signal to control switching of the power switch to transfer energy from a primary side to a secondary side of the power converter. A primary switching pattern circuit is configured to provide a primary switching pattern to operate the primary controller in a first mode of operation and a primary switch control circuit is coupled to the primary switching pattern circuit and configured to receive a control signal representative of turn-on of the power switch, to receive the primary switching pattern, and to output the switch drive signal. The primary switch control circuit operates in a first mode, a second mode, and a transition, wherein the primary switch control circuit operates in the second mode after the transition has been completed.

Abstract: A controller for a power converter includes a switching control coupled to switch a power switch to regulate an output of the power converter. A sensor is coupled to receive a signal from a terminal of the controller that represents a line input voltage during at least a portion of an on time of the power switch, and an output voltage of the power converter during at least a portion of an off time of the power switch. The sensor is coupled to sample the signal from the terminal during the portion of the on time of the power switch and to generate a sample input line voltage signal. An output regulator is coupled between the sensor and the switching control to output an output regulation signal to the switching control. The switching control is coupled to switch the power switch in response to the output regulation signal.

Abstract: A controller configured for use with a power converter and a power switch comprising a primary controller coupled to the power converter and configured to provide a switch drive signal to control switching of the power switch to transfer energy from a primary side to a secondary side of the power converter. A primary switching pattern circuit is configured to provide a primary switching pattern to operate the primary controller in a first mode of operation and a primary switch control circuit is coupled to the primary switching pattern circuit and configured to receive a control signal representative of turn-on of the power switch, to receive the primary switching pattern, and to output the switch drive signal. The primary switch control circuit operates in a first mode, a second mode, and a transition, wherein the primary switch control circuit operates in the second mode after the transition has been completed.

Abstract: A power converter includes an energy transfer element coupled between an input and an output of the power converter. A switch is coupled to the energy transfer element and a control circuit. The control circuit includes a drive signal generator to generate a drive signal to control switching of the switch to regulate the 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 for a period of time determined by a timer circuit 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.

Abstract: A controller for a power converter includes a switching control coupled to switch a power switch to regulate an output of the power converter. A sensor is coupled to receive a signal from a terminal of the controller that represents a line input voltage during at least a portion of an on time of the power switch, and an output voltage of the power converter during at least a portion of an off time of the power switch. The sensor is coupled to sample the signal from the terminal during the portion of the on time of the power switch and to generate a sample input line voltage signal. An output regulator is coupled between the sensor and the switching control to output an output regulation signal to the switching control. The switching control is coupled to switch the power switch in response to the output regulation signal.

Abstract: A controller includes a first power circuit, a second power circuit, and a charging control circuit. The first power circuit is coupled to a bypass terminal and a first terminal to be coupled to receive charge from a secondary winding. The first power circuit transfers charge from the first terminal to the bypass terminal. The second power circuit is coupled to the bypass terminal and a second terminal to be coupled to a receive charge from an output of a power converter. The second power circuit transfers charge from the second terminal to the bypass terminal. The charging control circuit controls which of the first and second power circuits transfers charge to the bypass terminal.

Abstract: A power converter controller includes a primary controller configured to operate in a first mode to control a power switch with a primary switching pattern. A communication link is coupled to the primary controller. A secondary controller coupled to the communication link. The secondary controller is galvanically isolated from the primary controller. The secondary controller is configured to initiate a transition operation with the primary controller to take control of the power switch with one or more control signals through the communication link. The primary controller is configured to acknowledge receipt of the one or more control signals through the communication link to the secondary controller and transition from the first mode to a second mode.

Abstract: A circuit for regulating an output level of a power converter includes an adjustment circuit to be coupled to a receive a feedback signal representative of an output level of the power converter. The adjustment circuit is coupled to generate a comparison result signal. A control circuit is coupled to receive the comparison result signal and an oscillating signal. A switch including a first terminal, a second terminal and a control terminal is coupled to the control circuit. The control circuit is coupled to generate a control signal to control switching of the switch. The switch is operable to couple or decouple the first terminal and the second terminal in response to the control signal received at the control terminal. The control signal is responsive to the oscillating signal and to a change in the comparison result signal.

Abstract: A method for regulating an output of a power converter includes receiving a signal from an auxiliary winding of an energy transfer element of the power converter. The energy transfer element includes an input winding coupled to an input of the power converter, an output winding coupled to the output of the power converter, and the auxiliary winding. The signal represents a line input voltage of the power converter during at least a portion of an on time of a power switch coupled to the input winding. The signal represents an output voltage of the power converter during at least a portion of an off time of the power switch. The power switch is switched in response to the signal to regulate the output of the power converter.

Abstract: A power converter includes an energy transfer element coupled between an input and an output of the power converter. A switch is coupled to the energy transfer element and a control circuit. The control circuit includes a drive signal generator to generate a drive signal to control switching of the switch to regulate the 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 for a period of time determined by a timer circuit 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.

Abstract: A controller for use in a power converter that includes a current limit generator coupled to receive a feedback signal representative of an output of the power converter and generate an initial current limit signal. The controller includes a modulation circuit coupled to output a modulation signal which is a percentage of the initial current limit signal. An arithmetic operator is coupled to receive the initial current limit and selectively receive the modulation signal and output a current limit. A comparator is coupled to receive a current sense signal representative of a switch current conducted by a primary switch. A drive circuit is coupled to generate a drive signal to control switching of the primary switch to regulate the output of the power converter in response to the comparator output signal, and the drive circuit turns off the primary switch when the switch current has reached the current limit.

Abstract: A method for controlling an output of a power converter with a control circuit includes generating a drive signal to control switching of a switch to regulate the output of the power converter. It is detected if a switching period of one switching cycle of the drive signal exceeds a threshold switching period. The drive signal is disabled when a period of a switching cycle of the drive signal exceeds the threshold switching period for a threshold consecutive number of switching cycles.

Abstract: A controller for use in a power converter that includes a current limit generator coupled to receive a feedback signal representative of an output of the power converter and generate an initial current limit signal. The controller includes a modulation circuit coupled to output a modulation signal which is a percentage of the initial current limit signal. An arithmetic operator is coupled to receive the initial current limit and selectively receive the modulation signal and output a current limit. A comparator is coupled to receive a current sense signal representative of a switch current conducted by a primary switch. A drive circuit is coupled to generate a drive signal to control switching of the primary switch to regulate the output of the power converter in response to the comparator output signal, and the drive circuit turns off the primary switch when the switch current has reached the current limit.