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 controller for use in a power converter includes a comparator to compare a current sense signal with a current limit to generate a comparator output signal representative of whether a switch current has reached the current limit. A drive circuit controls switching of a power switch to regulate an output of the power converter in response to a feedback signal and the comparator output signal. The drive circuit turns off the power switch in response to the comparator output signal. A current limit generator generates an initial current limit in response to the feedback signal. The current limit is responsive to the initial current limit. A light load sense circuit outputs a light load signal in response to sensing a light load condition of the power converter. A modulation circuit outputs a modulation signal and modulates the initial current limit in response to the light load signal.

Abstract: A method for regulating an output of a power converter includes receiving a signal at a single terminal of an integrated circuit controller. The signal at the single terminal represents a line input voltage of the power converter during at least a portion of an on time of a power switch. The signal at the single terminal 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 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 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 method for controlling an output of a power converter includes switching a switching element with drive signals that are generated for switching a switching element during normal operation when an energy requirement of one or more loads at the output are above a low-load threshold. A non-regulated dormant mode of operation is entered when the flow of energy to the output is detected to be less than the low-load threshold value for more than a first period of time. The control circuit is powered down when in the non-regulated dormant mode of operation the control circuit is unresponsive to stop regulating the flow of energy to the output of the power converter. The control circuit remains in the non-regulated dormant mode of operation for a second period of time before powering up again to resume generating the drive signal and regulating the flow of energy.

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

Abstract: A secondary control circuit includes a voltage regulator circuit coupled to an output of the power converter to provide a regulated power supply. One or more switched loads are coupled between a first terminal and an output ground terminal. The first terminal is coupled to the output of the power converter. Each switched load is coupled to draw a respective current from a load current to clamp the output of a power converter. One or more comparator circuits are coupled to a second terminal. The second terminal is coupled to receive an output sense signal. Each comparator circuit is coupled to receive a reference signal that is a scaled representation of a first reference signal. Each switched load is switched in response to a respective comparator circuit to draw a respective current from the load current of the power converter to clamp the output of the power converter.

Abstract: A method for regulating an output of a power converter includes receiving a signal at a single terminal of an integrated circuit controller. The signal at the single terminal represents a line input voltage of the power converter during at least a portion of an on time of a power switch. The signal at the single terminal 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 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 controller includes a switching control coupled to switch a power switch of a power converter to regulate an output of the power converter. A sensor is 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, and 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 an output of the sensor, and includes a first current source, an internal voltage supply coupled to the first current source, and a buffer circuit coupled to receive the signal from the single terminal. The first current source is coupled to supply a first current to the buffer circuit.

Abstract: A method for controlling an output of a power converter includes switching a switching element with drive signals that are generated for switching a switching element during normal operation when an energy requirement of one or more loads at the output are above a low-load threshold. A non-regulated dormant mode of operation is entered when the flow of energy to the output is detected to be less than the low-load threshold value for more than a first period of time. The control circuit is powered down when in the non-regulated dormant mode of operation the control circuit is unresponsive to stop regulating the flow of energy to the output of the power converter. The control circuit remains in the non-regulated dormant mode of operation for a second period of time before powering up again to resume generating the drive signal and regulating the flow of energy.

Abstract: A controller for use in a power converter includes a comparator to compare a current sense signal with a current limit to generate a comparator output signal representative of whether a switch current has reached the current limit. A drive circuit controls switching of a power switch to regulate an output of the power converter in response to a feedback signal and the comparator output signal. The drive circuit turns off the power switch in response to the comparator output signal. A current limit generator generates an initial current limit in response to the feedback signal. The current limit is responsive to the initial current limit. A light load sense circuit outputs a light load signal in response to sensing a light load condition of the power converter. A modulation circuit outputs a modulation signal and modulates the initial current limit in response to the light load signal.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A controller for a power converter that may sense whether the power converter is in a light load condition. If the power converter is a light load condition, the switching frequency may be within the audible noise range. Once the controller senses the light load condition, the controller may modulate the switching frequency of the power switch such that the switching frequency is no longer within the audible noise range. The controller comprises of a current limit generator coupled to generate an initial current limit signal and receive a feedback signal. The controller may sense a light load condition of the power converter and output a light load signal. As a result of the light load signal, the controller may modulate the initial current limit in response to the light load signal indicating a light load condition.

Abstract: A controller for a power converter that may sense whether the power converter is in a light load condition. If the power converter is a light load condition, the switching frequency may be within the audible noise range. Once the controller senses the light load condition, the controller may modulate the switching frequency of the power switch such that the switching frequency is no longer within the audible noise range. The controller comprises of a current limit generator coupled to generate an initial current limit signal and receive a feedback signal. The controller may sense a light load condition of the power converter and output a light load signal. As a result of the light load signal, the controller may modulate the initial current limit in response to the light load signal indicating a light load condition.

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 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.