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 for use in a power converter includes a secondary controller coupled to receive a feedback signal representative of an output of the power converter to generate d a request signal. A primary controller is coupled to receive the request signal to generate a primary drive signal. The primary drive signal is coupled to control switching of a power switch to control a transfer of energy from the input to the output of the power converter. A frequency to on-time converter included in the primary controller is coupled to receive the request signal. The frequency to on-time converter is coupled to control the duration of on-time pulses included in the primary drive signal in response to a period of the request signal.

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 use in a power converter includes a control circuit capable of detecting whether an AC voltage source is coupled to an input of the power converter, and whether the AC voltage source is uncoupled from the input within a first period of time. A control circuit is coupled to drive a switch in a first operating mode when the control circuit detects that the AC voltage source is coupled to the input, and drive the switch in a second operating mode when the control circuit detects that the AC voltage source is uncoupled from the input. The control circuit is capable of discharging a capacitance coupled between input terminals of the power converter to a SELV level through a discharge path and the switch within a second period of time. An RC time constant of the discharge path is less than or equal to one second.

Abstract: An integrated circuit package includes a portion of a lead frame disposed within an encapsulation. The lead frame includes a first conductor including a first conductive loop and a third conductive loop disposed substantially within the encapsulation. A second conductor formed in the lead frame is galvanically isolated from the first conductor and includes a second conductive loop disposed substantially within the encapsulation proximate to the first conductive loop to provide a communication link between the first and second conductors. The third conductive loop is wound in an opposite direction relative to the first conductive loop. A transmit circuit is disposed within the encapsulation and is coupled to the second conductor to provide a transmitter current. A receive circuit is disposed within the encapsulation and is coupled to the first conductor to receive a transmitter induced signal in response to the transmitter current.

Abstract: A controller to regulate a power converter includes a terminal coupled to receive an enable signal including enable events representative of an output of the power converter. A drive circuit is coupled to generate a drive signal to control switching of a power switch to control a transfer of energy from an input of the power converter to the output of the power converter. The drive circuit is coupled to turn on the power switch when an enable event is received in the enable signal. A current limit threshold generator is coupled to the drive circuit to generate a current limit threshold signal. The current limit threshold signal varies each switching cycle of the power switch. A time between consecutive enable events in the enable signal is the switching cycle of the power switch.

Abstract: A method of providing an input switching request signal to an input side switch includes determining a switching request window indicative of relaxation ringing during a first switching cycle. It is determined that the input side switch is operating in a discontinuous conduction mode (DCM) mode of operation during a second switching cycle. It is determined that the switching request window is open during the second switching cycle. The input switching request signal is enabled in response to determining the switching request window is open.

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 that includes a primary winding and a secondary winding, and is coupled to transfer energy between the primary winding and the secondary winding. An enable circuit is coupled to generate an enable signal in response to a feedback signal falling below a threshold. A controller is coupled to control switching of a power switch coupled to the primary winding to regulate an output of the power converter. The controller includes a drive circuit coupled to output a drive signal in response to the enable signal, and a current limit threshold generator coupled to output a current limit threshold signal to the drive circuit in response to the drive signal. The current limit threshold signal varies in response to a time between events of the enable signal over a range of loads coupled to the output of the power converter.

Abstract: A power converter includes an energy transfer element and a circuit coupled to the input of the power converter. The circuit includes a switch and a control circuit capable of detecting whether an AC voltage source is coupled to the input, or uncoupled from the input within a first predetermined time. The control circuit is coupled to drive the switch in a first operating mode when the AC voltage source is coupled, drive the switch in a second operating mode when the AC voltage source is uncoupled, and is capable of discharging a capacitance coupled between input terminals of the power converter to a threshold voltage level through a discharge path and through the switch within a second predetermined time. An RC time constant of the discharge path is less than or equal to one second and the threshold voltage level is less than or equal to ten volts.

Abstract: A controller for use in a power converter includes a power switch including a drain, a source, a control input, and a tap. The power switch includes a first transistor coupled to a second transistor, a drain of the first transistor is coupled to the drain of the power switch and the source of the first transistor is coupled to the tap. A tap sense circuit is coupled to the tap. A drive circuit is coupled to receive an indicator signal from the tap sense circuit. The indicator signal is indicative of a voltage at the tap or the current through the first transistor. The drive circuit is coupled to receive a feedback signal representative of an output quantity of the power converter. The drive circuit is coupled to generate a drive signal to control switching of the power switch in response to the indicator signal and the feedback signal.

Abstract: A method for regulating a power converter includes initiating a transition of a switch coupled to an input side of the power converter from an OFF to an ON state to regulate a transfer of energy from the input to an output side of the power converter after a switch control signal generator receives an enable signal and if a feedback signal representative of an output of the power converter indicates a change in an output of the power converter. The enable signal is generated to communicate a control signal from the output to the input side in response to a first signal representative of a voltage on an output terminal that oscillates in response to an ending of the transfer of energy. The transition of the switch from the OFF to the ON state occurs substantially at a time that the first signal reaches an extremum.

Abstract: An integrated circuit package includes an electromagnetic communication link formed by a portion of a lead frame within an encapsulation. The lead frame includes a first conductor forming a first conductive loop a second conductor forming a second conductive loop galvanically isolated from the first conductive loop. The second conductive loop is magnetically coupled to the first conductive loop to provide a magnetic communication link between the first and second conductors. A first transceiver circuit includes a transmit circuit coupled to the first conductive loop. A second transceiver circuit includes a receive circuit coupled to the second conductive loop. A signal transmitted from the transmit circuit included in first transceiver circuit and coupled to the first conductor is coupled to be magnetically communicated through the magnetic communication link to the receive circuit included in second transceiver circuit and coupled to the second conductor.

Abstract: An integrated circuit package includes an encapsulation and a lead frame. A portion of the lead frame is disposed within the encapsulation. The lead frame includes a first conductor having an inner conductive loop disposed substantially within the encapsulation and a second conductor galvanically isolated from the first conductor. The second conductor includes an outer conductive loop disposed substantially within the encapsulation proximate to and magnetically coupled to the inner conductive loop to provide a communication link between the first and second conductors.

Abstract: An ac-dc power supply includes a dc-dc converter coupled to an input of the ac-dc power supply. The input of the ac-dc power supply is coupled to receive an ac input voltage and an ac input current. The dc-dc converter includes a regulated output and a reservoir output. A controller is coupled to receive sense signals from the dc-dc converter. The controller is coupled to control the dc-dc converter to regulate the regulated output in response to the sense signals. The controller is further coupled to control a waveform of the ac input current to have a substantially same shape as a waveform of the ac input voltage. A regulator circuit is coupled to the regulated output and the reservoir output. The controller is coupled to the regulator circuit to control a transfer of energy from the reservoir output to the regulated output through the regulator circuit.

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 controller includes a primary controller and a secondary controller. The primary controller is coupled to receive one or more request signals from the secondary controller and transition a power switch from an OFF state to an ON state in response to the received request signals. The secondary controller is coupled to transmit the request signals to the primary controller and control the amount of time between the transmission of each of the request signals. The secondary controller includes a timing circuit that sets a minimum amount of time between the transmission of the request signals. The secondary controller also includes a secondary switch control circuit coupled to trigger the timing circuit in response to transmitting a request 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 power converter includes an energy transfer element that includes a primary winding and a secondary winding, and is coupled to transfer energy between the primary winding and the secondary winding. An enable circuit is coupled to generate an enable signal in response to a feedback signal falling below a threshold. A controller is coupled to control switching of a power switch coupled to the primary winding to regulate an output of the power converter. The controller includes a drive circuit coupled to output a drive signal in response to the enable signal, and a current limit threshold generator coupled to output a current limit threshold signal to the drive circuit in response to the drive signal. The current limit threshold signal varies in response to a time between events of the enable signal over a range of loads coupled to the output of the power converter.