Abstract: An ac-dc power converter controller includes a switch driver circuit 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 an output of the power converter. An input sense circuit is coupled to receive an input sense signal representative of the input of a power converter. A sense enable circuit is coupled to generate a sense enable signal in response to the drive signal. The sense enable signal is coupled to control the input sense circuit to sense the input sense signal for an extended duration of time after the power switch turns OFF.

Abstract: An electrical circuit for a power supply includes a primary-side controller integrated circuit (IC) that outputs a drive signal on a switch pin to control a switching operation of a switch that is coupled to a primary winding of a transformer. The primary-side controller IC places the switch pin at high impedance during a sense window and turns on the switch in response to sensing a dynamic detection signal on the switch pin during the sense window. The dynamic detection signal is induced by a secondary-side controller IC by controlling switching of a switch that is coupled to a secondary winding of the transformer when the output voltage drops below a predetermined threshold during standby or other low load conditions.

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: A control circuit for use in an isolated power converter includes an output-side first controller having a switch control signal generator and an extremum locator. The switch control signal generator communicates a control signal to a second controller on the input side of the power converter via an isolated interface to initiate a transition of a switch from an OFF state to an ON state. The extremum locator enables the switch control signal generator to communicate the control signal in response to an oscillating voltage signal at an output terminal of the energy transfer element. The extremum locator enables the switch control signal generator such that the transition of the switch from the OFF state to the ON state occurs substantially at a time that the oscillating voltage signal reaches an extremum.

Abstract: An ac-dc power converter controller includes a switch driver circuit 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 an output of the power converter. An input sense circuit is coupled to receive an input sense signal representative of the input of a power converter. A sense enable circuit is coupled to generate a sense enable signal in response to the drive signal. The sense enable signal is coupled to control the input sense circuit to sense the input sense signal for an extended duration of time after the power switch turns OFF.

Abstract: A power converter controller includes a switch driver circuit 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 an output of the power converter. An input sense circuit is coupled to receive an input sense signal representative of the input of a power converter. A sense enable circuit is coupled to receive the drive signal to generate a sense enable signal to control the input sense circuit in response to the drive signal. The sense enable signal is coupled to control the input sense circuit to sense the input sense signal continuously in response to a first load condition, and sense the input sense signal only during a fraction of a switching period of the power switch in response to a second load condition.

Abstract: A latching comparator includes a switching logic circuit coupled to receive a first signal from a first signal circuit, and a second signal from a second signal circuit. The switching logic circuit is further coupled to receive a latching signal that is a rectangular pulse waveform in either a first or a second state. An output circuit having an input terminal is coupled to the switching logic circuit. The input terminal of the output circuit is coupled to receive both the first and second signals to compare the first signal and second signal when the latching signal is in the first state. The input terminal of the output circuit is coupled to receive only one of the first and second signals when the latching signal is in the second state.

Abstract: A control circuit for use in an isolated power converter includes an output-side first controller having a switch control signal generator and an extremum locator. The switch control signal generator communicates a control signal to a second controller on the input side of the power converter via an isolated interface to initiate a transition of a switch from an OFF state to an ON state. The extremum locator enables the switch control signal generator to communicate the control signal in response to an oscillating voltage signal at an output terminal of the energy transfer element. The extremum locator enables the switch control signal generator such that the transition of the switch from the OFF state to the ON state occurs substantially at a time that the oscillating voltage signal reaches an extremum.

Abstract: A latching comparator includes a switching logic circuit coupled to receive a first signal from a first signal circuit, and a second signal from a second signal circuit. The switching logic circuit is further coupled to receive a latching signal that is a rectangular pulse waveform in either a first or a second state. An output circuit having an input terminal is coupled to the switching logic circuit. The input terminal of the output circuit is coupled to receive both the first and second signals to compare the first signal and second signal when the latching signal is in the first state. The input terminal of the output circuit is coupled to receive only one of the first and second signals when the latching signal is in the second state.

Abstract: A latching comparator includes a switching logic circuit coupled to receive a latching signal, a first signal and a second signal. An output circuit having an input terminal is coupled to the switching logic circuit. The input terminal of the output circuit is coupled to receive both the first and second signals through the switching logic circuit in response to the latching signal being in a first state. The input terminal of the output circuit is coupled to receive only one of the first and second signals through the switching logic circuit in response to a signal representative of an output terminal of the output circuit and in response to the latching signal being in a second state.

Abstract: A power converter controller includes an input sense circuit to receive an input sense signal representative of an input of a power converter. A zero-crossing detector is coupled to the input sense circuit to be responsive to the input sense signal falling below a first zero-crossing threshold and rising above a second zero-crossing threshold to determine zero-crossing intervals. A timer circuit is coupled to the zero-crossing detector to determine peak intervals and to synchronize an enable signal generated to enable the input sense circuit to sense the input of the power converter during the peak intervals of the input of the power converter. A comparator circuit is coupled to the input sense circuit and the timer circuit to detect if the input of the power converter is greater or less than one or more thresholds during the peak intervals of the input of the power converter.

Abstract: A power converter controller includes an input sense circuit to receive an input sense signal representative of an input of a power converter. A zero-crossing detector is coupled to the input sense circuit to be responsive to the input sense signal falling below a first zero-crossing threshold and rising above a second zero-crossing threshold to determine zero-crossing intervals. A timer circuit is coupled to the zero-crossing detector to determine peak intervals and to synchronize an enable signal generated to enable the input sense circuit to sense the input of the power converter during the peak intervals of the input of the power converter. A comparator circuit is coupled to the input sense circuit and the timer circuit to detect if the input of the power converter is greater or less than one or more thresholds during the peak intervals of the input of the power converter.

Abstract: A power converter controller includes a switch driver circuit 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 an output of the power converter. An input sense circuit is coupled to receive an input sense signal representative of the input of a power converter. A sense enable circuit is coupled to receive the drive signal to generate a sense enable signal to control the input sense circuit in response to the drive signal. The sense enable signal is coupled to control the input sense circuit to sense the input sense signal continuously in response to a first load condition, and sense the input sense signal only during a fraction of a switching period of the power switch in response to a second load condition.

Abstract: A controller includes a current sense circuit and a voltage regulation circuit. The current sense circuit generates a first signal that indicates whether a current through a sense terminal exceeds a first threshold current level, which indicates a fault condition of a power converter. The voltage regulation circuit regulates the sense terminal to a first voltage level when the current through the terminal is less than the first threshold current level and regulates the sense terminal to a second voltage level when the current exceeds the first threshold current level. The current sense circuit generates a second signal that indicates whether the current through the sense terminal exceeds a second threshold current level while the sense terminal is regulated to the second voltage level. The response circuit generates an output signal that determines a response of the controller to the fault condition based on the second signal.

Abstract: A method, in a power supply controller, of responding to an increase in current through a terminal of the power supply controller, is disclosed. The method includes regulating the terminal to a first voltage level and sensing a magnitude of a first current through the terminal while the controller is regulating the terminal to the first voltage level. The method also includes providing an initial response by the power supply controller in response to the magnitude of the first current exceeding a first threshold current level and then regulating the terminal to a second voltage level after the magnitude of the first current exceeds the first threshold current level. The magnitude of a second current through the terminal is sensed while the controller is regulating the terminal to the second voltage level and the controller determines a final response based on the magnitude of the second current.

Abstract: An example controller for a power supply includes a drive signal generator and a compensation circuit. The drive signal generator is to be coupled to control switching of a switch included in the power supply to regulate an output voltage of the power supply in response to a sensed output voltage such that the output voltage of the power supply is greater than an input voltage of the power supply. The compensation circuit is coupled to the drive signal generator and is also coupled to output an offset current to adjust the sensed output voltage in response to the input voltage of the power supply.

Abstract: A latching comparator includes a switching logic circuit coupled to receive a latching signal, a first signal and a second signal. An output circuit having an input terminal is coupled to the switching logic circuit. The input terminal of the output circuit is coupled to receive both the first and second signals through the switching logic circuit in response to the latching signal being in a first state. The input terminal of the output circuit is coupled to receive only one of the first and second signals through the switching logic circuit in response to a signal representative of an output terminal of the output circuit and in response to the latching signal being in a second state.

Abstract: An integrated control circuit according to aspects of the present invention includes an oscillator, a capacitor, and a logic gate. The oscillator generates a periodic timing signal that cycles between a first logic state for a first time duration and a second logic state for a second time duration. The capacitor receives a charge current in response to the periodic timing signal transitioning to the first logic state, where a voltage on the capacitor increases for the first time duration to an initial value. The logic gate generates a periodic output signal having a duty ratio that is responsive to a time that it takes the capacitor to discharge from the initial value to a reference voltage. A period of the periodic output signal is the period of the periodic timing signal.

Abstract: An example power supply controller includes a switch duty cycle controller coupled to receive a feedback signal and a duty cycle adjust signal. The switch duty cycle controller is coupled to generate a drive signal coupled to control switching of a switch, which is coupled to an energy transfer element, to regulate energy delivered from an input of a power supply to an output of the power supply. The power supply controller also includes a gain selector circuit coupled to receive an input voltage signal, which is representative of an input voltage to the power supply, to generate the duty cycle adjust signal received by the switch duty cycle controller. The duty cycle of the drive signal to be varied in response to a plurality of linear functions over a range of values of the input voltage signal.

Abstract: A method, in a power supply controller, of responding to an increase in current through a terminal of the power supply controller, is disclosed. The method includes regulating the terminal to a first voltage level and sensing a magnitude of a first current through the terminal while the controller is regulating the terminal to the first voltage level. The method also includes providing an initial response by the power supply controller in response to the magnitude of the first current exceeding a first threshold current level and then regulating the terminal to a second voltage level after the magnitude of the first current exceeds the first threshold current level. The magnitude of a second current through the terminal is sensed while the controller is regulating the terminal to the second voltage level and the controller determines a final response based on the magnitude of the second current.