Abstract: 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.

Abstract: A circuit to discharge a capacitance between input terminals of a power system is disclosed. An example circuit includes a control circuit coupled to an input of a power system. The control circuit is coupled to detect whether an electrical energy source is coupled to an input of the power system. A switch is also included and is coupled to the control circuit and to the input of the power system. The control circuit is coupled to drive the switch in a first operating mode when the electrical energy source is coupled to the input of the power system. The control circuit is coupled to drive the switch in a second operating mode when the electrical energy source is uncoupled from the input of the power system. A capacitance coupled between input terminals of the input of the power system is discharged through the switch to a threshold voltage in less than a maximum period of time from when the electrical power source is uncoupled from the input terminals of the power system.

Abstract: 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.

Abstract: A high voltage power supply method and apparatus is disclosed. An example power supply circuit includes a rectifier circuit coupled to receive an AC input voltage. A switchmode power converter circuit is coupled to the rectifier circuit to receive a rectified input voltage to generate a regulated output voltage. A switch is coupled between the rectifier circuit and the switchmode power converter circuit. A sense circuit is coupled to detect the AC input voltage. The sense circuit is coupled to turn off the switch when an absolute value of the AC input voltage exceeds a first threshold value. The sense circuit is coupled to turn on the switch when the absolute value of the AC input voltage is below a second threshold value.

Abstract: 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 that has a first input coupled to sense a voltage representative of a current flowing through a switch during an on time of the switch. The comparator has a second input coupled to receive a variable current limit threshold that increases during the on time of the switch. A feedback circuit is coupled to receive a feedback signal representative of an output voltage at an output of a power supply. A control circuit is coupled to generate a control signal in response to an output of the comparator and in response to an output of the feedback circuit. The control signal is to be coupled to a control terminal of the switch to control switching of the switch.

Abstract: An example power converter includes a power switch, a controller, and a current offset circuit. The controller is coupled to switch the power switch between an ON state and an OFF state to regulate an output of the power converter. The controller is adapted to terminate the ON state of the power switch in response to a switch current flowing through the power switch reaching a switch current threshold. The current offset circuit is coupled to generate an offset current in response to an input voltage of the power converter and an input current of the power converter is adjusted in response to the offset current.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A driver circuit included in a power supply having a rectifier coupled to a single phase AC input voltage is disclosed. An example driver circuit includes a drive signal generator to generate a drive signal to be coupled to a variable impedance element. A voltage sensor is coupled to the drive signal generator and is to be coupled to sense a voltage across a high voltage capacitance. The driver circuit is to be coupled to control the variable impedance element in response to the voltage sensor. A low voltage capacitance is allowed to receive current from the input if the sensed voltage is less than a second threshold value. The low voltage capacitance is prevented from receiving current from the input if the sensed voltage is greater than a first threshold value.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.

Abstract: 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 that has a first input coupled to sense a voltage representative of a current flowing through a switch during an on time of the switch. The comparator has a second input coupled to receive a variable current limit threshold that increases during the on time of the switch. A feedback circuit is coupled to receive a feedback signal representative of an output voltage at an output of a power supply. A control circuit is coupled to generate a control signal in response to an output of the comparator and in response to an output of the feedback circuit. The control signal is to be coupled to a control terminal of the switch to control switching of the switch.

Abstract: A power supply including a regulation circuit that maintains an approximately constant load current with line voltage. In one embodiment, a regulation circuit includes a semiconductor switch and current sense circuitry to sense the current in the semiconductor switch. The current sense circuitry has a current limit threshold. The regulation circuit current limit threshold is varied from a first level to a second level during the time when the semiconductor switch is on. One embodiment of the regulation circuit is used in a power supply having an output characteristic having an approximately constant output voltage below an output current threshold and an approximately constant output current below an output voltage threshold.

Abstract: A control circuit for use in a power converter with an unregulated dormant mode of operation is disclosed. In one aspect a power converter 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. 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 period of time has elapsed.

Abstract: A power supply controller method and apparatus measuring impedance is disclosed. An apparatus according to aspects of the present invention includes a sense circuit coupled to a sense terminal. A regulation circuit coupled to the sense circuit and coupled to regulate the sense terminal to a first voltage level when a current flowing through the sense terminal is less than a first threshold current level. The regulation circuit is further coupled to regulate the sense terminal to a second voltage level when the current flowing through the sense terminal reaches the first threshold current level. A response circuit is coupled to the sense circuit and is responsive to the current flowing through the sense terminal when the sense terminal is regulated at the second voltage level.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.

Abstract: A power supply controller measuring impedance includes a sense circuit coupled to a sense terminal. A regulation circuit is coupled to the sense circuit and is also coupled to regulate the sense terminal to a first voltage level when a current flowing through the sense terminal is less than a first threshold current level. The regulation circuit is further coupled to regulate the sense terminal to a second voltage level when the current flowing through the sense terminal reaches the first threshold current level. A response circuit is coupled to the sense circuit and is responsive to the current flowing through the sense terminal when the sense terminal is regulated at the second voltage level.

Abstract: A reduced cost energy transfer element for power converter circuits. In one embodiment, an energy transfer element according to an embodiment of the present invention includes a magnetic element having an external surface with at least a first winding and a second winding wound around the external surface of the magnetic element without a bobbin. As such, energy to be received from a power converter circuit input is to be transferred from the first winding to the second winding through a magnetic coupling provided by the magnetic element to a power converter circuit output.

Abstract: A high voltage power supply method and apparatus is disclosed. An example power supply circuit includes a rectifier circuit coupled to receive an AC input voltage. A switchmode power converter circuit is coupled to the rectifier circuit to receive a rectified input voltage to generate a regulated output voltage. A switch is coupled between the rectifier circuit and the switchmode power converter circuit. A sense circuit is coupled to detect the AC input voltage. The sense circuit is coupled to turn off the switch when an absolute value of the AC input voltage exceeds a first threshold value. The sense circuit is coupled to turn on the switch when the absolute value of the AC input voltage is below a second threshold value.

Abstract: Various techniques directed to providing temporary peak power from a switching regulator are disclosed. In one aspect, a switching regulator includes a switch that is to be coupled between a power supply input and an energy transfer element of the power supply. A controller is coupled to be responsive to a feedback signal to be received from an output of the power supply. The controller is coupled to switch the switch in response to the feedback signal to regulate the output of the power supply. An oscillator is coupled to provide an oscillating signal to the controller to determine a maximum switching frequency of the switch. The oscillating signal is coupled to oscillate at a first frequency under a first moderate load condition at the power supply output. The oscillating signal is coupled to oscillate at a second frequency under a second peak load condition at the power supply output.