Abstract: An active clamp switching power converter circuit includes a sensing circuit that generates a sensed auxiliary winding voltage of an auxiliary winding around the core having a same polarity as the secondary winding. A controller controls switching of a power switch coupled to the primary winding to control current through the primary winding and controls switching of an active clamp switch based on the sensed voltage to control leakage energy when the power switch is turned off. The controller regulates timing of the switching to achieve a zero voltage switching condition prior to turning on the power switch for power efficient operation.

Abstract: An active clamp switching power converter circuit includes a sensing circuit that generates a sensed auxiliary winding voltage of an auxiliary winding around the core. A primary side controller controls switching of a power switch coupled to a primary winding to control current through the primary winding and controls switching of the active clamp switch based on the sensed voltage to control leakage energy when the power switch is turned off. The primary side controller regulates timing of the switching to achieve a zero voltage switching condition prior to turning on the power switch for power efficient operation.

Abstract: An active clamp switching power converter circuit includes a sensing circuit that generates a sensed auxiliary winding voltage of an auxiliary winding around the core having a same polarity as the secondary winding. A controller controls switching of a power switch coupled to the primary winding to control current through the primary winding and controls switching of an active clamp switch based on the sensed voltage to control leakage energy when the power switch is turned off. The controller regulates timing of the switching to achieve a zero voltage switching condition prior to turning on the power switch for power efficient operation.

Abstract: An active clamp switching power converter circuit includes a sensing circuit that generates a sensed auxiliary winding voltage of an auxiliary winding around the core. A primary side controller controls switching of a power switch coupled to a primary winding to control current through the primary winding and controls switching of the active clamp switch based on the sensed voltage to control leakage energy when the power switch is turned off. The primary side controller regulates timing of the switching to achieve a zero voltage switching condition prior to turning on the power switch for power efficient operation.

Abstract: A method includes generating output power based on a switching signal, comparing the output power to a target power, increasing the output power using a pulse frequency modulation (PFM) and pulse width modulation (PWM) when the output power is less than the target power, and decreasing the output power using the PFM and PWM when the output power is greater than the target power. An apparatus includes a power regulator configured to generate output power based on a switching signal, and a pulse frequency and width modulation (PFWM) controller coupled to the power regulator, and configured to compare the output power to a target power and to increase or decrease the output power using a PFM and pulse PWM according to the comparison result.

Abstract: A system includes an inductance, a sensing circuit, a filter circuit, and a switch. The inductance includes a first terminal connected to (i) an output of a power supply supplying a DC voltage and (ii) a load, and a second terminal connected to a node. The sensing circuit is configured to sense voltage at the node. The filter circuit is configured to filter the voltage at the node, and output a filtered voltage. The switch is configured to communicate with the node, and control current through the load based on the filtered voltage.

Abstract: A first filter outputs a first signal in response to receiving an input signal. The first signal has a first state in response to the input signal reaching a first threshold voltage on a leading edge of the input signal, and a second state in response to the input signal reaching the first threshold voltage on a trailing edge of the input signal. A second filter outputs a second signal in response to receiving the input signal. The second signal has the first state in response to the input signal reaching a second threshold voltage on the leading edge of the input signal, and the second state in response to the input signal reaching the second threshold voltage on the trailing edge of the input signal. A detection circuit determines, based on times when the first and second thresholds are reached, whether the input signal is received from a triac.

Abstract: Aspects of the disclosure provide a method that including receiving a sensed signal corresponding to a current flowing through an energy transfer module in response to an on/off state of a forward-type triode for alternating current (TRIAC), determining the TRIAC on/off state based on the sensed signal, and controlling the energy transfer module based on the determined TRIAC on/off state.

Abstract: Aspects of the disclosure provide a method for driving dimmable load. The method includes detecting a dimming characteristic in an energy source from which a load draws a first energy according to the dimming characteristic. The dimming characteristic requires a second energy in addition to the first energy to be drawn from the energy source to sustain an operation of the energy source. The method further includes biasing a switch to consume the second energy. The second energy and the first energy are drawn from the energy source to sustain the operation of the energy source.

Abstract: Power converters having bleeder circuits are disclosed. For example, in an embodiment, a power converter can include a controllable TRIAC in series with a rectifier that together produces a controllable rectified voltage at a first node, a first inductor having a first end and a second end, the first inductor being electrically connected to the first node at the first end, and electrically connected to a first power lead of a transistor and an anode of a diode at the second end, a load capacitor having a first end and a second end, the load capacitor being electrically coupled to the first node at the first end of the load capacitor, and electrically coupled to a cathode of the diode at the second end the load capacitor, control circuitry to control switching of the transistor, and a bleeder circuit coupled to the second end of the inductor, the bleeder circuit including a resistor in series with a coupling capacitor.

Abstract: An apparatus includes an energy storage device, a driver circuit configured to receive energy from the energy storage device, and a bleed circuit configured to reduce an amount of the energy received by the driver circuit from the energy storage device. The bleed circuit is configured to reduce the amount of the energy received by the driver circuit during a startup period. The energy storage device may include a transformer, the driver circuit and bleed circuit being coupled to first and second windings of the transformer, respectively. A method includes receiving, by a driver circuit, energy from an energy storage device, and reducing, using a bleed circuit, the energy received by the driver circuit during a startup period. The energy storage device may include a transformer, the driver circuit and bleed circuit being coupled to first and second windings of the transformer, respectively.

Abstract: Aspects of the disclosure provide a method for driving dimmable load. The method includes detecting a dimming characteristic in an energy source from which a load draws a first energy according to the dimming characteristic. The dimming characteristic requires a second energy in addition to the first energy to be drawn from the energy source to sustain an operation of the energy source. The method further includes biasing a switch to consume the second energy. The second energy and the first energy are drawn from the energy source to sustain the operation of the energy source.

Abstract: Aspects of the disclosure provide a circuit that includes a controller. The controller is configured to receive a signal indicative of a current flowing in a magnetic component and control a switch in connection with the magnetic component to shape a peak current of the current flowing in the magnetic component. The controller shapes the peak current from a first peak current level to a second peak current level in order to reduce an amplitude of a ripple in a current drawn from a triode for alternating current (TRIAC) during a time to satisfy a holding current requirement of the TRIAC.

Abstract: A controller for a power conversion circuit that includes an inductor, a diode, and a switch. The controller includes a counter configured to determine, based on a first voltage input to the inductor, an on-time of the diode. The on-time of the diode corresponds to an amount of time that the diode is conducting a first current to a load of the power conversion circuit. A current estimation circuit configured to estimate, based on the on-time of the diode and an on-time of the switch, an output current of the power conversion circuit. The on-time of the switch corresponds to an amount of time that the switch is conducting a second current. A pulse width modulator is configured to provide, based on the estimated output current, a gate drive signal to the switch. The gate drive signal selectively transitions the switch between an on state and an off state.

Abstract: Aspects of the disclosure provide a circuit that includes a detector and a controller. The detector is configured to detect a firing start by a triode for alternating current (TRIAC) in a power supply. The controller is configured to control a switch in connection with a magnetic component in response to the firing start to shape a profile of a current pulled from the power supply to satisfy a latch current requirement and a hold current requirement of the TRIAC.

Abstract: In one embodiment, a dimmer circuit is coupled to an electronic load and receives an alternating current (AC) signal. A phase control circuit turns the dimmer circuit on for a first portion of the AC signal to turn on the electronic load. The dimmer circuit turns off during a second portion of the AC signal to turn off the electronic load. A switch is coupled to the phase control circuit. The switch is controlled to couple the phase control circuit to ground when the dimmer circuit is off where the switch is part of a power supply supplying power to the electronic load.

Abstract: Aspects of the disclosure provide a circuit that includes a switch control circuit and a timing control circuit. The switch control circuit is configured to enable/disable a pulse width modulation (PWM) switch control to a regulator to transfer power to a load. The timing control circuit is configured to enable an analog to digital converter (ADC) to convert an analog signal to a digital stream when the PWM switch control is disabled in order to reduce noise in the digital stream due to switching activities in the regulator.

Abstract: Aspects of the disclosure provide a method for driving dimmable load. The method includes detecting a dimming characteristic in an energy source from which a load draws a first energy according to the dimming characteristic. The dimming characteristic requires a second energy in addition to the first energy to be drawn from the energy source to sustain an operation of the energy source. The method further includes biasing a switch to consume the second energy. The second energy and the first energy are drawn from the energy source to sustain the operation of the energy source.

Abstract: Aspects of the disclosure provide a circuit that includes a detector and a controller. The detector is configured to detect a firing start by a triode for alternating current (TRIAC) in a power supply. The controller is configured to control a switch in connection with a magnetic component in response to the firing start to shape a profile of a current pulled from the power supply to satisfy a latch current requirement and a hold current requirement of the TRIAC.

Abstract: A light emitting diode (LED) lighting system includes a first string of first LEDs emitting light having a first color. A second string of second LEDs emits light having a second color and connected in series with the first string of first LEDs; A first switch and a second switch are connected in series. A regulator module is configured to modulate the first switch and the second switch to provide a desired current ratio. The desired current ratio corresponds to a ratio of a first current through the first string of first LEDs to a second current through the second string of second LEDs.