Marvellworld Trade Ltd.

Marvell International Limited

Maxim Integrated Products, Inc.

Huayuan Semiconductor (Shenzhen) Limited Company

Jinho Choi

Wanfeng Zhang

Hao Peng

Tuyen Doan

Daniel Reed

Pantas Sutardja

Biing Long Shu

Yangsoo Park

Sehat Sutardja

ChiYoung Kim

Young Chul Ryu

Chang Qian

Ravishanker Krishnamoorthy

Junjie Zheng

Radu Pitigoi-Aron

Liang Yan

Jye Sheng Hong

Richard M Myers

Yee-Huan Ng

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.

Controlling an active clamp switching power converter circuit based on a sensed voltage drop on an auxiliary winding

A method for suppressing voltage overshoot at an output of a voltage regulator is disclosed. The voltage regulator includes at least one channel having a first set of (high-side) transistors and a second set of (low-side) transistors. In implementations of the method, an output voltage at an output of at least one channel of a voltage regulator is detected and compared with a reference voltage. A rate of change associated with the output voltage is also determined and compared with a threshold rate of change. When the output voltage is greater than the reference voltage and the rate of change is greater than the threshold rate of change, a resistance value associated with the second set of transistors is increased from a first resistance value to a second resistance value to prevent the output voltage from overshooting and/or to suppress an output voltage overshoot.

System and method for output voltage overshoot suppression

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.

Pfm-pwm control for power regulators

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.

Line voltage detection circuit

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.

Resonant converter with synchronous rectifier feedback

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.

Method and apparatus for controlling TRIAC dimmable device

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.

Method and apparatus for dimmable LED driver

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.

Overshoot prevention for deep dimming startup

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.

Current shaping scheme in TRIAC dimmable LED driver

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.

Dimmer circuit for electronic loads

Power converters that produce less noise are disclosed. For example, in an embodiment, power converter can include a first inductor magnetically coupled to a second inductor, wherein a first end of the second inductor is electrically open and a second end of the second inductor is electrically coupled to ground via a second capacitor, a transistor electrically connected to the first inductor, and control circuitry to control switching of the transistor, wherein when the transistor is repeatedly switched on and off by the control circuitry, a current loop is formed through the transistor, the second capacitor, the first inductor and the second inductor, the current loop causing a reduced amount of switching noise to be generated by the power converter.

Reduced noise power converter using novel shield

Aspects of the disclosure provide a method. The method includes determining a power adjustment to a load, determining whether a switching frequency of a pulse width modulation (PWM) signal is within a specific range, and adjusting the switching frequency of the PWM signal based on the power adjustment to control power transfer to the load. The switching frequency is adjusted to remain in the specific range.

Method and apparatus for controlling a power adjustment to a lighting device

Aspects of the disclosure provide a power circuit to provide electric energy with control and protection for driving a load, such as a light emitting diode (LED) array, and the like. The power circuit includes a converter, a voltage feedback module, a current feedback module and a controller. The converter is configured to receive electric energy from an energy source and to deliver the electric energy for driving the load. The voltage feedback module is configured to generate a first feedback signal based on a voltage of the delivered electric energy. The current feedback module is configured to generate a second feedback signal based on a current of the delivered electric energy. The controller is configured to receive the first feedback signal and the second feedback signal, and to control the converter to receive and deliver the electric energy based on the first feedback signal and the second feedback signal.

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Saratoga, CA, United States of America

Jinho Choi