Huayuan Semiconductor (shenzhen) Limited Company

Power Integrations, Inc.

Chunming Guo

Chenglong Zhang

Peng Hu

Marvin Espino

Christian Pura Angeles

Jose Requinton Del Carmen, Jr

Zhiwei Qiu

Shengfeng Li

Linkai Li

A PFC circuit includes: a boost inductor, an auxiliary winding, an auxiliary switch tube, a main switch tube, a clamping capacitor, a series resistor and a control module; the boost inductor and the auxiliary winding have mutual inductance, a first terminal of the auxiliary winding is connected to a first terminal of the auxiliary switch tube, a second terminal of the auxiliary switch tube is connected to a first terminal of the clamping capacitor, a second terminal of the clamping capacitor is connected to a first terminal of the series resistor, and a second terminal of the series resistor is connected to a second terminal of the auxiliary winding; the main switch tube is connected between the boost inductor and the ground; and the control module is respectively connected to a control terminal of the main switch tube and a control terminal of the auxiliary switch tube.

PFC circuit with auxiliary switch tube and control method thereof

The invention provides a switching power supply and an electronic device, comprising an active clamp circuit and a transformer, the active clamp circuit including a first clamp capacitor, a second clamp capacitor, and a path guiding module that is connected at two terminals of the first clamp capacitor and two terminals of the second clamp capacitor respectively; the path guiding module, the first and the second clamp capacitors are all directly or indirectly connected to a primary side of the transformer; the path guiding module is configured to guide the first and the second clamp capacitors to obtain an electric energy from different positions on the primary side of the transformer in a first time period, and to guide the first and the second clamp capacitors to discharge the primary side of the transformer after being connected in parallel with each other in a second time period.

Switching power supply and electronic device

A power converter includes: a switching transistor, a transformer, a control circuit; the control circuit is configured to determine a target voltage in a process that the switching transistor is driven to conduct; the target voltage can represent a voltage change of an input terminal of the switching transistor; when the target voltage starts to drop but is higher than a reference voltage, drive a control terminal of the switching transistor with a first driving current; when the target voltage decreases to be lower than the reference voltage, drive the switching transistor with a second driving current; the second driving current is higher than the first driving current; the switching transistor is driven by the first driving current for part or all of the time before entering the Miller plateau stage, and is driven by the second driving current after starting to enter the Miller plateau stage.

Power converter, method for driving switching transistors and a power supply system thereof

Enhanced active preload circuits for an LED driver implementing phase-angle dimming are disclosed. The enhanced active preload circuits may be used with any type of phase-angle control dimmer that either controls the leading edge or trailing edge of the line voltage cycle. In one example, the enhanced active preload circuitry may be used with an isolated or non-isolated LED driver converter having a Triac leading edge phase-angle control dimmer by directly sensing (e.g., by sensing the dimming level using an output/load voltage signal or output/load current signal) or indirectly sensing (e.g., by sensing a signal of output or bias winding) the Triac conduction angle. The enhanced active preload circuitry may advantageously improve performance of the LED driver by extending the dimming ratio at deep dimming and by adjusting the preload sinking current in response to a preload control signal.

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Shenzhen, China

Chunming Guo