Leadtrend Technology Corporation

Yu-Bin Wang

Ming-Nan Chuang

Yi-Shan Chu

Yuan-Wen Chang

Yu-Chuan Liu

Hsing-Kuo Chao

A control circuit includes an auxiliary pin for receiving an auxiliary voltage of an auxiliary winding of a power converter; a first detection unit for detecting a first time point when the auxiliary voltage begins resonance, and outputting a first detection signal according to the first time point; a second detection unit for detecting a second time point when the auxiliary voltage reaches a predetermined voltage, and outputting a second detection signal according to the second time point; a delay time controller for obtaining a delay time according to a output time difference between the first detection signal and the second detection signal, and outputting a driving signal with delay of the delay time when receiving the second detection signal; and a gate control signal generator for generating a gate control signal to a power switch of the power converter according to the driving signal of the delay time controller.

Control circuit applicable to power converter and operation method thereof

A pulse width modulation (PWM) control circuit is applied to a power converter with a charging capacitor. The PWM control circuit includes a PWM signal generator, a first comparator, and a reference voltage modulator. A PWM signal generator generates a PWM signal to control a power switch in the power converter. Two input terminals of the first comparator respectively receive a first reference voltage and a sensing voltage, which is proportional to a primary-side current of a transformer. When the power switch is turned on and the sensing voltage rises to the level of the first reference voltage, the first comparator outputs a first control signal to the PWM signal generator. Then, the PWM signal generator outputs a signal to turn off the power switch. The reference voltage modulator outputs the first reference voltage according to a feedback voltage relative to the output voltage of the power converter.

Pulse width modulation control circuit applied to charge output capacitor

A control method for adjusting leading edge blanking time in a power converting system is disclosed. The control method includes: receiving a feedback signal relative to a load connected to an output terminal of the power converting system; determining the leading edge blanking time to be a first value if the feedback signal has a magnitude about a first voltage; and determining the leading edge blanking time to be a second value if the feedback signal has a magnitude about a second voltage, wherein the first value is smaller than the second value, and the first voltage is greater than the second voltage.

Control method for adjusting leading edge blanking time in power converting system

A control circuit for adjusting leading edge blanking time is disclosed. The control circuit is applied to a power converting system. The control circuit adjusts a leading edge blanking time according to a feedback signal relative to a load connected to the output terminal of the power converting system. An over-current protection mechanism of the power converting system is disabled within the leading edge blanking time.

Control circuit for adjusting leading edge blanking time and power converting system using the same control circuit

A charging device with boundary mode control is disclosed. The charging device includes a transformer, a power switch, a detection circuit and a pulse-width modulation (PWM) controller. The power switch is electrically connected to one end of a primary-side winding of the transformer. The detection circuit is electrically connected to the primary-side winding and the power switch. The detection circuit detects the resonance of the parasitic capacitance of the power switch, thereby generating a detection signal for boundary mode control. The PWM controller generates a pulse-width modulation signal for driving the power switch, and turns on the power switch according to the detection signal.

Growing community of inventors

Hsin-Chu, Taiwan

Yu-Bin Wang