Weltrend Semiconductor Inc.

Leadtrend Technology Corporation

Chun-Teh Chen

Ren-Yi Chen

Ming-Ying Kuo

Yi Lun Shen

Ren Yi Chen

Yi-Shan Chu

Yuan-Wen Chang

Yu-Yun Huang

Jeng-Cheng Liu

Mu-Chih Lin

Chi-Pin Chen

Chia-Pauo Wu

A power converter capable of performing over-voltage protection and over-temperature protection converts an input voltage into an output voltage. A power switch is connected in series with a primary winding between the input voltage and an input ground. A power controller with a multi-function pin controls the power switch to control a winding current through the primary winding. The power converter has a multi-purpose circuit with first and second resistors, a rectifier and a thermistor. A connection node makes the first and second resistors connected in series between two ends of an auxiliary winding. The rectifier and the thermistor are connected in parallel between the multi-function pin and the connection node. The power controller can perform over-voltage protection and over-temperature protection via the multi-purpose circuit and the multi-function pin.

Power converter, power controller, and control method capable of providing multiple protections

A control method is introduced to operate an ACF power converter under a non-complimentary mode. A high-side switch is turned ON at least twice within a switching cycle of a low-side switch, to provide at least two high-side ON times. One of the high-side ON times follows the end of demagnetization time of a transformer in the ACF power converter, and the other follows the end of the blanking time that controls the maximum switching frequency of the low-side switch.

Control method in use of active-clamp flyback power converter

A power controller in a switching mode power supply dynamically performs high-voltage charging to maintain an operating voltage. The power controller includes a PWM signal generator, a high-voltage charging circuit, and a high-voltage charging controller. The PWM signal generator provides a PWM signal to a power switch to perform power conversion regulating an output voltage of the switching mode power supply at a voltage rating. The high-voltage charging circuit has a high-voltage-tolerant switch connected between a line voltage and the operating voltage, wherein rectifying an AC voltage generates the line voltage. The high-voltage charging controller turns ON the high-voltage-tolerant switch to perform high-voltage charging at the same time when performing the power conversion. The high-voltage charging directs a charging current from the line voltage through the high-voltage-tolerant switch to charge the operating voltage.

Switching mode power supply with dynamic high-voltage charging to maintain operating voltage

A driving controller for driving a transistor, includes an operation unit, a first adjustment unit, a second adjustment unit, a first comparator, a comparison unit. A first terminal of the transistor receives an operation voltage. The operation unit is coupled to a control terminal of the transistor. The first adjustment unit is used to increase a voltage of the control terminal of the transistor. The second adjustment unit is used to decrease the voltage of the control terminal of the transistor. The first comparator and the comparison unit are coupled to the first terminal of the transistor and used to compare the operation voltage with a first reference voltage to a third reference voltage respectively so that the transistor may be controlled accordingly.

Driving controller capable of dynamically adjusting voltage at control terminal of transistor

The power management integrated circuit has a startup circuit, a switch controller and a standby controller. Powered by a power source, the startup circuit provides electric power to an operational power source during a startup period. The switch controller controls a power switch to store or release energy in an energy conversion unit. Powered by the power source, the standby controller receives a standby signal. When the standby signal is asserted, the standby controller disables the startup circuit and the switch controller, thereby startup circuit not providing electric power to the operational power source and the switch controller continuously turning off the power switch.

Power management integrated circuit and power management method

A switching power supply includes a power switch, an adjusting circuit and a limit signal generator. The power switch operates according to a switch control signal. The adjusting circuit adjusts the turn-on time of the switch control signal according to a limit signal and a detecting signal which corresponds to the current passing the power switch. When the detecting signal exceeds or is equal to the limit signal, the limit signal generator samples a reference signal and updates the limit signal according to the sampled reference signal.

Switching power supply and related control method

A control circuit for use in a power converter has a multi-function terminal, a current comparator circuit, and an under-voltage detection circuit. The current comparator circuit compares current flowing through a power switch of the power converter with a reference value through the multi-function terminal when the power switch is on, and turns the power switch off when the current reaches the reference value. The under-voltage detection circuit determines whether an input voltage of the power converter is less than a predetermined value through the multi-function terminal when the power switch is turned off.

Growing community of inventors

Hsinchu, Taiwan

Chun-Teh Chen