Semiconductor Components Industries, LLC

Fairchild Semiconductor Corporation

Cheng-Sung Chen

Hangseok Choi

Lei Chen

Sangcheol Moon

Chi Chen Chung

Jintae Kim

Chi-Chen Chung

Wei-Hsuan Huang

A circuit for controlling a power converter includes an SR switching device, a light load detection circuit generating a load detection signal in response to a conduction signal and an operation mode signal, and an SR driver generating a control signal having a value according to the load detection signal and provide the control signal to the SR switching device. A method of controlling a power converter includes generating a load detection signal in response to a conduction signal and an operation mode signal and generating a control signal having a value according to the load detection signal. The control signal has a first value when the load detection signal is asserted and has a second value when the load detection signal is de-asserted.

Adaptive control of synchronous rectifier switching device

A Synchronous Rectifier (SR) controller circuit includes a dead time evaluation circuit, an offset voltage controller circuit, an off threshold control circuit, and a comparator circuit. The dead time evaluation circuit produces an indication of whether a measured dead time of an SR switching device is less than a target dead time. The offset voltage controller circuit determines an offset count using the indication, an offset voltage using the offset count, and high and low saturation indicators according to the offset count. The off threshold control circuit determines a threshold count using the high and low saturation indicators and an off threshold voltage using the threshold count. The comparator circuit determines whether a measured voltage of the SR switching device is greater than a virtual off threshold voltage, the virtual off threshold voltage corresponding to the off threshold voltage minus the offset voltage.

Automatic control of synchronous rectifier turn-off threshold

A flyback converter includes a primary-side switch that controls conduction of current on a primary side of a transformer and a synchronous rectifier on a secondary side of the transformer. A synchronous rectifier driver controls the conduction of the synchronous rectifier by adaptively adjusting a turn-off threshold of the synchronous rectifier.

Self-tuning adaptive dead time control for continuous conduction mode and discontinuous conduction mode operation of a flyback converter

A switching converter includes a synchronous rectifier and a synchronous rectifier driver that controls conduction of the synchronous rectifier. The synchronous rectifier driver turns OFF the synchronous rectifier in response to a turn-off trigger. The synchronous rectifier driver prevents the turn-off trigger from turning OFF the synchronous rectifier during a turn-off trigger blanking time that is adaptively set based on a conduction time of the synchronous rectifier.

Adaptive turn-off trigger blanking for synchronous rectification

A synchronous rectifier driver pre-positions a gate of a synchronous rectifier to allow for fast turn-off. The synchronous rectifier driver turns ON the synchronous rectifier by driving the gate at a high level for a period of time that is based on a previous conduction time of the synchronous rectifier. The synchronous rectifier driver thereafter drives the gate at a lower level that is sufficient to keep the synchronous rectifier ON. The synchronous rectifier can be quickly turned OFF by further reducing the level of the drive signal at the gate of the synchronous rectifier.

Growing community of inventors

Hsinchu, Taiwan

Cheng-Sung Chen