Bcd Semiconductor Manufacturing Limited

Rui-Xia Fei

Chao Chen

Shao-Hua Fang

Jian-Hua Duan

Qing-Hua Su

An electric power protection circuit connected in series to a secondary side circuit of a transformer in a switch mode power supply includes a voltage/current limiting device to get an electric power signal output from the secondary side circuit of the transformer that goes through current and voltage limitation before being output and a constant current/voltage controller to get the electric power signal which has the current and voltage limited by the voltage/current limiting device. The electric power signal further is undergone constant voltage/current control to achieve voltage overshoot protection.

Electronic power protection circuit and applications thereof

A power adapter with voltage-stabilized compensation includes a pulse frequency modulation circuit to generate a driving pulse which has a variable OFF time interval to control power transformed and output by a transformer. The power adapter also has an ancillary coil to induce a feedback signal on the secondary coil of the transformer. The pulse frequency modulation circuit includes a time interval modulation unit to receive the feedback signal and a feedback compensation unit. The time interval modulation unit sets a level voltage compared with the feedback signal to generate a sample signal to modulate the OFF time interval. The feedback compensation unit provides a compensation signal to the time interval modulation unit to change the size of the feedback signal or sample signal thereby to compensate the voltage output from the secondary side.

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Shanghai, China

Rui-Xia Fei