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Zhi-Jian Fan

Yung-Hong Wang

Disclosed are a power factor correction circuit and a power adapter, and the power factor correction circuit includes a sampler, a controller and a current limiter, and the controller includes an error amplification unit, a peak value adjusting unit, an ON/OFF computing unit and a phase lock unit. The sampler is coupled to the phase lock unit, and the current limiter is coupled to the error amplification unit and the ON/OFF computing unit, so as to achieve the effects of enhancing the power factor property of the power factor correction circuit, lowering the manufacturing cost, and improving the electric power utilization.

Power factor correction control circuit and power adapter thereof

Disclosed are a pulse frequency modulation circuit and a power adapter. The pulse frequency modulation circuit includes a first multiplier, a second multiplier, a third multiplier, a divider and an adder sequentially and electrically connected to one another. The second multiplier includes an output terminal connected to an input terminal of the divider, a first input terminal, and a second input terminal connected to an input terminal circuit of the adder. To prevent the uncertain timing of the critical operating status of the time control circuit detected by the conventional zero-crossing detection method, the pulse frequency modulation circuit and power adapter adopt the pulse frequency modulation circuit for computation and output a control signal to control the OFF/ON time of a transistor in the power adapter, so as to control the timing of the operating status of the power adapter precisely.

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Shanghai, China

Zhi-Jian Fan