Active power factor correction circuit and control method for pulse width modulation signals

An active power factor correction circuit and a control method for pulse width modulation signals are provided. The active power factor correction circuit is coupled to a load and an AC power supply supplying power at an alternating period, and includes an inductor unit, a first rectifier, a change-over switch, a grounding end and a pulse width modulation controller. According to the control method, the change-over switch intermittently switches on and off the first rectifier and the grounding end in a phase modulation stage under the control of pulse width modulation signals output by the pulse width modulation controller so that the inductor unit is alternately excited and discharged, and the change-over switch continuously breaks the circuit between the first rectifier and the groundingend in a continuous open circuit stage. 种主动功率因数校正电路以及脉冲宽度调节信号的控制方法。主动功率因数校正电路耦接于负载与以交变周期供电的交流电源，并且包含电感单元、第整流器、切换开关、接地端以及脉冲宽度调节控制器。其中，控制方法主要是利用脉冲宽度调节控制器所输出的脉冲宽度调节信号控制切换开关在脉波调制阶段间歇性地导通与关断第整流器与接地端，进而使电感单元交替性地激磁与放电；并使切换开关在连续断路阶段