A power control circuit includes a primary auxiliary winding, a startup module, a power control module, a rectifier module, and a clamping module. The primary auxiliary winding is configured to induce a voltage provided by a power circuit to generate an induced voltage. The startup module is configured to provide a startup voltage. The power control module is connected to the startup module and configured to output a control signal which controls the power circuit to supply power when the startup voltage input to the power control module is less than an upper threshold voltage. The rectifier module is connected to the primary auxiliary winding and configured to rectify the induced voltage generated by the primary auxiliary winding. The clamping module is connected between the rectifier module and the startup module is configured to clamp the induced voltage under the upper threshold voltage.

通过电源控制模块供电电路控制电源控制模块输出一定频率的驱动脉冲来实现电源电路的正常工作。然而，在电源电路中若交流电压源出现突然变化或电源电路的负载突然增加等情况时，电源控制模块供电电路的初级辅助绕组所感应产生的电压在半波整流二极管处会有尖峰产生，而若输入到电源控制模块供电电路的电源控制模块中的尖峰电压超过电源控制模块的上限阈值电压时，则电源控制模块处于过压保护状态而关闭，从而使得电源电路停止工作。