对A3型开关电源工作原理的一点讨论

Some Discussion on the Mechanism of the A3 Switch Power Supply

日本三洋公司A3型彩色电视机开关电源,关于其工作原理的争论比较多,对电路的分析也不尽相同。本文通过对A3型开关电源电路原理的分析和通过实验所观测到的现象以及所测得的数据,详细阐述了电路中振荡部分和稳压部分的工作原理,对其中有争议的某些元器件的工作过程,以及它们在电路中的作用提出了自己的观点和看法。着重阐述了三极管V512工作在开关状态,以及它在稳压过程和开关管振荡时的作用。同时,对该电源中真正的定时元件C515、R526、R517等元件作了重点的测试和说明。

The oscillating curcuit of a switch power supply is the core, while the understanding of the timing elements in this part is the key to the recognition of the mechanism of the switch power supply. There have been a lot of disputes about the circuit analysis of A3 switch power supply in the color TV sets made by Sanyo Company. The mechanism of oscillating part and voltage stabilizing part in the power supply are discussed based on the theoretical analysis and experiment. And some personal ideas about the mechanism and function of some elements in the related circuit are also put forward.