家用声频功率放大器保护电路及其检修

家用功率放大器功放部份已相当成熟,基本上都是采用OCL电路作后级,十几年来没有多大的变化,但是功放的保护电路却呈现百家齐放的局面,各个厂家都推出自己的保护电路,并且还在不断的演化当中,保护电路的故障率仅次于未级功率放大,是故障率较高的部位之一。一般都有几个部份连结而成（例如直流保护、过载保护、开机延时保护等）,并且一般是直流耦合,牵一而动百,维修有一定难度,介绍几种较常见的保护电路以及它们的检修方法。

Protection Circuit of Home Audio Power Amplifier and Its Maintenance

The technology of household power amplifier is ripe. In the past ten years, although OCL circuit is generally used for the latter class, Amp protection circuit has many different choice. The failure rate of protection circuit is only lower than the latter class power amplifier, which is one of part problem in high failure rate. It is normally linked by several parts （for example, DC-protection, overload protection, startup delay protection）. This part generally is DC-coupled and difficult for maintenance. This article describes several common protection circuits, as well as their repair methods.