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厦华、XT—7698T型74cm彩电,采用的保护电路除了常见的开关电源内设可控硅过压保护以外,其过流保护采用一种与众不同的控制方法。此保护电路并无新颖之处,但从其实用价值来讲,却具有非凡的保护效果,起到了使整机电路不致过度受损的独特作用。 1.开/关机电路及过流保护电路从图1可看出,由微处理器N34300(30)脚输出的开/关控制信号(高电平关机,低电子开机),控制着V801的导通与截止,继而切换+5V电压,为电源开/关机电路提供工作电压,此电压等同于触发电平。开/关机电路由V808、V809、V508及其外围电路构成。本
Xoceco, XT-7698T 74cm color TV, the protection circuit used in addition to the common switching power supply with SCR overvoltage protection, the overcurrent protection using a distinctive control method. This protection circuit is not novel, but in terms of its practical value, it has an extraordinary protective effect, played a unique role in the whole circuit will not be overly damaged. 1. On / off circuit and over-current protection circuit As can be seen from Figure 1, by the microprocessor N34300 (30) pin output on / off control signal (high power off, low electronic power), control the V801’s guide On and off, and then switch the +5 V voltage, the power on / off circuit to provide operating voltage, the voltage is equal to the trigger level. On / off circuit by the V808, V809, V508 and its peripheral circuits. this