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长虹TA两片机、TDA两片机开关电源都采用东芝X56P型(又称东芝Ⅱ型)开关电源电路,它是由分立元件组成的典型的自激振荡、脉冲频率调制(简称调频式)稳压、并联输出型开关电源电路(见图1)。并具有对市电适应范围宽(AC:120～260 V)、效率高(达80％以上)、安全性好(“冷”与“热”地隔离,机芯不带220 V市电)和通用性强(35～74 cm彩电均通用)等优点。因此它是我国目前彩电中应用最广泛的开关电源电路之—。一、看图解读要点 1.如何识别自激振荡电路?众所周知,开关电源电路实质上是以开关管为核心的LC间歇振荡电路(开关管交替地饱和导通与截止),因此要首先查找参与振荡有关电路,如:开关管及激磁绕组(激磁电感)、启动电路、正反馈绕组及正反馈耦合电路等。查找时以开关管(V806)为中心,向外看集电极与基极相连接
Changhong TA two-chip, TDA two-chip switching power supply are used Toshiba X56P type (also known as Toshiba Ⅱ type) switching power supply circuit, which is composed of discrete components of the typical self-oscillation, pulse frequency modulation Voltage, parallel output switching power supply circuit (see Figure 1). And has a wide range of mains adaptability (AC: 120 ~ 260 V), high efficiency (up to 80% or more), good safety (cold and heat isolation, the movement does not bring 220 V mains) Versatile (35 ~ 74 cm color TV are universal) and so on. Therefore, it is the most widely used in China’s color TV switching power supply circuit -. First, read the points to read 1. How to identify self-oscillation circuit? As we all know, the switching power supply circuit is essentially a switch LC as the core of the intermittent oscillation circuit (switch alternately saturated turn-on and turn-off), so to find the first participation Oscillation related circuits, such as: switch and excitation winding (excitation inductance), start-up circuit, positive feedback winding and positive feedback coupling circuit. Search to switch (V806) as the center, look out to connect the collector and base