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4.保护电路(1)过流保护1)开机防浪涌电流保护:由于刚开机时,电源各电容均处于未充电状态,各控制电路也处于失控状态,因此会在开机时产生很大的浪涌电流,损坏整流全桥或电源开关管,故采取了两方面措施加以保护:一是在交流电源输入回路中串入了负温度系数的热敏电阻RT802。其保护原理是:刚开机时,由于RT802温度较低,阻值相对较大,能抑制大电流形成。当正常工作后,有持续电流通过,由于热效应,RT802阻值迅速下降,
4. Protection circuit (1) over-current protection 1) boot anti-inrush current protection: Just turned on, the power of the capacitors are in an uncharged state, the control circuit is also out of control, it will have a large boot Inrush current, damaged rectifier full-bridge or power switch tube, so take two measures to be protected: First, the AC power input circuit in series with negative temperature coefficient thermistor RT802. The protection principle is: just boot, due to the lower temperature RT802, the resistance is relatively large, can inhibit the formation of high-current. When normal work, there is continuous current through, due to thermal effects, RT802 rapid decline in resistance,