一种高压高可靠性开关电源控制芯片

A high voltage high stability switching-mode controller chip

为了增强电源系统的可靠性,提出一种高压高可靠性开关电源控制芯片,该芯片引入一种新型的故障保护电路,通过同时监测误差放大器（EA）输出和峰值电流信号来检测过流和短路等故障.当EA输出电压超过4.2V或者峰值电压信号（由采样电阻得到）连续4个周期超过0.75V时,保护电路会及时切断控制器,保护变换器免受损害,同时降低了电路损耗.芯片还集成了软启动、限流保护、过压欠压保护和脉宽调制/跳脉冲调制（PWM/PSM）模式切换电路,该芯片采用CSMC 0.5μm 60VBCD工艺进行设计,已经成功流片.将该芯片应用于反激式转换器中,转换器可以将34~60V的输入电压转化成5V输出.测试表明：当故障发生时,控制芯片能够迅速切断控制器以保护整个转换器,而当故障消除后该控制器仍然可以自行重新启动;反激转换器最大输出电流为2.6A,静态电流小于1mA,最大效率为83.5%,线性调整率和负载调整率分别为0.02%/V和0.03%/A,具有良好的瞬态响应能力.

A switching-mode controller chip was proposed to enhance the reliability of power system.This chip introduces a novel fault protection circuit,which monitoring both error amplifier＇s（EA＇s）output and peak current to detect the fault such as over-current and short-circuit.If EA＇s output is larger than 4.2V or the peak voltage（generated by sampling resistor）surpasses 0.75Vin 4cycles,the protection circuit will shut down the controller to protect the converter from damage,which also saves the power.The chip integrates circuits of soft-start,current-limit,under-voltage and over-voltage protection and pulse width modulation/pulse skipping modulation（PWM/PSM）mode switching.This chip was implemented in CSMC 0.5μm 60VBCD process and was applied in a flyback converter which deliverd an output of 5V with input voltage ranging from 34-60V.Measurement results show that this controller chip can shut down the controller as soon as the fault occurs,protecting the converter from damage.The controller can self-restart when the fault is removed.The converter has a maximum load ability of 2.6Awhile its quiescent current is no more than 1mA.The maximum power efficiency is 83.5%.The line regulation and load regulation is only 0.02%/V and 0.03%/A respectively.The converter also presents an outstanding transient performance.