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UC3845的反馈回路

《请问一下TI工作人员,UC3845内部运放输出电流0.5mA是用电压源提供的还是电流源》

原文链接:http://www.deyisupport.com/question_answer/analog/power_management/f/24/t/64669.aspx?pi2132219853=2

TI员工Tom Li3回答:

如果采用你所给的含光耦的电路,那么UC3845内部的误差放大器其实是旁路掉的,在COMP端可以上拉一个电阻到VREF端。内部电流源为0.5mA,因此流过光耦副边的电流减去0.5mA就是流过上拉电阻的电流,由此可以得到COMP端的电压。

知识点:反馈回路是电路中很关键的,要保证稳压特性和瞬态响应,必须要考虑反馈回路的设计。长知识了!