单端输出的运放为什么不需要共模反馈

wlb645858329

如题 谢谢

gadflybook

因为只有一个输出信号，也就无所谓共摸的概念了。(当然如果可以2个输入，你只接一个输出的除外）

AcoAco

回复 1# wlb645858329
Single ended OPAMP with feedback around  has both its output common mode voltage level and its signal voltage level is forced by feedback. Differential OPAMP with feedback around has its output signal amplitude is forced by feedback but not its common mode output level. Therefore for differential OPAMP we need another feedback loop to stabilize common mode voltage.

带反馈的单端OPAMP周围具有其输出端的共模电压电平，并通过反馈的信号的电压电平被强制。带反馈的差分运算放大器，缓冲放大器周围其输出信号的振幅被强制通过反馈而不是它的共模输出电平。因此，差分运放，我们需要另外一个反馈回路，以稳定的共模电压。