图中电流镜偏置电路，不考虑体效应，问流过电阻R的电流是多少？大神稍微说明解释一下。
作者: wfcawy 时间: 2013-10-22 09:05
when the circuit achieve stable state, the current passing the resistor R is 20uA.
at the initial state, Pmos mirror sources40uA, while the Nmos mirror can only sink 20uA, so there is a net sourcing 20uA current charging to the parasitic capacitors of P/Nmos drain region. finally, the voltage on the upper node of the resistor raises, and push the PMOS to the linear region a bit, and make the sourcing ability weaker till 20uA, and then the balance is achieved.作者: kwankwaner 时间: 2013-10-22 09:23 回复 2#wfcawy
“at the initial state, Pmos mirror sources40uA, while the Nmos mirror can only sink 20uA” 有什么根据吗作者: 薛定谔的太极拳 时间: 2013-10-22 09:39 回复 2#wfcawy
红线为最右NMOS漏电流，黄线为最右PMOS源电流。
作者: 344567112 时间: 2013-10-22 10:18 回复 1#薛定谔的太极拳
没电源大小，没R大小，怎么求，最高20μA，也可能低于。作者: wfcawy 时间: 2013-10-22 11:02
it is an assumption, and it shows the conflict of the design.
A transient simulation can catch everything with the consideration of all the parasitic.
But the final conclusion will not change.作者: semico_ljj 时间: 2013-10-22 13:17
只可能20uA多一点 而且 PMOS处于线性区作者: jiang_shuguo 时间: 2013-10-22 14:30
很老的一个笔试题目了。作者: 薛定谔的太极拳 时间: 2013-10-22 18:15 回复 6#344567112