[SOLVED] Current Source with Op-Amp

[JZJIANG]

Hi, suppose we break the loop at the non-inverting input of the opamp, we can see the opamp contributes 180 phase shifting and the power transistor contribute 180 phase shifting, hence, in my opinion, it is a positive loop.

 

[FvM]

In the present circuit, the power transistor operates as a noninverting source follower.

 

[JZJIANG]

The power transistor is NMOS, is it?

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I know where I am wrong, I mistake the NMOS as PMOS, thank you for your explanation, BTW, could you help me with this question?
https://www.edaboard.com/threads/283387/