Hello, I need to create a high voltage, extremely accurate current mirror. I tried to make this circuit with analog circuitry and opamps but I get oscillations that I can not manage to quell and I don’t feel too comfortable floating a 16v opamp up to near 200v to act as a high side current mirror either, at least not as a long term solution.
This is what I had in mind.
Basically the M2 circuit is doing its own thing and I need M1 to replicate the DC current conditions of M2 as accurately as possible.
How accurate? Well the opamp I was using is accurate down to 1uv. This is even more an issue now that I’m using the feedback device on the low-side instead of high-side like I was before so now I have the accuracy of R6 7 8 and 9 to deal with.
Actually on that topic, I was wondering if some sort of auto calibration could be done to eliminate the error of those resistors. Even a small misreading will generate significant DC error at M1, even without those voltage dropping resistors in the way.
How feasible is this and what would be required?
Thanks in advance, I really need this circuit to work.