[SOLVED] Current Mirror OTA closed loop

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Fabien

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I everyone,

I've designed a fully differential current mirror OTA. It seems to work in open loop, but when I close the loop, even with a 100Gohms resistor, the positive output reaches Vdd and the negative the gnd. The current seems to flow only in the positive input branch.
For more details you can see the simulations snapshot.
Anyway, the OTA is stable (PM > 70°), a switched capacitor CMFB is designed and seems to work (in open loop both outputs are vdd/2).

Thank you for your help or advice.
 

OK, I got the problem! I connected the loop to the opposit input and it's working!
The idea came out during the night
 

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