Hi All,
I have a problem with an unstable design that I have tried. See the attacehd file for the schematic. The part number of the op-amp is ADA4691.
Now, I want to have stable current going through the R17 resistor. The current value is adjusted using C3 input of the op-amp between 0 and 3.3V which gives between 0mA and ~160mA.
Now, the problem is that this circuit is unstable.
In my understanding, it is unstable because the Vsense amplifier is 45times slower than the op-amp driving the NPN transistor. Am I correct?
The other question, is what would be the best way to make such a circuit stable?
I have a problem with an unstable design that I have tried. See the attacehd file for the schematic. The part number of the op-amp is ADA4691.
Now, I want to have stable current going through the R17 resistor. The current value is adjusted using C3 input of the op-amp between 0 and 3.3V which gives between 0mA and ~160mA.
Now, the problem is that this circuit is unstable.
In my understanding, it is unstable because the Vsense amplifier is 45times slower than the op-amp driving the NPN transistor. Am I correct?
The other question, is what would be the best way to make such a circuit stable?
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