I'm in the process of designing an electronic load for testing batteries. The goal is to control the load current in the range of 0 - 10 A with a 0 - 1.2 V signal from a DAC.
For easy calculations and usage of common values of resistors, a 12 mΩ shunt was chosen. The problem is that in the current configuration, a large overshoot/undershoot occurs when the input is driven with a square wave.
If I reduce the gain of the current sense amplifier from 10 to 2, or decrease the value of the shunt, the problem disappears. I would prefer not to do that, because then I would have to use lower voltage control signal, which is not ideal.
Is it possible to stabilize this circuit, while preserving the current sense gain of 10 and shunt value of 12 mΩ?
I've attached a schematic and a sample waveform below. The blue trace represents control voltage, the green trace represents current.