Hello,
Can you provide some background on the thinking behind the current sensor circuits in the DRV8312 and related development kits? Specifically, the rail connection and the frequency-response-setting components. We have heard high praise for these little amplifiers and are trying to understand them better:
1. The cap that I believe is there to bring in the frequency response of the op amp to give it a pole in the neighborhood of 700 Hz is in a place whose purpose is not obvious, in the input arm with the input resistor that sets the current into the feedback loop, rather than parallel with the sensing resistor or the feedback resistor. It creates a near-in zero in addition to a far-out pole...could you give some insight into this? It is marked as optional, whereas the much larger cap that is in parallel with the sense resistor is not marked as optional, but with that really tiny sense resistor, the pole created by the larger input cap is still quite far out. What was the thinking behind the frequency response design for this little amplifier?
2. Can you provide some background on the 33 Ohm resistor on the power input, between the opamp rail input and the board rail?
Thanks!
Regards,
JS