I'm working on part of a project and I need to build the circuit that reads the current through a phase of a motor using this IC from Allegro.
Assuming there will be no more than 5A, and using a VCC=5V, the IC will output between [0.5;4.5]V.
We need this to be turned into 3.3V to enter some microcontroller.
The first OpAmp turns [0.5,4.5] into [-3.3,-0.3667] and the second one turns it into [0.3667,3.3].
I understand a buck converter would not be ideal here because it takes a bit to get into steady-state again and the purposes for which this will be used may need a faster transition.
But why not a voltage divider? Surely with the limited amount of current (aprox 10mA, max 14mA) coming out of the sensor, it wouldn't be wasting any considerable amount of power. Each phase of the motor has ~125W of nominal power.