Differential Current Sensing Inside H Bridge

A differential current sensing that is inserted inside a H bridge circuit. is shown in the schematic diagram below. This circuit is one example of AD8205 application. The AD8205 measures current in both directions as the motor changes direction and H-bridge switches.

This circuit has high accuracy in current measurement because AD8205 is placed in the middle of the H-bridge. Compared with a ground referenced op amp, this circuit is better, because ground is unstable reference voltage, so ground referenced op amp is inaccurate. [Circuit’s schematic diagram source: Analog Devices Application Note]