In order to minimize common mode noise, a differential amplifier circuit is good solution for single-shunt feedback. Also, offset voltage circuit needs to avoid operation in the noise area near the zero voltage even though the current being measured is unipolar during motoring mode. When using F28004x with built-in op-amp, sensing circuit can be configured only by using external R, C passive components like Figure 5-1. The output voltage of PGA can be calculated by using Equation 5.

Figure 5-2 shows a typical current sensing circuit that uses an external differential amplifier that has an offset reference voltage by resistor divider and voltage follower. Voffset and Vout can be calculated by using Equation 6 and Equation 7, respectively.