Linear current sensing circuit for motor controller

A circuit for recovering a signal of interest which is offset by a common mode displacement, such is the case when the signal is the voltage across a current sense resistor located on the high side bus or between the switches of a motor controller circuit. The circuit of the present invention converts the voltage across the resistor into a pulse code modulated data, then downshifts the voltage, and then recovers the signal of interest at the lower voltage by demodulating the signal. The recovered signal is then processed, either with a synchronized sample and hold circuit to provide an analog output, or with a counter and latch to provide a digital output.