Described is a current sensor comprising: a main resistive branch having a target device coupled to a load at a first node; a replica resistive branch having a replica device which is a replica of the target device, the replica device coupled to a current digital to analog converter (DAC) at a second node; and an analog to digital converter (ADC) coupled directly or indirectly to the first and second nodes, the ADC to generate an output coupled to the current DAC.