Patent ID: 8344793

Claim:
A semiconductor circuit configured to generate a current proportional to a differential voltage comprising: a bias circuit configured to generate a first bias current based upon a resistance of a resistor, and wherein the bias circuit provides a first bias voltage based upon the first bias current; a differential pair circuit including a first leg corresponding to a first voltage input and having a first leg current, a second leg corresponding to a second voltage input and having a second leg current, and a current source, wherein the current source provides a second bias current to the differential pair circuit based upon the first bias voltage; a current subtractor circuit including an output diode load, wherein the current subtractor circuit is coupled to the second leg of the differential pair circuit and the bias circuit wherein the current subtractor circuit is configured to generate a load current in the output diode load substantially equal to the second leg current minus one-half of the second bias current; an output current source configured to minor the load current, wherein the output current source produces an output current that is proportional to a voltage difference between the second voltage input and the first voltage input.