Patent ID: 7348910

Claim:
A reference module apparatus for a root mean square (rms) detector circuit, the apparatus comprising: a first differential pair circuit having first inputs coupled together so as to operate, when in use, in a common mode; a second differential pair circuit having second inputs coupled together so as to operate, when in use, in the common mode; a current feedback circuit comprising a first differential input coupled to a tail of the first differential pair circuit and a second differential input coupled to a second tail of the second differential pair circuit, the current feedback circuit being arranged to generate, when in use, a corrective current in response to a difference in voltages applied between the first and second differential inputs; wherein the first and second differential pair circuits are arranged so as to generate, when in use, an offset between a first tail voltage at the first tail and a second tail voltage at the second tail, the offset corresponding to a base current drawn by the second differential pair circuit; and a compensation current corresponding to the corrective current is applied, when in use, to the first inputs of the first differential pair circuit.