US Patent 7915951 Locally calibrated current source

A microchip that can calibrate a plurality of circuits on the microchip with a current reference includes: at least a first circuit disposed on the microchip; at least a first local bias generation circuit, for generating a bias current that is input to the first circuit; an external current reference, coupled to the first local bias generation circuit, for updating the bias current; and a calibration logic, coupled to the first local bias generation circuit, for enabling the external current reference to update the bias current according to a valid calibration signal.