Patent ID: 8896378

Claim:
A differential amplifier circuit comprising a differential operational amplifier that includes a differential pair circuit to which differential input voltages are inputted and operates on the basis of a constant bias current supplied from a bias current source circuit, the differential amplifier circuit comprising a bias current generator circuit, wherein the bias current generator circuit comprises: a current monitor circuit configured to detect two currents flowing through the differential pair circuit in correspondence with differential input voltages inputted to the differential pair circuit, and detect a minimum current of the two currents with respect to a difference voltage of the differential input voltages as a monitored current; a current comparator circuit configured to compare the monitored current with the constant bias current supplied from the bias current source circuit, and output a voltage signal corresponding to a comparison result; and a current amplifier circuit configured to amplify and control the current flowing through the differential pair circuit based on the voltage signal corresponding to the comparison result, and wherein the bias current generator circuit performs negative feedback adaptive control such that the bias current flowing through the differential pair circuit increases as the monitored current decreases.