Differential amplifier circuit with ultralow power consumption provided with adaptive bias current generator circuit

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.