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

摘要

A differential amplifier circuit includes a differential operational amplifier that includes a differential pair circuit and operates based on a constant bias current supplied from a bias current source circuit, and the differential amplifier circuit includes a bias current generator circuit. A current monitor circuit detects two currents flowing through the differential pair circuit in correspondence with differential input voltages inputted to the differential pair circuit, and detects a minimum current of the two currents for a difference voltage of the differential input voltages as a monitored current. A current comparator circuit compares the monitored current with the constant bias current. A current amplifier circuit amplifies a voltage corresponding to the comparison result, and controls currents flowing through the differential pair circuit based on an amplified voltage, and the bias current generator circuit performs negative feedback adaptive control such that the bias current increases as the monitored current decreases.

主权项

1. 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.