ADAPTIVE OPERATIONAL AMPLIFIER BIAS CURRENT

摘要

An operation amplifier (op amp) having a bias current detection circuit that monitors the bias current flowing in an output stage of the op amp. When the bias current detection circuit detects that too much current is being wasted, e.g., sunk to ground, then the amount of bias current is reduced. Similarly, when the bias current detection circuit detects that insufficient bias current is being supplied to the output stage of the op amp, the amount of bias current is increased. In one implementation, the output of the bias current detection circuit may be signals indicative of, respectively, too much bias current and too little bias current, wherein those outputs are supplied to a state machine which is configured to control the amount of bias current being supplied in a stepwise fashion.

主权项

1. An operational amplifier circuit, comprising:
an input stage having at least one input node to receive an input signal; a bias current generator configured to generate a bias current; an output stage having at least one output node configured to output a signal responsive to the input signal input at the at least one input node and configured to receive the bias current from the bias current generator; and a bias current detection circuit configured to detect a comparison result of an amount of the bias current flowing in the output stage and a predetermined threshold and to control the bias current generator to generate the amount of bias current being supplied to the output stage in accordance to the comparison result.