Patent ID: 8139792

Claim:
A method of starting an amplifier circuit having an input stage and an output stage, the output stage having an output for driving a load, the input stage having a signal input for receiving a signal to be amplified and a feedback input connected to receive a feedback signal via a feedback path from the output of the output stage, the amplifier further comprising a biasing circuit for applying a bias signal to said feedback input at an appropriate level appropriate to establish a quiescent output voltage different from a ground reference level of the input stage, the method comprising the following steps in sequence: (a) with the output stage disabled, pre-charging the amplifier output over a period of time to a voltage corresponding to the ground reference level of the input stage; (b) with the biasing circuit effectively disabled and a zero input signal at said signal input, enabling the output stage; (c) activating said biasing circuit progressively so as to ramp said bias signal to said appropriate level over a further period of time, thereby driving the output progressively to said quiescent output voltage.