Patent ID: 8907721

Claim:
An audio amplification circuit comprising: an amplifier having an input for receiving an input signal (Vin), an output, and a digital control input for receiving an n-bit thermometer code, where n is an integer greater than 1; a comparator having a first input coupled to the output of the amplifier in order to receive an image of a signal output from the amplifier, a second input receiving a reference potential, and an output; a thermometer counter, having a selection input coupled to the output of the comparator, and an output configured to deliver the n-bit thermometer code to the digital control input of the amplifier, the thermometer counter configured to start from an initial value in which all n-bits are a first binary value then at each count transition a bit changes from the first binary value to a second binary value, while all the other bits of the n-bits do not change value; and wherein the amplifier comprises a differential input stage having a first and a second differential branch each traversed by a bias current, with the current in the first branch being modifiable by n basic current sources, which each deliver either a basic current that is identical for all basic current sources, or no current, as a function of the binary value of one of the respective n-bits of the n-bit thermometer code received at the digital control input.