Patent ID: 8705773

Claim:
An audio amplifier comprising: a compensation unit configured to generate a compensation signal based on a digital input signal, a digital reference code, a mode signal and a digital approximation code; an output unit configured to generate an output signal based on the compensation signal; a calibration unit configured to generate the digital approximation code based on the output signal and the mode signal, the digital approximation code including a plurality of bits that are generated sequentially; wherein the calibration unit includes: a comparator configured to compare an analog reference signal with the output signal in response to the mode signal to generate a comparison signal; a successive approximation register configured to generate the bits of the digital approximation code sequentially from a most significant bit to a least significant bit based on the comparison signal; wherein the compensation unit includes: a register configured to store the digital approximation code as a compensation code in response to the mode signal, the mode signal indicating a calibration mode or a normal mode, and wherein the compensation unit generates the compensation signal based on the digital approximation code and the digital reference code in the calibration mode, and generates the compensation signal based on the compensation code and the digital input signal in the normal mode; wherein the compensation unit further includes: a first multiplexer configured to output one of the digital reference code and the digital input signal in response to the mode signal; a second multiplexer configured to output one of the digital approximation code and the compensation code in response to the mode signal; and a subtractor configured to generate the compensation signal by subtracting an output of the second multiplexer from an output of the first multiplexer.