Patent ID: 8289064

Claim:
A differential offset calibration circuit, adapted to an adaptive filter, the adaptive filter having an input stage and an output stage, the output stage being coupled to the input stage and having a first output terminal and a second output terminal, and the differential offset calibration circuit comprising: a first controllable current source, coupled between a voltage source and the first output terminal; a second controllable current source, coupled between the first output terminal and a ground terminal; a third controllable current source, coupled between the voltage source and the second output terminal; and a fourth controllable current source, coupled between the second output terminal and the ground terminal, wherein when the first controllable current source and the fourth controllable current source are enabled, the second controllable current source and the third controllable current source are disabled, and when the second controllable current source and the third controllable current source are enabled, the first controllable current source and the fourth controllable current source are disabled.