Abstract: An auto-zero amplifier includes a main amplifier for amplifying an input signal; the main amplifier receives an offset-correction signal for cancelling an offset at a first common-mode level of the input signal. At the first common-mode level, the offset-correction signal is based on a first value stored using a first offset-storage element. When a change is detected in the input common-mode from the first level to a second level, the first offset-storage element is switched out and a second offset-storage element, having a second value based on the second common-mode level, is switched in.

Abstract: A multiple differential amplifier system and method for transconductance mismatch compensation which in a first phase connects to a differential switched input of a null amplifier, the differential signal input of the main amplifier, inverted, for compensating for offset errors and transconductance mismatches in the null amplifier; and storing in a null storage device connected to an auxiliary input of the null amplifier the output of the null amplifier representing the compensation for the offset error and transconductance mismatch of the null amplifier; and in a second phase connecting the differential switched input of the null amplifier to the differential feedback input of the main amplifier and storing in the main storage device connected to an auxiliary input of the main amplifier the output of the null amplifier representing the compensation for the main amplifier offset error and transconductance mismatch.