Patent ID: 7586368

Claim:
A chopper-stabilized amplifier comprising: (a) a first amplifier, (b) input chopper circuitry coupled to an input of the amplifier for chopping an input signal and applying the chopped input signal to the input of the first amplifier; (c) output chopper circuitry coupled to an output of the first amplifier for chopping an output signal produced by the first amplifier, the first input chopper circuitry and the output chopper circuitry being clocked by a first clock signal; (d) first and second compensation capacitors each having a first terminal coupled to an output of the chopper-stabilized amplifier; (e) switched capacitor notch filter circuitry having an input coupled to an output of the output chopper circuitry and performing an integrate and transfer function on a chopped output signal produced on a first output of the output chopper circuitry by operating synchronously with a chopping frequency of the first clock signal to notch-filter noise signals on the chopped output signal, the first switched capacitor notch filter being clocked by a second clock signal, the switched capacitor notch filter circuitry further including (1) a first switch for coupling a second terminal of the first compensation capacitor to the first output of the output chopper circuitry in response to the second clock signal and a second switch for coupling the second terminal of the first compensation capacitor to a first input of a second amplifier in response to a third clock signal which is out of phase with the second clock signal, and (2) a third switch for coupling a second terminal of the second compensation capacitor to the first output of the output chopper circuitry in response to the third clock signal and a fourth switch for coupling the second terminal of the second compensation capacitor to the first input of the second amplifier in response to the second clock signal; and (f) the output of the chopper-stabilized amplifier being coupled to an output of the second amplifier.