Patent ID: 7209000

Claim:
An amplifier circuit having a circuit input and an circuit output, comprising: first and second amplifiers cascaded together, each having an input and an output, the circuit input being coupled to the input of the first amplifier and the circuit output being coupled to the output of the second amplifier; a first chopper having an input coupled to the circuit input and an output coupled to an input of a third amplifier, an output of the third amplifier being coupled to an input of a second chopper, the second chopper having an output coupled to a fourth amplifier coupled as an integrator with capacitor feedback, an output of the integrator being coupled to an input of a fifth amplifier or attenuator, an output of the fifth amplifier or attenuator being coupled to combine with the output of the first amplifier as the input coupled to the second amplifier; one or more first compensation capacitors coupled between the output of the second amplifier and the input of the second amplifier; one or more second compensation capacitors coupled between the output of the second amplifier and the input to the integrator; the amplifiers and capacitors being chosen to provide an amplifier circuit frequency response that is flat for low frequencies, and which rolls off at 6 dB per octave above the low frequencies.