This disclosure describes a chopper stabilized instrumentation amplifier.
The amplifier is configured to achieve stable measurements at low
frequency with very low power consumption. The instrumentation amplifier
uses a differential architecture and a mixer amplifier to substantially
eliminate noise and offset from an output signal produced by the
amplifier. Dynamic limitations, i.e., glitching, that result from chopper
stabilization at low power are substantially eliminated through a
combination of chopping at low impedance nodes within the mixer amplifier
and feedback. The signal path of the amplifier operates as a continuous
time system, providing minimal aliasing of noise or external signals
entering the signal pathway at the chop frequency or its harmonics. The
amplifier can be used in a low power system, such as an implantable
medical device, to provide a stable, low-noise output signal.