A readout circuit based on chopping modulation and correlated double sampling

摘要

The present invention discloses a readout circuit based on chopping modulation and correlated double sampling, comprising a chopper, wherein an output terminal of the chopper is sequentially connected in series with a preamplifier, a GmC low-pass filter, a correlated double sampling unit and a low pass filter; a signal is modulated to a high frequency by the chopper, and further amplified by the preamplifier, then enters the GmC low-pass filter to output a differential sinusoidal signal at a chopping frequency, passes through the correlated double sampling unit so that the flicker noise introduced by preamplifier is cancelled while the offset noise introduced by the chopper is also eliminated, and finally passes through the low pass filter to be filtered out. The present invention provides a sufficient gain to amplify a voltage signal output by a sensor, and can suppress noise, mainly suppressing the flicker noise.