In order to estimate the effect of noise on differential capacitance measurement circuit and in response to the needs of high precision accelerometer

analyze on the influence of noise sources in charging/discharging differential capacitance measurement circuit

set up the circuit noise model and equivalent acceleration noise formula of circuit is obtained. By measuring current circuit

the relation between measurement time difference and acceleration difference in open loop state is achieved

the order of magnitude of acceleration noise in circuit is deduced. Calculation results show that with given parameters

order of magnitude of circuit noise is about 10

-6

gn.Noise of comparator will obviously affect the circuital noise performance

the common mode

parasitic capacitance and threshold of comparator will also affect the circuital noise performance.