Based on spinning-current and chopping technologies

a low noise

high precision readout circuit for Hall current sensor is researched and designed. On the basis of traditional single-channel with chopper-instrument amplifier

a high frequency path is added and improvement is carried out on structure of traditional low-pass filtering

introduce a ripple reduction loop

which realizes the cancellation of offset voltage and 1/f noise. Circuit simulation verification is conducted. By SMIC 0. 18 μm complementary metal oxide semiconductor（ CMOS）process. With the Spectre simulation

the whole circuit-3 dB bandwidth is up to 675 k Hz

the ripple rejection ratio is 65. 6 dB

the input-referred noise power spectral density（ PSD） is 21 n V/Hz

1/2

and

the common-mode rejection ratio（ CMRR） is 120 dB

which meets the requirements of high precision Hall current sensor readout circuit.