高电源抑制比与低噪声带隙的基准源研究

Study on Bandgap Reference with High Power Rejection Ratio and Low Noise

针对传统带隙基准源受噪声、失调电压、温度系数影响大和电源抑制比(power supply rejection ratio,PSRR)低等问题,阐述一种具有高PSRR、低噪声的带隙基准电压源。通过采用在运放中加入斩波调制电路,利用其调制特性,滤除具有高频成分的噪声和失调电压,降低了电路中产生的噪声,采用PMOS共源共栅负载的NMOS共源共栅负反馈放大电路提高了电路的PSRR。电路使用HLMC28nm CMOS工艺实现,Spectre仿真结果表明,在3V电压下,基准输出电压为1.22V,低频时PSRR为-150db;在1 kHz频率下的输出噪声为165.6nV/Hz^(1/2)。

Aiming at the problems that the traditional bandgap reference is greatly affected by noise,offset voltage,temperature coefficient and low power supply rejection ratio(PSRR),this paper expounds a bandgap reference with high PSRR and low noise.By adding a chopper modulation circuit to the operational amplifier and using its modulation characteristics,the noise with high frequency components and offset voltage are filtered out,and the noise generated in the circuit is reduced.The PSRR of NMOS cascode negative feedback amplifier with PMOS cascode load is improved.The circuit is implemented using HLMC 28nm CMOS technology.The spectre simulation results show that the reference output voltage is 1.22V at 3V.PSRR is-150db at low frequency.The output noise at 1kHz frequency is 165.6nV/Hz^(1/2).