CN-121979355-A - Low-temperature drift high PSRR band gap reference circuit

CN121979355ACN 121979355 ACN121979355 ACN 121979355ACN-121979355-A

Abstract

A low-temperature drift high PSRR band gap reference circuit belongs to the field of analog integrated circuits and comprises a positive temperature current generation circuit, a negative temperature current generation circuit, a sectional curvature temperature compensation circuit, a power supply rejection ratio PSRR enhancement circuit and a current-voltage conversion circuit. The positive temperature current generating circuit generates a current positively correlated with absolute temperature, the negative temperature current generating circuit generates a current negatively correlated with absolute temperature, the sectional curvature temperature compensating circuit generates a CTAT current in a low temperature region and a PTAT current in a high temperature region, the PSRR enhancing circuit increases the suppression of output reference voltage to power supply fluctuation, and the voltage converting circuit converts the superimposed current of the positive temperature coefficient current, the negative temperature coefficient current and the sectional compensation current into a target voltage. The invention realizes low impedance to ground by adding the low impedance loop and connecting with the band gap reference in parallel, ensures that the power supply fluctuation has small influence on the output reference voltage, and has simple structure.

Inventors

WANG ZIXUAN
WANG GUOHUA
XIE ZUSHUAI
LIANG YUE
WANG YANG
CAI ZHIKUANG

Assignees

南京邮电大学

Dates

Publication Date: 20260505
Application Date: 20260330

Claims (3)

1. The low-temperature drift high PSRR band gap reference circuit is characterized by comprising a positive temperature current generating circuit, a negative temperature current generating circuit, a zero temperature current generating circuit, a power supply rejection ratio PSRR enhancing circuit, a segmentation curvature compensating circuit and a current-voltage converting circuit; The PSRR enhancement circuit is used for improving the suppression of reference voltage VREF on power supply fluctuation, the positive temperature current generation circuit is used for generating current I PTAT positively related to absolute temperature, the negative temperature current generation circuit is used for generating currents I CTAT and I CTAT1 negatively related to absolute temperature, the zero temperature current generation circuit is used for generating current I ZTAT not related to absolute temperature, the current I ZTAT is obtained by adding the current I CTAT and the current I PTAT , the piecewise curvature compensation circuit is used for generating current I COMP used for compensating the current in a high temperature area and the current in a low temperature area, and the voltage conversion circuit is used for converting superimposed current of positive temperature coefficient current I PTAT , negative temperature coefficient current I CTAT and piecewise curvature compensation current, namely I COMP , into target voltage VREF.
2. The low-temperature drift high PSRR bandgap reference circuit of claim 1, wherein the PSRR enhancement circuit comprises PMOS transistors MP1, MP2, MP3 and MP4, NMOS transistors MN1, MN2, MN3, MN4 and MN5, wherein gates of MP1 and MP2 are connected with drains of MP1 and MN1, drains of MP2, MN2 and MN3 are connected with sources of MP3 and MP4, gates of MN1, MN2, MN4 and MN5 are connected with drains of MN5 and MP4, gates of MN3 are connected with drains of MP3 and MN4, sources of MN1, MN2, MN3, MN4 and MN5 are connected with ground GND, and sources of MP1 and MP2 are connected with a power supply VDD.
3. The low temperature drift high PSRR bandgap reference circuit of claim 1, wherein the piecewise curvature compensation circuit comprises PMOS transistors MP9, MP10, MP11, MP12, MP13, MP14, MP15, MP16, NMOS transistors MN6, MN7, MN8, MN9, wherein the gates of MP9, MP10 are connected with the drains of MP10, MP11, MN6, MP11, MP16 and V ZTAT , MP12, MP15 and V CTAT1 , the drains of MP12, MN7 are connected with the gates of MN6, MN7, the gates of MP13, MP14 are connected with the drains of MP14, MP15, MN8, the drains of MP16, MN9 are connected with the gates of MN8, MN9, the drains of MP9, MP13 are connected with one end of R5, R6, the sources of MP9, MP10, MP11, MP12, MP13, MP14, MP15, MP16 are connected with the drains of MN EG, and the sources of MN6, MN7, MN8, MN9 are connected with the ground GND.

Description

Low-temperature drift high PSRR band gap reference circuit Technical Field The invention relates to a low-temperature drift high PSRR band gap reference circuit, belonging to the field of analog integrated circuit design. Background In most analog and mixed signal circuitry, bandgap reference circuits used to generate a constant voltage reference are a very important component in a variety of circuitry. Since circuitry needs to operate in various environments, and the voltage output accuracy of the bandgap reference circuit determines the maximum achievable accuracy of the overall circuitry, the low temperature coefficient of the reference voltage and the output voltage are critical to ripple suppression of the power supply. The bandgap reference circuit is used as a power supply unit in a chip and is a basic module in an integrated circuit. The ideal band gap reference circuit can provide stable reference voltage which is not influenced by external factors such as process, power supply voltage, temperature and the like, and further supplies power for each circuit module of the chip. Conventional bandgap reference circuits typically superimpose a CTAT current formed from the base-emitter voltage of a BJT transistor and a PTAT current formed from the base-emitter voltage difference of two BJT transistors operating at different current densities and then replicate the superimposed current to the output path where resistor R3 is located, thereby forming a reference voltage that is insensitive to temperature. However, if we need a high precision reference source, there are many factors affecting the reference voltage precision, such as process parameter fluctuations, nonlinearities, bipolar transistor current gain variations, and power supply, amplifier offset and noise, etc., where the presence of nonlinear high order temperature terms and power supply fluctuations are the most dominant factors limiting the reference precision. The nonlinear high-order temperature term which cannot be offset by simply and linearly superposing the PTAT current and the CTAT current is only relied on, and a power supply for restraining power supply fluctuation is not added, so that great systematic output deviation is caused. In order to solve the problems of temperature drift and power supply fluctuation of the traditional band gap reference circuit and obtain more accurate reference voltage, the invention provides a band gap reference circuit with low-temperature drift and high PSRR. Disclosure of Invention The invention aims to provide a high-precision output band gap reference circuit with a simple structure and a low-temperature drift high power supply rejection ratio, which can obtain an extremely low temperature coefficient and reduce the influence of power supply fluctuation on output reference voltage. The main innovation point of the invention is that the total current is compensated by temperature curvature adjustment of the sectional curvature compensation current, so that the temperature characteristic of the finally obtained reference output voltage presents a low temperature coefficient characteristic, and a low impedance loop is provided, the impedance of VREG to the ground is reduced, and the suppression of the reference voltage to the power supply fluctuation is improved. The low-temperature drift high PSRR band gap reference circuit has simple structure and few branches, and reduces the power consumption of the whole circuit. A segmented curvature temperature compensated bandgap reference circuit. The device comprises a positive temperature current generating circuit, a negative temperature current generating circuit, a zero temperature coefficient current generating circuit, a piecewise curvature compensating circuit, a PSRR enhancing circuit and a current-voltage converting circuit. The PSRR enhancement circuit is added with one(Gmp 3 is the transconductance of the PMOS tube MP3, ro3 is the impedance of the PMOS tube MP3, gmn3 is the transconductance of the NMOS tube MN 3), a low-impedance loop is connected in parallel with a band gap reference circuit (namely, a negative temperature coefficient current generating circuit, a zero temperature coefficient current generating circuit, a current-to-voltage converting circuit and a piecewise curvature compensating circuit, which form a whole), so that the power supply rejection ratio of a reference voltage is improved, the positive temperature current generating circuit is used for generating a current I PTAT positively related to absolute temperature, the negative temperature current generating circuit is used for generating a current I CTAT negatively related to absolute temperature, the zero temperature current generating circuit is used for generating a current I ZTAT not related to absolute temperature, the zero temperature compensating circuit is used for generating I COMP for compensating higher-order temperature related components in the current, and stabil