Research And Implementation Of A Reference Voltage Source With Wide Input Range And High Precision

With the rapid development of electronic equipment,power management system has become an indispensable part of it.As a kind of analog integrated circuit integrating high voltage drive,logic control and precise output,wide input reference voltage source has a broad application prospect and a good development trend in high precision ADC and automotive electronics.The wide input high precision reference voltage source designed in this thesis focuses on the temperature coefficient,linear adjustment rate and load capacity of the output voltage,while taking into account the balance between the load adjustment rate,static power consumption and other parameters.This thesis first analyzes the working principle and implementation mechanism of the wide input voltage source circuit,and then from the circuit theory,focuses on the temperature coefficient and linear adjustment rate and other parameters of the influence factors are analyzed in detail,and finally based on the wide input high-precision reference voltage source input characteristics,temperature coefficient,linear adjustment rate and power suppression ratio and other parameters of the compromise relationship.A reference voltage source is designed to meet the requirements of wide input voltage range,low temperature coefficient and low linear adjustment rate.The wide input high-precision reference voltage source designed in this thesis firstly uses a current extraction pre-modulated module,which can not only suppress the influence of wide range of power supply voltage changes on the output voltage to improve the linear adjustment rate,but also has a good performance in anti-PVT characteristics,so as to stabilize the output 3V voltage for the low-voltage circuit in the rear stage.Secondly,in order to achieve good temperature coefficient performance,a new high-order curvature compensation module and an adaptive negative feedback loop are used in the low-voltage band-gap reference module,which not only eliminates the high-order curvature nonlinear term in the first-order temperature compensation current,but also improves the noise suppression performance.Finally,in the high-precision LDO module,in order to reduce the negative effects brought by the transient changes of load current,the overshoot and undershoot reduction module is used to suppress the overshoot and undershoot voltage,and the adaptive frequency compensation module is used to compensate the changes in the frequency of the zero and pole of the loop under different loads,so as to improve the stability of the output voltage,the load capacity and the transient response ability.Based on the SMIC180nm BCD process,a reference voltage source with wide input range and high precision was designed in this thesis,with a layout area of 0.3312 mm~2.The simulation results show that:the power supply voltage was in the range of 4.5V～35V,the temperature was in the range of-45℃～125℃,the output voltage was 2.5V,the temperature coefficient is 1.47ppm/℃,the line sensitivity was 1.87ppm/V,the power supply rejection ratio was-103d B@DC,-26.5d B@5MHz and the current consumption was 215.12μA.