Research On High Temperature Resistant Chip For High Voltage Precision Voltage Reference Source

The voltage reference source is an indispensable circuit in analog integrated circuits.It has the characteristics of being less affected by temperature,power supply,process,etc.,and can provide a high-precision voltage reference for the system.It is widely used in integrated circuit chips such as analog-to-digital converter ADC,Temperature sensor,Power management chips and Phase-locked loops.In high temperature and high voltage applications,such as oil and gas survey systems,as the depth of the well deepens,the temperature becomes higher and higher,and the chip system needs to overcome the adverse effects of high temperature,so the stability of the voltage reference source is challenged.At present,the main high-temperature-resistant chip products rely on foreign imports.Therefore,the research on high-temperature and high-voltage chip products is of practical significance.Based on the 0.18?m CMOS high-temperature and high-voltage process,this paper studies and designs a voltage reference source chip that can work normally at 175 ?,and the power supply voltage is up to 45V,which can be integrated into various high-voltage power supply chip systems.The voltage reference source designed in this article consists of a bandgap reference source and a linear regulator.The bandgap reference source is used to provide a reference voltage that is not affected by temperature and power,and the size is 1.2V;the linear regulator is used to convert 1.2V.The reference voltage scales up and provides load current capability.This paper first analyzes the basic principles of the bandgap reference source,compares the advantages and disadvantages of various circuit structures,and gives its main performance indicators.Then the failure of the integrated circuit at high temperature is analyzed,the zero-temperature coefficient gate bias theory is applied to design the bandgap reference source circuit,and the temperature characteristic of the sub-threshold CMOS transistor is used to temperature compensate the bandgap reference source voltage at high temperature.Secondly,analyze the basic principle of the linear regulator as a buffer stage circuit,and give its important performance indicators.The designed buffer circuit scales the bandgap reference voltage and can provide up to 40mA load current.Then the load transient response is analyzed,and the overshoot voltage generated by the voltage reference source at the output terminal under high power supply voltage input is reduced.Using the Cadence Virtuoso analog IC design platform,the SPECTRE simulation environment is used for circuit design,layout design,and before and after simulation.The post-simulation results show that the temperature coefficient of the pre-stage high temperature bandgap reference voltage is 12.2ppm/? and the low frequency power rejection ratio is 93dB in the temperature range of-40??175? under the power supply of 45V.After adding the buffer stage circuit of the linear regulator,when the output of the reference voltage source is 10V,and the power input range is 10.8V?45V,the circuit can work normally,and the temperature coefficient and bandgap reference within the temperature range of-40??175? are consistent,which is 12.2ppm/?.The simulation results show that the circuit can work in a wide range of power input and has a low temperature coefficient in a wide range of temperature.