Design Of High Precision Bandgap Voltage Reference Circuit With Over Temperature Protection

Bandgap reference voltage source is indispensable module in analog-to-digital converter,digital-to-analog converter,system-on-a-chip,low-dropout regulator and other common power management chip system.In recent years,with the rapid development of digital integrated circuit technology,some analog modules can be replaced by digital circuits,however,continuous signals and analog signals must be realized by analog integrated circuits.Because the accuracy of reference voltage will not be affected with the change of the temperature,power supply noise,load fluctuation and other external factors,it can provide high quality reference voltage in system and direct impact the performance of the system,so the optimization of voltage source is particularly important.High precision,low power consumption and low temperature drift of reference voltage has become the main direction of the current research.In order to limit temperature and power consumption of the chip,moderm electronic device chips usually contain over temperature protection module.When the circuit works are operated under extreme conditions for a long time,it will lead to increase current of chip,which directly leads to the change of the ambient temperature.Heat will continue to accumulate if cooling bad,leading to higher temperature of chip,it will directly cause internal circuit burned.chip temperature must be limited to protect chip.Firstly,this paper introduces the background,significance and the way to future development of bandgap reference voltage.The basic principle of bandgap reference voltage is analyzed in theory.Also traditional bandgap structures are analyzed and compared,including Kuijk,Widlar,Brokaw and Banba bandgap.Aiming at the shortcoming of high temperature coefficient,a piecewise curvature compensation structure is designed.The temperature curvature of reference voltage is compensated at low temperature and high temperature stage.Temperature coefficient of reference voltage is reduced to meet the design requirements.It' also considers the overall power consumption of the circuit,at the expense of less current consumption greatly improve the accuracy,enhancing the overall performance of the circuit.The basic principle of over temperature protection circuit is given.Aim at the poor stability of traditional over temperature protection circuit,temperature protection signal was produced by the current with different temperature coefficient to improve stability.Based on 0.18 ?mBCD process model and HSPICE simulation,the results show that power supply voltage varies from 2.5V?5V,bandgap reference voltage is 1.237V,line regulation rate(LNR)is 0.0357%.The power supply voltage is 5V,the Power Supply Rejection Ratio(PSRR)is 68.8dB,the static power consumption is 4.41 ?A,the temperature coefficient is 2.84ppm at-40?150?.The power supply voltage is 5V,the temperature rising and falling threshold were 150? and 136 ?,and the power supply voltage varies from 2.5?5V,hysteresis temperature fluctuation is 1.61? of the Over temperature protection circuit.The simulation results show that temperature coefficient of reference voltage is greatly reduced after curvature compensation and circuit has low working current.It shows excellent performance and meets the design requirements of low power consumption and low temperature drift.Over temperature protection circuit in the power supply voltage fluctuation,the temperature threshold and hysteresis quality with strong stability the.