Design Of Bandgap Reference With Low Temperature Drift And High PSRR

The bandgap reference is an important basic module in analog circuits and is widely used in circuits such as linear regulators,switching power supplies,and high-precision comparators.With the development of lithography and other manufacturing technologies,the size of integrated circuits is decreasing.With the rapid development of integrated circuits,higher requirements are put forward for the performance of circuits.Conventional reference sources have high temperature drift and low power supply rejection ratio,and are no longer suitable for many circuits that require accuracy.Therefore,it has great significance for the research of low temperature drift and high power supply rejection ratio.Based on the working principle of the bandgap reference source at home and abroad,a bandgap reference source with low temperature drift and high power supply rejection ratio is designed.Firstly,the paper analyzes the development history of the reference source and the research progress at home and abroad.After that,several different reference source structures and principles are compared,and the performance indicators of the reference source are introduced.Finally,the bandgap reference source required in this paper is designed.In order to reduce the temperature drift coefficient of the reference source,the second-order curvature compensation technique is used to cancel the second-order term in the triode base emitter voltage V_BEE by using the characteristics of MOS transistors operating in the sub-threshold region.In order to increase the power supply rejection ratio of the reference source,a pre-regulated voltage negative feedback circuit is added to the reference source to suppress the fluctuation of the power supply voltage.Based on the 0.5?m process library simulation,the designed operational amplifier and reference source circuit are simulated and analyzed.The simulation results show that the open loop gain of the op amp is 103.7dB,the phase margin is 65.7°,the unity gain bandwidth is 21.5MHz,the power supply rejection ratio of the operational amplifier is 109.5dB,and the common mode rejection ratio is 68.1dB.The operational amplifier has excellent performance and can meet the requirements of the reference source.The reference source circuit has a temperature drift coefficient of 6.844ppm/°C in the temperature range of-50¹50°C,which is not much different under different process angles.The power supply rejection ratio is 96.44dB at low frequencies and still as high as 67.5dB at 1MHz,which has a good suppression of power supply fluctuations at different frequencies.The startup time of the circuit is20.94?s,and the effective area of the layout is 55*290?m².