The Design Of High Precision Bandgap Reference

With the development of the semiconductor industry,integrated circuit is used in people's production and life.At the same time,with the advancement of technology,people's requirements for the performance of integrated circuits are getting higher and higher.The bandgap reference(BGR)as a module with providing a high-precision voltage,its performance directly affects the performance of the entire circuit system.Therefore,studying high-performance BGR is of great important.In this paper,a high-precision bandgap reference(BGR)with low temperature coefficient is introduced.First of all,the electrical characteristics,its principle and classical circuit structure of the BGR is presented.And this paper analyzes the high-order temperature compensation method.For the error factors affecting the bandgap reference,this paper designs special circuit to reduce the error.This circuit is designed based on CSMC 0.25?m 30V~60V BCD process in this paper.In order to achieve different output voltages of 2.5V,3.3V,4.096 V and 5V,this paper uses the Brokaw structure.The accuracy of the output voltage is improved by using voltage trimming circuit.For getting a lower temperature coefficient,this circuit uses temperature trim circuit to reduce the temperature coefficient and achieve the design requirements.This circuit is simulated by HSPICE based on CSMC 0.25?m 30V~60V BCD process.By simulating,as is shown that the bandgap reference circuit designed in this paper can provide four reference voltages of 2.5V,3.3V,4.096 V and 5V at room temperature(T=25 °C),and its accuracy error is 0.028%.,0.016%,0.024% and 0.028%,both lower than the required 0.06%.Its temperature coefficients at different output voltages are 5.5 ppm/°C,4.2ppm/°C,4.7ppm/°C,and 4.4ppm/°C,respectively,with the temperature range of-55°C to 125°C.At low frequency(below 100 Hz),the reference's loop gain is 60 dB,which ensures circuit to work steadily.The BGR's PSRR is around-100 dB at low frequency.When the power voltage varies within a specified voltage variation range,the circuit's line regulation is 2.25ppm/V,0.87ppm/V,0.72ppm/V,and 0.39ppm/V respectively.When the supply power varies fast,the startup time is 39.6?s,56.6?s,84?s and 100?s respectively.When the power varies slowly,the startup time is 817?s,481?s,556?s and 424?s respectively.When the load current varies from-0.6mA~0 and 0~10mA,the changes of output voltage are 50?A and 40?A,respectively.Finally,according to the layout design rules of integrated circuits,the layout design of the bandgap reference is designed.