The Design Of A Bandgap Voltage Reference

Voltage reference is the vital basic module which is widely adopted in analog circuits(mixedsignal circuits). It can supply a voltage with high precision and high stability. The powersupply, technics parameter and temperature has lesser effect to this voltage. Its temperaturestability and antinoise capability influence the precision and performance of the whole system.The purpose of this paper is to design a high precision bandgap voltage reference, which cansupply a steady voltage output for the charge pump of white LED.In this paper the present situation and developmental trend of voltage reference studiesboth at home and abroad will be presented. The performance index of voltage reference willbe introduced in detail, the principle and structure of bandgap voltage reference will beanalyzed, and then the different structure will be compared. By analyzing the power supplyrejection ratio(PSRR) and the principle of temperature compensation, the method ofimproveing the temperature characteristic will be summarized. The design of a bandgapvoltage reference circuit with high power supply rejection ratio and good temperaturecharacteristic is completed by applying curvature emendation, inside negative feedbacktechnology, RC filter, fast start-up circuit and out temperature protective circuit (OTP). At last,the circuits have been simulated with HSPICE simulation tools.The simulation results shows that, at the temperature range of -25℃to 110℃, thetemperature coefficient(TC) is about 8.7ppm/℃. In the frequency range of 100Hz to 10MHz,the average power supply rejection ratio is more than -100dB. At 125℃, the OTP have asignal to shut off the whole circuit. When temperature is lower than 115℃, the circuit willstart up again. This circuit has a Hysteresis Effect of 10℃.