The Design And Realization Of High Performance Bandgap Reference Source

The bandgap voltage reference, which has been widely used in practical applications, is one of the most important cells in analog integrated circuits. This dissertation aims at designing a high performance bandgap voltage reference using the BiCMOS process, which combines the both advantages of the Bipolar process and the CMOS process.The dissertation presents a general introduction of domestic and aboard development on bandgap voltage reference studies first. The adopted BiCMOS process and the influence which should be taken into account on the modeling of BJT have been referred later. The low TC(Temperature-Coefficient) and high PSRR(Power-Supply-Rejection-Ratio) are said as the high performance of the bandgap voltage reference, they are also the main challenges of the design. When comparing several kinds of temperature-compensation theory, the dissertation presents a new temperature-compensation method based on a conventional first-order temperature-compensated bandgap voltage reference. After adding a preregulator, the PSRR is sharply increased. Finally the high performance bandgap voltage is realized using a standard BiCMOS process.The main contributes of this dissertation are as follows:1. A first-order temperature-compensated bandgap voltage reference has been realized based on the standard BiCMOS process. The NPN transistors have been adopted in this circuit, which exhibit better performance in contrast with the PNP transistors in the CMOS process. The circuit designed has lower TC and better driving capability comparing with conventional first-order temperature-compensated structures.2. To reduce the temperature coefficient, this dissertation presents a new high-order temperature-compensation method, which cancels the nonlinear effect on temperature of the base-emitter voltage(VBE) of BJT. Thus, a high-order temperature-compensated bandgap voltage reference is obtained.3. As the low PSRR of the bandgap voltage reference, a preregulator is designed to provide the bandgap voltage reference a pseudo-power supply which is hardly influenced by the power supply and has enough driving capability.4. Two kinds of operational amplifier have been designed due to the voltage multiplication and output buffering. The output 100mV/1.5V/2.5V also exhibit good performance on TC and driving capability.After the taping out, the bandgap voltage reference achieves good performance n testing. During the 5V supply voltage and 30p capacitor load, The reference voltages are precise whose error is around 2%. The TC(temperature Coefficient)is about 40ppm/℃in the temperature range 27℃-75℃. When the supply voltage takes change from 4.5-5.5V, The line regulation is about 15.2mV/V.