The Desgin Of High Precision Curvature Corrected Bandgap Voltage Reference

As the scale of integrated circuits (IC), the voltage reference is widely used in power management chips, data converters, etc. The performance of the chips above is directly related to the accuracy of the voltage reference. With the constant development of the electronic technology, the industry calls for higher performance of the integrated circuits. As a key block of the integrated circuit, the design of the voltage reference is very important. Given the above, the design of the high precision bandgap voltage reference (BGR) is studied in this paper. The research is aimed to design a voltage reference with low temperature coefficient (TC) and high power supply rejection ratio (PSRR).In this paper, the basic topology and operational principle of the BGR is firstly discussed. Based on the previous research, the high order temperature compensation and PSRR optimization techniques are studied and compared. Finally, a high order BGR with a mixed output stage is designed. Piecewise linear compensation technology is acquired to trim the high order temperature components of the reference voltage accurately, thus the TC of voltage reference is reduced effectively. In order to increase the PSRR of the BGR, pseudo power supply technique is adopted to pre-regulate the power supply of the BGR and it can provide a stable supply for the other blocks at the same time, which upgrades the performance of the whole chip.Based on a 0.5 um BiCMOS process and the Hspice simulation bench, the validation of the BGR designed is conducted. The TC of the BGR is 14.28ppm/℃ before the piecewise linear compensation, while is 0.43ppm/℃ after the compensation. Before the pre-regulation, the PSRR of the BGR is -75.5dB and the line regulation rate is 198.5uV/V, while the values are -97.7dB and 9.2uV/V respectively after pre-regulation. The result shows that, the precision of the BGR is upgraded obviously. The circuits designed for high order temperature compensation and pre-regulation are of great flexibility and portability.