Design of Bandgap Voltage Reference Circuit with High-PSR and High-Accuracy

In order to reduce the influence of power supply voltage fluctuation on the secondary voltage control loop in the switching power supply, high-PSR, and high-precision bandgap reference was designed. In this design, the bias module uses a positive feedback circuit to improve the circuit start-up speed, and the reference voltage is designed to improve the power supply rejection ratio of the circuit by combining a bias circuit with a negative feedback form. The circuit was designed based on the 0.18μm 30V BCD process, and the design was simulated and verified by Cadence Virtuoso software. Under a 5V power supply, the reference temperature coefficient is 20.7ppm/°C, and the power supply rejection ratio is −110dB below 100Hz. The results show that the design of this paper conforms to the application environment of the secondary control loop.