Design of a bandgap reference voltage source with low temperature coefficient and high precision

Abstract

This paper proposes a high-precision, low-temperature coefficient, and repair-free bandgap reference power supply circuit. This kind of bandgap reference source adopts the way of double-loop feedback, namely through two amplifiers to clamp the voltage to improve the performance of the circuit. The band gap reference source is mainly composed of four parts, including: band gap reference core circuit, amplifier, start-up circuit and Gaussian current compensation circuit. This article mainly analyzes the working principle of the core circuit of the bandgap reference, and derives the mathematical formula of the circuit. When the power supply voltage is 1.8V, the circuit is simulated in the temperature range of -40°C to 125°C with the Hspice software, and the reference source outputs stably. The voltage is 1.25V±4mv, the temperature coefficient is 3.7ppm/°C, and PSRR at low frequencies is -68dB.