Abstract: Based on the requirement of the preamplifier for the high stability of power supply voltage references, a three-branch reference circuit structure with simple structure, insensitive temperature and relatively high voltage stability was designed. A temperature-insensitive current is generated by Proportional (PTAT) and Complementary (CTAT) to Absolute Temperature, and a negative feedback loop created by the voltage gain generated by the third branch is used to improve the stability of the circuit by reducing the effect of supply voltage fluctuations on the output current. The simulation results show that when the power supply voltage is 5 V, the temperature coefficient is low at −25 - 145 °C. In the range of 0 - 14.5 kHz, the Power Supply Rejection Ratio (PSRR) is about −80 dB. The overall quiescent current is only 20 μA. This topology is very effective in designing the rejection ratio of the low-temperature drift power supply, and can provide stable operating current for the preamplifier.