Abstract: With the development trend of low power consumption and high integration of integrated circuits, the traditional under-voltage lockout circuit needs the external circuit to provide the bandgap reference voltage and bias currentand thecircuit structure is complicated. At the same time, when the under-voltage lockout occurs, the chip is turned off, the bandgap reference circuit should always work normally, which is not conducive to the reduction of chip power consumption. Aiming at the shortcomings of the traditional circuit structure, a triode-based under-voltage lockout circuit is designed. It does not require an external circuit to provide reference voltage and bias current. The circuit structure is simple and the response speed is fast. The threshold of the triode-based under-voltage lockout circuit is lessaffected by PVTand the power consumption is low. Based on the 0.18 μmBCD process, the simulation results show that when the power supply voltage drops, the circuit will shut down when the power supply voltage is less than 2.06 V, so as to avoid digital logic errors and device damagewhen the power supply voltage is too low. When the power supply voltage rises, the circuit restarts when the power supply voltage is greater than 2.38 V. In order to prevent the chip from flipping back and forth near the under-voltage lockout threshold, the under-voltage protection hysteresis is 320mV to prevent misoperation.The undervoltage locking threshold voltage accuracy is 1.36% in the temperature range from -40 ℃ to 85℃, , and the power consumption is only 22 μW.