A Wide Input Voltage Range, Low Quiescent Current LDO Using Combination Structure of Bandgap and Error Amplifier

Abstract

This paper presents a wide input voltage range, low quiescent current low-dropout voltage (LDO) regulator. Featuring the NPN transistors in the BGR circuit operate as the differential input pair of operational trans conductance amplifier (OTA). Current mirror with $\beta$ helper structure and class AB output stage of OTA are introduced to improve the accuracy of entire circuit. The proposed LDO is simulated based on 400 nm BCD process. The simulation results shows that the proposed LDO regulator achieved 3.2$\mu$A quiescent current with the fixed output voltage 3. 3V. The BGR output voltage has a 186ppm$/^{\circ}$C temperature coefficient (TC) when temperature varies from - 55°C to 125°C. The proposed LDO has a line regulation of 11mV when input voltage varies from 4.3V to 24V and a load regulation of 12.8mV with load current range from 5$\mu$A to 50mA. The STB(stability) analysis result shows that the circuit provides a gain over 55dB with a gain-bandwidth (GBW) above 5kHz, and a phase margin (PM) over 45 degree with a load capacitor equal to 1$\mu$F for different load conditions.