Design of self-referenced wide input voltage range LDO using enhanced current mirror buffer and improved lead compensation

Abstract

This letter presents the self-referenced architecture to simplify design process and current mirror based power stage with wide input voltage to expand the application range of low-dropout (LDO) regulator. Featuring a BiCMOS symmetrical operational transconductance amplifier (OTA) whose input and power supply are also the output of LDO, the LDO itself is a voltage reference as well as a voltage regulator. Improved phase lead compensation is applied with much smaller compensation capacitor, and enhanced current mirror (ECM) buffer is introduced. Experimental results of the proposed LDO in a 0.18 µm BCD process verified this self-referenced structure. The measured maximum input voltage is 12 V and the power supply rejection (PSR) is -40 dB at 50 KHz. The line regulation is 0.34 mV/V and total quiescent current is about 8.2 µA at light load.