Replica-Based Low Drop-Out Voltage Regulator with Assistant Power Transistors for Digital VLSI Systems

An advanced replica-based low drop-out (LDO) voltage regulator with assistant power transistors and bulk modulation digital VLSI systems is proposed in this paper. It utilizes seven current comparators with different aspect sizes to control seven assistant power transistors to compensate for the load current. As a result, the load regulation of the replica LDO is significantly improved, while the wide-load-range-stability which is critical for digital systems is not compromised. The proposed LDO is designed in a standard 0.18-mm CMOS process. Extensive simulation results show that, with a power supply of 1.2 V and output voltage of 1.0 V, the proposed LDO has a dropout voltage of 200mV when delivering 1~100mA to the load. The load regulation is 0.148mV/mA, and the supported load capacitance range is from 0 to 100nF.