A 2×VDD-enabled fully-integrated low-dropout regulator with fast transient response

This paper presents a 2×VDD-enabled fully-integrated CMOS low-dropout (LDO) regulator with fast transient response for cost-effective SoC power management applications with elevated-VDD supply. All the MOS transistors used in the proposed LDO regulator are low voltage (LV) MOSFETs, hence saving the high-voltage devices fabrication cost required in a conventional design. Two LV power transistors are cascaded in the power train. A mid-rail regulator is used to generate 1×Vdd voltage for the power transistors as well as the main error amplifier to guarantee safe operation. The mid-rail regulator employs stacking transistors to handle the high supply voltage. Moreover, miller compensation with adaptive biasing is used to achieve good stability and fast transient response. A proof-of-concept design is fabricated in a standard 0.18-μm CMOS process which achieves 3.3~3.6V nominal input, 3.1V nominal output and 100mA loading capability with all the transistors being 1.8V MOSFETs.