High current efficiency and fast transient response reconfigurable low drop-out regulator for wireless sensor network systems

Abstract

A reconfigurable low-dropout regulator (LDO) is proposed to achieve high current efficiency and fast transient response simultaneously for a wireless sensor network (WSN) system. A single transistor-controlled flipped voltage follower (STC-FVF) based reconfigurable LDO architecture is newly introduced to satisfy stable operation for both sleep mode and transceiver mode. It proposes 1) a switching network which selects whether to activate the light load regulator (LL-regulator) or the heavy load regulator (HL-regulator) depending on the load current, 2) an LL-regulator with a gain boosting loop achieving 93.8% current efficiency, and 3) an HL-regulator with an adaptive level-shifting impedance attenuation buffer (IAB) achieving 0.672 ns transient response. The proposed LDO is implemented in the 65-nm CMOS process showing a power supply rejection (PSR) performance of -59 dB at 10 kHz, and -21 dB at 20 MHz for accurate sensing in sleep mode and stable wireless body area networks (WBAN) operation respectively