93.8% Current Efficiency and 0.672 ns Transient Response Reconfigurable LDO for Wireless Sensor Network Systems

Current-efficient, fast-transient reconfigurable low-dropout regulator (LDO) is proposed for the wireless sensor network (WSN) system. The proposed LDO is designed and simulated in a 65 nm CMOS process showing the 3 key features: 1) a reconfigurable LDO architecture to achieve both low quiescent current (IQ) and wide bandwidth by adaptively adjusting to different load current conditions, 2) ultra-low-IQ and high PSR regulator for light-load efficient operation utilizing the gain boosting scheme within the flipped voltage follower loop, and 3) fast transient regulator for robust heavy-load operation with level-shifted impedance attenuation buffer (IAB) to reduce the supply ripples generated by wireless transceiver. The proposed LDO shows the state-of-the-art 93.8% current efficiency in the load condition of 1 μΑ, and achieves 0.672 ns response time even with 10 ns load transition.