A 257-nA quiescent current 200-mA load low-dropout regulator with reference sampling technique and loop reconfigurable technique

This paper proposes an ultra-low quiescent current low-dropout regulator (LDO) for Internet-of-Things and portable devices. To reduce power consumption in the reference, the conventional continuous-on reference is replaced by intermittent-on reference, and using switching capacitors to store reference voltage, which called reference sampling technique (RST). Meanwhile, to decrease the quiescent current in LDO main loop, the loop reconfigurable technique (LRT) is implemented. When the LDO with no load, the main loop is two-stage structure with small power transistor, which results in low quiescent current. When a heavy load is added, the main loop is changed into a three-stage structure with large power transistor. A prototype chip is fabricated in 0.35 μm CMOS process, occupying 0.6 mm² area and consumes 257 nA quiescent current. Furthermore, owing to the transient enhance circuit, when the load current jumps from 0 mA to 200 mA within 1 μS, the output settling time is about 10 μS, with an undershoot voltage of 160 mV.