Digitally assisted low dropout regulator design for low duty cycle IoT applications

This paper presents a digitally assisted low dropout (LDO) regulator with switched-bias current for internet-of-things (IoT) devices. The operation scenario and system requirements of the IoT devices are analyzed and discussed first. Then, a dedicated dynamic voltage scaling scheme for the very low duty cycle operation is introduced. Then, an LDO regulator with digitally controlled bias current is proposed, and designed in a 65nm CMOS process. In active mode, the quiescent current of the regulator is 28μA. And it is reduced to 45nA in sleep mode for the very low duty cycle applications. The simulation results show that the LDO regulator provides 11V/μs reference up-tracking capability, and -20dB worst case power supply ripple rejection across the full spectrum for both modes.