Power Management in Low-Power MCUs for Energy IoT Applications

In this paper, we identify and address the problems of designing effective power management schemes in low-power MCU design. Firstly, this paper proposes an application-based multipower domain architecture along with a variety of working modes to effectively realize the hierarchical control of power consumption. Furthermore, devices in energy IoT (eIoT) do not always work under the main power supply. When the main power supply is unavailable, the standby power supply (usually the battery) needs to maintain the operation and save the data. In order to ensure the complete isolation between these two power sources, it is always necessary to insert a diode in both select-conduction paths, respectively. In this paper, we built a stable and smooth power switching circuit into the chip, which can effectively avoid the diode voltage loss and reduce the BoM cost. In addition, in the sleep mode, considering the relaxed output voltage range and a limited driving capability requirement, an ultra-low-power standby power circuit is proposed, which can autonomously replace the internal LDO when in sleep, further reducing the sleep power consumption under the main power supply. Fabricated in a standard 0.11 mu m CMOS process, our comparative analysis demonstrates substantial reduction in power consumption from 1 mu A to 0.1 mu A.