Design of a DC-DC Converter Customized for Ultra-Low Voltage Operating IoT Platforms

With remarkable advances in IoT, big data, and AI, the fourth industrial revolution is upon us. Low power design methodologies and techniques have been greatly contributing to these advancements by addressing the critical issue of how to increase the device service life under a fixed and limited energy source. In particular, ultra-low power (ULP) technology, which exploits ultra-low voltage (ULV) operating circuit, has recently emerged as a cutting-edge technology for realizing ULP devices. Although a number of studies on ULV circuits have been made so far, and the results have been very successful, research on DC-DC converters optimized for the ULV operation must be carried out in order to use them ultimately in ULP devices. In this paper, a DC-DC converter with low power, small area, and high-resolution digital pulse width modulator (DPWM) for ultra-low voltage (ULV) operating IoT platforms is presented. The proposed DPWM design uses a much smaller number of D flip-flops than conventional ones, achieving significant power saving and area reduction while showing excellent resolution of power conversion. In addition, by utilizing the proposed DPWM, the DC-DC converters can take full advantage of the dynamic switch width modulation technology without overhead, greatly improving the power conversion efficiency under ultra light load conditions. A prototype DC-DC converter with the proposed DPWM is fabricated in Samsung 65nm technology, and the experimental work with this converter and a target ULV operating platform demonstrates that this converter is best suited for the target platform.