An Input-Independent Loop Type-III Buck Converter With PSRR Improvement and EMI Suppression for Enhancing the Security of Edge Devices

Abstract

This letter proposes an input-independent loop type-III buck converter (ILT3C) enhancing the security of edge devices. Compared to a conventional type-III buck converter, the ILT3C maximally improves power-supply rejection ratio as much as 34.1 dB to be robust against power injection attack. It also reduces the peak of electromagnetic interference as much as 35.8 dB <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> V to enhance the security from power side-channel attack. Furthermore, the external components such as an inductor and a capacitor of the converter should be integrated into a package to minimize its exposure to unknown hacking risks. Thus, the proposed converter operates with a high switching frequency ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">sw</sub> ) of 20 MHz and it can reduce the size of the external components enough to be placed in the package. The prototype converter was implemented in a 0.18- <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">μ</i> m CMOS process. This ILT3C achieves the maximum efficiency of 90.7% and occupies an active area of 0.195 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> .