A Single-inductor Triple-output Buck DC-DC Converter with Electromagnetic Gated Low Dropouts for Higher Resistance to Electromagnetic and Power Side-Channel Attacks with 3B Minimum Traces to Disclosure Improvement in Internet of Things Applications

Electronics in Internet of Things (IoTs) not only need high efficiency and compact size but also require high security ability to protect personal information. In the advanced encryption system (AES) engines of IoTs, side channel attack (SCA) can crack its secret keys through power consumption and electromagnetic (EM) energy leaked signature in the power chip. Therefore, the latest technologies focus on how to improve Minimum Traces to Disclosure (MTD) through the design of power converters to achieve high security. Digital low dropout (DLDO) regulator in [1] adds a fixed voltage and a random voltage to generate a random reference voltage to ensure the random power current at the cost of large output voltage ripple. A dummy loading in [2] is in parallel to the load to keep constant input current. Unfortunately, large power loss caused by the dropout voltage $( \mathrm{V}_{supply}- \mathrm{V}_{AES})$ and the leakage current $\mathrm{I}_{bleed}$ will reduce the efficiency in the top left of Fig. 1, although the EM leaked signature protection can be improved by different metal layers in the layout in [2]. Instead of LDOs, integrated switching regulators in [3–4] have a random switching frequency to disturb the input power where [3] uses a random delay generator and [4] utilizes a true random number generator (TRNG). It is difficult to crack its secret keys through the power signature but the EM leaked signature easily reveals the information since the inductor is off-chip (top right of Fig. 1). A well-designed power management (PM) has multiple outputs regulated by multiple single-inductor single-output (SISO) converters. Although inductor-based PM has high efficiency, obvious disadvantages include large-size indicators and EM leakage from inductors $\mathrm{L}_{1}- \mathrm{L}_{3}$.