84.7 percent Peak Efficiency Stress Tolerant DC DC Buck Converter For Li Ion Battery Driven Standby Circuits In 18nm FDSOI

A peak-current (IPK) limited Pulse-Frequency Modulation (PFM)-based SoC-compatible buck converter is designed in scaled-CMOS technology. In an Li-ion compatible input supply range of 2.7V-4.2V, it delivers a 0.55V output. It employs a low-power Bandgap reference, in-built push-pull voltage-regulators with adaptive-biasing, duty-cycled sensors and a failsafe asynchronous block. This architecture alleviates the need for a clock and limits inrush current at startup. Made using 3.3V bulk-MOSFETs, device voltage stress is managed for each sub-block. It only needs external L & C of 4.7µH & 4.7µF. Occupying an area of 660µm x 1465µm, it targets Standby mode of operation for low-power applications like Internet-of-Things (IoT) and Bluetooth Low Energy (BLE), supporting a load-current of 0.5mA to 10mA with >80% efficiency and has >70% efficiency till 0.1mA. It achieves a peak efficiency of 84.7% at 5mA load.