Design of Load-Dependent Dual-Mode 12V to 5V Step-Down Voltage Regulator for MCU-CPU Powered Wireless Sensor System

A power management unit to power a hybrid CPU wireless sensor system is first designed and simulated using LTSpice. Multiple operation modes and adaptive loading are simulated and studied. Transient response under various modes are measured, with best-worst undershoot of 0.183V-1V and best-worst overshoot of 0.184V-0.283V. Power efficiency is 94% at 3A maximum loading current and peak power efficiency is 96.2% at 1.5A loading current. The final PCB is constructed using freeware tools KiCAD.