Dynamic bootstrap voltage technique for high efficiency buck converter in universal serial bus power device supplying system

For high power universal serial bus (USB) devices, the dynamic bootstrap voltage (DBV) technique is proposed to keep high efficiency over a wide load range, including light and heavy loads. Besides, the silicon area of power management of the system-on-a-chip (Soc) can be effectively reduced to 50% of conventional design with P-type high-side power MOSFET. The test chip fabricated in 0.25μm CMOS process shows 92% peak efficiency from 1mA to 1A. The maximum driving current is higher than 3A with 88 % efficiency. Compared to that without the DBV technique, the efficiency is improved about 28%.