Very High Frequency Resonant Boost Converters

This document presents a resonant boost topology suitable for very high frequency (VHF, 30-300 MHz) dc-dc power conversion. The proposed design features low device stress, high efficiency over a wide load range, and excellent transient performance. Two experimental prototypes have been built and evaluated. One is a 110 MHz, 23 W converter which uses a high performance rf LDMOSFET. The converter achieves higher than 87% efficiency at nominal input and output voltages, and maintains good efficiency down to 5% of full load. The second implementation, aimed towards integration, is a 50 MHz 17 W converter which uses a transistor from a 50 V integrated power process. In addition, two resonant gate drive schemes suitable for VHF operation are presented, both of which provide rapid startup and low-loss operation. Both converters regulate the output using high-bandwidth on-off hysteretic control, which enables fast transient response and efficient light-load operation. The low energy storage requirements of the converters allow the use of coreless inductors in both designs, thereby eliminating magnetic core loss and introducing the possibility of easy integration.