A 500 W push-pull dc-dc power converter with a 30 MHz switching frequency

Abstract

D ESIGNERS of power conversion circuits are under relentless pressure to increase power density while maintaining high efficiency. Increased switching frequency is a primary path to higher power density. Prior work has shown that the use of switching frequencies in the VHF band (30 MHz-300 MHz) are a viable path to the achievement of gains in power density. A promising topology for VHF operation is the voltage-fed Class EF2 (Class Φ2) inverter based topology, where the use of controlled impedance at the switching frequency and its 2 nd and 3 rd harmonics provides both full soft switching and substantially reduced voltage stress compared to topologies such as Class E. However, such converters contain multiple resonant elements, and the tuning of the converter can be complicated due in part to the interaction of said elements. It is proposed that a pushpull version of the Class EF2 inverter can alleviate some of these difficulties. In particular, it is shown that odd and even frequency components can be independently tuned without interaction, and furthermore that center-tapped inductors may be used to reduce the total volume occupied by said inductors. The benefits include simplified design and increased power density. Evidence is presented in the form of a push-pull Class EF2 (Class Φ2) unregulated 500 W prototype dc-dc converter with a 30 MHz switching frequency, an input voltage 150 VDC, and an output voltage of 65 VDC. This converter has an efficiency of > 81% under nominal conditions, including gate drive power.

Low loss thin film magnetics for high frequency power supplies

“…Recent advances in power conversion circuits have pushed their switching frequencies to 100's kHz and even in to MHz range [1,2]. These advances are due to the emergence of wide bandgap semiconductors such as GaN and SiC.…”

Single-Switch High-Frequency DC–DC Converter Using Parasitic Components

“…These concepts are also adopted for several isolated type converters in [21]- [25]. Galvanic isolation of a converter operating at several MHz switching frequency can be achieved by two ways: capacitive isolation and magnetic isolation.…”

Very high frequency resonant DC/DC converters for LED lighting

“…As both the physical size and price of these scale with the switching frequency (f S ), increasing f S into the Very High Frequency band (VHF, 30-300 MHz) will make it possible to achieve higher power density and lower cost. Increasing the switching frequency has several other advantages, which has been discussed in [4], [6], [15] and [16].…”