A Resonant Push–Pull DC–DC Converter With an Intrinsic Current Source Behavior for Radio Frequency Power Conversion
Nikolai Weitz, Samuel Utzelmann, Stefan Ditze, Martin März
Abstract
In this article, a resonant push–pull dc–dc converter suitable for switching frequencies in the MHz-range is investigated. Despite a simple design procedure with no need of multiresonant tuning, the converter topology is capable of providing a constant output current over a wide output voltage range in unregulated operation. Based on an analytical solution of steady-state operation, normalized dependencies of converter behavior are determined and used to formulate generalized design considerations. In order to verify the theoretical analysis, the design procedure of a 300-W prototype operating at a switching frequency of 6.78 MHz is described considering the impact of circuit parasitics on converter operation. The prototype provides a stable operation within the full output voltage range of 0–150 V and reaches a peak efficiency of 93% at the nominal output voltage. A rapid transient response of the converter is demonstrated by applying a closed-loop <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</small> / <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> -control to the prototype.