Current synchronous zero voltage switching resonant topology

Abstract

A power converter circuit provides low conversion losses, low generated noise and output power controllability. The circuit includes a controller, at least two transistors and an output network that provides impedance matching and operating point stabilization functions. The output network also enables zero voltage switching of the transistors, thus reducing radiated noise and minimizing (and possibly eliminating almost completely) switching losses. The controller circuitry includes an oscillator which is capable of self synchronizing to the resonant frequency of the components of the output network. Power modulation (e.g., for dimming of a lamp) is accomplished simply by desynchronizing and increasing the oscillator frequency. Thus, the control architecture allows the use of external parts of lower precision and cost while providing dimming capability in a single stage.