LLC resonant converter with windings fabricated on PCB

An LLC converter with windings fabricated on printed circuit board (PCB), said LLC converter comprising:

• a switching circuit electrically coupled to an input DC voltage for converting said input DC voltage into a switching signal;
• a resonant tank electrically coupled to said switching circuit, said resonant tank including a resonant inductor, a magnetizing inductor and a resonant capacitor connected in series to receive said switching signal for providing primary current;
• a transformer circuit electrically coupled to said resonant tank, said transformer circuit having a plurality of discrete transformers, each of said plurality of discrete transformers with a primary winding and a secondary winding, wherein said primary winding and said secondary winding are fabricated on a printed circuit boards (PCB) to reduce influence of stray characteristics caused by said primary winding and said secondary winding, wherein said PCB include a plurality of through holes, a plurality of layers and a plurality of windings, and locations of said plurality of through holes corresponding to said magnetic cores of said plurality of discrete transformers to make each of said magnetic cores passing through corresponding said plurality of through holes;
• wherein said plurality of windings arranged on each layer of said plurality of layers of said PCB surround corresponding magnetic cores of said plurality of discrete transformers to generate induced electromotive force, said windings arranged on said plurality of layers of said PCB include said primary winding or said secondary side winding;
• wherein primary winding of each of said discrete transformers is dynamically selected to be electrically coupled or isolated from said resonant tank, and is dynamically selected to be connected in series or in parallel with primary winding of other discrete transformers to form a dynamically varying equivalent primary winding, and enable parameters of said resonant tank to be tuned accordingly while maintaining turns ratio of said transformer circuit;
• and
• a rectifying and filtering circuit electrically coupled to said transformer circuit to rectify and filter a secondary current for providing an output voltage;
• wherein one end of said resonant inductor is connected in series to said switching circuit and another end of said resonant inductor is connected in series to said equivalent primary winding;
• wherein said magnetizing inductor is connected in series to said resonant capacitor, said resonant capacitor with one end is connected in series to said magnetizing inductor and another end is connected to said switching circuit;
• and
• wherein said magnetizing inductor is connected in parallel to said equivalent primary winding;
• wherein gain curve of said LLC resonant power converter is dynamically adjusted by electrically coupling an external excitation inductor, an external resonant inductor or an external capacitor to said resonant tank according to output current requirement of said LLC resonant power converter.