US 12,224,662 B2
LLC resonant converter with variable turns ratio
Chun-Chen Chen, Taoyuan (TW); Jian-Hsieng Lee, Taoyuan (TW); and Yao-Chun Tung, Taoyuan (TW)
Assigned to PHIHONG TECHNOLOGY CO., LTD., Taoyuan (TW)
Filed by PHIHONG TECHNOLOGY CO., LTD., Taoyuan (TW)
Filed on Oct. 15, 2022, as Appl. No. 17/966,833.
Claims priority of application No. 111133618 (TW), filed on Sep. 5, 2022.
Prior Publication US 2024/0079952 A1, Mar. 7, 2024
Int. Cl. H02M 3/335 (2006.01); H02M 1/12 (2006.01); H02M 3/00 (2006.01)
CPC H02M 3/015 (2021.05) [H02M 1/12 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An LLC converter with variable turns ratio, said LLC converter comprising:
a switching circuit 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 a primary current;
a transformer circuit electrically coupled to said resonant tank, said transformer circuit having a plurality of discrete transformers, each of said discrete transformers containing a primary winding and a secondary winding,
wherein said primary winding of each of said discrete transformers have different turns and are dynamically selected to be electrically coupled or isolated from said resonant tank, and are dynamically selected to be connected in series or in parallel with said primary side windings of other transformers to form a dynamically changed equivalent primary winding of said transformer circuit;
wherein turns of said secondary winding of each of said discrete transformers are fixed and the same, so that turns ratio of said transformer circuit can be dynamically changed accordingly; and
a rectifying and filtering circuit electrically coupled to said transformer circuit to rectify and filter a secondary current outputted by said secondary winding for providing an output voltage;
wherein one end of said resonant inductor is electrically coupled 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 inductor, said resonant capacitor with one end is connected in series to said magnetizing inductor and said equivalent primary winding, and with another end is coupled to said switching circuit;
wherein said magnetizing inductor is connected in parallel to said equivalent primary winding.