| CPC H02M 3/33576 (2013.01) [H02M 1/0058 (2021.05); H02M 1/083 (2013.01); H02M 3/33573 (2021.05); H02M 1/0009 (2021.05); H02M 1/0054 (2021.05)] | 11 Claims |

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1. A zero voltage switching circuit comprising:
a zero voltage switching unit configured to form a full-bridge circuit at a primary side of a converter and comprising a plurality of switches for zero voltage switching;
an adjustable inductor configured to perform zero voltage switching in resonance with a parasitic capacitor of the zero voltage switching unit, and be adjusted according to control of a control unit; and
the control unit configured to control inductance of the adjustable inductor according to an input voltage of the zero voltage switching unit or current flowing in the adjustable inductor,
wherein the control unit reduces the inductance of the adjustable inductor when the current flowing through the adjustable inductor increases, and increases the inductance of the adjustable inductor when the current flowing through the adjustable inductor decreases,
wherein the adjustable inductor comprises a plurality of inductor elements,
wherein each inductor element of the plurality of inductor elements comprises:
a first inductor having a predetermined inductance;
a second inductor coupled to the first inductor; and
a switching unit connected to the second inductor to turn on/off a closed loop comprising the second inductor, and
wherein the switching unit comprises two MOSFETs which have opposite connection directions,
wherein the control unit controls the inductance of the adjustable inductor by measuring an input current of the zero voltage switching unit, the current flowing through the adjustable inductor, or a current flowing through a load at a secondary side of the converter, and
wherein the control unit controls the inductance of the plurality of inductor elements differently by individually controlling the plurality of inductor elements.
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