Common-mode (CM) electromagnetic interference (EMI) reduction in resonant converters

A method comprising:

• obtaining an apparatus comprising a first inductor and a second inductor, the first inductor is coupled to a first node and a second node, the second inductor is coupled to a third node and a fourth node, and the first inductor and the second inductor form a transformer comprising a turns ratio;
• measuring a parasitic capacitance between the first node and the third node, the first node and the fourth node, the second node and the third node, or the second node and the fourth node;
• determining a compensation capacitance that is directly proportional to a first order of the turns ratio and not proportional to a square of the turns ratio;
• and
• adding to the apparatus a compensation capacitor comprising the compensation capacitance.

A method comprising:

• obtaining an apparatus comprising a first inductor, a second inductor, and a compensation capacitor, the first inductor is coupled to a first node and a second node, the second inductor is coupled to a third node and a fourth node, the first inductor and the second inductor form a transformer comprising a turns ratio, and the compensation capacitor comprises an adjustable compensation capacitance;
• measuring a parasitic capacitance between the first node and the third node, the first node and the fourth node, the second node and the third node, or the second node and the fourth node;
• and
• adjusting the adjustable compensation capacitance so that it is directly proportional to a first order of the turns ratio and not proportional to a square of the turns ratio.