Common mode noise cancellation for llc resonant converters

A power supply comprising:

• an input power factor correction stage configured to receive an AC input voltage and produce a DC an intermediate DC bus voltage;
• and
• a DC-DC conversion stage configured to receive the intermediate DC bus voltage and produce a DC output voltage, wherein the DC-DC conversion stage further comprises:
• a switching bridge having two input terminals configured to receive an input voltage and a switch node coupled to a primary winding of a transformer;
• at least one rectifier device coupled between a secondary winding of the transformer and an output of the DC-DC conversion stage;
• and
• a common mode noise compensation capacitor, a first terminal of the common mode noise compensation capacitor being coupled to a connection between the secondary winding of the transformer and the at least one rectifier device, and a second terminal of the common mode noise compensation capacitor being coupled to one of the two input terminals.

A power supply comprising:

• an input power factor correction stage configured to receive an AC input voltage and produce a DC an intermediate DC bus voltage;
• and
• a DC-DC conversion stage having first and second input terminals that receive the intermediate DC bus voltage and one or more switching devices operable to produce a DC output voltage, the DC-DC conversion stage further comprising:
• a transformer having a primary winding and a secondary winding;
• and
• a common mode noise compensation capacitor, a first terminal of the common mode noise compensation capacitor being coupled to the secondary winding of the transformer, and a second terminal of the common mode noise compensation capacitor being coupled to one of the first or second input terminals.