Resonant converter with pre-charging circuit for startup protection

A power converter comprising:

• first and second switching elements coupled in series across a DC power source;
• a controller configured to generate drive signals to the switching elements, wherein an output from the switching elements corresponds to a frequency of the gate drive signals;
• a resonant circuit comprising first and second capacitors, a resonant inductor, and output terminals for receiving a load, wherein:
• the resonant inductor and the first capacitor are coupled in series on a first end to a node between the first and second switching elements and on a second end to a circuit ground,
• the second capacitor and the load are coupled in series on a first end to a node between the resonant inductor and the first capacitor;
• and
• a pre-charge circuit comprising:
• a first resistor coupled between a positive rail of the DC power source and the node between the resonant inductor and the first capacitor, and
• a second resistor coupled between the circuit ground and the node between the resonant inductor and the first capacitor,
• wherein the pre-charge circuit is configured, after initially receiving power from the DC power source and prior to startup of the controller, to pre-charge at least one of the first and second capacitors in the resonant circuit.

A power converter comprising:

• first and second switching elements coupled in series across a DC power source;
• a controller configured to generate drive signals to the switching elements, wherein an output from the switching elements corresponds to a frequency of the gate drive signals;
• a resonant circuit comprising first and second capacitors, a resonant inductor, and output terminals for receiving a load, wherein:
• the second capacitor, the resonant inductor and the first capacitor are coupled in series on a first end to a node between the first and second switching elements and on a second end to a circuit ground, and
• the load is coupled in parallel with the first capacitor;
• and
• a pre-charge circuit comprising:
• a first resistor coupled between a positive rail of the DC power source and the node between the first and second switching elements, and
• a second resistor coupled between the circuit ground and the node between the first and second switching elements,
• wherein the pre-charge circuit is configured, after initially receiving power from the DC power source and prior to startup of the controller, to pre-charge at least one of the first and second capacitors in the resonant circuit.