This reference design is a 1-kW, 400-V to 12-V half-bridge resonant DC-DC platform, used to evaluate the load transient performance of hybrid-hysteretic control (HHC) with an F280039C controller. HHC is a method which combines direct frequency control (DFC) and charge control, and is charge control with an added frequency compensation ramp. With an additional inner loop, HHC can highly improve the load transient response performance of the inductor-inductor-capacitor (LLC) stage.

Additionally, this platform includes an interface for the LMG3422 half-bridge EVM on the primary side, so the power board can be configured to evaluate GaN performance in the LLC stage by some modifications of cutting off the MOSFET bridge.

• HHC controlled half-bridge LLC platform using F280039C
• Converting 400 V to 12 V with 1-kW ability
• Better load transient response than the Common Redundant Power Supply (CRPS) standard
• Monotonic soft-start with any load conditions
• Small output voltage ripple