NCP4390 Controller for LLC Resonant Converters onsemi NCP4390 Controller for LLC Resonant Converters is an advanced Pulse Frequency Modulated (PFM) controller with SR that offers good efficiency for isolated DC/DC converters. The NCP4390 controller employs a current mode control technique based on charge control. This technique combines the triangular waveform from the oscillator with the integrated switch current information to determine the switching frequency. onsemi NCP4390 Controller provides a better control-to-output transfer function of the power stage, simplifying the feedback loop design and allowing true input power limit capability. This controller features adaptive synchronous rectification control with dual-edge tracking and closed-loop soft-start for monotonic rising output. Typical applications include automotive onboard chargers, intelligent 100W-2kW+ offline and industrial power supplies, large LED displays, telecom front-end power, entry-level servers, and computing power.