Topology | LLC Resonant Converter |
Input voltage | 90-265 V |
Output 1 | 12 V / 20 A |
IC revision | 1 |
This evaluation board user’s manual provides basic information about a high efficiency, low no-load power consumption reference design that was tailored to power All-in-One PC or similar type of equipment that accepts 12 VDC on the input. The power supply implements PFC front stage to assure unity power factor and low THD, current mode LLC power stage to enhance transient response and secondary side synchronous rectification to maximize efficiency. This design note focuses mainly on the NCP1399 current mode LLC controller description – please refer to NCP1602 and NCP4305 materials to gain more information about these devices. The NCP1399 is a current mode LLC controller which means that the operating frequency of an LLC converter is not controlled via voltage (or current) controlled oscillator but is directly derived from the resonant capacitor voltage signal and actual feedback level. This control technique brings several benefits compare to traditional voltage mode controllers like improved line and load transient response and inherent out of zero voltage switching protection. The LLC controller also features built-in high voltage startup and PFC operation control pins that ease implementation of a power supply with PFC front stage and no standby power supply on board. The enhanced light lad operation scheme of the LLC controller allows SMPS design to fulfill the latest no-load and light load consumption limits and still keep output voltage regulated with excellent transient response from no-load to full-load steps.