The presented 300 W Ultra−high Power Density Adapter (UHPD) evaluation board demonstrates ON Semiconductor’s high performance controllers, drivers and discrete semiconductor content capabilities that enable efficient UHPD designs implementation. This reference design includes the Synchronous PFC boost converter which is operating in the Discontinuous Conduction or Critical Conduction Mode (DCM/ CrM) depends on loading and LLC power stage with secondary side synchronous rectification.
The PFC front stage is driven by NCP1616 controller, which assures unity power factor and low input current THD. Synchronization of the PFC boost SR switch is secured by the NCP4306 high performance SR controller. The LLC stage operates at 500 kHz switching frequency while nominal load is applied. Power stage is managed by the NCP13992 high performance current mode LLC controller. Thanks to the GaN High Electron Mobility Transistors (HEMT) implemented in both power stages at primary side, the high efficiency is easily maintained despite that system operates at high frequency.
GaN Systems’ GS66504B are incorporated as primary side power switches. Synchronous rectifier (SR) stage used in the secondary side composes from NCP4306 and two paralleled 60V power MOSFETs for each branch. SR MOSFETs and controllers are implemented on the dedicated SR MODULE daughter card to ease main power board PCB design and to achieve maximum efficiency.
Ultra−high power density is achieved thanks to the modular design, used controllers/ drivers, GaN HEMT and dedicated power magnetics design: the main filter chokes of the board have been specifically designed in collaboration with Würth Elektronik.
