GaN-based QR Adaptor Reference Design 

This design suits laptops, smartphones, and other USB-C-powered devices, highlighting its superior energy efficiency, compact form factor, and compliance with international EMI standards.

High-efficiency power adapters are essential in modern electronics, enabling compact and energy-saving solutions for consumer and industrial applications. Gallium Nitride (GaN) transistors have transformed the power industry by delivering high power density and efficiency, making them ideal for lightweight, high-performance adapters. The GS-EVB-ADP-65WQR-GS1, a 65W USB-C AC-DC adapter from GaN Systems Inc, exemplifies the advantages of GaN-based power conversion. 

The GS-EVB-ADP-65WQR-GS1 by GAN Systems uses the high-performance 650V, 150mΩ GaN transistor (GS-065-011-1-L) for optimized power conversion. The adapter achieves a peak efficiency exceeding 93.6% and boasts a remarkable power density of 18.5W/in³ in a cased design. It also meets EMI EN55032 Class B standards for both conducted and radiated emissions, ensuring its reliability in various environments. Furthermore, the design surpasses CoC Ver5 Tier 2 standards for average efficiency and standby power consumption, making it a competitive choice for environmentally conscious, high-performance power supplies.

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The circuit architecture of this reference design highlights the performance capabilities of GaN transistors. On the primary side, the GaN transistor works with the NCP1342 Quasi-Resonant (QR) controller, ensuring efficient energy conversion. On the secondary side, a 100V Si MOSFET with the NCP4306 synchronous rectification (SR) controller is utilised for effective rectification. A dedicated Power Delivery (PD) protocol controller also ensures USB-C compatibility, making the adapter suitable for a wide range of devices. This architecture provides robust performance while maintaining compact dimensions.

The design complies with EMI EN55032 Class B standards, with margins of 10dB for conducted EMI and 6dB for radiated EMI, tested at 230V and 110V AC inputs. Thermal performance is equally impressive; after 30 minutes of full-load operation at an ambient temperature of approximately 25°C, the PCB temperature remains below 100°C, while the maximum temperature on the cased adapter’s surface does not exceed 66°C. These metrics underline the design’s operational stability and efficiency.

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This reference design showcases the potential of GaN transistors in compact, high-performance USB-C adapters. Applications include fast chargers for consumer electronics, industrial controllers, and efficient power supplies for IoT devices. By leveraging GaN technology, the design achieves exceptional power density, energy efficiency, and compliance with international standards, making it an invaluable resource for design engineers developing next-generation power adapters.

GAN Systems has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.