GaN power adapter reference design delivers high power density

Transphorm, Inc. and Silanna Semiconductor have introduced a GaN power adapter reference design that combines Transphorm’s SuperGaN Gen IV platform with Silanna’s proprietary active clamp flyback (ACF) PWM controller. The open frame, 65-W USB-C Power Delivery (PD) charger delivers a peak efficiency of 94.5% with an uncased power density of 30 W/in3.

These performance levels outperform the currently available competing solutions using silicon superjunction mosfets or e-mode GaN transistors, according to the companies. This design targets laptops, tablets, smartphones, and other IoT devices.

GaN power adapter reference design delivers high power density

Image: Transphorm

A key component in the reference design is Transphorm’s SuperGaN FET. The TP65H300G4LSG is a 650-V, 240-mΩ device in an industry standard PQFN88 package that leverages the SuperGaN Gen IV platform for improved performance. The GaN FET touts high reliability and, unlike e-mode devices, protective external circuitry such as additional bias rails or level shifters are not needed, said the company, which contributes to the high efficiency.

The reference design also includes Silanna’s SZ1130, claimed as the first fully-integrated ACF PWM controller that integrates an adaptive digital PWM controller, an active clamp FET, an active clamp gate driver, and a UHV startup regulator. The highly integrated controller, designed for up to 65-W output power, including USB-PD and Quick Charge applications, contributes to highly efficient and high-power-density adapters.

Schematic, design files, and bill of materials for the GaN power adapter reference design are available from both manufacturers. For Silanna, contact [email protected] Files for Transphorm’s TDADP-SIL-USBC-65W-RD can be downloaded here.


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