New Industry Products

# GaN Systems Offers Reference Designs for 3kW AC/DC Power Supplies

October 14, 2021 by Gary Elinoff

## The two power supply unit (PSU) designs offer either full bridge LLC resonant converter or bridgeless totem-pole PFC formats.

Both of the new reference designs feature GaN Systems’ GS-065-030-2L, a 650V E-mode GaN transistor. Both versions exceed 80 plus titanium efficiency requirements and offer power densities of over 80W/inch3.

## The Need to Reduce Data Center Energy Consumption

As noted by Paul Wiener, VP of Strategic Marketing at GaN Systems, “With the expanding volume of data, game-changing solutions are needed to reduce energy consumption and contribute to a more sustainable future in our data centers, and these PFC and LLC reference designs take PSUs to the next level."

In his article, "Dollar per Density," Mr. Wiener describes how the industry’s current mandate of “$per watt” is shifting towards “$ per density”, where density is a function of not only power but also size. It is expected that the European Union’s “Lot 9” 2023 regulatory policies for data center power supply infrastructure are heavily influence this subtle but important shift in focus.

## What are the 80+ Titanium Efficiency Requirements?

The “80 PLUS” Titanium standard is a measure of power supply efficiency. The standard varies by power supply input voltage and percentage of rated load. Generally, the greatest efficiencies at 50% load are required to satisfy this standard. Complete results are found at the CLEAResult site.

## The GS-EVB-BTP-3KW-GS Evaluation Board and Reference Design

A continuous conduction mode (CCM) bridgeless totem pole (BTP) PFC evaluation board and reference design, the GS-EVB-BTP-3KW-GS operates from a 90 to 264 VRMS input and supplies 400 VDC output. The 3kW output derates to 1.5 kW at low line.

##### Simplified schematic of a Bridgeless Totem Pole PFC (BTPPFC). Image courtesy of GS-EVB-BTP-3kW-GS Technical Manual.

This design offers a 99% peak power efficiency and a power factor of 0.99. Power density is 78 W/in3. EMI compliance is to EN55033 Class A CE.

A basically simpler circuit, this design has a lower parts count than previous similar designs, and only one inductor is required,

The evaluation board features a 127 x 124 x 40 mm3 form factor.

## The GS-EVB-LLC-3KW-GS Evaluation Board and Reference Design

A 3kW LLC resonant converter is a full-bridge LLC resonant converter, the GS-EVB-LLC-3KW-GS Evaluation Board achieves a power density of above 100W/inch3 and a power efficiency of greater than 96%. Input can range from 380 to 420 VDC, with output at 54V and a full load current of 55A. The resonant and target frequency is 250 Khz, while the maximum frequency is 450 Khz. The unit features forced hot air cooling, with a power density at 146W/inch3.

##### A simplified block diagram for the GS-EVB-LLC-3KW-GS reference design. Note the resonant tank formed by resonant inductor Lr, resonant capacitor Cr, and transformer Tr. Image courtesy of the GS-EVB-LLC-3KW-GS technical manual.

Including the forced hot air feature, the dimensions for this EVB are 80 x 140 x 30mm.

Applications for this design include telecom and industrial switched-mode power supplies (SMPS). The design will also find application in power conversion for data centers.