Scope and purpose

This document introduces a complete system solution from Infineon Technologies AG for a high power density

3.3 kW power supply unit (PSU) which targets specifications for server and datacenter applications.

This document describes the converter hardware, provides with a summary of the experimental results and

design recommendations for the complete Infineon solution, including an innovative planar magnetic

construction. The REF_3K3W_HFHD_PSU comprises a front-end AC-DC converter and a back-end isolated DC-DC

converter. The AC-DC converter is an interleaved bridgeless totem pole (ILTP) stage featuring two phases that

provide power factor correction (PFC) and limits total harmonic distortion (THD). The back-end DC-DC is a GaN

half-bridge (HB) LLC converter with full bridge (FB) rectification, which provides safety isolation and regulates

the output voltage. The PSU also features a baby-boost converter to comply with the hold-up time specifications

of server applications with a reduced overall bulk capacitance, increasing the overall power density.

The measured peak efficiency of the complete PSU at 230 VAC input line is 97.4 percent, not including the internal

fan and the overall outer dimensions of 72 mm x 192 mm x 40 mm, yielding to 98 W/inch³ power density.

The main Infineon components used in the REF_3K3W_HFHD_PSU are:

• CoolSiC™ 650 V M1, 57 mΩ TOLL (IMT65R057M1H), and EiceDRIVER™ 2EDB9259Y

for the fast legs of the totem-pole PFC converter

• CoolMOS™ 600 V CM8, 16 mΩ TOLL (IPT60R016CM8), EiceDRIVER™ 1EDN8511B, and 1EDB8275F for the slow

leg of the totem-pole PFC converter and the static switch of the baby boost converter

• CoolGaN™ 650 V GIT, 35 mΩ TOLL (IGT65R035D2), EiceDRIVER™ 1EDN8550B, and 1EDB8275F

for HB switches at the primary side of the LLC converter

• OptiMOS™ 80 V, 4.6 mΩ source-down (IQE046N08LM5), and EiceDRIVER™ 2EDB7259K

for the synchronous rectification (SR)s switches at the secondary side of the LLC converter

• CoolMOS™ 600 V G7, 80 mΩ (IPT60R080G7), CoolSiC™ 600 V diode (IDL10G65C5), and

EiceDRIVER™ 1EDB8275F for the baby boost converter

• ISOFACE™ 4DIR1400H digital isolator for the primary to secondary isolation in the LLC converter

• XMC4200-Q48K256 microcontroller for the implementation of the PFC control