ER 2102 PL52 2102 154546 Server and data center 3 kW 50 V PSU EVAL 3KW 50V PSU About this document Authors Manuel Escudero, Matteo-Alessandro Kutschak, David Meneses Scope and purpose This document introduces a complete Infineons system solution for a 3 kW power supply unit (PSU) targeting the newly released OCP rectifier V3 specifications for servers and data centers. The PSU comprises a front-end AC-DC bridgeless totem pole converter followed by a back-end DC-DC isolated half-bridge LLC converter. The front-end totem pole converter provides power factor correction (PFC) and total harmonic istortion (THD). The LLC converter provides safety isolation and a tightly regulated output voltage. The measured peak efficiency of the complete PSU at 230 V is 97.5 percent, not including the internal fan, and AC 97.4 percent, including the internal fan. The overall outer dimensions of the PSU are 73.5 mm x 520 mm x 40 mm, which yields a power density in the range of 32 W/inch (1.95 W/cm). This document describes the converter hardware, a summary of the experimental results and several design recommendations for the complete Infineon solution, also including an innovative in-house planar magnetic construction. The main Infineon components used in the EVAL 3KW 50V PSU are: CoolSiC 650 V 48 m (IMZA65R048M1H) in the totem pole PFC half-bridge 600 V CoolMOS 17 m (IPW60R017C7) in the totem pole PFC synchronous rectifiers (SRs) 600 V CoolMOS CFD7 24 m (IPW60R024CFD7) in the LLC primary-side half-bridge OptiMOS 5 80 V 3.7 m (BSC037N08NS5) in the LV bridge EiceDRIVER 1EDB8275F and 1EDB9275F, single-channel drivers for CoolMOS, CoolSiC and CoolGaN EiceDRIVER 2EDF7275F dual-channel driver for CoolMOS, CoolSiC and OptiMOS XMC1404 microcontroller for the totem pole PFC control implementation (XMC1404-LQFP-64) XMC4200 microcontroller for the LLC control implementation (XMC4200-F64k256AB) Reference board/kit Product(s) embedded on a PCB, with focus on specific applications and defined use cases that can include software. PCB and auxiliary circuits are optimized for the requirements of the target application. Note: Boards do not necessarily meet safety, EMI and quality standards (for example UL, CE) requirements. Engineering Report Please read the Important notice and the Safety precautions and the Warnings V 1.0 www.infineon.com/eval 3kw 50v psu page 1 of 43 2021-02-27 Server and data center 3 kW 50 V PSU EVAL 3KW 50V PSU Table of contents Table of contents About this document ....................................................................................................................... 1 Table of contents ............................................................................................................................ 2 Safety information your safety is our goal ....................................................................................... 3 Important notice ............................................................................................................................ 3 Operating instructions .................................................................................................................... 3 Safety precautions .......................................................................................................................... 4 1 The board at a glance .............................................................................................................. 5 1.1 Main features ........................................................................................................................................... 6 1.2 Block diagram .......................................................................................................................................... 7 2 System and functional description ........................................................................................... 9 2.1 Bridgeless totem pole PFC .................................................................................................................... 10 2.1.1 Totem pole PFC magnetics .............................................................................................................. 11 2.2 Half-bridge LLC ...................................................................................................................................... 11 2.2.1 Half-bridge LLC magnetics ............................................................................................................... 12 3 Experimental results ............................................................................................................. 14 3.1 Totem pole PFC ..................................................................................................................................... 14 3.1.1 Boost diode operation ..................................................................................................................... 14 3.1.2 Boost switch operation .................................................................................................................... 15 3.1.3 SRs polarity detection ...................................................................................................................... 17 3.1.4 Soft-start ........................................................................................................................................... 18 3.2 Half-bridge LLC ...................................................................................................................................... 19 3.2.1 ZVS switching ................................................................................................................................... 20 3.2.2 Soft-start ........................................................................................................................................... 21 3.2.3 Output voltage ripple ....................................................................................................................... 22 3.2.4 Resonant capacitor voltage ............................................................................................................. 23 3.3 Power supply unit.................................................................................................................................. 24 3.3.1 Hold-up time .................................................................................................................................... 25 3.3.2 Temperature..................................................................................................................................... 26 3.3.3 Efficiency .......................................................................................................................................... 27 3.3.4 Power factor and THD ...................................................................................................................... 27 3.3.5 EMI .................................................................................................................................................... 28 4 Design tips............................................................................................................................ 30 4.1 Driving 4-pin CoolSiC .......................................................................................................................... 30 4.2 Driving 3-pin CoolMOS ........................................................................................................................ 30 4.3 Driving the ORing OptiMOS ................................................................................................................ 31 4.4 Driving the SR OptiMOS ...................................................................................................................... 32 4.5 Generating the multiple auxiliary driving voltages .............................................................................. 32 5 Schematics ........................................................................................................................... 34 5.1 Main board ............................................................................................................................................. 34 5.2 Control card ........................................................................................................................................... 35 5.3 Bill of materials ...................................................................................................................................... 36 6 References and appendices .................................................................................................... 41 6.1 Abbreviations and definitions ............................................................................................................... 41 6.2 References ............................................................................................................................................. 41 Revision history............................................................................................................................. 42 Engineering Report 2 of 43 V 1.0 2021-02-27