3kW Power Supply Design with Easy

Manufacturability for 48 V Bus Power Architecture Ahmed Nabih, Qiang Li and Fred C. Lee

Center for Power Electronics Systems (CPES)Virginia Polytechnic Institute and State University

48 V Power Architecture

Why 48 V power architecture ?

• Less dissipation Loss from power supply to Load

• No UPS or battery charger needed

Ecosystem for Datacenter and Telecom

• More Efficient than 12V architecture

• More power per server rack

400V/48V 3kW DC-DC

Half Bridge LLC

Limited power (<1kW)

Mature topology Easy to design and control

Three Phase Interleaved LLCParallel phasesHandle more power

Complex magnetic structure

Full-bridge LLC with Matrix transformer

CPES Solution

Easier Manufacturability

Litz Wire Magnetics

100kHz

PCB Magnetics

1MHz

Challenge: Low frequency design with Litz wire magnetics(more labor more cost)

Hardware Demonstration

Solution #1

Solution #2

• Utilize Transformer leakage as resonant inductor

• Smaller footprint and high power density solution cSR

cSR CSR

CSR

CSRc SR

SR cC SR

1 2

43

Layer 2 (Primary)

Layer 4 (Secondary )

1 2

43

1 2

43

c SR

C SR

Layer 3 (Primary)

55

5 5

1 2

43

Flux distribution in core

Proposed 5-Leg core

Leakage in center Leg

Efficiency 97.4%Power Density 400W/in3

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0 1000 2000 3000

Effi

cie

ncy

%

Power