Reference Design of High Efficiency Power Supply for Server

More efficient than earlier reference designs with the same circuit topology thanks to the latest semiconductor devices.

Introducing a new reference design for a 1U sized power supply with DC 12 V of output voltage and 1.6 kW (max) of output power, suitable for data center servers that require reduced power consumption.

As data center power consumption continues to rise, there is a growing need for server power supplies that boost efficiency, reduce loss and cut power consumption. Toshiba has brought its latest power devices, digital isolators, etc., to a server power supply reference design that is more efficient than earlier designs. The design provides all key information, including circuit diagrams and circuit board patterns.

Reference Design of High Efficiency Power Supply for Server


  • High efficiency with Toshiba’s latest power devices and digital isolators
    More efficient that previous designs

  • Functions required for the server power supply are equipped in 1U rack size
    Integrates PFC, DC-DC converter, output ORing circuit and auxiliary power supply for internal control circuit

  • Editable design data (data for EDA tools) and board processing data provided
    The same power supply can be manufactured or changed to meet specifications by editing on EDA tool.

Efficiency characteristic

As the number of data centers continues to climb, and with it the number of installed serves, it is more important than ever to lower the level of power consumption. As consumption is greatly affected by the conversion efficiency of server’s power supply unit, high efficiency is a core requirement. Our reference design meets this need and consumes less power by being more efficient in the full-load range than the current reference design, achieving 95.4 % (output: 0.8 kW) and 93.4% (output: 1.6 kW) when input is AC 230 V.

Efficiency Curves
Efficiency Curves

Blocks diagram

The same topology as the current 1.6 kW server power supply: a semi-bridgeless PFC, phase-shifted full-bridge converters, and an ORing output circuit.

Simple Block Diagram
Simple Block Diagram

Used Toshiba Items

Power MOSFET TK125N60Z1 (under development)

MOSFET with fast switching capability, suitable for PFC

  • Drain-Source voltage: 600 V (Max)
  • Drain current: 20 A (Max)
  • On-resistance: 0.105 Ω (Typ.) @VGS = 10 V
  • Gate input charge: 28 nC (Typ.) @VGS = 10 V

Power MOSFET TK095N65Z5

MOSFET suitable for bridge circuit with high-speed diode

  • Drain-Source voltage: 650 V (Max)
  • Drain current: 29 A (Max)
  • On-resistance: 0.079 Ω (Typ.) @VGS = 10 V
  • Gate input charge: 50 nC (Typ.) @VGS = 10 V
  • Reverse recovery time: 115 ns (Typ.)


Optimization of cell structure achieves low on-resistance and a low output charge.

  • Drain-Source voltage: 80 V (Max)
  • Drain current: 120 A (Max)
  • On-resistance: 1.9 mΩ (Typ.) @VGS = 10 V
  • Output charge: 90 nC (Typ.) @VDS = 40 V


Low on-resistance contributes to loss reduction.

  • Drain-Source voltage: 30 V (Max)
  • Drain current: 150 A (Max)
  • On-resistance: 0.41 mΩ (Typ.) @VGS = 10 V
This third generation product improves the trade-off between forward voltage and total capacitive charge

SiC Schottky Barrier Diode TRS6E65H

This third generation product improves the trade-off between forward voltage and total capacitive charge

  • Repetitive peak reverse voltage: 650 V (Max)
  • Forward DC current: 6 A (Max)
  • Forward Voltage: 1.2 V (Typ.) @IF = 6 A
  • Total capacitive charge: 17 nC (Typ.) @VR = 400 V
Digital isolator DCL540C01

Digital isolator DCL540C01

A quad channel digital isolator with magnetic coupling structure

  • Propagation delay: 10.9 ns (Typ.)
  • Channel matching (same direction): 3.2 ns (Max)
  • High CMTI:100 kV/μs (Min)
  • Power supply voltage: 2.25 to 5.5 V

Reference design overview

An AC-DC power supply capable of 1.6 kW (max) output, with a single-phase AC 100 V system and 200 V system as inputs and DC 12 V output. The board size is 307 mm × 135 mm, and the height is 43 mm, allowing placement in a 1U rack size server.

  • Input voltage: AC 90-264 V
  • Output voltage: DC 12 V
  • Output power: 0.8 kW (100 V system input), 1.6 kW (200 V system input)
  • Height: 43 mm (including base sheet metal and top plate)
1.6 kW Server Power Supply (Upgraded)
1.6 kW Server Power Supply (Upgraded)
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