300W Isolated DC-DC Converter

This reference design provides specification, block diagram and PCB layout data of 300W isolated DC-DC converter which is small size and suitable for consumer applications.

Features of 300W Isolated DC-DC converter.
Block diagram of 300W Isolated DC-DC converter.


  • Total efficiency : 94.5%(Vin=48V, 100% load)
  • Outline size : 82mm x 82mm x 24mm
  • Provides appropriate power MOSFETs and photocouplers totally.


Input voltage DC 36 to 75V
Output voltage DC 12V
Output power 300W
Circuit topology Phase Shift Full Bridge + Synchronous Rectification
Efficiency curves of 300W Isolated DC-DC converter.
Efficiency Curves

Design Documents

Design Documents contain the documents below.

Design Data

Design Data contains the contents listed below.

*1:Actual PCB was designed on CR5000BD. The other files were made from CR5000BD file.

*2:The data was generated on CR5000BD.

Used Toshiba Items

Part Number Device Category Portion Usage Description
Power MOSFET (N-ch single 60V<VDSS≤150V) Primary side・4 N-ch MOSFET, 100 V, 0.0115 Ω@10V, TSON Advance, U-MOSⅨ-H
Power MOSFET (N-ch single 60V<VDSS≤150V) Secondary side synchronous rectification・4 N-ch MOSFET, 100 V, 0.0037 Ω@10V, SOP Advance, U-MOSⅨ-H
Photocoupler (photo-IC output) Communication between primary side and secondary side・2 Photocoupler (photo-IC output), High-speed, 20 Mbps, 3750 Vrms, 5pin SO6
Schottky barrier diode Secondary side・1 30 V/1 A Schottky Barrier Diode, S-FLAT
Small-signal Schottky barrier diode Secondary side・7 40 V/0.5 A Schottky Barrier Diode, SOD-882(CST2)

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