Overview
Solutions
HW Evaluation Tools
Resources
Tools and Software
Key Products
Get Started

The single-switch forward converter represents a valid alternative to the single-switch flyback topology in isolated, off-line, step-down converters with high output current requiring galvanic isolation in the 100 to 300 W power range. Unlike flyback converters, in a forward converter energy transfers instantly to the transformer and does not rely on it for energy storage. Transformers can thus have higher magnetizing inductance and no air gap, providing better transformer utilization. The transformer’s secondary output is then L-C filtered to ensure lower output voltage ripple while peak current – and thus stress – on the active transistor is reduced.

On the flip side, compared to a flyback topology, the transformer must be reset after a few cycles to avoid saturation. In this case, a higher voltage rating for the primary power MOSFET, an extra output inductor and a freewheeling diode are needed.

We have a complete offer of primary-side PWM and synchronous rectification controllers, power MOSFETs and diodes together with a range of hardware and software evaluation and development tools including reference designs to help developers design high-efficiency, size optimized forward converters.

00 Files selected for download

Technical Documentation

    • Description Version Size Action
      AN1768
      ADMISSIBLE AVALANCHE POWER OF SCHOTTKY DIODES
      1.1
      46.82 KB
      PDF
      AN2025
      CONVERTER IMPROVEMENT USING SCHOTTKY RECTIFIER AVALANCHE SPECIFICATION
      1.1
      147.59 KB
      PDF
      AN604
      Calculation of conduction losses in a power rectifier
      3.2
      137.74 KB
      PDF
      AN4021
      Calculation of reverse losses in a power diode
      1.0
      120.47 KB
      PDF
      AN2623
      Evaluation board for off-line forward converter based on L5991
      1.2
      1.24 MB
      PDF
      AN4829
      Fishbone diagrams for a forward converter
      1.1
      1.35 MB
      PDF
      AN1453
      NEW FAMILY OF 150V POWER SCHOTTKY
      1.1
      131.48 KB
      PDF
      AN5046
      Printed circuit board assembly recommendations for STMicroelectronics PowerFLAT packages
      4.0
      4.82 MB
      PDF
      AN5088
      Rectifiers thermal management, handling and mounting recommendations
      2.0
      2.32 MB
      PDF
      AN443
      SERIES OPERATION ON FAST RECTIFIERS
      2.1
      202.48 KB
      PDF
      AN869
      Tj max limit of Schottky diodes
      2.2
      60.9 KB
      PDF
      AN1768

      ADMISSIBLE AVALANCHE POWER OF SCHOTTKY DIODES

      AN2025

      CONVERTER IMPROVEMENT USING SCHOTTKY RECTIFIER AVALANCHE SPECIFICATION

      AN604

      Calculation of conduction losses in a power rectifier

      AN4021

      Calculation of reverse losses in a power diode

      AN2623

      Evaluation board for off-line forward converter based on L5991

      AN4829

      Fishbone diagrams for a forward converter

      AN1453

      NEW FAMILY OF 150V POWER SCHOTTKY

      AN5046

      Printed circuit board assembly recommendations for STMicroelectronics PowerFLAT packages

      AN5088

      Rectifiers thermal management, handling and mounting recommendations

      AN443

      SERIES OPERATION ON FAST RECTIFIERS

      AN869

      Tj max limit of Schottky diodes

Presentations & Training Material

    • Description Version Size Action
      Primary side regulation controllers portfolio
      1.1 MB
      PDF

      Primary side regulation controllers portfolio

Publications and Collaterals

    • Description Version Size Action
      500-650 V MDmesh™ M2: The New ST’s High Voltage Super-junction MOSFET Series 1.0
      720.83 KB
      PDF
      600-650 V MDmesh™ M2: The ST’s new Super-junction HV MOSFET series 1.0
      755.53 KB
      PDF
      800-1050V MDmesh™ K5 ST’s first super-junction VHV MOSFET Series 1.0
      516.44 KB
      PDF
      Field-Effect Rectifier Diodes Advantageously replace Schottky (60V and 100V) 1.0
      1.29 MB
      PDF
      ST Diodes Finder : the new app for Android and iOS 2.0
      1.46 MB
      PDF

      500-650 V MDmesh™ M2: The New ST’s High Voltage Super-junction MOSFET Series

      600-650 V MDmesh™ M2: The ST’s new Super-junction HV MOSFET series

      800-1050V MDmesh™ K5 ST’s first super-junction VHV MOSFET Series

      Field-Effect Rectifier Diodes Advantageously replace Schottky (60V and 100V)

      ST Diodes Finder : the new app for Android and iOS

    • Description Version Size Action
      Diodes and rectifiers selection guide 2.0
      815.09 KB
      PDF

      Diodes and rectifiers selection guide

Development Tools

    • Part Number

      MOSFET product finder application for Android and iOS

      Linear and switching voltage regulators and voltage reference applications for smartphones and tablets

eDesignSuite

Converter

Input

V This option is required. And must be less than or equal to Volt. Max [V]
V This option is required. And must be greater than or equal to Volt. Min [V]

Output Power

V This option is required and must be a number.
A This option is required and must be a number.

Diodes and Rectifiers

Part number Description
FERD20U60DJFD 60 V, 20 A PowerFLAT Ultra-Low Vf Field-Effect Rectifier Diode (FERD)
FERD40H100S 100 V, 40 A Field-Effect Rectifier Diode (FERD)
STTH2002C 200 V, 20 A dual Ultrafast Diode
STTH3002C 200 V, 30 A dual Ultrafast Diode
STTH6003 300V , 60 A dual Ultrafast Diode
Part number
60 V, 20 A PowerFLAT Ultra-Low Vf Field-Effect Rectifier Diode (FERD)
100 V, 40 A Field-Effect Rectifier Diode (FERD)
200 V, 20 A dual Ultrafast Diode
200 V, 30 A dual Ultrafast Diode
300V , 60 A dual Ultrafast Diode

Power Management

Part number Description
L5991 Current Mode PWM
Part number
Current Mode PWM

Power Transistors

Part number Description
STB5N80K5 N-channel 800 V, 1.50 Ohm typ., 4 A MDmesh K5 Power MOSFET in a D2PAK package
STF140N6F7 N-channel 60 V, 0.0031 Ohm typ., 70 A STripFET F7 Power MOSFET in a TO-220FP package
STF24N60M2 N-channel 600 V, 0.168 Ohm typ., 18 A MDmesh M2 Power MOSFET in TO-220FP package
STH140N8F7-2 N-channel 80 V, 3.3 mOhm typ., 90 A STripFET F7 Power MOSFET in H2PAK-2 package
STP40N60M2 N-channel 600 V, 0.078 Ohm typ., 34 A MDmesh M2 Power MOSFET in TO-220 package
Part number
N-channel 800 V, 1.50 Ohm typ., 4 A MDmesh K5 Power MOSFET in a D2PAK package
N-channel 60 V, 0.0031 Ohm typ., 70 A STripFET F7 Power MOSFET in a TO-220FP package
N-channel 600 V, 0.168 Ohm typ., 18 A MDmesh M2 Power MOSFET in TO-220FP package
N-channel 80 V, 3.3 mOhm typ., 90 A STripFET F7 Power MOSFET in H2PAK-2 package
N-channel 600 V, 0.078 Ohm typ., 34 A MDmesh M2 Power MOSFET in TO-220 package