Forward Converter
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.
Resources
Technical Documentation
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AN1768: ADMISSIBLE AVALANCHE POWER OF SCHOTTKY DIODES | 1.1 | 46 KB |
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AN2025: CONVERTER IMPROVEMENT USING SCHOTTKY RECTIFIER AVALANCHE SPECIFICATION | 1.1 | 147 KB |
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AN604: Calculation of conduction losses in a power rectifier | 3.2 | 137 KB |
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AN4021: Calculation of reverse losses in a power diode | 1.0 | 120 KB |
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AN2623: Evaluation board for off-line forward converter based on L5991 | 1.2 | 1 MB |
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AN4829: Fishbone diagrams for a forward converter | 1.1 | 1 MB |
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AN1453: NEW FAMILY OF 150V POWER SCHOTTKY | 1.1 | 131 KB |
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AN5046: Printed circuit board assembly recommendations for STMicroelectronics PowerFLAT™ packages | 3.0 | 5 MB |
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AN5088: Rectifiers thermal management, handling and mounting recommendations | 2.0 | 2 MB |
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AN443: SERIES OPERATION ON FAST RECTIFIERS | 2.1 | 202 KB |
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AN869: Tj max limit of Schottky diodes | 2.2 | 60 KB |
Presentations & Training Material
Publications and Collaterals
| Description | Version | Size | |
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500-650 V MDmesh™ M2: The New ST’s High Voltage Super-junction MOSFET Series | 1.0 | 720 KB |
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600-650 V MDmesh™ M2: The ST’s new Super-junction HV MOSFET series | 1.0 | 755 KB |
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800-1050V MDmesh™ K5: ST’s first Super-junction VHV MOSFET Series | 1.0 | 1 MB |
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Field-Effect Rectifier Diodes Advantageously replace Schottky (60V and 100V) | 1.0 | 1 MB |
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ST Diodes Finder : the new app for Android and iOS | 2.0 | 1 MB |
| Description | Version | Size | |
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Diodes and rectifiers selection guide | 2.0 | 815 KB |
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Power MOSFET Selection Guide | 1.0 | 1 MB |
