Power Devices for AC/DC Adapters and Switching Power Supplies
MOSFETs, SiC diodes and bridge rectifiers for flyback, forward and LLC power supplies from 5 W to 300 W. Part selection by topology, not by catalogue page.
A switching power supply converts AC mains into a regulated DC output through a high-frequency converter, and its efficiency is decided by which devices switch and rectify. OCENME supplies the device set for adapters and open-frame supplies from 5 W to 300 W: 650 V super junction MOSFETs for the primary, 30–100 V MOSFETs for synchronous rectification, and bridge rectifiers from 1 A to 8 A for the input.
Scope of supply in this sector
This page covers flyback, forward, quasi-resonant and LLC topologies from 5 W to 300 W at universal input. Supplies above 300 W or with active PFC usually move to SiC devices, which are covered under the PFC and telecom pages.
Requirements
| Input range | 90–264 V AC universal, 375 V DC bus typical |
|---|---|
| Primary switch class | 650 V super junction, 7 A to 20 A |
| Secondary rectifier | 30–100 V MOSFET from 3 mΩ, or Schottky below 20 V output |
| Input bridge | 1 A to 8 A, 600–1000 V, in-line package |
| Switching frequency | 45–150 kHz quasi-resonant; 65–130 kHz fixed frequency |
| Efficiency target | DoE Level VI and CoC Tier 2 for external adapters |
| Standby power | Below 75 mW at no load for most Level VI adapters |
Materials we machine for this sector
- Silicon super junction and trench die
- GPP bridge die
- Copper lead frames
- UL 94V-0 mould compound
Applicable standards
- DoE Level VI (10 CFR 430) for external power supplies
- EU CoC Tier 2 efficiency
- IEC 62368-1 for safety of the end product
- EN 55032 / CISPR 32 for EMI of the end product
Typical parts
- 650 V super junction MOSFET, 150 mΩ to 340 mΩ, TO-220F and TO-252
- 100 V synchronous rectifier MOSFET from 5.5 mΩ, TO-220 and PDFN 5×6
- 30 V and 60 V load-switch MOSFETs, TO-252 and PDFN
- Bridge rectifiers, 1 A to 8 A, MBF, ABS, KBP, MSB
- 650 V SiC Schottky diode for continuous conduction mode PFC above 75 W
Quality risks specific to this sector
These are the failure modes we see most often in this industry. They are listed because knowing them before design review is cheaper than discovering them at first article.
- Bridge rectifier undersized on RMS current, so it runs at its junction limit inside a sealed case
- Synchronous rectifier selected on voltage rating only, ignoring body-diode recovery in discontinuous mode
- Primary snubber tuned at room temperature, then failing at low-temperature start-up when the clamp voltage rises
- Efficiency measured at nominal 230 V only, hiding the worst case at 90 V input
Compliance and capability questions
Which devices decide efficiency in a 65 W USB-PD adapter?
Three do most of the damage: the primary switch, the synchronous rectifier and the transformer. At 65 W a quasi-resonant flyback with a 650 V super junction primary and a 100 V synchronous rectifier in PDFN typically reaches 92–94% at nominal input. The bridge rectifier contributes roughly 1% and is usually chosen on cost and thermal headroom rather than efficiency.
When does an adapter need a PFC stage?
Above 75 W for external supplies sold into the EU and above 75 W for many other markets, power factor correction becomes a regulatory requirement rather than a design choice. Below that, a passive solution or none at all is normal. The PFC stage brings a 650 V SiC Schottky or super junction MOSFET into the bill of materials.
Can you supply the whole device set for one adapter?
Yes — primary super junction MOSFET, secondary synchronous rectifier, bridge rectifier and PFC diode all come from the same catalogue, which means one supplier questionnaire, one PCN process and one lot traceability chain. That consolidation is usually worth more to a mid-size adapter maker than a fraction of a cent on a single part.
What documentation do adapter makers ask for?
A datasheet with characterised curves at the actual gate drive voltage, a lot test record, a reliability report for the part number and a material declaration. Automotive-style PPAP is not normally requested; safety certification evidence for the end product is the adapter maker’s responsibility, not the component supplier’s.
Industries we also supply
LED Drivers & Lighting Power
An LED driver is a current source, not a voltage source, so its devices are chosen for the current loop and the thermal environment rather than for output voltage alone. OCENME supplies 500–650 V MOSFETs, fast recovery diodes and bridge rectifiers for isolated flyback, non-isolated buck and PFC boost LED drivers from 5 W to 200 W..
View sectorTelecom & UPS Power
Telecom rectifiers and UPS systems run continuously at high ambient with a service life measured in a decade, so device selection is driven by derating margin and long-term stability rather than by peak efficiency. OCENME supplies 650 V super junction MOSFETs, SiC Schottky diodes and fast recovery diodes for rectifier PFC stages and UPS inverter legs, with HTRB and H3TRB reports per part number..
View sectorWelding Equipment
An inverter welding machine runs a high-frequency transformer at high current and high duty cycle, so its diodes must survive repeated high di/dt commutation rather than steady-state current. OCENME supplies 600–1200 V fast recovery diodes and 500–650 V MOSFETs for welding inverter stages, with IFSM, Trr and thermal cycling data stated per part number..
View sectorSolar & Energy Storage
A solar inverter or battery converter moves power in both directions at high frequency, so device choice is driven by switching loss and body-diode behaviour rather than by conduction loss alone. OCENME supplies 650 V and 800 V SiC MOSFETs, 650 V SiC Schottky diodes and 650 V super junction MOSFETs for boost stages and battery converters from 200 W to 10 kW..
View sectorSend the part number and the operating conditions
Tell us the voltage class, current, switching frequency and what the device is replacing. You will get a datasheet, a parameter comparison at matched conditions, and a quotation with MOQ and lead time.