Switching Converter, SMPS Transformers

Part Number	Description / PDF	Quantity
750815045 Würth Elektronik Midcom	OFFLINE XFRM WE-UNIT TI LM3448	15
750313995 Würth Elektronik Midcom	TRANS FLYBACK LM5017 WE-FB	172
750311771 Würth Elektronik Midcom	TRANS FLYBACK LT3748 500UH SMD	0
750815039 Würth Elektronik Midcom	TRANS OFFLINE WE-UNIT TI UCC2860	0
750310167 Würth Elektronik Midcom	POWER OVER ETHERNET TRANSFORMER	0
750315230 Würth Elektronik Midcom	PUSH-PULL TRANSFORMER	484
7491195331 Würth Elektronik Midcom	TRANS FLYBACK POE SMD	139
750311661 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB LT3512	0
750811512 Würth Elektronik Midcom	OFFLINE TRANSFORMER WE-UNIT	0
750313054 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB	13
750813144 Würth Elektronik Midcom	TRANS OFFLINE600UH LT3799 LT4180	490
750340477 Würth Elektronik Midcom	TRANS FLYBACK NXPSSL1750 550UH	0
750813141 Würth Elektronik Midcom	TRANSFORMER POWER ICL8001G PCB	0
760871543 Würth Elektronik Midcom	TRANSFORMER OFFLINE 1.31MH 4000V	412
750871830 Würth Elektronik Midcom	TRANS FLYBACK NXP STARPLUG 900UH	0
750032173 Würth Elektronik Midcom	POWER OVER ETHERNET TRANSFORMER	0
750314463 Würth Elektronik Midcom	XFMR ISOL BUCK CONV DC/DC CONV	0
750311688 Würth Elektronik Midcom	TRANS FLYBACK LT3748LT3575 50UH	0
750313417 Würth Elektronik Midcom	OFFLINE TRANSFORMER	186
750316819 Würth Elektronik Midcom	PUSH-PULL TRANSFORMER TOR5.8/3.1	890

Switching Converter, SMPS Transformers

1. Overview

Switching Mode Power Supply (SMPS) Transformers are critical components in power electronics systems, enabling efficient voltage conversion through high-frequency switching techniques. Unlike traditional linear transformers, SMPS transformers operate at frequencies typically above 20 kHz, allowing reduced size, weight, and improved energy efficiency. These components are essential for modern power management solutions in electronics, renewable energy systems, and industrial automation.

2. Main Types and Functional Classification

Type	Functional Characteristics	Application Examples
Discontinuous Mode (DCM) Flyback	Galvanic isolation, single-switch control	AC-DC adapters, battery chargers
Continuous Mode (CCM) Flyback	Higher power density, lower ripple current	LED drivers, industrial power supplies
Forward Converter	Efficient for medium power levels, requires reset circuit	Server power supplies, telecom equipment
Push-Pull	Balanced magnetic utilization, high efficiency	High-end audio amplifiers, welding machines
Half-Bridge/Full-Bridge	High power capability, symmetrical switching	Electric vehicle charging, solar inverters

3. Structure and Components

Typical SMPS transformer construction includes:

Core materials: Ferrite (Mn-Zn or Ni-Zn), Powdered Iron, Amorphous alloys
Winding configuration: Primary/secondary windings with optimized turn ratios
Insulation system: Bobbins, tape insulation, and potting compounds
Termination: Tin-plated copper leads or surface-mount pads
Shielding: Electrostatic shields for EMI reduction

4. Key Technical Specifications

Parameter	Importance
Input Voltage Range	Determines compatibility with power sources
Output Power Rating	Defines maximum energy transfer capability
Switching Frequency	Impacts size, efficiency, and EMI performance
Turns Ratio Accuracy	Affects voltage regulation precision
Isolation Voltage	Ensures safety and dielectric strength
Efficiency (Typical >90%)	Reduces thermal management requirements
Operating Temperature	Determines reliability in harsh environments

5. Application Fields

Major application sectors include:

Consumer Electronics: Mobile device chargers, laptop adapters
Industrial: Motor drives, PLC power supplies, test equipment
Telecommunications: Base station power systems, optical network equipment
Renewable Energy: Solar inverters, energy storage systems
Automotive: On-board chargers (OBC), DC-DC converters
Medical: Isolated power supplies for diagnostic equipment

6. Leading Manufacturers and Products

Manufacturer	Representative Product	Key Features
TDK-Lambda	PWM Switching Transformer	High-density design, 150kHz operating frequency
Coilcraft	XEL60xx Series	Ultra-low profile, 25A saturation current
Pulse Electronics	PA5477NL	Integrated EMI filtering, automotive qualified
Bel/Signal Transformer	125-2011-F	Medical-grade isolation, 4kV withstand
Delta Electronics	TMA-101-01	High-efficiency (94%), 1kW power rating

7. Selection Guidelines

Key considerations for optimal selection:

Power requirements (continuous vs peak load)
Switching frequency compatibility with controller ICs
Thermal management capabilities
Creepage/clearance distances for safety certification
Cost-performance trade-offs
Package dimensions and mounting requirements
Compliance with standards (UL, IEC, AEC-Q)

8. Industry Trends

Current development directions include:

Miniaturization through higher operating frequencies (>1MHz)
Integration with wide-bandgap semiconductors (GaN/SiC)
Advanced nanocrystalline core materials
AEC-Q qualified components for automotive electrification
Smart transformers with embedded sensing
RoHS-compliant, halogen-free construction

Market forecasts indicate 8.2% CAGR through 2028, driven by 5G infrastructure and renewable energy adoption.