Switching Converter, SMPS Transformers

Part Number	Description / PDF	Quantity
750311456 Würth Elektronik Midcom	TRANS FLYBACK LT3748 100UH SMD	0
750315836 Würth Elektronik Midcom	XFRMR FLYBACK DC/DC CONV SMD	261
750311306 Würth Elektronik Midcom	TRANS FLYBACK LT3575 100UH SMD	0
750310018 Würth Elektronik Midcom	POWER OVER ETHERNET UEBERTRAGER	0
750311271 Würth Elektronik Midcom	TRANS FLYBACK LT1725 20.4UH	0
7491199331 Würth Elektronik Midcom	TRANS FLYBACK POE 127UH SMD	15
760390011 Würth Elektronik Midcom	TRANSFORMER 1MH SMD	628
750342859 Würth Elektronik Midcom	POWER TRANSFORMER, MID-IMAXIB	48
750315832 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB	0
750311553 Würth Elektronik Midcom	TRANSFORMER FLYBACK LM3445	27
7491196331 Würth Elektronik Midcom	TRANS FLYBACK POE SMD	9
749196118 Würth Elektronik Midcom	WE-FLEX FLEXIBLE TRANSFORMER FOR	0
750370026 Würth Elektronik Midcom	TRANS OFF LINE POWER ST VIPER15L	0
750316032 Würth Elektronik Midcom	PUSH-PULL TRANSFORMER WE-PP	112
750310799 Würth Elektronik Midcom	TRANS FLYBACK LT3573 25UH SMD	12
750871110 Würth Elektronik Midcom	TRANS OFF LINE POWER ST VIPER28	23
750311607 Würth Elektronik Midcom	TRANS FLYBACK LT3748 14UH SMD	1000
749196138 Würth Elektronik Midcom	WE-FLEX FLEXIBLE TRANSFORMER FOR	0
750341143 Würth Elektronik Midcom	TRANSFORMER PLANAR 170UH SMD	0
750310022 Würth Elektronik Midcom	POWER OVER ETHERNET-UEBERTRAGER	0

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.