Switching Converter, SMPS Transformers

Part Number	Description / PDF	Quantity
750370047 Würth Elektronik Midcom	TRANS FLYBACK LT3573 30UH SMD	573
750340681 Würth Elektronik Midcom	POWER TRANSFORMER	0
750310743 Würth Elektronik Midcom	TRANS FLYBACK POE+ 38UH SMD	201
760895731 Würth Elektronik Midcom	WE-LLCR RESONANT CONVERTER 475H	19
750811050 Würth Elektronik Midcom	FLYBACK XFRM WE-FB LT LT3748	0
750316112 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB	359
750315837 Würth Elektronik Midcom	XFRMR FLYBACK DC/DC CONV SMD	0
750314225 Würth Elektronik Midcom	TRANS FLYBACK LM5017 WE-FB	0
749119133 Würth Elektronik Midcom	WE-POE POWER OVER ETHERNET TRANS	483
7508116312 Würth Elektronik Midcom	SMD OFFLINE TRANSFORMER WE-UNIT	62
7508170311 Würth Elektronik Midcom	XFRMER FLYBACK AC/DC CONV SMD	175
7491182012 Würth Elektronik Midcom	TRANSFORMER OFF LINE 4000V	0
750311660 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB LT8300	645
750311385 Würth Elektronik Midcom	TRANS FLYBACK LT3748 15UH SMD	136
750811137 Würth Elektronik Midcom	TRANS 3000V SMD	0
750310660 Würth Elektronik Midcom	TRANS OFF LINE POWER ST VIPER17H	0
749196540 Würth Elektronik Midcom	TRANSFORMER 3.4UH 1.91A SMD	55
760895751 Würth Elektronik Midcom	WE-LLCR RESONANT CONVERTER 400H	28
750811913 Würth Elektronik Midcom	SMD OFFLINE TRANSFORMER WE-UNIT	20
750314839 Würth Elektronik Midcom	XFRMR RES CONV DC/DC CONV SMD	48

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.