Switching Converter, SMPS Transformers

Part Number	Description / PDF	Quantity
B78334B1033A003 TDK EPCOS	XFRMER DC/DC CONV SMD	1198
750313975 Würth Elektronik Midcom	TRANS FLYBACK LT8301	306
750311675 Würth Elektronik Midcom	TRANS FLYBACK LT3575LT3748 25UH	115
13324-T084 Sumida Corporation	XFRMR	750
VP2-0066-R PowerStor (Eaton)	PULSE XFMR 3.2UH SMD	0
EPC3472G-LF PCA Electronics, Inc.	POE FLYBACK XFM 5V, 25W	480
750311592 Würth Elektronik Midcom	TRANS FLYBACK LT3748 8UH SMD	0
750313959 Würth Elektronik Midcom	WE-FB FLYBACK TRANSFORMER	10
750315831 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB	0
ECO2020SEO-D06H015 TDK Corporation	INDUCTOR/XFRMR	0
750315830 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB	0
PH0810CNL PulseLarsen Antenna	XFMR DC/DC CONV SMD	2
760895631 Würth Elektronik Midcom	WE-LLCR RESONANT CONVERTER 500H	0
7508110420 Würth Elektronik Midcom	OFFLINE TRANSFORMER WE-UNIT	0
749196231 Würth Elektronik Midcom	WE-FLEX FLEXIBLE TRANSFORMER FOR	0
750310007 Würth Elektronik Midcom	TRANS FLYBACK LM5070LM5071LM5072	10
PA4470.006NLT PulseLarsen Antenna	TRANSFORMER FLYBACK DM 1.8W SMT	0
750315319 Würth Elektronik Midcom	FLYBACK TRANSFORMER WE-FB	0
750314952 Würth Elektronik Midcom	POWER TRANSFORMER	0
749196121 Würth Elektronik Midcom	WE-FLEX FLEXIBLE TRANSFORMER FOR	175

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.