Custom EF25 High Frequency Transformer for Flyback SMPS Power Supply Charger

1.Product Description

The EF25 high-frequency transformer is a compact ferrite core transformer designed specifically for flyback topologies in switch mode power supplies (SMPS), battery chargers, and power adapters. The power range is 10W to 30W, the operating frequency is 20kHz to 200kHz, the performance is stable, the temperature rise is low, and the efficiency is high. 5+5 pin configuration, inductor voltage size, and other specifications are fully customizable. Very suitable for applications with limited space but requiring reliability and customized specifications.

Application Scenario: 24W USB-C Fast Charger for smartphones and tablets

How the EF25 Transformer Works in This Product:
Inside the charger, the EF25 high frequency transformer is used in a flyback SMPS circuit. It steps down the high voltage AC (100-240V) to a low voltage DC (5V, 9V, 12V, or 15V) while providing isolation for safety. The transformer operates at 100kHz switching frequency, delivering up to 24W of power (e.g., 12V / 2A or 15V / 1.6A). Its compact EF25 core size fits perfectly inside the small USB-C charger housing, while the custom winding ensures low leakage inductance and high efficiency (>88%), reducing heat generation during fast charging.

Why Choose the EF25 for This Application:

• Small footprint fits slim charger design

• Supports multiple output voltages for fast charging protocols (QC/PD)

• Low temperature rise ensures safe surface temperature

• Customizable parameters meet specific voltage and current requirements

2.Performance Characteristics