Specifying a high frequency transformer is rarely just a matter of sending an input voltage and an output voltage to a supplier. In a switching power supply, the transformer is part of the energy transfer path, the isolation barrier, the thermal design, and the EMI behavior of the whole converter. A small change in frequency, duty cycle, leakage inductance, or winding arrangement can change the final result on the bench.
BaoHui Tech manufactures high frequency transformers for switching power supplies, inverters, UPS systems, chargers, industrial controls, and other power electronics applications. From a manufacturing point of view, the best projects usually begin with clear electrical limits and a realistic picture of the operating environment.
Start with the converter topology
The same power level can require different transformer construction depending on whether the circuit is flyback, forward, half-bridge, full-bridge, LLC resonant, or push-pull. In a flyback converter, the transformer stores and releases energy, so air gap design and saturation margin are central. In an LLC or bridge converter, the transformer is closer to an isolation and voltage conversion device, while leakage inductance may be controlled as part of the resonant behavior.
Before requesting a quote, it helps to share the topology, operating frequency, expected duty cycle range, control IC if available, input voltage range, output voltage, output current, and target efficiency. These details allow the transformer manufacturer to avoid guesswork in core size, turns ratio, and winding arrangement.
Frequency changes the mechanical design
High frequency operation reduces core size, but it also introduces new loss mechanisms. Core loss, copper loss, skin effect, proximity effect, and winding capacitance become more visible as frequency increases. A transformer designed for 50 kHz may not behave well at 250 kHz even if the turns ratio looks similar on paper.
For higher-frequency designs, winding method matters. Litz wire, foil, multi-strand wire, sectional winding, and insulation tape choices can all be used to control temperature rise and leakage inductance. The correct choice depends on current, frequency, safety requirements, and the space available in the bobbin window.
Do not treat insulation as an afterthought
For isolated power supplies, insulation requirements should be defined early. The design team should know whether the transformer needs basic insulation, reinforced insulation, specific creepage and clearance distance, hipot test voltage, or compliance with a particular safety standard. If the transformer is used in EV charging, medical equipment, industrial drives, or grid-connected products, these requirements may be stricter than a general consumer power supply.
Thermal rise is the real-world test
Datasheets and calculations are useful, but transformer temperature rise under load is one of the most practical indicators of design quality. A high frequency transformer may pass a no-load test and still run too hot inside a closed power supply. Ambient temperature, airflow, enclosure material, nearby heat sources, and duty cycle all matter.
Information to send when requesting a custom transformer
- Topology and switching frequency
- Input and output voltage range
- Output power and peak current
- Isolation voltage and safety requirements
- Target dimensions or available PCB space
- Expected ambient temperature and cooling method
- Required certifications or test standards
FAQ
What is a high frequency transformer?
A high frequency transformer is a magnetic component designed to transfer energy at switching frequencies much higher than mains frequency, often used in SMPS, inverters, chargers, and DC-DC converters.
Can BaoHui Tech make custom high frequency transformers?
Yes. BaoHui Tech supports custom transformer manufacturing based on electrical specifications, mechanical size, safety requirements, and application conditions.