A custom inductor in a DC-DC converter has to do more than meet an inductance value. It must handle ripple current, avoid saturation, control DCR, manage AC loss, fit the available board space, and maintain acceptable temperature rise. If these factors are not specified, the converter may work in light-load testing but fail at high load or high temperature.
BaoHui Tech manufactures custom inductors, transformers, filters, and magnetic components for power supplies, inverters, UPS systems, chargers, and industrial electronics. DC-DC converter inductors are a common example of why magnetic components should be designed around real circuit conditions.
Inductance value is only the starting point
The inductance value affects ripple current, transient response, control loop behavior, and peak current. A lower inductance value may reduce size and improve transient response, but it can increase ripple current and stress switching devices. A higher value may reduce ripple but increase size, DCR, and cost.
Engineers should define input voltage range, output voltage, output current, switching frequency, topology, allowable ripple, and control mode before requesting a custom inductor.
Saturation current must match peak conditions
The inductor must avoid saturation at peak current, including startup, overload, transient load, and high-temperature operation. Saturation reduces inductance and can cause current to rise quickly. This may damage MOSFETs, diodes, controllers, or the inductor itself.
Saturation current should be defined with a clear inductance drop criterion, such as a percentage drop from nominal inductance. The test condition matters.
DCR and AC loss both create heat
Low DCR reduces conduction loss, but high frequency current also creates AC winding loss. Skin effect and proximity effect can become important as switching frequency and ripple current increase. Core loss also depends on material, frequency, flux swing, and temperature.
A good custom inductor balances copper loss and core loss. Reducing one loss source without checking the other can move the heat rather than solve it.
Core material changes behavior
Ferrite, powder core, sendust, amorphous, and nanocrystalline materials each have different saturation behavior, loss characteristics, temperature response, and cost. The correct core material depends on current waveform, switching frequency, allowed ripple, size target, and thermal requirement.
For high-current converters, distributed gap materials may provide smoother saturation behavior. For other designs, a gapped ferrite core may be more efficient or easier to control.
Production testing should reflect real use
Common tests include inductance, DCR, dimensions, visual inspection, and insulation if required. For critical applications, current-biased inductance and temperature rise testing may be needed. A nominal inductance test without bias current may not predict converter performance.
BaoHui Tech can support custom inductor development based on electrical requirements, mechanical size, thermal targets, and production volume.
FAQ
What information is needed for a custom DC-DC converter inductor?
Provide inductance, rated current, peak current, ripple current, switching frequency, converter topology, size limits, thermal conditions, and test requirements.
Can BaoHui Tech manufacture custom inductors?
Yes. BaoHui Tech manufactures custom inductors and magnetic components for DC-DC converters, inverters, power supplies, UPS systems, and industrial electronics.
A reliable DC-DC converter inductor is specified from waveform, current, thermal environment, and production testing, not from inductance alone.