Why do PTH inductors exhibit excellent saturation characteristics in high-current applications?
Publish Time: 2026-02-24
In modern high-power-density power systems, inductors, as key components for energy storage and filtering, directly determine the system's stability and efficiency through their anti-saturation capability. Especially in high-current applications such as server power supplies, electric vehicles, and industrial frequency converters, magnetic saturation in inductors can lead to a sharp drop in inductance, current runaway, accelerated temperature rise, and even circuit failure. PTH inductors are highly favored by engineers due to their superior performance in maintaining stable inductance even under high current.1. Core: Application of High Saturation Flux Density MaterialsThe superior saturation characteristics of PTH inductors stem from the high saturation flux density of the magnetic materials they use. While traditional ferrite materials have good high-frequency characteristics, their low Bsat value makes them prone to saturation under high current. Most high-performance PTH inductors use metal alloy powder cores or composite magnetic materials, whose Bsat values can reach over 1.0T, far exceeding those of ordinary ferrites. This means that with the same magnetic circuit cross-sectional area, it can carry a higher magnetic flux, thus significantly improving the saturation current. Furthermore, the naturally occurring micro-air gaps within the powder core material form a "distributed air gap" structure, effectively suppressing the saturation problem caused by excessively high permeability, resulting in a smoother magnetization curve and stronger resistance to DC bias.2. Structural Design: Optimizing the Magnetic Circuit and Increasing Copper Filling RatioBesides materials, structural design is another key to improving saturation resistance. PTH inductors generally adopt an integrated magnetic shielding structure, with high magnetic circuit closure, low leakage flux, and energy concentrated inside the magnetic core, reducing external interference and improving magnetic efficiency. More importantly, their coils are mostly wound with flat copper wire. Compared to traditional round wire, flat wire has a larger cross-sectional area and a higher filling ratio, which not only significantly reduces DC resistance and heat generation but also allows for more turns or thicker wires within a limited space, thereby increasing current carrying capacity. A high copper filling ratio means that a larger current can be carried in the same volume, directly pushing up the saturation current threshold.3. Process and Thermal Management: Ensuring Long-Term StabilityIn high-current applications, temperature rise is a significant factor affecting inductor performance. Increased temperature leads to a decrease in the Bsat of the magnetic material, accelerating saturation. PTH inductors utilize a through-hole mounting structure, with leads penetrating the PCB to form a robust mechanical and electrical connection. This design not only enhances resistance to vibration and shock but, more importantly, provides an efficient heat conduction path from the device body to the copper layers inside the PCB. Combined with a low DCR design, overall heat loss is lower, and temperature rise is more controllable, thereby indirectly maintaining the high Bsat characteristics of the magnetic core and avoiding performance degradation caused by overheating.4. Application Scenarios: High-Reliability Verification FieldsIn fields with high reliability requirements, such as server power supplies, new energy vehicle OBCs, and industrial motor drives, PTH inductors, with their high Isat, low loss, and strong noise immunity, have become key components in high-current DC-DC converters. Even under continuous high current and dynamic load fluctuations, they maintain stable inductance, ensuring efficient operation of the power system.The superior saturation characteristics exhibited by PTH inductors in high-current applications are a testament to the deep integration of materials science, electromagnetic design, and manufacturing processes. Built upon a high-Bsat magnetic core, supported by a flat wire high-fill structure, and guaranteed by through-hole heat dissipation and shielding design, it creates an ideal solution that combines high power density and high reliability. In power electronic systems that demand high efficiency, compactness, and stability, PTH inductors not only withstand high currents but also maintain minimum performance requirements, making them a crucial support for advancements in modern power supply technology.
