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Custom winding service scheme for high-frequency coils for GaN and SiC applications
2026-08-06
With the widespread adoption of gallium nitride (GaN) and silicon carbide (SiC) wide-bandgap semiconductor devices, the operating frequency of switching power supplies has soared from the traditional 60kHz to 100kHz to the ultra-high frequency range of 200kHz to 3MHz, driving the evolution of power equipment towards smaller size, higher power density, lower temperature rise, and higher efficiency. The performance breakthrough of wide-bandgap power supplies is not only dependent on the upgrade of chip architecture and circuit topology, but more crucially, it is constrained by the winding process of high-frequency magnetic components. The traditional loose winding method using thick round wires cannot solve the industry pain points such as skin effect, proximity effect, parasitic parameter drift, and soaring losses at ultra-high frequencies, becoming the key bottleneck restricting the energy efficiency and stability of GaN and SiC power supplies.
For the specific working conditions of wide-bandgap power supplies, specialized high-frequency coil winding services have emerged. The core includes two major processes: precise twisting of Leeds wires and flat winding of planar inductors, precisely adapting to high-end scenarios such as GaN high-frequency fast charging, SiC vehicle OBC, industrial high-frequency LLC resonant power supplies, energy storage inverter power supplies, and server high-density power supplies.
- GaN/SiC High-Frequency Conditions: The Fatal Adaptation Shortcomings of Traditional Coil Winding
The core advantage of wide-bandgap semiconductor devices is fast switching speed, low conduction loss, and support for ultra-high frequency operation. However, the electromagnetic loss problem brought by high-frequencyization is completely transferred to the coil system of transformers and inductors, which are magnetic components. The traditional switching power supply uses single-strand thick round wires and manual loose winding methods. At ultra-high frequency conditions above 200kHz, this method will expose structural defects that cannot be avoided, directly offsetting the performance advantages of wide-bandgap chips.
Firstly, the high-frequency skin effect leads to explosive growth in loss. At 100kHz, the copper material's skin depth is only 0.21mm, and above 300kHz, it is less than 0.12mm. The central conductor of the thick round wire is completely idle, the effective conductive area is significantly reduced, the AC resistance (ACR) increases several times, and copper loss rises sharply, resulting in excessive power supply temperature rise and a cliff-like drop in efficiency. Secondly, the proximity effect interference intensifies. When the winding layout is unreasonable, the magnetic fields between layers interfere with each other, generating additional eddy current losses, causing high-frequency buzzing, EMC interference exceeding standards.
At the same time, the consistency of winding process parameters is extremely poor. The loose-wound coils have greatly varying leakage inductance, parasitic capacitance, and winding tightness. In the high-frequency variable-frequency working mode of GaN/SiC, it is prone to batch problems such as resonance point deviation, power drift, dynamic load instability, and low efficiency at light load. Moreover, the traditional coils are bulky in size and have low window utilization, unable to meet the product iteration requirements of thinness and high power density for wide-bandgap power supplies.
It is clear that the performance limit of GaN and SiC power supplies is determined by the high-frequency coil winding process. To release the advantages of high frequency, high efficiency, and miniaturization of wide-bandgap devices, it is necessary to abandon the traditional winding scheme and adopt professional Leeds wire winding and planar inductor winding services, solving the problems of high-frequency loss and parameter out-of-control at the winding structure level.
It is clear that the performance limit of GaN and SiC power supplies is determined by the high-frequency coil winding process. To release the advantages of high frequency, high efficiency, and miniaturization of wide-bandgap devices, it is necessary to abandon the traditional winding scheme and adopt professional Leeds wire winding and planar inductor winding services, solving the problems of high-frequency loss and parameter out-of-control at the winding structure level.
- High-Frequency Wire Twisting Service (Leeds Wire): Core Solution for Ultra-High Frequency Low Loss
The Leeds wire winding is the core process for adapting to all high-frequency scenarios in GaN/SiC and is also the mainstream solution for high-end high-frequency power supplies in mass production. Different from the common multi-strand winding, the specialized twisted wire winding adopts ultra-fine insulated single wires, precise repositioning of twisting, and a constant-tension precise winding system. This fundamentally suppresses the high-frequency skin effect and proximity effect, perfectly adapting to the wide-bandwidth high-frequency working conditions ranging from 200 kHz to 3 MHz.
1. Core process principle of twisted wire winding
The Leeds twisted wire uses multi-strands of copper wires with diameters of 0.05 to 0.1 mm that are independently insulated. They are then twisted layer by layer with a fixed twisting distance. The diameter of each single wire is strictly controlled to be within twice the depth of the high-frequency skin effect, ensuring that each fine wire can evenly participate in conduction, completely avoiding the single wire skin effect. At the same time, through the periodic repositioning process, each wire alternately exists in the inner and outer regions of the magnetic field, evenly canceling out the eddy current loss caused by the proximity effect. Compared to ordinary round wire winding, the high-frequency copper loss can be reduced by 40% to 60%, and the overall conversion efficiency can be increased by 3% to 7%.
2. Core standards for specialized customization winding
High-end high-frequency twisted wire winding services are not simply the winding of wire materials, but a full-process parametric and standardized customization. First, based on the power supply frequency, power, and temperature rise requirements, precisely match the number of strands, wire diameter, and twisting distance structure. For high-frequency scenarios, a multi-layer unequal-strand twisted structure is adopted, optimizing the uniformity of current distribution; second, using a fully automatic CNC constant-tension winding equipment, the tension fluctuation is controlled within ±1%, with neatly arranged wires, no overlapping wires, no gaps, and precise control of leakage inductance and parasitic capacitance; finally, supporting standardized end stripping, tin plating, and insulation reinforcement processes to eliminate hidden defects such as inter-strand short circuits, open circuits, and oxidation.
3. Adaptation scenarios and core advantages
The Leeds twisted wire winding is flexible and adaptable, covering various scenarios such as GaN high-frequency fast charging, portable energy storage power supplies, industrial LLC resonant converters, and SiC small-power vehicle power supplies. The core advantages are prominent: ultra-high-frequency loss is low, temperature rise is stable, there is no high-frequency howling, efficiency is balanced across the full load range, no hard-switching loss at low load, perfectly matching the frequency characteristics of wide-bandwidth power supply conversion; the automation production consistency is high, the deviation of batch inductance, leakage inductance, and resistance dispersion is controlled within ±3%, eliminating performance stratification in batches; the structure is flexible and shock-resistant, after vacuum immersion coating and curing, it can withstand the vibration and temperature change impact of vehicle-mounted and outdoor complex conditions.
- Planar inductor winding service: Optimal solution for ultra-high power density miniaturization
Planar inductor winding is an advanced process for high-power, ultra-thin, and ultra-high-frequency scenarios of SiC. It completely overturns the traditional three-dimensional coil structure and adopts flat copper foil and planar layer-by-layer winding technology to create a flat, low-height, high-heat dissipation, and low-parasitic coil system. It is the core lightweight solution for current 300 kHz and above ultra-high-frequency, high-power wide-bandwidth power supplies.
1. Core principle of planar winding process
Planar inductors abandon the traditional round wire three-dimensional winding mode and use ultra-thin high-purity copper foil as the conductor, combined with PI high-temperature-resistant insulating film, to stack and wind on the planar magnetic core substrate. The thickness of the coil is maximally compressed, the utilization rate of the magnetic core window from traditional 50% to 60% is increased to over 75%, and the coil volume is reduced by 30% to 50% under the same power. The flat conductor structure can perfectly adapt to the high-frequency current flow characteristics, with uniform current distribution, no central ineffective area, and at the same time, the large planar heat dissipation area can quickly conduct heat, completely solving the heat accumulation problem in ultra-high-frequency conditions.
2. Key technical points of planar winding
The specialized planar inductor winding has strict process standards: the thickness of the copper foil is precisely matched according to the working frequency, and for high-frequency scenarios, 0.1 to 0.2 mm ultra-thin copper foil is selected to meet the skin depth requirements; the interlayer insulation uses high-temperature-resistant and high-voltage-compliant composite films, precisely controlling the interlayer spacing, balancing safety insulation and parasitic capacitance; using a symmetrical layer-by-layer winding structure, the magnetic field is evenly distributed, significantly reducing leakage inductance and EMI interference; Unified CNC cutting, deburring, and edge-fitting processes eliminate the risks of copper foil tip discharge and insulation damage, and are suitable for high-voltage and high-frequency conditions.
3. Core advantages and applicable scenarios
The planar inductor winding has four core advantages: extremely small size, excellent heat dissipation, extremely low parasitic parameters, and extremely high batch consistency. Compared to twisted wire coils, the planar structure leakage inductance can be reduced by 20% to 30%, the parasitic capacitance is smaller, the high-frequency waveform is cleaner, and it perfectly suits 300kHz and above ultra-high frequency, high-current scenarios of SiC high-power vehicle OBC, server high-frequency power supplies, photovoltaic inverters, industrial high-frequency high-power converters, etc. At the same time, the flat structure can meet the ultra-thin design requirements of the entire machine and is the exclusive process for high-end high-density wide-band power supplies.
- Twisted Wire Winding vs. Planar Winding: Precision Selection Comparison in GaN/SiC Scenarios
Both high-frequency winding processes have their respective advantages in terms of compatibility. They precisely match different power, frequency, and scenarios for wide-band power supplies, maximizing equipment performance, balancing efficiency, volume, and cost.
In terms of working frequency matching, the Leeds twisted wire winding is suitable for the 100kHz to 800kHz medium-high frequency range, covering most civilian and industrial GaN fast charging power supplies; the planar winding focuses on the 300kHz to 3MHz ultra-high frequency range, suitable for SiC high-power high-frequency equipment. In terms of loss performance, the twisted wire process is more cost-effective in the medium and low frequency bands, while the planar winding has lower loss and better temperature rise in ultra-high frequency high-current conditions.
In terms of volume and power density, the planar inductor has significant advantages, being extremely lightweight and having a higher space utilization rate; the twisted wire coil has stronger flexibility and is suitable for conventional size miniaturization requirements. In terms of cost, the Leeds twisted wire winding process is mature and has moderate production costs, suitable for large-scale civilian products; the planar winding process requires high precision and is suitable for high-end high-power, high-margin industrial and vehicle products.
Optimal production combination solution: For small and medium power GaN high-frequency power supplies, Leeds twisted wire winding is preferred, balancing low loss and cost performance; for high-power SiC high-frequency power supplies and ultra-thin high-density equipment, planar inductor winding is preferred to achieve ultimate miniaturization and high efficiency; for high-end LLC resonant power supplies, a "primary winding twisted wire + secondary winding planar" mixed winding scheme can be adopted to balance leakage inductance, loss, and batch consistency.
- Core value of professional high-frequency winding services in mass production
Compared to enterprises' own winding, small workshops' manual processing, professional high-frequency coil winding services optimize the entire process of high-frequency winding for high-frequency conditions, solving the three core pain points of mass production.
Firstly, it completely solves the problem of high-frequency loss by using precise twisted wire and planar winding processes, suppressing skin effect and proximity effect from the source, ensuring the full release of the high-frequency performance of wide-band chips, and achieving efficient, low-temperature, and low-noise operation of the entire machine.
Secondly, it achieves ultimate batch consistency, with full-process automated CNC production, parameter programs locked, avoiding manual process deviations, with extremely low batch dispersion of inductance, leakage inductance, withstand voltage, and temperature rise parameters, and eliminating the problem of batch performance stratification and frequent after-sales failures. Thirdly, it shortens the R&D and production cycle, and professional customization services can quickly match winding schemes according to topological requirements, without enterprises repeatedly trying and modifying molds, significantly improving the efficiency of new product iteration, and enabling the rapid implementation of high-frequency power supplies.
At the same time, standardized insulation, welding, immersion coating, and reinforcement processes can meet strict standards such as vehicle AEC-Q200, industrial safety standards, energy efficiency certification, etc., avoiding the risk of failure in the certification re-testing of the entire machine, and empowering the product for marketization and high-endization.
- Summary
The high-frequency, miniaturization, and high-efficiency upgrade of GaN and SiC wide-band power supplies cannot be achieved without the support of high-end coil winding processes. Traditional extensive winding schemes cannot adapt to ultra-high-frequency conditions and are the core bottleneck restricting the performance of high-end power supplies. The two core services of Liza Line - precise wire winding and planar inductor winding - have specifically addressed industry pain points such as high-frequency loss, parameter drift, bulky volume, and unstable batch production. They are respectively suitable for medium-high frequency civilian mass production and ultra-high frequency high-power high-end scenarios.
In the current rapidly evolving wide bandgap power supply industry, refined, specialized, and customized high-frequency coil winding services have become the core barrier to distinguish ordinary power supplies from high-end high-efficiency power supplies. Precisely selecting wire winding or planar winding schemes, matching equipment conditions and product positioning, can maximize the performance advantages of GaN/SiC devices, achieve all-round upgrades of power supply to high efficiency, small volume, high stability, and long lifespan, and provide core process guarantees for the mass production of high-end high-frequency switching power supplies.
Custom coils offer precise magnetic wire solutions for high-frequency power transformers and chokes.
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