Planar Magnetics Patents: Who Leads, Where the Gaps Are 2026
- Concentration is moderate, not dominant. the leader holds 4 records and the ranked field of 31 companies splits the top 10 at just 60.9% of all 46 records in scope.
- Filing tripled from 2021 to 2024. growth of +200% over that span, with 2025 the peak year so far at 7 filings — though the two most recent years are still filling in.
- The field is almost entirely magnetics-classed. H01F covers 82.6% of the 46 records, while power conversion (H02M) sits at only 26.1%, pointing to a claim base built around the coil and core, not the converter topology.
Filing growth compares 2021 (2 records) with 2024 (6) — a three-year span. 2024 is the most recent year we treat as complete: publication lags filing by roughly 18 months, so 2025 onwards are still filling in and any growth rate that ends there would understate the field. Top-5 share is the combined record count of the five largest assignees divided by all 46 records in scope (CR5), not by the ranked leaders only.
What this landscape covers
This dataset tracks patent filings at the intersection of planar transformer and PCB-integrated magnetics constructions, narrowed to documents that address winding capacitance, leakage inductance control, thermal path, insulation creepage, manufacturing repeatability or profile height in the claims or description. It spans 46 published records from 2015 through the 2026-07-31 cut-off.
The scope is deliberately narrow: it excludes general power-conversion patents that do not touch these specific magnetics design constraints, and excludes planar transformer filings that never mention a manufacturing, thermal or insulation limitation. That makes the set a proxy for where engineers are running into the physical limits of flattening a transformer, not a proxy for the broader power-electronics patent volume.
Filing trend and technology composition
Two views of the same 46-record set: how filing activity has moved year over year, and which IPC subclasses carry the claim volume.
Filing trend, 2017–2026
Filings moved from 2 in 2017 to a peak of 7 in 2025, with the 2021-to-2024 span showing +200% growth (2 to 6). 2025 and 2026 are undercounted because publication typically lags filing by around 18 months, so the true recent trend is higher than shown.
IPC subclass composition
H01F (magnets, inductors and transformers) appears in 82.6% of the 46 records, confirming this is fundamentally a magnetics-construction dataset. H02M (power conversion) reaches 26.1%, and smaller footprints in H05K, H03K, B60L, G01V, H10P and H01R mark adjacent applications rather than the core claim territory. Because records can carry multiple classes, these shares sum to well over 100%.
Shares are the percentage of the 46 records in scope. A patent can carry several IPC classes, so the shares add up to more than 100%.
Go deeper on Planar Magnetics for Compact Converters with Eureka
This page is one run against one query. Ask Eureka your own question about planar magnetics for compact converters and every answer comes back with the patent numbers behind it.
Try EurekaMost-cited records in this set
US20090002111A1 — Wideband planar transformer
A method of arranging and fabricating parallel primary and secondary coils of a wideband planar transformer is provided. The spacing and width of the coils are disposed to extend the bandwidth from DC to GHz and allow for high frequency coupling when the core permeability drops, achieving low reflected energy and low loss over a wide bandwidth. A bottom mold with a pattern of hole-pairs and vertically inserted conductive elements couples to a top mold so a middle portion of the conductive elements spans between them; dielectric material envelopes that middle portion.Filed by Planarmag, Inc., published 2009-01-01.
| # | Publication no. | Patent title | Citations |
|---|---|---|---|
| 1 | US7502234B2 | Planar transformer power supply | 269 |
| 2 | US20090002111A1 | Wideband planar transformer | 76 |
| 3 | US20060028313A1 | Component arrangement with a planar transformer | 56 |
| 4 | US20050083714A1 | Power converter employing a planar transformer | 41 |
| 5 | US20050242916A1 | Low noise planar transformer | 38 |
| 6 | US7821374B2 | Wideband planar transformer | 37 |
| 7 | US20040174241A1 | Planar transformer and output inductor structure with single planar winding board and two magnetic cores | 36 |
| 8 | US6927661B2 | Planar transformer and output inductor structure with single planar winding board and two magnetic cores | 33 |
| 9 | US7233224B2 | Component arrangement with a planar transformer | 25 |
| 10 | US7292126B2 | Low noise planar transformer | 24 |
Citation counts inside this corpus skew toward older filings simply because they have had longer to accumulate citations — read them as a signal of influence on later designs, not of current commercial relevance.
Each row carries its publication number; clicking a row searches Eureka by that number.
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Reading the ranking, the trend and the citation table together points to a field that is active but not locked up by any single player.
No single assignee controls the space
The leader holds only 4 of the 46 records, and the top 5 combined reach 37.0% of all records in scope. That leaves a long tail across the 31 ranked companies, with fifth place at 3 records and tenth place at just 2.
Activity tripled in three years
Filings rose from 2 in 2021 to 6 in 2024, a +200% move, with 2025 posting the highest count so far at 7. Because publication lags filing by roughly 18 months, the 2025–2026 figures will likely revise upward.
Claims cluster on the magnetic structure
H01F dominates at 82.6% of the 46 records, while H02M (power conversion circuitry) sits far behind at 26.1%. The construction of the coil, core and winding is where the claim density lives, not the converter topology around it.
Filing activity is US-centred with a European and PCT tail
The United States receives 28 of the tracked filings, well ahead of Europe (EPO) at 6, WIPO/PCT at 4, China at 3, Canada at 2 and Germany at 1. That skew matters when deciding where freedom-to-operate checks are most urgent.
Eureka can read the same corpus for gaps instead of for coverage: under-claimed branches adjacent to planar magnetics for compact converters, with the prior art for and against each one.
Who is filing, and where the field is still open
The ranked list of 31 companies shows a moderate leader with no runaway concentration, and recent-year momentum data suggests several previously active filers have gone quiet in the latest year.
A narrow lead, not a monopoly
The top-ranked assignee holds 4 of the 46 records in scope, only one ahead of fifth place at 3. That gap is too thin to call this a single-company field.
A long tail below the top 10
Tenth place holds only 2 records, and the top 10 combined reach 60.9% of all 46 records. The remaining share is spread across single- and double-filing entrants.
Several established filers show no latest-year activity
Multiple previously active assignees, including two with a -100% year-over-year change, show zero filings in the latest tracked year. That is consistent with the general 18-month publication lag rather than a real pullback.
| Assignee | Recent year | YoY |
|---|---|---|
| KeyEye Communications | 0 | — |
| Infineon Technologies AG | 0 | — |
| Ferroamp Elektronik | 0 | — |
| Ballard Power Systems | 0 | — |
| Hyundai Mobis Co., Ltd. | 0 | -100% |
| Texas Instruments Inc. | 0 | -100% |
| Flextronics International (Flex) | 0 | — |
| McMaster University | 0 | — |
Where to take this landscape
The dataset points to specific next steps depending on whether the goal is freedom-to-operate, design-around strategy, or scouting white space.
Check freedom-to-operate against the US-heavy filing base
With 28 of the tracked filings at the US receiving office, a design intended for the US market should be checked against this cluster first, then against the smaller EPO and PCT groups.
Run an FTO scan in EurekaMap the under-claimed sub-areas before committing claim language
Thermal path and insulation creepage constructions show thinner IPC density than the core H01F cluster, which may leave room for a differentiated first claim.
Explore white space in EurekaTrack the assignees showing renewed momentum
Several top assignees show zero filings in the latest year, which given the publication lag may reverse as 2025–2026 filings continue to publish; monitoring is more useful than concluding they have exited.
Set up assignee tracking in EurekaCommon questions on planar magnetics patents
Across the 46 records in this dataset, the leading assignee holds 4 records, with fifth place at 3 and tenth place at 2. That is a moderate lead rather than a dominant one: the top 5 assignees together account for 37.0% of all 46 records, and the top 10 reach 60.9%. Practically, this means no single company's patent estate covers the whole design space, and a freedom-to-operate review needs to check across the ranked field of 31 companies rather than one or two names.
Filing activity grew substantially in the recent period covered by complete data, rising from 2 filings in 2021 to 6 in 2024, a +200% increase. 2025 shows the highest count so far at 7 filings. Because patent publication typically lags actual filing by around 18 months, the 2025 and 2026 figures are undercounted and should not be read as a slowdown; the underlying trend through the last complete year is clearly upward.
The dominant classification is H01F (magnets, inductors and transformers), appearing in 82.6% of the 46 records, which confirms this field is primarily about magnetic component construction rather than circuit topology. H02M (power conversion) is the next largest at 26.1%, with smaller footprints in H05K (printed circuits), H03K (pulse technique), B60L (EV propulsion), G01V (geophysics-adjacent sensing uses), H10P and H01R. Because a single record can carry multiple IPC classes, these percentages add up to more than 100%, so they should be read individually rather than summed.
The evidence points to under-claimed territory around insulation creepage path geometry, thermal via arrays beneath planar windings, multi-layer PCB winding capacitance cancellation, automated winding repeatability tolerancing, and low-profile core-to-connector integration. These areas show thinner filing density than the core H01F magnetic-structure cluster that carries 82.6% of records. A first claim in these areas would need to tie a specific manufacturing tolerance or geometric feature to a measurable performance limit, such as creepage distance versus voltage rating, rather than claiming the general construction.
The United States is the leading receiving office with 28 of the tracked filings, followed by Europe (EPO) with 6, WIPO/PCT filings with 4, China with 3, Canada with 2, and Germany with 1. This distribution suggests that US filing strategy and prior art should be the first checkpoint for any new design, with European and PCT coverage as a secondary but still meaningful consideration.
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Disclaimer. This page is generated from Patsnap Eureka data drawn from a limited snapshot of global patent and scientific-literature records, and is provided for general information and reference only.
Patent data carries inherent limitations: recent filings (typically the most recent 18–24 months) are under-counted due to standard publication lag; counts may be reported at either a patent-family or a patent-record basis and are not always directly comparable; classification, applicant-name, and citation data may contain errors, duplicates, or omissions; and the underlying search query defines and constrains the scope shown. As a result, the analysis may be incomplete or inaccurate and may not reflect the full technology landscape.
Nothing on this page constitutes an exhaustive prior-art, novelty, freedom-to-operate, or validity search, nor does it constitute legal, financial, investment, or professional advice, and it should not be relied upon as such. Any patent, commercial, or strategic decision should be verified independently and reviewed with qualified patent, legal, and domain professionals. Patsnap makes no warranties, express or implied, as to the accuracy, completeness, or fitness for any particular purpose of the information presented.
Machine translation. Assignee and organisation names originally recorded in Chinese, Japanese or Korean have been rendered into English by an AI translation step so that the tables stay readable. These renderings are best-effort and may not match a company’s registered English name; the original name is what the underlying patent record carries, and it is what any Eureka query launched from this page uses.