The dataset shows filing activity concentrated among a small set of major industrial and electronics groups, with a long tail of smaller entrants holding only one or two filings each. Recent-year momentum data is arguably more useful than cumulative counts alone, because several historically top-ranked assignees show zero filings in the latest year. Anyone assessing current competitive activity should weight recent filings, not just total portfolio size, since publication lag means the newest filings from active players may not yet appear in the count.

Filing volume peaked in 2019 at 121 records, held near a 112 midpoint through 2022, and dropped to 17 in the most recent partial year. That decline pattern predates the roughly 18-month publication lag that always understates the newest year, so while the very latest figure should be read cautiously, the multi-year trend from 2019 onward points to a plateau or decline rather than continued growth. This is typical of a converter topology whose core claim space has already been substantially staked out.

The United States leads with 493 records, followed by China at 290, then Europe (EPO) and Japan each around 97, India at 97, and the WIPO PCT route at 81. Together the US and China account for more filings than the other four routes combined, which means a freedom-to-operate or filing strategy that ignores either jurisdiction is missing the majority of the documented activity. Companies building global products in this space should treat US and Chinese filings as the primary reference set.

Beyond the core power-conversion classification (H02M), the largest overlaps are with grid and power-supply systems (H02J, 218 records) and electric vehicle propulsion (B60L, 107 records). Smaller but active overlaps appear in variable control systems, magnetics and transformers, digital processing, semiconductor devices, and heating/lighting circuits. The relative size of these secondary classes suggests EV and grid applications are the most patent-active downstream uses of the core converter topology, while other application areas remain comparatively under-claimed.

US20220045618A1, filed by Delta Electronics and published in 2022, describes a bidirectional DC-DC converter with three or more ports sharing a common transformer, controlled through variable-frequency, delay-time, or phase-delay methods that can operate similarly to a series-resonant or dual active bridge converter. It matters because multi-port architectures sharing a single transformer are a less crowded claim area than two-port designs, based on the IPC distribution in this dataset. Anyone designing a multi-port converter with shared magnetics should review this filing's claim scope closely before finalizing a control architecture.