In this dataset, it's a patent family whose title, abstract or claims combine resonant converter language — LLC converter, resonant DC-DC — with gate driver terms such as adaptive dead-time control or isolated gate drive. That combination captures both the power topology and the drive-circuit side of the design, which is why the IPC mix spans power conversion (H02M), pulse/logic circuits (H03K) and inductor/transformer classes (H01F) rather than sitting in one bucket. It excludes generic gate driver patents that don't specify a resonant or LLC topology.

The filing trend says no, at least not on raw counts: 2017 was the peak year at 123 families, and by the 2022 midpoint filings had settled at 110, a flat-to-declining pattern through to the present. The very low count in 2026 is a partial year and should not be read as a collapse — publication typically lags filing by around 18 months. Overall the shape looks like a mature technology with steady incremental filing rather than a fast-growing one.

Filing activity concentrates among established power-electronics, lighting-driver and semiconductor firms with long histories in switch-mode and resonant power supply design, alongside a long tail of smaller and single-filing entrants. Several of the largest holders show no recorded filings in the most recent year, which — given publication lag — is more likely an incomplete latest year than an actual exit. The co-assignee pairs in the data mostly link a parent company to its own subsidiary rather than pointing to cross-company collaboration.

The clearest gaps sit adjacent to the dense H02M topology cluster rather than inside it: gate driver ICs paired with wide-bandgap secondary rectifiers, isolated gate drive transformer design specifically for GaN half-bridges, and self-driven synchronous rectification pushed to higher switching frequencies all carry comparatively few records relative to core LLC dead-time control claims. H01L (semiconductor devices) is thin across the whole dataset at only 55 records, suggesting driver-IC-level claims are less crowded than converter-topology claims. Any of these still warrants a targeted freedom-to-operate search before assuming it's open.

H02M covers power conversion circuits generally, and this search combines resonant/LLC converter language with gate driver terms — so most matched records describe how the converter and its switching timing are structured, which falls under H02M. H01L covers semiconductor devices as physical components, and comparatively few of the 1,507 records claim the driver silicon itself rather than the circuit or control scheme around it. That gap is a reasonably reliable signal that claim pressure sits on topology and control, not on driver IC design.