The ranked assignee list contains 26 companies, with the leading filer holding 16 of the 65 records in scope. The top 5 filers together account for 73.8% of all 65 records, and the top 10 account for 96.9%, so the field is heavily concentrated at the top with a long tail of single- or few-filing entrants below it. That concentration means most of the foundational drive-circuit claim space is already occupied by a small number of assignees rather than spread evenly across the field.

Filings rose from 3 in 2017 to a peak of 18 in 2020, then fell toward 1 by 2024, a -75% move across that three-year span. That looks like a slowdown, but publication lags filing by roughly 18 months, so 2025 and 2026 figures are still filling in and should not be read as the field going quiet. The safest read is that the initial wave of foundational filing has passed its peak, not that new work has stopped.

The core classes are H02M (power conversion, 89.2% of the 65 records) and H03K (pulse technique & logic circuits, 52.3%), reflecting that most filings describe both the power-switching circuit and the logic that drives it. Vehicle-specific classes — H02P (motor control, 35.4%), B60L (EV propulsion, 26.2%) and B60K (vehicle propulsion & drive, 7.7%) — and semiconductor-device classes H10D and H01L (10.8% and 9.2%) appear on a meaningful minority of records, since a single filing typically carries several IPC codes at once.

US20180343009A1, filed by Texas Instruments and published 2018-11-29, claims a gate driver with a drive signal input and output terminal, a gate drive circuit between them, and a serial communication interface coupled to the drive-signal input terminal. That scope blocks designs where a serial bus sits between the drive-signal input and the gate-drive circuit itself. It does not reach architectures where serial communication is used only for separate telemetry that never touches the drive-signal path, which is the most direct design-around.

The thinnest documented branches are H05K (printed circuits & assemblies) and B60K (vehicle propulsion & drive), each covering only 7.7% of the 65 records, well below the 89.2% and 52.3% carried by the core H02M/H03K drive-circuit classes. That gap points to packaging- and drivetrain-integration claims — for example, a gate-drive stage physically integrated onto the power-module substrate — as an area with comparatively little claimed prior art relative to how much engineering effort actually goes into that part of a real traction inverter.