Why GaN
Humanoid Joints Run at the Voltage Where GaN Wins
A robot joint is a 48V motor drive packed into a sealed actuator, and GaN is the transistor that fits.
Humanoid joint motors run from 48V battery buses, peaking near 96V, and each motor drive has to fit inside an actuator the size of a soda can, next to the motor and gearbox. Gallium nitride (GaN) transistors switch five to 10 times faster than silicon MOSFETs with no reverse-recovery loss, so the drive needs smaller inductors and capacitors and runs cooler in a sealed actuator. Below about 40V silicon remains competitive; above 650V silicon carbide takes over.
| Parameter | Silicon MOSFET | GaN-on-Si | SiC MOSFET | For robot joints |
|---|---|---|---|---|
| Bus voltage sweet spot | Under 40V strong; 40V to 100V competitive | 40V to 200V | 650V to 1,700V | GaN fits the 48V humanoid bus |
| Practical switching frequency | Up to about 100 kHz | 100 kHz to 1 MHz | 50 to 200 kHz | GaN allows the smallest inductors and capacitors |
| Reverse recovery loss | Body diode recovery loss | None; no body diode | Low | GaN removes the main hard-switching loss |
| Gate charge | Baseline | Several times lower | Lower than silicon | Less gate drive power across dozens of joints |
| Cost per device | Lowest | Above silicon, falling | Highest | Premium acceptable at robot volumes |
| Qualification depth | Decades of automotive use | Mostly chargers and data center power | EV traction | Silicon is the most proven; GaN is catching up |
Drive topology
Three Half-Bridges Per Motor, Integrated Where Possible
Each brushless DC motor is driven by a three-phase inverter: three half-bridges, six transistors. A motor-control MCU runs field-oriented control and sends PWM signals; the gate driver turns them into GaN gate voltages of about 5V to 6V with dead time to prevent shoot-through. Integrated parts such as TI's LMG2100 and ST's MasterGaN put the driver, level shifter and protection in the same package as the GaN switches, cutting board area and parasitic inductance at high switching frequency. Tesla's Optimus Gen 2 has 28 body actuators; at six switches each that is 168 GaN transistors per robot before the hands.
Suppliers
China's Innoscience Leads Power GaN; Infineon and TI Make Their Own
| Supplier (HQ) | Robot-relevant parts | Manufacturing | Position |
|---|---|---|---|
| Innoscience (Suzhou, China) | 100V and 650V GaN-on-Si discretes and half-bridges | Own 200mm fabs in Zhuhai and Suzhou; manufacturing deal with ST (2025) | Largest power GaN maker, ~31% in 2025; natural supplier to Chinese robot makers |
| Infineon (Munich), with GaN Systems | CoolGaN discretes and half-bridges, 100V to 650V | Villach (Austria, 300mm GaN pilot) and Kulim (Malaysia) | ~16% of power GaN in 2025, second place |
| Texas Instruments (Dallas) | LMG2100 and LMG3xxx GaN half-bridges with integrated drivers | Own GaN fabs in Dallas and Aizu, Japan; capacity quadrupling (October 2024) | Robot joint reference designs at 48V; makes its own wafers |
| EPC (El Segundo, CA) | Low-voltage chip-scale GaN FETs and motor drive ICs | Fabless; foundry partners in Taiwan | Low-voltage specialist; actively targets humanoid joints |
| Navitas (Torrance, CA) | GaNFast monolithic GaN with driver and protection | Fabless; moving from TSMC to Powerchip and GlobalFoundries Vermont | Chargers and data center power first; 100V parts fit robots |
| STMicroelectronics (Geneva) | MasterGaN integrated driver and GaN; STM32 motor-control MCUs | Catania and Tours; Innoscience as a manufacturing partner | MCU plus GaN pairing for joint controllers |
| Renesas (with Transphorm) | 650V cascode GaN | Goleta, California and Aizu | High-voltage focus; less relevant at 48V |
GaN fabs and the TSMC exit are covered on GaN Power and RF Fabs.
Fleet-scale demand
A Million Robots a Year Needs About 168 Million GaN Switches
| Scale | Robots a year | GaN switches a year | Supply posture |
|---|---|---|---|
| Pilot | 100 to 1,000 | 17,000 to 168,000 | Distributor stock covers it |
| Early ramp | 10,000 to 50,000 | 1.7 to 8.4 million | Within today's capacity; qualification narrows the supplier list |
| Volume | 100,000 | About 17 million | Needs supply agreements and robot-grade parts |
| Mass market | 1,000,000 | About 168 million | Needs new 200mm GaN-on-Si capacity planned 3 to 5 years ahead |
Qualification
No Robot Standard Exists, So Automotive Grade Stands In
Walking, falling and collisions add shock, vibration and thermal cycling closer to automotive than industrial duty. AEC-Q101, the automotive discrete standard, is the usual proxy, but it was written for vehicle temperature and vibration profiles. Robot makers either accept AEC-Q101, negotiate custom qualification with suppliers, or test at the platform level, each adding 12 to 24 months. The suppliers chosen in qualification during 2026 and 2027 at Tesla, Figure, Agility, 1X, Unitree, UBTech and AgiBot stay in place for the life of each actuator design.
Supply risks
Foundry Exit, Qualification and a Split Market
| Risk | What happens | Severity |
|---|---|---|
| TSMC's GaN exit | Fabless GaN designers lose their main foundry by July 2027 and must requalify at Powerchip, GlobalFoundries or elsewhere | High |
| No robot qualification standard | AEC-Q101 is the proxy; robot makers add 12 to 24 months of their own qualification | High |
| Chinese supply split | Chinese robot makers buy Innoscience; Western makers lean on Infineon, TI and EPC, splitting the market | Medium |
| Wafer capacity at mass volume | A million-robot year adds demand comparable to large existing GaN markets | Medium by 2029 |
| Gallium | China produces ~99% of primary gallium and licenses its export | Medium |
Record
Page Record
- Covers
- GaN motor drive ICs for humanoid joints: device choice, drive topology, suppliers, fleet-scale demand, qualification and risks
- Sources
- Yole Group power GaN share via SemiconductorX GaN Power and RF Fabs; Texas Instruments GaN capacity release, October 2024; Tesla Optimus Gen 2 actuator count; company product pages
- Last verified
- October 2026