News: Microelectronics
25 February 2026
EPC adds 3-phase BLDC motor drive inverter evaluation board for humanoid robot joint applications
Efficient Power Conversion Corp (EPC) of El Segundo, CA, USA — which makes enhancement-mode gallium nitride on silicon (eGaN) power field-effect transistors (FETs) and integrated circuits for power management applications — has released the EPC91122, a high-performance 3-phase brushless DC (BLDC) motor drive inverter evaluation board specifically engineered for humanoid robot joint applications. Featuring EPC’s highly integrated EPC33110 3-phase ePower Stage module, the EPC91122 delivers up to 20ARMS (28Apeak) phase current in an ultra-compact form factor optimized for space-constrained robotic joints, integrating all key functions of a complete motor drive inverter, including a micro-controller, motor shaft angular sensor, housekeeping power supplies, and accurate voltage and current sense.
The EPC91122 is mechanically optimized to fit directly inside humanoid joint motors. The complete GaN inverter occupies a 32mm-diameter inner circle, surrounded by a 55mm external frame that supports mechanical mounting and lab connectivity. This design lets the inverter fit inside the motor chassis, which lowers loop inductance and boosts the power density and dynamic performance.
The EPC33110 is the main part of the system. It is a three-phase co-packaged module with a maximum voltage of 100V. It has three monolithic GaN half-bridges with built-in gate drivers, bootstrap circuits, and level shifters. The device has an RDS(on) of 11.7mΩ + 13mΩ and can switch at frequencies of up to 150kHz, which means that it may use smaller passive components and respond quickly to changes.
The board operates from a wide input range, making it well suited for battery-powered robotic systems. It integrates all critical subsystems required for a complete motor drive inverter, including:
- onboard 5V and 3.3V housekeeping power supplies;
- phase current sense gain: 44mV/A;
- DC bus voltage sense gain: 44.89mV/V;
- encode default resolution: 1024 pulses per revolution with Z index;
- STM32G431 micro-controller for motor control;
- RS485 communication interface;
- JTAG/SWD programming connector for firmware development.
The EPC91122 comes pre-programmed to operate at 100kHz PWM with 50ns dead-time, showcasing the high-speed switching capability enabled by GaN technology. Thermal testing under real-world operating conditions confirms the board’s capability for continuous and pulsed operation.
“The EPC91122 highlights how GaN-based power stages enable unprecedented integration and power density in humanoid robotics,” says Marco Palma, director, motor drives systems and applications. “By combining high-frequency switching, integrated drivers, sensing and communication in a 32mm circular inverter, designers can embed a complete 3-phase motor drive directly inside robotic joints while achieving up to 20ARMS performance.”
The EPC91122 is suitable for humanoid robot joints, compact servo drives, robotics, drones, and eMobility platforms. Complete design support files, including schematic, bill of materials (BOM) and Gerber files are available on the EPC91122 product page.
The EPC91122 reference design board is priced at $ 470. Reference design boards and devices are available for immediate delivery from distributor Digi-Key Corp.
EPC launches 3-phase BLDC motor drive inverter for robot joints and UAVs
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EPC launches 3-phase BLDC motor drive inverter reference design
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