Efficient Power Conversion (EPC) has introduced the EPC91132, a compact 3-phase BLDC motor drive inverter reference design that sets a new benchmark for power density in humanoid robots and drones.
Design and integration
The EPC91132 is a 23mm-diameter reference design inverter built around the EPC33110 GaN three-phase module. This module integrates three half-bridges, gate drivers, bootstrap circuitry, and level shifters into a single 6mm x 6.5mm QFN package. It operates from a single 5V supply up to 80V, with a typical on-resistance of 11.7mΩ and support for 3.3V or 5V logic inputs.
Monolithic GaN integration eliminates the need for discrete gate drivers, sharply reducing component count and simplifying PCB layout. The result is a platform that accelerates system development for next-generation motion systems.
Performance and capabilities
The EPC91132 delivers continuous current of 11A RMS per phase at 48V with switching frequencies up to 100kHz. In drone motor testing, the system demonstrated excellent thermal performance, with minimal temperature rise under propeller airflow. The inverter includes a microcontroller, regulated power supplies, DC bus voltage sensing, current sensing with embedded over-current protection, and an onboard magnetic encoder for rotor position and speed control.
The board features a flexible breakout-ring design; removing the outer ring yields a 23mm diameter that fits directly into small drone motors such as the Vertiq 23-06 platform. Real-time monitoring and programming are available through an RS-485 communication interface.
Market significance
Next-generation humanoid robots and drones demand lighter, smaller, and more efficient power electronics. GaN technology enables motor drive systems to operate above 100kHz while minimizing conduction and switching losses. This improves efficiency, dynamic response, and control bandwidth, while reducing passive component size and overall volume. The EPC91132 demonstrates how monolithic GaN integration can deliver the switching speed, power density, and thermal performance required for these applications.
Complete design support files, including schematics, bill of materials, and Gerber files, are available from EPC. The evaluation board is priced at $406.25 and is available immediately from Digi-Key and Mouser.
Outlook
The EPC91132 marks a significant step toward practical, high-density power electronics for autonomous systems. As humanoid robots and drones evolve from prototypes to production platforms, monolithic GaN integration will be a key enabler for reducing size and weight while maintaining efficiency. EPC’s reference design provides a proven blueprint for engineers accelerating development in this space.
