Efficient Power Conversion (EPC) has introduced the EPC91118, a new reference design that brings gallium nitride (GaN) technology into the heart of humanoid robotics. Designed for space-limited and weight-sensitive systems such as robot joints and small UAVs, the 32 mm circular board delivers up to 15 ARMS per phase across a 15–55 V input range.
At the centre of the design is the EPC23104 ePower™ Stage IC, a GaN monolithic half-bridge that integrates gate drivers, level shifters, input logic, and power stage into one package. Its ability to switch at 100 kHz allows designers to eliminate electrolytic capacitors entirely, replacing them with MLCCs to shrink overall size and improve long-term reliability.
Despite its size, the EPC91118 is packed with everything needed for high-performance BLDC motor control:
3-phase power stage with 15 ARMS output per phase
Integrated current and voltage sensing
High-resolution magnetic encoder (up to 12-bit SPI)
STM32G431 microcontroller with FOC algorithm support
RS485 half-duplex communication interface
On-board 5 V and 3.3 V supplies via DC-DC converters
Careful thermal design helps keep everything under control. Heat from the power stage is transferred through thermal vias and out via an external aluminium ring, allowing for conduction cooling even when airflow is limited. The circular layout makes it especially well-suited to humanoid limbs and other tight enclosures.
The layout isn’t just about space; it’s about integration. The design team intended this board to sit directly inside robotic joints: shoulders, elbows, and knees. For drones, it offers a lightweight drive stage that fits neatly within the motor housing. With no need for external sensors, encoders, or bulky control units, the EPC91118 simplifies what would traditionally require multiple stacked boards.
The EPC91118 reference board is available now for $394.02. The core EPC23104 IC is priced at $2.69 in volumes of 3,000 units. Both are stocked at Digi-Key.
EPC’s new motor drive doesn’t just save space, it removes complexity. By combining sensing, control, and power into a single circular module, it gives engineers working on humanoid robots and aerial systems a cleaner way to build motion into their designs. This is what GaN makes possible: more capability in less space, with fewer compromises.
Read the original announcement here.
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