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A GaN-Based 3-Phase Inverter Reference Design for 96–150 V Motion Systems: EPC9196

A GaN-Based 3-Phase Inverter Reference Design for 96–150 V Motion Systems: EPC9196

GaN Talk – Federico Unnia Jun 10, 2025

Designing compact, efficient BLDC motor drives for 96–150 V battery systems presents a unique set of challenges. The power stage must handle moderate voltages with fast switching and low conduction losses, all while maintaining robust current sensing and protection features. Until now, there has been no off-the-shelf reference design that directly addresses this operating point.

The EPC9196 fills this gap. It is a 25 ARMS, 3-phase inverter evaluation board based on EPC2304 eGaN® FETs, developed for motion control applications such as:

  • Steering drives in AGVs and mobile robots
  • Low- to mid-power robotic actuators and servo joints
  • Traction motors for small electric platforms

Architecture Overview

The EPC9196 integrates three half-bridge power stages using EPC2304 GaN FETs (200 V, 5.0 mΩ max RDS(on)), gate drivers, current and voltage sensing, and thermal and overcurrent protection. Key electrical specifications include:

  • Input voltage range: 30 V – 170 V
  • Output current: Up to 25 ARMS (35 Apk) per phase
  • Switching frequency: Up to 150 kHz
  • dv/dt optimization: <10 V/ns to reduce EMI and motor noise
  • Phase current sense bandwidth: 400 kHz using ACS37003-based frontend
  • Voltage and temperature monitoring: All phases, DC rail, and onboard AD590 thermal sensor
Block diagram of EPC9196 board
Figure 1: Block diagram of EPC9196 board in BLDC drive example application

Why 25 ARMS Matters

Many motor drive applications—especially in autonomous systems—require current in the 25–400 ARMS range. Most commercial reference designs focus on <15 A low-voltage systems or >50 A high-power drives. The EPC9196 is the first reference design optimized for 96–150 V operation with 25 ARMS capability.

This allows designers to evaluate GaN-based solutions under representative operating conditions without resorting to oversized development platforms or unverified custom designs.

Device Selection: EPC2304

The EPC2304 was selected based on its QFN package, 200 V rating, and lowest available RDS(on) in its class. Key device characteristics include:

  • RDS(on): 5.0 mΩ max
  • QG: 22.3 nC typ. at VGS = 5 V
  • Figure of Merit (RDS(on) × QG): Suited for high switching frequencies with minimal conduction loss
  • Thermal design: Top-side cooled for straightforward heatsink attachment

The EPC9196 includes mounting features for a quarter-brick style heatsink and is validated with t-Global and Bergquist TIMs to ensure proper dielectric isolation and thermal performance.

Thermal Characterization

Under continuous operation at 60 kHz PWM, 150 VDC input, and natural convection cooling:

  • Without heatsink: 8.5 ARMS per phase at <50°C ΔT
  • With heatsink: 13 ARMS per phase at <50°C ΔT
  • In short transients: Capable of 25 ARMS per phase
EPC9196 GaN FET temperature rise as a function of ambient temperature in steady state condition and in 10 second transients
Figure 2: EPC9196 GaN FET temperature rise as a function of ambient temperature (26°C) in steady state condition (left) and in 10 second transients (right).

System-Level Integration

The EPC9196 supports standard controller platforms via a 40-pin interface (EPC9147x series), enabling quick pairing with:

  • TI TMS320F28379D (LaunchPad)
  • ST NUCLEO-G431/474 series
  • Microchip dsPIC33
  • Renesas RA6T2

Voltage and current sense signals are scaled to 3.3 V logic levels, compatible with most embedded ADCs. Overcurrent protection can be hardware-enforced (via jumper) or software-monitored.

Connection diagram of the EPC9196
Figure 3: Connection diagram of the EPC9196 configured as a motor drive inverter

Application Notes

  • The integrated sense circuitry enables fast feedback loop bandwidths suitable for FOC or SVPWM control strategies.
  • Dead time can be minimized to <50 ns due to the zero reverse recovery characteristic of the GaN FETs.
  • The board layout supports low loop inductance and clean switching node transitions, verified via scope captures.

Accessing the Design

The EPC9196 is available for evaluation and development. Design files are available through EPC’s product page.

For teams developing GaN-based motion control systems in the 96–150 V class, the EPC9196 offers a validated, documented platform for rapid prototyping and performance benchmarking.

Phase current and switching node voltage
Figure 4: Phase current and switching node voltage

To support your GaN-based design journey, EPC offers a suite of tools and expert guidance. Explore our GaN First Time Right resources for layout tips, thermal design advice, and simulation models to ensure success on your first pass. Have a question? Our engineers are ready to help—Ask a GaN Expert and get personalized support tailored to your application.

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