The 12V-60V three-phase GaN inverter design offers efficiency, precise current sensing, and sensorless control for robotics and motor drives.
This reference design from Texas Instruments (TI) showcases a high-power density 12V to 60V 3-phase power stage using three LMG2100R044 100V, 35A GaN half-bridges with integrated GaN FETs, driver, and bootstrap diode. It is designed for motor-integrated servo drives and robotics applications. The IN241A current sense amplifier ensures accurate phase-current sensing, while DC-link and phase voltages are measured to support advanced sensorless designs like InstaSPIN-FOC. The design features a TI BoosterPack compatible 3.3V I/O interface for seamless connection to a C2000 MCU LaunchPad or C2000 microcontrollers, enabling quick evaluation of TI’s GaN technology. The design is suitable for various applications, including robot servo drives, servo drive power stage modules, linear motor power stages, mobile robot motor control, and drone accessories.
Low-voltage three-phase inverters operating from 12V to 60V DC and delivering up to 1.5kW are widely used in applications like collaborative robots, automated mobile robots, AGVs, servo systems, and drones. In many of these cases, the power electronics are integrated with the motor, requiring a compact design with high efficiency and power density to minimize size and weight while avoiding the need for a heat sink.
Higher PWM switching frequencies, up to 100kHz, help reduce the size of the DC-bus capacitor by allowing the use of ceramic instead of electrolytic capacitors. This also reduces current and torque ripple in low-inductance brushless AC motors, improving control precision. However, increasing the switching frequency leads to higher inverter losses. In traditional 48V silicon FET inverters, switching losses at 40kHz PWM can become dominant over conduction losses, generating excess heat that requires a larger heat sink, increasing system cost, weight, and size.
GaN FETs address this issue by switching faster than silicon MOSFETs, reducing switching losses. However, certain package types can limit GaN FET performance at high slew rates. Integrating the GaN FET and driver in a single package reduces parasitic inductance and optimizes switching.
The TIDA-010936 reference design features a compact three-phase inverter using three 100V, 35A half-bridge GaN power modules. These modules integrate the driver and two 80V GaN FETs in a small 5.5mm × 4.5mm QFN package, minimizing gate and power loop impedance. The PCB includes mounting holes for an optional heat sink compatible with top-side cooled GaN power modules. An integrated bootstrap diode further reduces space for the high-side GaN-FET bias supply.
For precise and compact phase current measurements, the design incorporates a 1mΩ shunt resistor and an INA241 differential precision current sense amplifier. The INA241 provides high common-mode rejection and integrated PWM rejection, supporting a ±33A measurement range with a unipolar 0V to 3.3V output centered at 1.65V.
TI has tested this reference design. It comes with a bill of materials (BOM), schematics, assembly drawing, printed circuit board (PCB) layout, and more. The company’s website has additional data about the reference design. To read more about this reference design, click here.
