EPC's new 100 V GaN FET enables smaller motor drives for e-bikes, robots and drones

The EPC9194 GaN-based inverter reference design significantly improves the efficiency and torque of the motor drive system while more than doubling the power per unit weight (specific power) . The inverter is so small that it can be integrated into the motor housing, achieving the lowest electromagnetic interference, highest density and lightest weight.

EPC9194, a three-phase BLDC motor drive inverter reference design, is available from EPC. It operates from a 14V to 60V input supply voltage range and can deliver up to 60 Apk (40 ARMS) output current. This voltage range and power make the solution ideal for a variety of three-phase BLDC motor drives, including e-bikes, e-scooters, drones, robots, and DC servo motors.

The EPC9194 demo board features six 100 V eGaN FETs (EPC2302) in a 3mm x 5mm QFN package. The board measures only 130 mm x 100 mm (including connectors). The EPC2302 eGaN FETs have extremely low RDS(on) (only 1.8 mOhm) and very small QG, QGD and QOSS parameters, resulting in low conduction and switching losses. The package is a thermally enhanced QFN package with an exposed top for efficient heat dissipation to a heat sink and wettable sides for easy inspection.

Compared to a Si MOSFET-based solution with the same RDS(on) operating at 16 kHz PWM frequency, this reference design using six EPC2302s cuts the estimated total power consumption at 20 ARMS and 100 kHz PWM frequency in half. The 100 kHz PWM frequency enables quasi-pure sinusoidal current, reduces vibration and distortion in the motor, and thus improves the motor system efficiency by about 7%. In addition, the 100 kHz PWM frequency can reduce input filters and eliminate/reduce electrolytic capacitors.

The EPC9194 integrates all the key circuit functions required to support the entire motor drive inverter, including gate drivers, regulated auxiliary power rails to help manage power, voltage and temperature sensing, accurate current sensing and protection functions.

At 48 V input voltage and 100 kHz PWM frequency, the board can handle 20 ARMS current in steady-state condition at 60°C temperature rise without heat sink. With heat sink, it can handle 30 ARMS current in steady-state condition.

The EPC9194 is compatible with a variety of controllers from different manufacturers, enabling rapid development and shortened design cycles. EPC provides a control interface board (EPC9147X) to operate this inverter reference design with common BLDC motors. The EPC9194KIT contains the EPC9194 evaluation board and controller board, allowing the board to be easily connected to the microcontroller design kit:

• EPC9147A controller board for interfacing to Microchip's popular microcontrollers

• EPC9147C controller board for connecting to popular microcontrollers from ST

• EPC9147B controller board for interfacing to TI's popular microcontrollers

• EPC9147E controller board for interfacing to a variety of common microcontrollers

“Designers can use our GaN FETs to create lighter, more efficient, battery-powered motor drives for e-mobility and robotics applications,” said Alex Lidow, CEO of EPC. “GaN devices enable motor systems to be smaller, lighter, quieter, more powerful, and more precise while improving EMI, reducing the need for EMI filtering and capacitors, and eliminating the need for electrolytic capacitors and input filter inductors.”

Price and availability

The EPC9194 reference design board is priced at $909 each and is available immediately from Digi-Key.

Designers interested in replacing silicon MOSFETs with GaN devices can use EPC’s GaN Power Bench cross-reference tool to find suggested GaN alternatives based on your desired operating conditions.