EPC Debuts GaN-Based, Bidirectional 1.5kW Demonstration Board
This 48/12 VDC solution’s 97% efficiency allows for air cooling, making water cooling unnecessary
The EPC9137 demonstration board is scalable, allowing two or three converters to be paralleled for 3kW or 4.5kW output. The device includes four EPC2206 100-volt eGaN FETs. It is controlled by the EPC9528 controller module that sports a Microchip dsPIC33CK256MP503 16-bit digital controller.
The four EPC2206s are highlighted in this depiction of the EPC9137 with the four EPC2206 eGaN Fets circled. Image courtesy of EPC
The EPC9137KIT includes both the EPC9137 evaluation board and the EPC9528 controller board
According to EPC, by 2025, one of every 10 vehicles sold worldwide is projected to be a 48-volt mild hybrid (MHEV). The company’s contention is that these vehicles will require bidirectional 48 volt to 12 volt converters, with power capacities ranging from 1.5- to 6kW. The priorities that manufacturers of these devices need to strive for are low costs, small size and high reliability.
As per Alex Lidow, CEO of EPC “eGaN FETs provide the fast switching, small size, and high efficiency needed to further reduce the size and weight of 48V – 12V automotive power system converters. The demonstrated superior reliability of GaN FETs make them ideal for this very demanding application.” He goes on to say that “The EPC9137 is an ideal example of the capabilities of GaN FETs to increase frequency and efficiency to allow smaller inductance for less phases and higher power density.”
Advantages of eGaN Fets over Silicon MOSFETs
EPC eGaN FETs operating at a 250 kHz switching frequency can achieve 97% efficiency. Compared to a silicon-based solution, this allows the EPC9137KIT, according to EPC, to operate three times faster, take up 35% less space and weight as well as offering 1.5% greater efficiency. The efficiency points are critical, as greater efficiency translates into less waste heat, which makes water cooling unnecessary.
The EPC9137 Evaluation Board
Operating in buck mode, the EPC9137 accepts inputs ranging from 20 to 60 VDC and provides an output of 12 VDC at 125 amps. In boost mode, 48 VDC at 29 amps is sourced from a 12 to 15 VDC input. The unit switches at 250 kHz and efficiency is 96% or better in either direction.
There is protection against input under-voltage and over-voltage, over-temperature and Inductor over-current. The unit employs average current mode control, which gives a greater immunity to noise and stray pulses.
The EPC9528 Controller
The EPC9528 controller is designed to work with those EPC modules and evaluation boards, such as the EPC 9137, that need an external controller to function. The unit as shipped is initially programmed as a buck converter by default. It can be reprogrammed to function as a boost converter by means of boost firmware available from the EPC website.
- 48 volt MHEVs
- The EPC9137 PCB is sized at 120 by 80 mm
- The power module is only for evaluation purposes and cannot be used for commercial products. There is no FCC approval and no EMI tests have been conducted.