DC/DC demonstration board is scalable for efficient hybrid vehicles
A scalable 1.5kW 48V/12V DC/DC demonstration board powered by GaN FETs has been released by Efficient Power Conversion (EPC). The EPC9137 is designed for efficient, smaller, faster, bi-directional converters for mild hybrid cars and battery power back-up units, advised EPC. It is a two-phase 48 to 12V bi-directional converter that delivers 1.5kW with 97 per cent efficiency in a small footprint.
The design of the demonstration board is scalable. Two converters can be paralleled to achieve 3kW, or three converters can be paralleled to achieve 4.5kW. The board features four EPC2206 100 V eGaN FETs and is controlled by a module that includes the Microchip dsPIC33CK256MP503 16-bit digital controller.
By 2025, one of every 10 vehicles sold worldwide is projected to be a 48V mild hybrid, said EPC. Advantages of these 48V systems are to boost fuel efficiency, deliver four times the power without increasing engine size, and reduce carbon-dioxide emissions without increasing system costs. These systems will require a 48V to 12V bi-directional converter, with power ranging from 1.5 to 6.0kW. The design priorities for these systems are size, cost and high reliability, reported EPC.
EPC’s eGaN FETs can operate with 97 per cent efficiency at 250kHz switching frequency, enabling 800W/phase compared to silicon-based solutions, which are limited to 600W/phase due to the limitation on the inductor current at 100kHz maximum switching frequency. EPC advised that eGaN FETs allow the number of phases to be reduced from five to four for a 3.5 KW converter while increasing efficiency. The efficiency of a four-phase GaN converter operating at 250 kHz is 1.5 per cent higher than a five-phase silicon MOSFET-based converter operating at 100kHz.
The DCDC converter is three times faster, greater than 35 per cent smaller and lighter, and offers greater than 1.5 per cent higher efficiency compared to silicon MOSFETs, continued EPC. The cost for the overall system is also reduced. The efficiency and thermal performance of GaN FETs enables air cooling instead of water cooling and their small size reduces heat-dissipating aluminium housing for additional system cost saving.
The EPC9137 demonstration board is available for immediate delivery from Digi-Key.