DC/DC buck converters for performance eMotorsport

By switching from silicon (Si) transistors to gallium nitride (GaN), BrightLoop was able to increase the switching frequency of their design from 200 kHz to 600 kHz, while keeping the same efficiency.

This design change increased the power density of the solution by a factor of approximately two and this resulted in lower cost by enabling the implementation of a smaller enclosure.

EPC’s EPC2029 is an 80V, 48A eGaN FET featuring a 1mm ball pitch. The wider pitch allows for placement of additional and larger vias under the device to enable high current carrying capability despite the extremely small 2.6x4.6mm footprint.

Compared to a silicon power MOSFET with similar on-resistance, the EPC2029 is much smaller and has many times superior switching performance, making it ideal for applications such as BrightLoop’s high frequency BB SP DC/DC converter.

BrightLoop’s converters are used primarily in motorsports and supercars with other applications including commercial and off-highway vehicles. Future higher power versions are coming next year to address the mild hybrid applications such as electrical starting assistance.

The BB SP is relevant in any dual voltage architecture (14/48V or 14/24V), or where a certain load is available only with a voltage that is different from the regular network (for example a 48V pump on a 14V car), in which case the conversion can be done by the BB SP locally, just in front of the load.

To make the use of BB SP interesting, it needs to have negligible losses and weight compared with the rest of the system. This is possible thanks to EPC’s eGaN FETs. For example, a 48V actuator plus BB SP using GaN can be lighter weight than the equivalent 12V actuator.

Another important feature is the ability to implement a closed control loop at 600kHz, same as the switching frequency. The resulting bandwidth is so high, that very little capacitance is required. This has meant that electrolytic capacitors could be avoided, and only ceramic capacitors were used in the BB SP, reducing further the size and cost, while dramatically improving reliability.

Florent Liffran, CEO of BrighLoop Converters, said, “BrightLoop Converters is excited to partner with EPC and to leverage their great expertise in GaN power transistors. Using EPC products has allowed us to design best-in-class solutions for automotive applications with converters that are drastically smaller and lighter than competition, such as the BB SP. We are proud to provide our customers with the best power conversion technologies on the market.”

Wolfram Krueger, EPC’s VP of Sales for EMEA, added: “This is a great example of where our eGaN FETs demonstrate real advantage over silicon FETs by delivering performance in a significantly smaller package and the extreme reliability that is needed in these ultra-fast supercars. We are delighted to be working with BrightLoop Converters and are looking forward to working together on future applications.”