Environmental pressures are creating pressure to quickly adopt newer, cleaner, and more efficient transportation options.  In 2025, 1 in 10 vehicles sold are expected to be a more fuel efficient 48 V mild hybrid.  These systems will require a 48V – 12V bidirectional converter, with power ranging from 1.5 kW to 6 kW. The design priorities for these systems are size, cost, and high reliability. GaN power conversion solutions are perfect to support a 48 V to 12 V bidirectional converter used in these newer models.

A new reference design demo board, the EPC9165, is available to help jump start the design of a 2 kW bi-directional converter.  The EPC9165 is a synchronous buck/boost converter with other supporting circuitry including current sensors and temperature sensor.  The EPC9528 controller board ships with the EPC9165 to incorporate digital control and housekeeping power supply; this board uses the dsPIC33CK256MP503 digital controller from Microchip.

Brick DC-DC converters are widely used in data center, telecommunication and automotive applications, converting a nominal 48 V bus to (or from) a nominal 12 V bus. Advances in GaN integrated circuit (IC) technology have enabled the integration of the half bridge and gate drivers, resulting in a single chip solution that simplifies layout, minimizes area, and reduces cost.

This application note discusses the design of a digitally controlled bi-directional 1/16th brick converter using the integrated GaN power stage for 48 V-to-12 V application, with up to 300 W output power, and peak efficiency of 95%.

The standard dimension of the 1/16th brick converter is 33 x 22.9 mm (1.3 x 0.9 inch). The height limit for this design is set to 10 mm (0.4 inch).