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.

The 48 V/12 V automotive evaluation power modules (EPC9137, EPC9163, EPC9165, etc) utilize the two-phase synchronous buck/boost topology. The edge connectors and controller card are also designed to operate two modules in parallel with one controller, effectively achieving four-phase and therefore double the rated current and power. An example using EPC9137 modules are shown in Figure 1.