The aggregator portion of the i.MX Power Profiling System sits between the "smart" current sensor boards and the host computer. It provides power and signal connections to each connected sensor board. The communication is done over I2C, where three I2C bus extenders (PCA9518) effectively provide a dedicated bus to each I2C device, to better allow for cabling.
More information will follow... Layout images, schematic and FRDM-KL25Z code attached below.