Multichannel auto-ranged current sensing for automotive control units

Thanks to the development of the vehicle technologies and the introduction of new features, automotive ECUs can absorb a very wide range of current during their normal activity, depending on the different operational conditions (workload or active functionalities). In the ECUs testing activities it is fundamental to monitor the power consumption, to verify if the current draining is compatible with the vehicle operating conditions. Most commercial solutions do not allow to measure the current drain in the whole operating range with the required accuracy, and their integration in automated testing solutions is often not possible. From this need, there is a growing interest in developing a custom solution to measure a wide current range with a high accuracy. The final target of this thesis is to design and build a device that can meet the aforementioned requirements on four channels. For this purpose, different sensor technologies have been compared and analyzed. The two main technologies, which have been employed in the final system, are based on the volt-amperometric method (Shunt resistor), and on the magnetic induction field sensing (Hall-Effect sensor). Advantages, disadvantages and finally yet importantly the limit of each instrument have been compared, to understand what is the best solution to cover the desired range. Lastly, the device must be able to switch automatically between different ranges, to guarantee the proper accuracy. Moreover, the sensed measurements need to be transmitted to the automatic testing equipment via serial interface and on CAN bus for further processing.