Novel ringing suppression circuit to achieve higher data rates in a linear passive star CAN FD

Abstract

As the number of electronic control units (ECUs) in an automobile steadily increases, the demand for achieving higher data rates and connecting even more ECUs to the Controller Area Network (CAN) also rises significantly. Recently, as a method to achieve higher data rates up to 10 Mbps without change in the existing CAN system, CAN FD (CAN with Flexible Data-rate) is suggested. However, it is difficult to establish a CAN FD communication under the conventional CAN network configuration which makes it necessary to limit network size because of shortening in the bit decision timing while the ringing convergence time is the same as in conventional CAN. In this paper, we pick up a typical network configuration where the number of ECUs which can be connected in a linear passive star is less than 4 ECUs when the data rate for the data phase is 2 Mbps. We develop evaluation boards each of which is equipped with a CAN transceiver embedding the ringing suppression circuit which we have proposed and a CAN FD controller. We apply them to CAN FD and show an effect on higher data rates up to 2 Mbps under the conventional network configuration connecting 8 ECUs.