In-vehicle communication becomes secure and reliable

4th November 2016

Enaie Azambuja

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Around 60 electronic control units communicate with each other in vehicles today via the CAN. The need for in-vehicle communication is growing as the amount of networking increases and more comfort and automation are implemented. The new protocol variant CAN FD allows a higher data bandwidth and transmission speed. This saves time in programming, in tests and diagnostic routines as well as for SOTA.

With its TLE925x CAN FD transceivers, Infineon Technologies makes data exchange up to 30 times faster than today. The TLE925x reaches transmission speeds of up to 5 Mbit/s. Compared to the classical CAN transceivers with a maximum of 8 byte, the CAN FD transceivers such as TLE925x can send a payload of up to 64 byte per message.

This opens up the possibility to check the transmitted data for consistency in the transmitting control unit and to sign it with a 21-bit checksum instead of the 17-bit possible so far. Longer checksums ensure reliable communication between the control units. This makes it possible to better secure data transmission in the vehicle without the application software becoming more complex in the electronic control unit.

The TLE925x CAN FD transceivers are used, for example, in body control modules and gateways, in power steering, engine and transmission control units as well as in radar and camera-based driver assistance systems. On average, every vehicle today has 17 CAN transceivers. The number should rise to more than 20 within the next five years.

The TLE925x CAN FD transceivers permit an interface voltage to the microcontroller of 3.3 V as well as 5 V for best-possible signal symmetry. The more symmetrical the signals are, the better the electromagnetic compatibility (EMC) is.

Compared to the previous CAN generation, Infineon has improved the robustness of the CAN FD transceivers to electromagnetic interference (EMI) in the standard frequency range of 1 MHz to 1 GHz.

The electromagnetic emission (EME) of the TLE925x between 150 kHz and 1 GHz is lower than in any other CAN transceiver available today. At the same time the CAN FD transceivers pass electrostatic discharge tests (ESD) of at least ±8 kV according to IEC61000-4-2.

Infineon offers a comprehensive portfolio of products for a wide variety of bus segments such as CAN FD, CAN with Partial Networking, High-Speed-CAN, LIN and FlexRay. For the protocol variant CAN FD with 5 Mbit/s, Infineon offers, apart from the TLE925x transceivers compliant to ISO11898-2:2016, the matching system basis chips in the TLE9278 Multi-CAN Power-SBC family. The TC3xx multicore microcontrollers in the AURIX family have up to 12 CAN FD channels according to ISO 11898-1:2015 and round off CAN FD portfolio of Infineon.

The CAN FD transceivers in the TLE925x family are already available in sample quantities. They are delivered in the RoHS-compatible standard package DSO-8 or in the extremely compact package TSON-8 with dimensions of only 3mm x 3mm. Volume production is due to start in February 2017. The CAN FD transceivers are compatible with the present classical CAN transceivers.