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In the past, automobiles were made up of many independent electronic systems. Even the assembly lines that were used to manufacture the vehicles required the operation and management of multiple independent systems. However, the advent of the Internet of Things (IoT) has changed automotive electronics and assembly dramatically. The connectivity that used to only be available in the home or office is now available in modern automobiles. The car itself has now become the center of communication.

BroadR-Reach protocol applications within a vehicle
New protocols are being developed and implemented to promote connectivity and facilitate broadband-like automobile communications. While the increase in connectivity is making automobiles safer and providing more capabilities to consumers, it is also presenting technical challenges to the engineers who design these modules. As automotive circuit functionality becomes more advanced, the technologies from which the chipsets are made become smaller and denser. As a result, the chipsets are more susceptible to electrostatic discharge (ESD). Design engineers need to be cognizant of the unique circuit protection requirements of these chipsets to ensure their reliability in the automotive environment.

This article will discuss the characteristics and benefits of three new communication protocols: V2X, BroadR-Reach® and Analog High Definition (AHD). Then, it will examine the unique ESD protection requirements for each protocol and identify the latest circuit protection solutions designed to ensure the long-term connectivity and reliability of automotive electronics.

The Power of New Protocols

Manufacturers and design engineers will want to utilize new protocols to meet consumer demands for increased safety, convenience, and mobile communications. The following protocols are at various stages of development and implementation.

V2X Provides Safe and Efficient Road Travel

AHD camera compatibility in an automobile
The V2X protocol enables the vehicle to communicate with roadway infrastructure and other vehicles, providing enhanced safety and efficiency for drivers. While the protocol concept has been tested, the standards and hardware/software coordination are still under development.

Vehicle-to-vehicle (V2V) communications allow the vehicle to perform dynamic calculations based on the velocity and location of other vehicles. When the calculation indicates an imminent collision, the system notifies the driver or autonomous vehicle to take evasive action. This technology prevents the vehicle from hitting other vehicles or pedestrians. The U.S. Department of Transportation reported that V2V communications could address up to 79 percent of vehicle crashes.

Vehicle-to-infrastructure (V2I) communications allow the traffic system to collect key information such as the vehicle’s rate of speed and the direction of the moving vehicle. During rush hour, the system can use this data to control the timing of traffic lights, enabling synchronized, highly efficient traffic movement.

In addition, V2X could allow location-based advertising and promotion. For example, when a driver is approaching a particular city or neighborhood, he or she could receive information about items in that city based on a preset profile or preferences. The driver could be notified about a sale at a retail store along his or her route, or even a restaurant serving his or her favorite cuisine.

BroadR-Reach Replaces Slow Buses and Decreases Cabling

Currently in the early stages of implementation, BroadR-Reach technology will allow multiple in-vehicle systems, such as infotainment and automated driver assistance, to simultaneously access high-bandwidth data throughput over a single, unshielded twisted pair cable.

A potential application of BroadR-Reach technology involves streamlining communication on the controller area network (CAN) bus network. The CAN bus is used to communicate with many important systems in the vehicle, including the engine control module (ECM), powertrain control module (PCM), anti-lock braking system, instrument cluster, air bags, and cruise control. While the CAN bus standard is reliable and fault tolerant, it is relatively slow. Since modern vehicles are now expected to collect information from hundreds of sensors throughout the vehicle, this may create a severe bandwidth issue — especially when digital video signals are added to the system.

As an Ethernet-based protocol, BroadR-Reach enables 100 Mbps communication while only using two communication lines instead of four. It can be used as a high-speed link that can move various types of data around the vehicle. Or it can be used to aggregate a large number of slow lines (e.g., CAN bus), thus eliminating the need to run those lines around the vehicle. Therefore, one BroadR-Reach bus can take the place of many slow buses, reducing the physical amount of cable that is installed in the vehicle. The reduction in cable will lead to cost savings, a reduction in overall vehicle weight, and simplified cable routing.

AHD Enables Fast, Versatile Video Transmission

AHD 1.0 Tx/Rx is being developed to handle analog signals from multiple types of high-definition cameras located around the vehicle for surveillance and safety. It transmits 720p at 25fps/30fps with minimal data loss, while supporting COMET and CVBS signals simultaneously.

Although the cameras use analog signals, they must be able to transmit high-definition video throughout the vehicle’s network. AHD is designed to transmit a variety of high-definition video signals that could otherwise be handled by a complex HDMI connection. By supporting multiple video transport protocols, AHD proves to be very versatile and allows for backward compatibility for legacy modules that will not phase out immediately. The AHD line can carry the new high-speed data as well as lower speed protocols on the same wire, using the same chipset.

The Strength of Circuit Protection Solutions

Automotive circuit protection solutions for advanced communication protocols
Transient voltage suppression (TVS) diode used in AHD video application
With the increase in IoT devices and new communication protocols, unique demands are imposed on engineers who build automotive applications and modules. To create robust, reliable designs, engineers should consider ESD protection solutions early in the design process to address the heightened sensitivity of today’s automotive chipsets. In addition, engineers should review and understand the system-level ESD testing required for these modules. The ESD protection solutions shown in the table will help design engineers develop automotive modules that meet the safety and test standards of the latest communication protocols.

Conclusion

In the age of IoT, new protocols are being developed to promote safety and facilitate automobile-based communications. V2X is designed to help vehicles to communicate with the road and each other to prevent collisions and optimize traffic flow. BroadR-Reach and AHD are being developed to increase the speed and efficiency of high-speed data transmission, including high-definition video signals. Highly sensitive chipsets and demands for faster data require exceptional ESD protection for automotive modules that will utilize these new protocols. Low-capacitance, low-clamping ESD protection devices in a compact footprint will help make advanced automobile operation safe, reliable and efficient.

This article was written by James Colby, manager of semiconductor business development at Littelfuse, Inc., Chicago, IL. For more information, visit www.littelfuse.com

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