Reliable Connectivity Solution for LEVs & CAVs
There is currently a significant technological shift occurring across the automotive industry. The first and most evident aspect is the movement from traditional transportation running on internal combustion engines (ICEs) to electric vehicles (EVs) in an aim of reducing global emissions. But beyond this initiative, there are further developments which are altering the automotive landscape and creating new design challenges which must be met.
In an aim to elevate road safety and efficiency, as well as reduce driver workload, vehicles are becoming smarter, and this applies not just to passenger cars but also to commercial, construction and agricultural vehicles (CAVs). Mirroring developments in consumer vehicles, CAV manufacturers are continuing to evolve advanced driver-assistance system (ADAS) services, as well as deploying bespoke autonomous and remote-control systems in the search for greater operational effectiveness and safety. While the developments are similar to that of passenger vehicles, CAVs bring a number of unique challenges that must be addressed.
Similarly, we are seeing a global diversification of transportation, especially within the urban environment. New solutions, such as e-bicycles, e-scooters, delivery robots, and other light electric vehicles (LEVs) are helping to reduce reliance on cars and alleviate pressure on traditional city personal and commercial transportation, all while having a lower impact on the environment.
Whether we are talking about the growth of CAVs or LEVs, in both cases, the underlying electronic infrastructure is immensely different and usually inherently more complex than historic automotive in-vehicle networks (IVNs). Arrays of sensors, controllers, battery electronics and communication systems that are capable of not just internal connection but connection to other vehicles and cloud services are creating a host of additional design considerations.
In this article, we will explore onsemi’s extensive experience across automotive IVNs, investigation solutions suitable for the latest LEVs and CAVs, as well as a look to the future of in-vehicle networking.
What are LEVs and CAVs?
LEVs or powered light vehicles (PLVs) are seen by many as a key ingredient in solving our current planet harming transportation services. In line with this theme, the European Union has unveiled its Green Intelligent Affordable New Transport Solutions (GIANT) program. With 24 development partners involved, its aim is to produce innovative solutions that will facilitate the production of cost-effective light electric vehicles for urban transportation across the globe. LEVs cover everything from pedelecs to small passenger cars, with emerging applications across both consumers and commercial.
In terms of usage, on the consumer side, you have personal transportation solutions such as e-bikes, e-scooters, electric mopeds, and low-powered electric motorbikes, and small (6-9kW) electric cars. Which ease pressure on public transportation and reduce car usage, whilst allowing more dynamic movement through additional usage of footpaths and bike lanes.
On the commercial side, you also have many of the above, as well as industry and operation specific LEVs like driverless taxis and small delivery vehicles, which reduce the usage of vans and cars in urban environments. In all cases, emissions can be reduced while efficiency can be increased, which is just as important with many modern city’s expansion rate straining their infrastructure. The importance of the LEV market is reflected in its predicted compound annual growth rate (CAGR) of 9.74% between 2022 to 2032 [1].
In conjunction with the commercial LEVs, CAVs also cover a variety of considerably larger vehicles which use a range of powertrains, including ICEs, electric, hybrid systems, and other alternatives, such as biofuel and hydrogen engines. Example vehicles can include everything from forklifts and tractors to mining equipment and haulage trucks.
While there are similar pushes with CAVs to reduce emissions through hybrid and electric drivetrains, a considerable section of industry development is focused on increasing autonomous and remote operation to raise efficiency and safety by removing humans from dangerous environments such as mines and logging facilities.
Moving from Domain and Zonal Control
With both LEVs and CAVs, there is a departure from the typical IVNs seen in cars produced in the past few decades. Typically, cars have used domain control units (DCUs) which manage a specific area of the vehicle based on its operation, such as infotainment, engine, chassis and ADAS. For onsemi, their range of OEM approved CAN, FlexRay and LIN products, as well as additional wireless solutions, have fulfilled the needs of automakers’ domain-based architectures for over 30 years.
But evolution across more sophisticated LEVs and CAVs has meant that existing network speeds and inherent system complexity cannot meet many applications, with existing domain IVN being too slow and heavy. Manufacturers need faster solutions which use a zonal design to reduce system complexity and streamline cabling.
Equally, there is a demand for systems which reduce costs, as well as being agile and able to be easily adapted and upgraded to allow alterations on the go without excessive redesigns or retrofits. Weight reduction is another important aspect, with solutions that reduce cabling being extremely popular in LEV applications, where power and battery sizes are limited.
onsemi IVN
Helping to fulfil the needs of the latest LEV and CAV designs onsemi have a wide range of products covering key communication methods such as CAN-FD, LIN, and automotive ethernet. onsemi’s technologies are approved by all major automotive OEMs, delivering the highest quality, excellent electromagnetic compatibility (EMC) performance and simple system integration through intelligent design.
NCV7343 and NCV7422
Delivering high-speed CAN-FD communication at low-power, thanks in-part to advanced wake-up over CAN bus facilities, onsemi’s NCV7343 is suited for a wide range of LEV and CAV applications.
This fourth-generation solution delivers data rates of 5Mbps and features excellent EMC performance, making it ideal for both LEVs and CAVs which are powered by electric motors or working in noisy environments. The state-of-the-art dual-flat no-leads (DFN) packaging features wettable flanks that are compatible with PCB automated optical inspection (AOI) and X-Ray systems, and each device is AEC-Q100 Grade 0 approved. The IO and bus detection also help to support intelligent error diagnostics and allow for easy system integration.
The NCV7422 is one of the most popular products in onsemi’s current IVN lineup. It is a two-channel physical layer device for LIN protocol communication, which offers increased reliability compared to two separate single-channel solutions, as well as reducing the system component count.
Furthermore, it has robust EMC performance, making it suitable for usage in noisy environments, as well as refined DFN packaging. As a LIN controller it is suitable for use in LEV and CAV systems such as window actuators, door actuators, mirror motor control, and heater element control.
Figure 1: A typical circuit diagram for an onsemi NCV7422 implementation (Image source: onsemi)
Automotive 10BASE-T1L Networking
Figure 2 – IEEE802.3.cg specifications compared (Image source: onsemi)
Automotive ethernet is proving a key technological enabler for LEVs and CAVs, especially as the complexity of their systems continues to grow. 10BASE-T1L is the short range automotive and industrial tailored variant of ethernet defined by IEEE802.cg (Figure 2).
Along with targeting shorter distances, 10BASE-T1L crucially includes physical layer collision avoidance (PLCA) and carrier sense multiple/access collision detection (CSMA-CD) in half-duplex mode, which allows for collision avoidance in multiple node operation. This element is key for zonal and more complicated vehicle architectures and allows numerous devices to be connected to a host controller, providing each node with an allocated transmission frame to avoid network collisions and allow the entire bandwidth to be utilised.
While slower than 100BASE and 1000BASE ethernet, 10BASE-T1L is twice as fast as CAN-FD and for most IVN applications offers an ideal balance of speed, processing power requirement and cost, without the complexity of alternatives such as FlexRay.
The NCN26010 from onsemi is the first 10BASE-T1S integrated Ethernet MACPHY transceiver on the market that fully supports OPEN alliance requirements. It provides robust multi-point communication for automotive environments, enabling greater utilisation of twisted pair ethernet with enhanced noise immunity. It features an SPI interface and can connect multiple devices via a single pair ethernet (SPE) using one MACPHY per port, helping to reduce vehicle cabling.
The selective sleep and wake features enable advanced power saving across nodes while power over data line (PoDL) is natively supported as each transceiver is DC insulated from the BUS via coupling capacitors, helping to optimise system architecture. Within LEVs and CAVs, 10Mbps ethernet is ideal for replacing a range of protocols such as CAN, LIN, RS485, RS232 and FlexRay, and can streamline designs as well as simplifying the manufacturing of wiring looms. For LEVs and CAVs systems such as suspension feedback, mirror controls, ADAS services and more can all use 10BASE-T1S.
Alongside from the MACPHY 10BASE-T1S NCN26010, onsemi also offer the PHY only 10BASE-T1S NCN26000, as well as the NCV7311, NCV7410 and NCV7310 transceiver interfaces.
Figure 3 – Example automotive 10BASE-T1S ethernet applications (Image source: onsemi)
onsemi NCV-RSL15
Figure 3 – Example automotive 10BASE-T1S ethernet applications (Image source: onsemi)
Secure low-powered wireless communication through Bluetooth Low Energy (BLE) is a vital requirement for many LEVs, such as e-bikes, e-scooters, and small electric cars, as well as many CAVs. Used for functions such as remote keys and tire pressure monitoring, some manufacturers are also exploring using BLE for battery management systems (BMS).
The NCV-RSL15 features 10-20 times lower sleep current and up to six times lower operating consumption, when compared to competing auto qualified parts, helping to extend battery range and life. The integrated general-purpose microcontroller unit (MCU) allows for over-the-air updates, analogue, I2C and SPI connectivity, while the integrated ARM CryptoCell provides increased security.
By supporting BLE 5.2 up to eight connections at the same time, considerably more than previous Bluetooth technology. The NCV-RSL15 is simple to integrate into designs with automotive AEC-Q100 and PPAP qualification, as well as coming with wettable flanks, allowing for simple visual inspection during assembly.
Conclusion
The automotive industry is a transforming landscape with endless expanding opportunities for diversification of existing solutions in a bid to bring newfound intelligence and efficiency to our transportation systems. In the urban arena, LEVs are rapidly growing, filling consumer and commercial applications alike, delivering increased sustainability and relieving pressure on existing infrastructure. Likewise, CAVs are benefiting from increased functionality, such as ADAS and remote operation, to increase safety and operational effectiveness.
With both of these two diverse sectors comes a wide range of demands for the vehicle’s own internal architecture. It is here where design engineers rely on electronic suppliers, such as onsemi, who have the extensive experience and product ranges needed to cover the latest applications requirements.
For onsemi, their focus on aligning to industry recognised automotive, electronics and networking standards provides automakers with robust and easy to integrate solutions designed to suit the needs of a wide range of implementations. Innovative LEVs and CAVs will play an important role in solving our current transportation issues and the move towards widespread sustainability, but if these solutions are to succeed, the automotive industry needs similar innovation from its component suppliers.
References
[1] "https://www.precedenceresearch.com/light-electric-vehicles-market,” Precedence Research, 2022. [Online].
