The Evolution Of Automotive Electronics Design
The number, functionality, and complexity of today’s automotive electronics has grown beyond leaps and bounds over the past several years. Certainly, the flagship of this technology is the Tesla automobile. But, even for those of us who can’t afford a Tesla, there is an increasingly widespread utilization of this technology in mid-range and even lower-end new cars. This article will describe the design environment represented by this technology and its deployment, and also discuss the ways in which this technology has been incorporated into the Tesla.
So much technology, so much functionality
There’s increasing discussion about the widespread deployment of self-driving vehicles in the coming years, but even as we wait for that technology to arrive, there is a high level of functionality found in today’s automotive technology. Obviously, this technology is not without its challenges in terms of what is needed on the product development side. Specific characteristics of automotive electronics include:
- Automotive electronics have the same signal integrity needs as all other complex, high-functioning electronic products.
- What is unique about the automotive environment:
- The electronics have to operate in temperatures from -60°to +135° and do that for 20 years.
- The electronics have to tolerate years of shock and vibration.
- They are always driven by cost.
- Reliability is nearly as important as cost, and may soon surpass it as the key factor.
- With modern cars, there has to be fairly high-bandwidth networks.
- Automotive electronics have to operate across a broad spectrum of frequencies from stereo to 70Ghz radar (bumper radars) and everything in between, including GPS, Bblue tooth, and wireless Ethernet. Example: Tesla is constantly communicating to cell phone towers and reporting all kinds of information to the manufacturer regarding where a car is and how it is performing.
- The addition of autopilot features creates another level and quantity of requirements.
- Cars contain the broadest spectrum of electronics of almost any product that can be named. They may be equal to the electronics contained in airplanes.
- Designer skill sets have to range from very, very high currents associated with batteries, motors and generators to 70 GHz radars.
- PCBs range from one-layer flex circuits up to 12-layer boards.
Lee Ritchey, Founder and President of Speeding Edge notes, “People expect cars to run with no failures for 20 years. We now think if something fails in 10 years, it’s something weird. As part of this reliability, we expect never to have to repair our cars.”
Can You Hear Me Now?
Obviously, all of the products within an automobile that are now interconnected require some sort of communication methodology. The original technology was comprised of the Controller Area Network (CAN) bus. This bus enables many different microcontrollers and different types of devices to communicate real time but it does not require a host computer. With CAN, when you plug an access device into your car it scans all the things on the CAN network. The network operates at different speeds as follows: Class C CAN operates at 1 Mbps; Class B operates at 125 Kbps and Class A at 10 Kbps. Ritchey notes, “About all that CAN could do was to keep your interlocking brakes functioning. Most of today’s cars have replaced the CAN bus with an Ethernet network. It will access data at a much higher rate and also provide the bandwidth that is necessary for the other high-demand electronics such as the various cameras that are installed on today’s cars.”
Depending on the make of car and the model, the amount of technology can range from the “common” to the very sophisticated. It doesn’t seem so long ago, in terms of the lifespan of technology, that GPS navigation systems were offered in automobiles. Initially, as add-ons, they were often only available on the more expensive car makes and models. And, their cost was definitely a bit daunting. Now GPS technology is ubiquitous (including on our mobile devices) and it may be difficult to find a car that does not have GPS on it as a standard feature or, at the least, as a reasonably priced add-on. For high-end vehicles, the technology incorporated on them has experienced a maturation process similar to Moore’s law. With every new model year, there is an increasing amount of new technology available.
At the top of the automotive pyramid in terms of latest generation of technology sits the Tesla. Ritchey states, “There is nothing more complex than a Tesla. And, because of all that technology, it has real time bug reporting. On the Tesla, there are something like 10 cameras with huge amounts of image processing. For example, when you come up behind a car that has a bike mounted on the back of it, the technology within the Tesla recognizes that it is a bicycle across the back not a stand-alone bicycle which is sitting over somewhere by itself. The Tesla can tell the difference between a motorcycle and a walker. It puts a picture up on your screen and you can see it all. This does not have anything to do with the autopilot. It has to do with image processing which some people call AI. It’s recognizing things one at a time and deciding what to do with them. “
“I had the opportunity to travel in a Tesla on a long-distance trip from Santa Rosa to the Grand Canyon,” Ritchey continues. “I assumed that the car figured out what was in front of it with radar but instead, it is finding that out with cameras. If you have the autopilot on, the car will not allow you to change lanes if the cameras show that there is something in the other lane. All of this location information is being done based on the images from the cameras that are being processed. The images themselves don’t pop up on the screen of the graphic but the display does show you what is in your lane and in the lanes that are on both sides of you. For example, if there is an 18-wheeler, the display shows the image of a truck.”
While the Tesla does have an autopilot, by no means does it have a self-driving capability. Ritchey notes, “While the Tesla does have an autopilot, you do have to have your hands on the wheel or it raises hell. If you have your hands off the wheel for a certain amount of time, the autopilot pulls the car to the shoulder. It has a lot of alarms that make a lot of sound but if you don’t respond, it pulls over to the side of the road and it parks.”
Even with all of its sophistication and technology, the capabilities of the Tesla are not limitless. Ritchey explains, “In certain configurations of lanes, the Tesla got confused. For example, it automatically centers between two lines it sees so if you have a lane coming in from the side, it goes out of the lane it is in. If the white lines disappear, it gets lost. That’s why there is so much effort being put into painting the lines on the roads. “
“And,” Ritchey adds, “Despite an Ethernet that operates at 5 Mbps, the car depends on there being local cell phone towers. Everything about the Tesla counts on cell phone towers. It does not operate off of satellite. It follows that iIf there is no cell phone connection, some of the stuff inside the car doesn’t work, such as reporting. “
Getting From Point A to Point B
One of the challenges associated with all-electric cars is their distance range. In most instances, going on a long-distance drive depends on the location of chargers. Although the number of charging stations is continually growing, they are not always on the path on which you are traveling.
With the Tesla, Ritchey notes that the integrated network of charging stations makes it possible to drive the car on a route that could be a bit more off the beaten track. “In going from point A to point B, in this instance from Santa Rosa to the Grand Canyon, the technology within the Tesla plotted out what the best way was to go. And, because you have to know where the charging stations are, it says right on the map where the stations are and where you should stop next. We were never more than 150 miles from a charging station. Half of the charging stations in each place we stopped were called super charged. They would do a full-up charge in 45 minutes. And, on purpose, they all are right next to where we could eat lunch.“
Ritchey explains, “When you plug the car into a charging station, that station knows which car is being charged because there is an account that has already been set up. You give Tesla a credit card so that when you fill up your car, the cost of the charge is automatically put on your credit card. Even with the cost of the charging, on our trip we equated the cost of our trip to a hundred miles to the gallon with a conventional car.”
We’ve Come So Far
With all of the new “bells and whistles” represented by the technology in today’s cars, there are still some givens. They include:
- The expectation is that if it is -40° you can start your car. Conversely, if it is 120° above, you can start your car. (In the desert, before you start a car, the temperature inside the driver side of the car can be 180°).
- There are probably 10 specialties involved in designing the electronics in today’s cars.
- As noted, there is a wide range of PCB implementations in any car from 1 layer flex circuits to 12 layers. As an example, all the LED lights are one- or two-layer PCBs.
- As new technology matures and becomes more cost-effective, there are some elements that will be mandated in order for vehicles to be insured.
- Ritchey says, “I imagine that collision avoidance and back-up cameras will become factors such if you don’t have them, your insurance rates will be higher.”
What’s On the Horizon?
Ritchey explains, “For years we have had semiconductors that could do a lot of high tech stuff but the things that will fail are the connections. I can’t remember the last time that I fixed something that was not a failed connection. Silicon rarely fails.”
“The good news is that we are getting away from failures by getting rid of connections and integrating everything into one chip,” Ritchey continues. “The wires that connect one computer to another is about the only place you have for a failure now. The work I see being done on connectors for cars is better than what is in a laptop because of the fact that it has to tolerate a lot of environmental conditions. In the early days of ICs, we would not sell to automotive companies because the requirements were too strict. The packages were not reliable and the ICs would not operate under certain operating temperatures. With each iteration of semiconductor technology, the amount of capability that goes into automotive electronics also scales”.
The complexity and diversity of the electronics in today’s automobiles has become somewhat
commonplace. Once all of the environmental and operating requirements within a car for are taken into account, the capabilities and the reliability of this technology will only continue to increase. In truth, today’s high-scale electronics will become tomorrow’s expected capabilities especially as it relates to the safety and reliability of next-generation vehicles. From the design perspective taking all of the operating requirements into account early on in the product development stage will ensure that the technology will function right the first time, every time.