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We are at a historic, palpable turning point in the automotive industry. There’s a tremendous amount of pressure on automakers to innovate and redefine vehicle usage. Not only do they need to meet consumer demand, but they must also keep up with changing safety and environmental regulations. As a result, automakers are increasing the number of sensors used within and around vehicles to provide their customers with greater safety and functionality, which requires sensor manufacturers to miniaturize and improve previous technologies.

In this article, I’ll highlight three key trends that will significantly increase the number of sensors used in vehicles in the next 10 years: advancements in infotainment systems, additional safety and autonomous driving features, and a rise in electrification.

Trend No. 1: Infotainment systems are becoming more advanced

The rate of technology adoption within vehicles to include the latest infotainment features and trends is exponential. The user experience is becoming much more than just a drive.

As shown in Figure 1, the number of displays used in a typical vehicle is increasing – from reconfigurable instrument clusters to center consoles to passenger entertainment. At the same time, display quality is also increasing thanks to larger screens with finer resolutions and greater brightness levels. E-mirrors for rear and side views are also becoming more common, as are wireless charging modules and additional media hubs. Cars are starting to feel like seamless extensions of smartphones, with consumers expecting aesthetically clean touch surface designs, which leads to additional integrated circuits (ICs) like inductance-to-digital converter (LDC) sensors that enable a “force touch” feature on surfaces that are not screens, with the ability to detect the amount of force applied.

Figure 1: Modern, feature-packed Infotainment and cluster systems (Source: Texas Instruments)

LDC sensors like the LDC3114-Q1 from Texas Instruments (TI) enable a seamless user interface (UI) experience with touch-on-metal, plastic or glass surfaces for UI around the center console.

Additionally, 3D Hall-effect sensors such as TI’s TMAG5170-Q1 enable position detection in e-shifters (gear shifters) and infotainment control of joysticks and knobs, which are often combined with touch and UI features around center consoles.

Supporting all of these new features and displays requires additional ICs in smaller form factors, which has led to the miniaturization of ICs and printed circuit boards (PCBs) while achieving even greater functionality. The challenge is that when you decrease the size of the module that houses PCBs while increasing processing requirements, you have the perfect recipe for higher operating temperatures. This is primarily caused by greater power consumption due to more processing and a decrease in airflow caused by smaller form factors – both of which are compounded by the environment, since infotainment systems are often exposed to sunlight for a majority of their lifetime.

Since temperature sensors play such an important role in helping avoid damage to circuits caused by overheating, automakers are increasing the number of temperature sensors used on a typical PCB and prioritizing reliability and accuracy during product selection. Placing temperature sensors in system hot spots such as the microcontroller, power supply or backlight LED display helps keep these components within their recommended operating conditions, which enables the infotainment system to deliver the performance and reliability expected by consumers.

Finding the right type of temperature sensor can be tough given the thousands of options available. One that won’t break the bank, and which is more reliable than traditional negative temperature coefficient thermistors, is TI’s TMP61-Q1 linear thermistor. The increased accuracy of the TMP61-Q1 helps minimize temperature error safety margins to prevent false triggering. This enables control systems to operate closer to thermal limits and throttle or shut down only when needed.

Over the next few years, you can expect to see an increase in not only the number of sensing products, but higher accuracy and integration within infotainment systems, with the goal to enable additional user experience features and a more entertaining drive.

Trend No. 2: Additional safety and autonomous driving features

Not all cars are made equal, especially when tailored for certain markets. But government regulations are closing the standard safety feature gap to ensure consumer safety. For example, in 2019, the Indian government mandated active and passive safety features installed in all vehicle models sold in its country. In order to add these safety features to low- and mid-tier models, automakers need to add more sensors to sense the environment within and around a vehicle.

You’ll find a great example of this trend in rearview cameras. They were only available on luxury models 10 years ago but are now a standard safety feature for most new vehicles; it’s hard to find a new car without it. Another example is driver monitoring systems, which are also increasing in popularity. So if history repeats itself, I wouldn’t be surprised to see widespread adoption of more advanced safety features.

Advanced safety features are a part of advanced driver assistance systems (ADAS). Initially known for cruise control, ADAS have morphed into so much more, taking sensors on vehicles to a whole new level in order to support features such in-cabin monitoring, blind-spot detection, lane departure warning, parking assistance – even the latest autonomous driving technology.

Figure 2 shows the different levels of autonomous driving and their corresponding features. Although there are many roadblocks in reaching level 5 autonomy, automakers are working toward making that a reality.

Figure 2 Levels of automated driving (Source Texas Instruments)

Autonomous driving functions cannot exist without cameras and ultrasonic, radar or LiDAR sensors on the edge to sense the environment around a vehicle. As more automakers race to reach higher levels of autonomous driving, an increase in the number of sensors is inevitable. But where are you going to put them?

This is where miniaturization comes into play – where package size and integration shine. For example, today’s high-end vehicles feature a multi-chip single radar system. Given the use of multiple discrete components, these radar systems are big and bulky when they need to be smaller, lower power, and cost-effective. TI offers automotive millimeter-wave (mmWave) radar sensor solutions such as TI’s AWR1843 that have processing co-located with the front end to reduce the size and form factor of radar systems by 50%. TI also offers a higher level of integration with antenna-on-package mmWave radar devices such as TI’s AWR1843AOP, which enable the efficient mounting of multiple radar systems around a vehicle.

It’s not just high-data-intensive sensors that are in demand; much smaller building-block sensors will ensure the safety and long-term performance of computationally intensive processors for sensor fusion and artificial intelligence. If a processor overheats, has too much current draw, or is exposed to high humidity levels, its performance can degrade or it may break completely, affecting ADAS functionality. Temperature, current, and even humidity sensors like the HDC3020-Q1 keep these processors and other ADAS components like LiDAR sensors within their specified operating conditions to prevent damage.

ADAS have more stringent system-level safety requirements than other automotive systems, because as vehicles become more intelligent, they also become more complex. More complexity raises safety concerns, especially as autonomous driving becomes mainstream. Automotive Safety Integrity Level (ASIL) ratings establish requirements to mitigate risks and ensure standard safety procedures when designing these systems. As a result, many subsystems throughout a vehicle must have system-level functional safety.

One common requirement in functional safety is redundancy. In order to meet redundancy requirements, automakers are rapidly adopting sensors for safety-critical control systems, further multiplying the number of sensors. Sensor manufacturers like TI have noticed this trend and focused on making it easier for engineers to find and use sensors, whether in designs targeted to meet functional safety standards or in competitively differentiated safer systems.

Trend No. 3: A rise in electrification

Automakers are going all-in on electric vehicles (EVs). Why EVs? Well, a quiet ride and instant torque aren’t the only reasons why they are gaining traction; there’s a much larger force at play related to government goals to reduce carbon dioxide emissions.

Many countries have announced target dates and pledges with regards to electric vehicle sales. For example, South Korea announced a target date of 2050 to become carbon-neutral, with corresponding plans to increase the number of EVs on the road to almost 3 million by 2025 through an extension of EV tax benefits and specific EV purchase targets for rental cars. The details of each country’s target may vary, but the common goal is to phase out internal combustion engine (ICE) vehicles over time with regulations and incentives such as tax breaks or subsidies.

How does increased EV production affect the demand for sensors? Compared to ICE vehicles, EVs have increased requirements for voltage, current, temperature, and humidity sensing, because large subsystems such as the onboard charger, DC/DC converter, inverters, and battery-management system (BMS) all deal with high voltage or currents. Each one of these systems require close monitoring to minimize the threat of current surges, thermal runaway, and even corrosion or shorts from moisture leakage.

High sensor accuracy in these systems could translate to shorter EV charging times and even longer battery life. For example, more accurate temperature readings can decrease margins of error, thus preventing false triggering of control systems and enabling closer operation to thermal limits, throttling or shutting down only when necessary. Total accuracy when using temperature sensors is related to the sensor and surrounding components, layout techniques used, and thermal conduction paths, so it’s essential to keep in mind best practices when using surface-mount temperature sensors.

TI’s TMP126-Q1 temperature sensor helps systems take preemptive action to reduce the risk of thermal damage with a temperature slew-rate alert that detects rapid temperature changes before they reach dangerous levels, reducing the risk of thermal runaway. Not only are sensors like the TMP126-Q1 accurate, they are also reliable thanks to the low sensor drift of its silicon material. In BMS with high charging currents, it’s important to maintain current-sensing accuracy to properly know a battery cell’s state of charge. Using accurate and low-drift current sensors such as TI’s INA229-Q1 can help maintain EV battery efficiency over time, temperature, and humidity levels.

Conclusion

Sensors will only continue to increase over time as infotainment systems become more advanced, safety and autonomous driving features propagate, and electric vehicles increase their market share. To help automotive engineers optimize their designs, semiconductor manufacturers are providing smaller, more accurate, and power-efficient sensors. With so many sensors available, product selection can be overwhelming. It’s important to establish what criteria matters most – focusing on parameters such as accuracy, drift, and size is a great way to narrow down your options.

About the author

Bryan Padilla is a product marketing engineer at Texas Instruments. He has a lifelong interest in the automotive market and a professional focus on sensing technologies.

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