Position Sensors - the hidden heroes of the automotive industry
How position sensors and other tiny but essential components that have long gone unseen in vehicles are now taking center stage as the car industry embraces electrification and battery power.
Some types of electronics components attract a lot of attention – today, for instance, the powerful GPUs which train AI models are constantly in the news.
Others quietly perform important but largely unseen functions. Some of ams OSRAM’s longest-running product lines fall into this second category, including its magnetic and inductive position sensors, its capacitive sensors, and battery monitoring chips.
Manufacturers of products such as industrial pumps and fans use the position sensors to make highly efficient and smooth-running electric motors.
A capacitive sensor in a vehicle’s steering wheel helps maintain safety, because it reliably detects the touch of the driver’s hands when in assisted driving mode.
Large industrial equipment powered by a battery can run for longer between charges when it uses cell-level information provided by an ams OSRAM battery monitoring sensor.
These brilliantly engineered sensor ICs are doing a valuable job – but few people except the engineers who design them into circuits would previously have noticed them. Now, however, these ‘hidden heroes’ have come to the attention of a much bigger audience in the automotive industry. That’s because of electrification, a trend seen not only in the drivetrain of electric vehicles (EVs), but also in the enhancement of many previously mechanical functions, such as steering or braking control, which can be made more reliable and efficient when they are driven by a battery-powered electric motor.
Drawing on unique analog semiconductor technology developed in ams OSRAM laboratories, these products had already achieved breakthroughs in position sensing performance and the accuracy of battery system measurement before the car industry knew it needed them.
Now these hidden heroes provide a solution to the tough problems that the automotive market faces today, making valuable improvements possible to the comfort, efficiency, performance and safety that new cars offer.
Products with a long history of development
The products which have started to excite the automotive industry are the result of engineering R&D conducted throughout the 2000s, drawing on the expertise of ams OSRAM in the fields of sensing and analog semiconductor technology.
The research culminated in a series of breakthroughs which created hugely superior performance and value in their product segments. In capacitive sensors, ams OSRAM achieved higher sensitivity than ever before. In battery monitoring sensors, increases in their accuracy, precision and bandwidth produced more useful information about a battery’s state of charge and health.
In position sensors, the ams OSRAM engineers spotted that existing products were either unreliable and had a limited lifespan (potentiometers) or were bulky and expensive (resolvers). Other position sensor manufacturers knew that the magnetic principle of measurement was viable, but all previous magnetic position sensors had been plagued by interference from stray magnetic fields which are generated by devices such as high-voltage cables or electric motors.
The brilliant ams OSRAM discovery was differential sensing: each position sensor IC has four separate magnetic sensor elements and uses differential measurement between pairs of elements to cancel out the effect of stray magnetism.
Different technical approaches pursued by other chip manufacturers failed to match this performance in the past – and still none can rival it. ams OSRAM remains to this day the leader for stray field immunity in magnetic position sensors.
Its innovation in position sensing extended to another technology, inductive position sensing. Here, ams OSRAM engineering know-how and semiconductor fabrication excellence have produced sensor ICs which offer exceptional accuracy, flexible integration options, and high stray field immunity, and at much less cost than a resolver.
These products were developed and introduced before the mass market for EVs emerged. The initial market opportunities for these high-performance yet compact and reliable ams OSRAM devices were in vehicles, robots, power tools, and industrial and medical equipment.
But it turns out that the trend for electrification across the automotive industry calls for accurate position sensors that are small and light, and that are immune to stray magnetic fields: a perfect description of the original ams OSRAM position sensors that were developed before the EV became a mainstream product.
And because a battery rather than a fuel tank is the vehicle’s source of energy, accurate current and voltage sensing for battery monitoring have become mission-critical functions. Here too, ams OSRAM sensor ICs provide an ideal solution.
This is why electrification is creating a wider market for these sensor types, and why ams OSRAM is gearing up to produce the products in higher volumes than ever before.
Proliferation of motors in vehicles calls for compact position sensors
The changes brought about by the rise of automotive electrification are increasing safety and improving the user experience, as well as enabling the phasing out of fossil fuel power.
Electrification requires the installation of motors throughout the vehicle, often in limited spaces. This puts a premium on compact solutions which can cope with the rigors of automotive operation - particularly exposure to vibration, shock, and extremes of temperature - and which do not require expensive shielding.
This is the sweet spot for the ams OSRAM portfolio of magnetic and inductive position sensors. Magnetic position sensors are best suited to the smallest applications: they can be implemented with their associated passive components in a very small footprint. They are also the simplest solution to integrate into a system. Accuracy is typically ±0.5°. Magnetic position sensors are generating most interest in applications such as active suspension and steer-by-wire systems.
Other applications require the ultimate in measurement accuracy: the higher the accuracy, the better the system’s control of torque, giving the highest efficiency and smoothest operation. For instance, the higher accuracy – typically ±0.3°over a full-scale 360° range - of the ams OSRAM inductive position sensors is of great value in the drivetrain of EVs. The inductive position sensors’ accuracy is even better over a less than full-scale range, so they are also finding uses in active pedals and brake-by-wire systems.
And these are by no means the only applications for magnetic and inductive position sensors in newly electrified functions: they offer great value in applications such as chassis position measurement and active damping systems, as well as traditional functions such as the sunroof, window lifter, and power seats.
Accurate power monitoring strengthens trust in battery’s fuel gauge
Another hidden hero of the automotive world from ams OSRAM is the battery monitoring chip: highly integrated, a device such as the AS8510 combines extremely accurate current sensing, supporting the fuel gauge function of an EV, with voltage sensing, for monitoring cells’ state of health, in a small 20-pin SSOP package. The accurate current measurement enabled by the AS8510 helps EV manufacturers to extend their vehicles’ range by reducing the margin of error that needs to be added to fuel gauge readings, giving the driver higher confidence in the vehicle’s indication of the charge remaining in the battery.
Capacitive sensor enhances safety of driver assistance systems
Recently, the addition of autonomous driving capabilities to new cars has created a need for advanced hands-on steering wheel detection. Backed by long experience in the field of IQ sensing, ams OSRAM had already developed a high-performance capacitive sensor for the steering wheel. This ams OSRAM technology has become the industry standard for reliable detection of the driver’s hands on the wheel. Adoption of this foolproof detection principle is now spreading to other parts of the car, including important exterior applications such as door handles.
And its value is not only in its performance and reliability: it turns out that ams OSRAM’s ability to produce, package and test sensor ICs in-house is a game changer for the automotive industry, because it enables customers to secure a stable and reliable supply. This is extremely important for all categories of demanding customers, and especially the automotive industry.
Developing products hand-in-hand with customers
Even while these products find new uses in electrified automotive functions, ams OSRAM has committed to continuing their development. In collaboration with customers, ams OSRAM is working to make these products even more easily applicable to vehicle designs. New developments include:
- Improved IC designs to provide more functionality in sensors which implement various measurement technologies
- The addition of new interface options
- The introduction of new package formats
- Deeper support for functional safety requirements
So the rise in demand for these hidden hero products is set to accelerate as they become more widely applicable to electrified and automated functions in the vehicles of tomorrow.
Their success is a tribute to know-how developed by ams OSRAM – and lays the foundations for a new generation of hero products to emerge soon.