More than 750 million position sensors have been sold. The secret behind ams' Hall sensor

Hall magnetic sensors have been used in electronic systems for decades. The original application of Hall sensors provided the most basic switching functions. For example, when you close the lid of a laptop, it is usually a Hall switch to detect this so the display can automatically turn off to save power.

 But in the 21st century, Hall sensor technology has become increasingly sophisticated. Today, Hall-based position sensors can measure the rotation angle of an electric motor or a car's steering wheel very accurately. In products developed by ams, a complete rotary position sensor is integrated into a single silicon chip: from the Hall sensor array to signal conditioning (amplifying the sensor's tiny signal) to a processor that converts the magnetic field measurement into position coordinates.

Mission-critical components

As these sensor devices become more sophisticated, their role in electronic systems becomes increasingly important. In fact, in many automotive and industrial systems, lives depend on position sensors. Whether a magnetic sensor measures how far a driver turns a car’s steering wheel or tracks the position of a medical robotic arm performing open-heart surgery, there is no room for error. It is also important not to allow sensors to fail or malfunction unexpectedly.

In these applications, there are many questions for position sensors and the companies that make them. Fortunately for our customers, ams has many years of experience supplying mission-critical position sensors and helping manufacturers build safety in from the ground up.

For 15 years, ams has been supplying magnetic position sensors worldwide: We have shipped more than 750 million high-performance position sensors for use in automotive as well as other industrial products where failure is not an option. That is why all our position sensors offer a unique and very special feature: differential sensing technology.

Steering without interference

Whether in the car or in the factory, magnetic position sensors are subject to strong magnetic interference caused by motors, solenoids, high-voltage cables and other sources. The unique differential sensing structure invented by ams provides inherent immunity to these so-called "stray magnetic fields." Even in the traction motors driving the wheels of electric vehicles (one of the most complex magnetic environments you can imagine), this immunity means that ams position sensors can work continuously to produce accurate angle measurements without distortion or delay. 

Intrinsic immunity to stray magnetic fields is a feature of all ams position sensors, including those used in high-speed motors in electric vehicles and other applications where measurement of 360° rotation is required.

We have also developed other ways to make our products extremely reliable. Dual-die position sensors provide fully redundant operation. Self-diagnostic and system check functions ensure that the sensor is functioning properly at startup and during operation. These features help our automotive customers comply with ISO26262 - an important industry standard for verifying the safety of automotive electronic systems.

Compliance with ISO 26262 is just one of the ways we go beyond traditional position sensor products to meet the specialized needs of the automotive and industrial markets. Today, ams offers the industry's most advanced and application-ready portfolio of magnetic position sensors for motor control and other mission-critical functions.

The sophistication of these integrated sensor devices from ams is a far cry from the basic Hall switches of the 20th century. It all comes from ams' innovation leadership, and OEMs in the industrial and automotive markets can continue to rely on ams' technology to meet their application needs.

Author: Michael Pichler is a senior system engineer and team manager at ams, leading the application engineering team at the Image Sensor Solutions division of ams AG, with more than 10 years of experience in the semiconductor industry. He is responsible for technical support of position sensors for the industrial, automotive and medical markets.