High speed rotary position sensor takes on safety-critical automotive applications

Unterpremstaetten, Austria -- ams releases the AS5147P, an ultra-high speed magnetic rotary
position sensor which offers reliable performance in automotive applications compatible with the requirements of the ISO26262 functional safety standard. Providing accurate absolute and incremental measurement outputs at speeds up to 28,000 revolutions per minute (rpm), the AS5147P is ideal for safety-critical applications such as electric power steering (EPS), brake and accelerator pedals, pumps, double-clutch transmissions, starter motors, alternators and windscreen wiper motors.

Its appeal to automotive system designers rests on a combination of high measurement accuracy at high rotation speeds, high reliability, low system cost and support for standards compliance. The AS5147P draws on patented DAEC™ (Dynamic Angle Error Correction) technology to deliver accurate position measurements even at extremely high rotation speeds. The DAEC compensation scheme reduces the propagation delay inherent in the sensor’s signal chain to almost zero.

As a result, the AS5147P’s angle error is a negligible 0.02° at 1.7krpm, 0.17° at 14.5krpm and 0.34° at 28krpm. The DAEC function also enables the device to refresh its measurement output every 1.9μs. High reliability and low system cost in automotive applications are assured by the AS5147P’s intrinsic immunity to stray magnetic fields. Strong stray magnetic fields are present in vehicles, particularly those with a partially or wholly electric drivetrain, which contain powerful electric motors and high current-carrying conductors. These stray magnetic fields are much stronger than that of the small target magnet with which a magnetic position sensor is paired.

The unique differential sensing principle of the magnetic position sensors from ams makes them immune by design to stray magnetism. This means that automotive system designers can avoid the need to incorporate bulky and expensive magnetic shielding into their products, reducing their size, weight and cost when compared to designs based on competing magnetic position sensor ICs. The high sensitivity of the AS5147P also enables the use of a small (6mm diameter), low-cost target magnet.

More information about ams can be found at http://www.ams.com