Dual-sensor package for automotive ASIL D systems

October 29, 2014 // By Graham Prophet
Infineon has introduced dual-sensor package devices for safety critical automotive applications; the redundant sensor architecture supports ASIL D Systems and helps shrink system footprint and reduce cost.

Typically, Infineon says, reliable and precise sensing of the steering torque in an electric power steering system currently needs two sensor chips. With its dual-sensor package this will in future be reduced to one sensor chip. Infineon has introduced two device families of linear Hall sensors and angle sensors in the dual-sensor package. It supports ASIL D systems and reduces physical space requirements and system cost; for example in steering applications requiring high availability. The dual-sensor package was developed at the Infineon site in Regensburg, Germany.

By using an innovative stack mounting technology, devices in the linear Hall sensor and angle sensor families combine two independent sensors within standard and space-saving PG-TDSO packages only about 1mm thin. Instead of the common approach of side-by-side sensor placement, Infineon stacks the two sensors with a patented flip-chip technique. This saves space and cost in safety critical applications, such as electric power steering (EPS), throttle control, pedal position and brushless DC motor control in such areas as EPS motors, transmission and clutch actuators.

The dual-sensor package integrates two linear Hall sensors or two angle sensors. Both sensors have separate power supply and separate signal outputs. They are electrically independent due to galvanic isolation. This means that the two sensors work independently which increases reliability of the system. The SMD packages have 8 pins or 16 pins: using the same packages, Infineon also offers single sensor versions.

Sensor redundancy is of particular interest for new generations of EPS systems with increased ISO 26262 requirements and for other safety critical applications that rely on Hall effect torque sensors and GMR/AMR (Giant Magneto Resistance / Anisotropic Magneto Resistance) angle detection. The dual-sensor package supports ASIL D systems; Infineon provides ISO 26262 documents and safety expertise to assist its customers – automotive system suppliers – in the design of ISO compliant systems. The footprint of the dual-sensor package is identical to that of a single-sensor device.