Infineon introduces a new dual-channel Hall sensor for automotive applications

Infineon has announced the launch of a new dual-channel Hall sensor, the TLE4999I3. The TLE4999I3 sensor IC integrates two Hall sensors into a single device for automotive applications with stringent control requirements. Infineon claims that the sensor is the first in the world to integrate two Hall sensor pieces of the ASIL D automotive system together.

The new sensor joins the Infineon Linear Hall sensor, which is mainly used for Angle and linear position sensing. All in all, Infineon now lists 19 linear Hall sensor products, four of which are labeled "bilinear Hall" ics for use in "functional-type safety systems." However, the new TLE4999I3 is the only product listed as "fully ISO 26262 compliant" in the Linear Hall IC list. At the same time, Infineon's XENSIV series of sensors includes a wide range of magnetic, pressure, radar and MEMS sensors for a variety of applications such as sensing current from the position of drones.

But what does it mean to be fully compliant with ISO 26262 - and what does ASIL D mean anyway?

What is ASIL D?

ASIL stands for vehicle safety integrity level. This is a classification system based on the ISO 26262 standard, but derived from the IEC 61508 standard. For its part, the ISO 26262 standard deals with the functional safety of road vehicles, a notoriously rugged and safety-focused application. It was revised to ISO 26262:2018 in 2018. The ASIL D classification represents the most stringent requirements, with the A classification the lowest (except for Level five, which indicates a lack of danger). According to the 2016 Arm presentation on the safety and security of automotive SoC Design, ASIL D indicates that the signal point failure mode (SPFM) is 99%, and the potential failure measure (LFM, LFM, LFM) is 99%. latent fault metric) is 90%.

XENSIV TLE4999I3 sensor

The XENSIV TLE4999I3 sensor is actually two Hall sensors integrated in a monolithic device. Combining two sensing elements into a single package makes it resilient and flexible to failure and more accurate due to its redundant backup measurement channels. And each channel can be programmed independently by EEPROM. According to the device's data sheet, the TLE4999I's two Hall-called main Hall probes and sub-Holger sensors each generate separate measurement channels, each with independently regulated analog power domains and bias units.

The analog signal is then fed again to a separate ADC (" HADC "for the main Hall element, and a multiplexed" sub HTS-ADC "for the sub-hall element), which then sends the signal to both DSPS. The DSP then calculates Hall measurements based on compensation parameters (i.e., stress and temperature drift) and provides a "digital Manchester-coded current modulated signal" compatible with PSI5 (Peripheral Sensor Interface 5) v2.1.