Groundbreaking new position sensors for ADAS applications

05-07-2022 | Allegro | Automotive Technologies

Allegro MicroSystems, Inc has launched its A33110 and A33115 magnetic position sensors. Designed for ADAS applications that need high levels of accuracy and heterogeneous signal redundancy, its newest sensors combine the company’s vertical Hall technology (VHT) with cutting-edge TMR technology in a single sensor package. These groundbreaking angle sensors are the first to provide this technology combination in a single package. This VHT + TMR offering is an excellent heterogeneous redundant sensor solution. It is an essential step toward enabling the reliability required for advanced levels of automation in vehicles.

Future automated and autonomous vehicles need advanced EPS systems with precise motor control capabilities and brake-by-wire or electromechanical braking systems with fast response time. Present-day systems generally use GMR or Hall-effect sensors. Compared to the GMR equivalents, the company's innovative TMR-on-silicon technology provides improved resolution and accuracy, offering up to eight times greater sensitivity. Measured against conventional Hall-effect sensors, the enhancement in resolution is even more pronounced.

The safe operation of a vehicle demands the highest level of diagnostic coverage in its safety-critical systems. The VHT featured in the new sensors allows accurate safety checks, including low-field and missing-magnet detection. These high-resolution sensors are ASIL D-compliant, with heterogeneous redundancy lowering the likelihood of dependent failures by using the best of TMR technology and VHT.

“As full autonomy comes closer to being a reality, automakers and Tier 1 suppliers are looking for position sensors that provide the greatest accuracy and safety while reducing system footprint and cost,” said Scott Milne, business line director for Position Sensors at Allegro. “By integrating both vertical Hall and TMR elements in a single package, Allegro’s new line of sensors enable customers to meet those needs with a sensor that provides high resolution and heterogeneous redundancy along with integrated diagnostics. There’s nothing else on the market like them, and we think they are a game-changer for the industry.”

These sensors offer magnetic angle sensing via the primary (TMR) and secondary (vertical Hall) transducers, each of which are processed by two independent channels, with independent regulators and temperature sensors. This unique configuration allows the high levels of safety and diagnostic coverage required for automated driving, incorporating on-chip channel-to-channel angle comparison and independent processing in digital signal paths, with no shared digital resources. Advanced algorithms in the devices provide the fast response time, independent gain/offset correction, angle calculation, and linearisation abilities demanded by safety-critical ADAS applications. The A33115 also incorporates a turns counter that tracks motion in 90-degree increments and a low-power mode with a user-programmable duty cycle that lowers power consumption when the IC is in a key-off position.

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