By info@ico28.com 
Melexis has put two of its MLX90423 three-axis magnetic flux sensors in the same package along with a magnetic wake-up sensor to detect linear and rotary movement in high-reliability applications such as brake and accelerator pedal position sensing in vehicles.
Called MLX90424, it can be powered directly from 12V without a regulator and measures linear displacement up to 30mm without physical contact.
The three dies are galvanically isolated, and multi-point programmable linearisation is possible.
“Reaching the state of the art in safety-critical and space-constrained applications like automotive brake systems demands tailored sensors,” according to the company. “MLX90424 offers redundancy through its dual linear position sensing, while the integrated magnetic switch allows the implementation of a power-saving mode.”
Qualification is to AEC-Q100, with position sensing up to ISO 26262 ASIL D and wake-up switching to ASIL B.
Stray magnetic fields up to 5mT (4kA/m) are tolerated in accordance with ISO 11452-8.
Packaging is TSSOP-16
Original article source:
FAQ
1.What is magnetic angle sensing in brake pedal systems?
Magnetic angle sensing is a technology used in brake pedal systems to measure the position and angle of the pedal through magnetic fields. It involves the use of sensors that detect changes in a magnetic field created by the movement of a magnet attached to the brake pedal mechanism.
2.Why is functional safety important in brake pedal sensing?
Functional safety ensures that the brake pedal system operates reliably, even in the presence of faults. This is critical for preventing accidents caused by brake failure, ensuring the system continues to perform safely and meets stringent automotive safety standards like ISO 26262.
3.How does magnetic angle sensing contribute to functional safety?
Magnetic angle sensors provide non-contact, wear-free measurements that are resistant to dirt, dust, and environmental conditions. Their accuracy and durability make them ideal for brake systems that require high reliability and redundancy to meet functional safety requirements.
4.What role does redundancy play in magnetic angle sensing for safety?
Redundancy in magnetic angle sensing means using multiple sensors or sensor channels to cross-check measurements. This ensures that if one sensor fails or provides inaccurate data, the system can still operate safely using backup information, which is a key principle in functional safety.
5.How does magnetic angle sensing improve brake pedal performance?
Magnetic angle sensors offer precise and real-time feedback on brake pedal position. This accuracy improves the responsiveness of electronic braking systems, leading to smoother and more controlled braking. It also enhances safety features like automatic braking in emergency situations.
6.What are the common challenges in implementing magnetic angle sensing in brake systems?
Challenges include ensuring immunity to external magnetic interference, managing sensor placement for optimal accuracy, and integrating the sensors into the vehicle’s functional safety architecture. Manufacturers also need to address any potential failure modes to comply with safety standards.
7.What standards govern the use of magnetic angle sensing in functional safety applications?
The primary standard is ISO 26262, which focuses on the functional safety of electrical and electronic systems in vehicles. Magnetic angle sensors for brake pedal sensing must be designed to comply with this standard, ensuring they meet the safety integrity level (SIL) required for the application.