SLYY229A February   2024  – March 2024 DRV5055-Q1 , LDC5072-Q1 , TMAG3001 , TMAG5110-Q1 , TMAG5111 , TMAG5115 , TMAG5170-Q1 , TMAG5170D-Q1 , TMAG5173-Q1 , TMAG5231 , TMAG5253 , TMAG5273 , TMAG6180-Q1 , TMAG6181-Q1

 

  1.   1
  2.   Overview
  3.   At a glance
  4.   Trend No. 1: The electrification of systems
  5.   Trend No. 2: The need for increased reliability and safety
  6.   Trend No. 3: The miniaturization of overall end-product form factors
  7.   Trend No. 4: The transition from rare earth materials to ferrites
  8.   Conclusion
  9.   References
  10.   Additional resources

Trend No. 2: The need for increased reliability and safety

While developing industrial, personal electronics and automotive systems, designers are concurrently thinking of how to make their designs more reliable in order to increase their product’s life span. A rather recent trend for position sensing involves a couple of different methods to achieve this goal – moving from mechanical systems to magnetic sensors and the acceleration of functional safety compliance.

Magnetic sensors eliminate constant mechanical wear and tear caused by friction. In cordless power tools, for example, the mechanical trigger design is the most prevalent failure mode, and manufacturers typically have a target of >200,000 cycles over the life of the product. The lifetime cycle targets vary by end product, but the expectation is that a magnetic-based solution has the potential to extend product life. Table 1 summarizes a few of these examples.

Table 1 Examples of industrial, personal electronics and automotive system applications moving to contactless methods.
Application Existing technology Benefit of using a position sensor over a mechanical sensor Recommended technologies
Triggers for cordless power tools and medical power drills Mechanical potentiometer designs
  • Increased life cycle of the trigger mechanism.
  • You can place the sensor directly on the main circuit board without the need for an external module.
 Hall effect and inductive
Refrigerator door open-and-close detection Microswitches
  • Provides an aesthetically looking door interface with no visible switch.
 Hall effect
Gaming controllers and keyboards Mechanical designs
  • Provides the ability to detect the amount of force being used on a specific button or trigger.
  • In gaming controllers, helps prevent drift over time.
 Hall effect and inductive

Steering systems:

steering stalk shifters, steering columns, knobs and e-shifters

 Mechanical designs
  • Provides a steer-by-wire method using electrical position signals with no wear and tear.
 Hall effect, inductive and AMR
Braking systems Mechanical hydraulic designs
  • Electronic brake-by-wire provides greater safety with fast response times.
 Hall effect and inductive

The advent of vehicle electrification and the addition of more electronics into almost every electrically powered product has accelerated the need for functional safety. The automotive industry follows International Organization for Standardization 26262 for automotive products, while the industrial sector follows International Electrotechnical Commission 61508. Functional safety aims to protect users by eliminating unreasonable risk caused by the malfunctioning of electronic systems. If the system fails, it should default to a predictable and known state.

There are several categories of automotive and industrial functional safety standards based on severity or consequence (how much injury could occur), exposure or likelihood (how likely it is), and controllability (how much control does the user have). A couple of examples in automotive systems that require the highest functional safety rating are EPS or shifter systems (e-shifters). Both systems often require the highest automotive rating (ASIL D) given the risks associated with their failure.

To comply with ASIL D requirements, system developers typically use redundant sensors or solutions that have two identical but independent sensors that are internally isolated from each other. There is a very low probability that both sensors will fail. These types of high-performance systems also need high-accuracy angle detection. The TMAG5170-Q1 3D sensor and its dual-die equivalent, the TMAG5170D-Q1, have built-in diagnostics features for both device and system levels.