One or two die approach to automotive sensors
ISO 26262 is intended to be applied to safety-related systems that include one or more electrical and/or electronic (E/E) systems and that are installed in series production passenger cars with a maximum gross vehicle mass up to 3 500 kg. ISO 26262 does not address unique E/E systems in special purpose vehicles such as vehicles designed for drivers with disabilities.
Systems and their components released for production, or systems and their components already under development prior to the publication date of ISO 26262, are exempted from the scope. For further development or alterations based on systems and their components released for production prior to the publication of ISO 26262, only the modifications will be developed in accordance with ISO 26262.
ISO 26262 addresses possible hazards caused by malfunctioning behaviour of E/E safety-related systems, including interaction of these systems. It does not address hazards related to electric shock, fire, smoke, heat, radiation, toxicity, flammability, reactivity, corrosion, release of energy and similar hazards, unless directly caused by malfunctioning behaviour of E/E safety-related systems.
ISO 26262 does not address the nominal performance of E/E systems, even if dedicated functional performance standards exist for these systems (e.g. active and passive safety systems, brake systems, Adaptive Cruise Control).
ISO 26262-1:2011 specifies the terms, definitions and abbreviated terms for application in all parts of ISO 26262.
Roland Einspieler from magnetic position sensor supplier ams describes the measures it has taken to support the ISO26262 compliance programmes of automotive customers
Under the provisions of ISO26262, the new functional safety standard, automotive component manufacturers have to develop a new safety process flow for every new application that they support.
This means that, for a component that is specific to a single application, the component supplier has to implement one safety process flow.
The challenge is much greater for standard parts that can be used in multiple applications.
Every new standard sensor from ams is now developed in accordance with the process defined in ISO26262.
The aim is that every part should meet the target safety grading for every application in which a customer might use it. This means carrying out a different safety analysis for each potential application.
An important element of every ISO26262 development flow is the Failure Mode, Effects and Diagnostic Analysis (FMEDA), which establishes a device’s critical failure mode.
The results of the FMEDA are affected by the safety requirements set by the customer for each application. In other words, this FMEDA will be done for each position sensor and for each application in which the sensor might be used.
For each application, it is possible to calculate the single fault metric, the latent fault metric and the FIT (failure in time) rate.
The FMEDA process flow identifies the limits for the four ASIL levels defined in ISO26262.
For more read: One or two die approach to automotive sensors