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功能安全 is quickly becoming the hot automotive term. Although people often use the term interchangeably with “quality,这两个词有明显的不同. And that distinction between “quality” and “functional safety” is important to recognize, especially when you’re talking with suppliers and collecting pertinent information to assess overall system risk.
First, let’s look at the recognized industry definitions for both terms:
质量 (low defective parts per million or DPM)
- A measure of excellence or a state of being free from defects, deficiencies and significant variations … to improve quality, effort to eliminate the source of defects … 1
功能安全 (the above definition plus detection and control)
- Absence of risk due to hazards caused by the failure of Electrical / Electronic E/E systems during operation … to improve safety, detect faults and control failure … i.e. 移除或消除不确定性2
Let’s unravel these distinctions a bit. 在上面的定义中, quality refers to the fundamental design of the product and the test and yield processes that ensure the product can achieve as close to zero defects as possible
But functional safety focuses on two aspects: systematic and 随机故障覆盖率. 功能安全的第一个方面, 系统故障覆盖, ensures that the product is designed using well-defined processes and methodologies. This means that it doesn’t have failure modes that are systematic or inherently flawed due to poor methodologies used when the device was designed.
For example, a systematic fault could happen when a row decoder for DRAM is designed incorrectly. 作为的结果, the wrong memory location would be addressed because it was “systematically” designed incorrectly. There would be no resulting yield fallout from a quality perspective because the device is operating in the manner it was designed to, 但不是以我们想要的方式.
The second aspect of functional safety, 随机故障覆盖率, ensures that — when a device is operating in a harsh environment where power supplies can be perturbed, or electromagnetic interference (EMI) in the system gets too great, or neutron flux causes a bit to flip — these events are detected. Unfortunately, all these events can and do occur.
而半导体器件, 比如DRAM, are designed to be as immune to these types of activities as possible, a bit flip — where a logic level 1 may get reversed to a logic level zero or vice versa — may occur. 而这种情况是不可避免的, it’s important to be able to flag such an event so that the system can make the right decision on how to address this failure. 响应, 由系统设计者决定, could range anywhere from initiating no system action to crippling the vehicle because the memory failure was associated with an electronics control unit (ECU) responsible for control over the vehicle.
作为汽车行业的领导者, 微米 has invested in developing leadership products that support functional safety. We refer to them as SAFER automotive memory since we are the only supplier in the industry with an ASIL-D, 符合ISO 26262认证的内存.
For more information about functional safety and our flagship SAFER memory, check out the following links on the 微米 website:
- 汽车功能安全
- 微米 Delivers ASIL-D ISO 26262 Certified LPDDR5 for Safety Requirements
- 美光推出全球首款1.5TB microSD Card and 汽车 Functional Safety-Certified 内存 to Fuel Data at Intelligent Edge
- Building Safety Into 汽车 Silicon — 微米 Is Leading the Charge
- Bulletin: Functional Safety on Chips Out Loud Podcast
- DRAM in Safety Critical 汽车 Systems
1. 基于 ISO 26262文档.
2. Detect and control can be at the level of supplier or system integrator.
即将到来的...The 微米 SAFER automotive memory blog series provides insights on the role memory and storage play in Functional Safety. SAFER incorporates five key concepts: (S) Safest solution currently available in the industry, (A)汽车思维, (F)故障覆盖率, (E)工程领导, (四)风险管理. Each letter associated with SAFER will have a corresponding blog with associated content.
