Automotive Electronics Development to Automotive Grade Standards
The share of electronics in a vehicle keeps rising, from body control modules to intelligent cabins, from battery management to domain controllers, and the requirements have risen with it. A part that goes into a car is not a consumer part with a different label: it has to work across a wide temperature range, survive vibration, meet electromagnetic compatibility limits and satisfy a quality system that can be audited. Automotive electronics development is therefore a different process rather than a different market.
The Standards That Apply
Components are selected against the AEC-Q series of qualification standards for discrete devices and integrated circuits. Where a function can affect safety, the development follows a functional safety approach, with the hazard analysis and the safety mechanisms that the relevant level requires, applied to the hardware and the software together. The manufacturing system holds IATF 16949 certification for automotive quality management, which is the framework the whole flow is audited against.
Environmental requirements come on top of those. A wide temperature range, usually from minus forty degrees to eighty five or one hundred and twenty five degrees, constrains the choice of every component and the way the board is cooled. The electrical environment of a vehicle is not clean, so the supply circuit has to survive load dump, reverse connection and voltage droop in line with the relevant test standards, and the EMC behaviour has to be addressed during the design rather than corrected at the test house.
The Areas Covered
Body control covers modules that drive lamps, windows and locks, where the recurring problems are multi channel drive capability, power consumption in sleep and the LIN or CAN communication that connects them. The intelligent cabin covers centre consoles, instrument clusters and entertainment units, where the difficulty is the performance of the processor, the display interface and the multimedia data path.
New energy vehicles bring their own set: battery management, on board chargers and direct current converters, all of which combine high voltage isolation, high current measurement and insulation monitoring. Vehicle communication covers telematics units, connectivity modules and keyless entry, with cellular communication, satellite positioning and secure element handling in one package. Sensor modules include tyre pressure monitoring, radar and ultrasonic devices, where signal processing, power consumption and size are the constraints.
Design Points Specific to the Application
Circuit design begins with the environment rather than with the function. The temperature range fixes the component grades and the derating that has to be applied, and it drives the thermal design, because a device that is adequate at room temperature may be outside its rating inside a closed box in summer. The supply design has to cope with the transients the vehicle produces, so the protection, the filtering and the hold-up are designed together and verified against the standard that applies.
Compatibility is planned in the layout, using a stack-up with continuous references, a partition between the digital, analog and power sections, a defined grounding scheme and filtering placed where the interference originates. A design that treats this as an afterthought pays for it with extra components added later.
Where a function is safety related, the mechanisms are designed rather than added. That means the diagnostics that detect a fault, the behaviour that limits the consequence of it, and the documentation that shows the analysis was carried out. It also means the software is developed under the same discipline, with the traceability from requirement to implementation to test.
How the Development Is Sequenced
The requirement is established first: the function, the performance figures and the grade of the product, from which a system architecture and a hardware concept follow. That is reviewed with the customer before the detailed design begins, so that a misunderstanding is found while it is still a conversation.
The detailed design then covers the schematic, the board and the firmware, and a first prototype is built for functional verification, with the cost of the bill of materials assessed in parallel so that the product is not designed to a cost it cannot reach.
The prototype is then put through the full sequence of functional, performance and environmental testing, and the results drive the design changes that take it to the required level. The last stage is a small production batch, which verifies that the process is stable and completes the certification work that the product needs before volume.
Because the same group fabricates boards and assembles them, the transition from development to production does not involve a change of supplier. The design is released, the boards are made, the assemblies are built, and the answers to questions about the process come from the people who operate it.
What the Deliverables Look Like
The customer receives the schematic, the board source file, the production data, the bill of materials, the firmware source, the test specification and the test report, together with the technical package that supports the certification filing. The documentation is produced as the work proceeds rather than assembled at the end, because a safety related project is judged on the record as much as on the board.
The amount of time a development takes follows its complexity. A body control module with a moderate function typically reaches a first prototype within two to three months of the requirement being confirmed, while a complex cabin or domain controller takes six months or more, and the plan is issued with the estimate.
Our PCB design and layout group works to these requirements, PCB manufacturing produces the boards in a certified facility, and the assemblies are built by industrial PCBA under the records held by quality management.
Testing and the Evidence It Produces
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The test plan for a vehicle grade product is broader than the plan for a consumer one, and it is written down before the prototype is built rather than assembled afterwards. Functional testing confirms that the module does what it is supposed to do. Performance testing measures the figures the specification names, across the temperature range rather than at room temperature alone. Environmental testing covers the temperature cycling, the damp heat, the vibration and the shock that the installed environment will apply, and compatibility testing covers the emissions and the immunity limits.
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Each test produces a record that is kept with the project: the conditions, the equipment, the measured values and the pass or fail judgement. Where a test fails, the change that follows is documented with the reason, and the test is repeated. That record is what a customer audit or a certification body asks to see, and a project that has been developed without it cannot produce it retrospectively.
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Prototypes are also built in the same way for each iteration, so that the comparison between one revision and the next is meaningful. A prototype built by hand that behaves differently from the production process tells the team something about the hand build rather than about the design.
FAQ
How long does an automotive development take? A moderately complex module reaches a first prototype in two to three months, and a complex cabin or domain controller in six months or more, quoted from the requirement.
What is different about an automotive grade design? The components are qualified to the AEC-Q standards, the temperature and vibration requirements are wider, the compatibility work is planned rather than corrected, and the documentation is complete enough to be audited.
Can the product be built after development? Yes. Fabrication and assembly are available in the same group, so the transition from prototype to volume does not require a change of supplier.
