The electronics department at Well Engineered uses a systematic approach when presented with a product idea or challenge. Most projects require some ECAD/MCAD collaboration, such as determining the features for mounting the PCB, how user interface items will be selected to meet electrical specs (i.e. LED brightness), as well as mechanical specs (IP rating, cutout shape/size, etc.). However, if these mechanical aspects are ignored, the following workflow describes how Well Engineered will tackle any electronics project.
Design-Choice and the Block Diagram
The first step is to make decisions about the function of the electronics and the best way to accomplish those functions (i.e. use Bluetooth to communicate with a phone through the use of RF module #AB12). This design-choice step is repeated for each desired function, summarised by a block diagram. The block diagram includes a "block" for everything that has electricity flowing through it (connectors, fuses, switches, front panel controls, etc.). It is the human-readable overview of how the circuit board will work.
Component Testing, Capture and the Schematic
The next step is to electronically record the decisions made in the first step. Designers study the data sheets of every part and choose all of the supporting components. It is at this step that the details of the electronics are added to the block diagram (datasheet says you need a 10u capacitor? What thermal characteristic does it need? What equivalent series resistance? What size? What model number? How much current will the traces carry? How much voltage?). The result is a detailed schematic showing each of the components of the various circuits and how they interact.
The components are tested to ensure they will perform in the schematic. In some cases, major components have demo modules available for purchase that can be tested without breadboarding/PCB creation. If not, then this stage might require a test PCB, a breadboard, or custom surface mount breakout boards for testing.
Once the components are verified against the requirements, the schematic goes through the capture step where the setup is confirmed and laid out in a logical manner that is easy to follow. This step has to be done by drafters who are familiar with the capture software used by the company (at Well Engineered, Altium is used).
Layout and PCB Design
Once there is a properly captured schematic, the drafter transitions to the layout. There are two major tasks:
a) decide exactly where everything should go (PCB design)
b) import the data into the layout program (this is the "layout" itself)
Well Engineered uses Altium software for the layout and PCB design.
PCB Manufacturing and Assembly
When the layout is complete, it is used to generate files that can be sent for PCB Manufacturing, and then PCB Assembly. The completed boards are then tested. The testing inevitably shows deficiencies with the PCB (RF traces too close to digital traces are picking up noise; ESD from the connectors has damaged a pad that was too small or insufficiently protected; etc.).
PCB deficiencies lead to changes to the schematic (more capturing), and changes to the PCB (more layout). The manufacturing and assembly process are then repeated, followed by more testing.
Firmware Design / Test and Integration Testing
Almost certainly there will be a microcontroller in the design, and it will need to be programmed and tested. At first, a demo board and some dummy loads are used, and then later using the actual assembled PCB (sometimes called a PCBA, to distinguish it from a bare PCB).
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