In the research of PCB inversion technology, the reverse deduction schematic diagram refers to the inversion of the PCB file diagram or the drawing of the PCB circuit diagram directly according to the physical object of the product , which aims to illustrate the principle and the working state of the circuit board. In addition, the circuit diagram is also used to analyze the functional characteristics of the product itself. In the forward design, the general product development must first carry out the schematic design, and then carry out the PCB design according to the schematic .
Whether used to analyze circuit board principles and product operating characteristics in reverse studies, or as the basis and foundation of PCB design in forward design, PCB schematics have a special role. So, according to the documentation diagram or the real thing, how to reverse the PCB schematic, what details should the reverse process pay attention to?
1. Reasonable division of functional areas
When the schematic diagram of the PCB board is reversely designed, the reasonable division of the functional area can help engineers reduce unnecessary trouble and improve the efficiency of drawing. Generally speaking, components with the same function on the PCB will be arranged in a centralized manner, and the functional division area can have a convenient and accurate basis when the schematic is reversed. However, the division of this functional area is not arbitrary. It requires engineers to have a certain understanding of electronic circuit related knowledge. First, find out the core components in the functional unit, and then find out the other components of the same functional unit according to the trace connections to form functional partitions. The formation of functional partitions is the basis of the schematic diagram. Also, during the process, don't forget to use the component serial numbers on the board, they can help you partition functions faster.
2. Find the benchmark
This reference piece can also be said to be the main part of the PCB replica board at the beginning of the schematic drawing. After identifying reference parts, drawing against the pins of these reference parts can ensure the accuracy of the schematic to a greater extent. For engineers, the determination of reference parts is not a very complicated issue. Often, the component that plays a major role in the circuit can be selected as the reference part. They are usually bulky and have many pins, which facilitate stretching. Such as integrated circuits , transformers , transistors, etc., can be used as suitable references.
3. Correctly distinguish lines and draw lines reasonably
In order to distinguish the ground wire, the power wire and the signal wire , the engineer also needs to master the relevant power supply knowledge, circuit connection knowledge, PCB wiring knowledge and so on. The difference between these lines can be analyzed from the connection of the components, the width of the copper foil of the circuit, and the characteristics of the electronic product itself. In wiring diagrams, ground wires can be used in a large number of ground symbols in order to avoid wire crossing and scatter. Various lines can be clearly distinguished by using different lines of different colors, and special symbols can be used for various components, and even unit circuits can be drawn individually and finally combined.
4. Master the basic framework and learn from similar schematic diagrams
For the framework and principle drawing methods of some basic electronic circuits, engineers need to master, not only to directly draw some simple and classic unit circuits, but also to form the overall framework of electronic circuits. On the other hand, don't ignore that similar electronic products have certain similarities in the schematic diagram of the PCB copy board. Engineers can take advantage of similar circuit diagrams and perform the reverse of new product schematics based on their experience.
5. Check and optimize
After completing the schematic, the reverse design of the PCB schematic must be completed by passing the tests and checking the links. The nominal values of components that are sensitive to PCB distribution parameters need to be checked and optimized. According to the PCB file diagram, the schematic diagram is compared and analyzed to ensure that the schematic diagram and the file diagram are completely consistent. If the schematic layout is found to be non-compliant during inspection, schematic adjustments will be made until it is fully reasonable, standardized, accurate and clear.