Detailed explanation of the reverse push principle when PCB copying

In the research of PCB reverse technology, the reverse push principle diagram refers to the reverse push out according to the PCB document drawing or the direct drawing of the PCB circuit diagram according to the actual product, which aims to explain the principle and working condition of the circuit board. Moreover, this 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 it is used to analyze circuit board principles and product operating characteristics in reverse research, or is reused as the basis and basis of PCB design in forward design, PCB schematics have a special role. So, how to reverse the PCB schematic diagram according to the document diagram or the actual object, and what details should be paid attention to during the reverse calculation process?　　1. Reasonable division of functional areas　　 When the reverse design of the schematic diagram of a good PCB circuit board, the reasonable division of functional areas can help engineers reduce unnecessary troubles and improve drawing efficiency. Generally speaking, components with the same function on a PCB board will be arranged in a concentrated manner, and dividing the area by function can have a convenient and accurate basis when inverting the schematic diagram.　　 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 the core component in a certain functional unit, and then according to the wiring connection, you can find other components of the same functional unit along the way to form a functional partition. The formation of functional partitions is the basis of schematic drawing. In addition, in this process, don't forget to use the component serial numbers on the circuit board cleverly. They can help you perform functional partitioning faster.　　Second, distinguish the lines correctly and draw the wiring reasonably. 　　 For the distinction between ground wires, power wires, and signal wires, engineers also need to have relevant power supply knowledge, circuit connection knowledge, PCB wiring knowledge, and so on. The distinction of these lines can be analyzed in terms of the connection of components, the width of the copper foil of the circuit, and the characteristics of the electronic product itself. In the wiring drawing, in order to avoid the crossing and interpenetration of lines, a large number of grounding symbols can be used for the ground line. Various lines can use different colors and different lines to ensure that they are clear and identifiable. For various components, special signs can be used, or even Draw the unit circuits separately and combine them at the end. 3. Find the right reference part. This reference part can also be said to be the main component used at the beginning of the schematic drawing. After the reference part is determined, the reference part is drawn according to the pins of these reference parts, which can guarantee the principle to a greater extent. The accuracy of the graph. For engineers, the determination of reference parts is not very complicated. Under normal circumstances, the components that play a major role in the circuit can be selected as reference parts. They are generally larger in size and have more pins, which is convenient for drawing. Such as integrated circuits, transformers, transistors, etc., can all be used as suitable reference components. 4. Master the basic framework and draw lessons from similar schematic diagrams. Engineers need to be proficient in the framework composition and principle drawing methods of some basic electronic circuits, not only to be able to directly draw the basic components of some simple and classic unit circuits, but also Can form the overall framework of the electronic circuit.　　 On the other hand, don’t ignore that the same type of electronic products have a certain similarity in their schematic diagrams. Engineers can draw on similar circuit diagrams to reverse the schematic diagrams of new products based on the accumulation of experience.　　5. Checking and optimization　　 After the schematic drawing is completed, the reverse design of the PCB schematic can be said to be completed after testing and checking. The nominal value of the components sensitive to the PCB distribution parameters needs to be checked and optimized. According to the PCB file diagram, the schematic diagram is compared and analyzed to ensure that the schematic diagram is completely consistent with the file diagram.