For SMT circuit board designers, if they want to design a simple PCB board, a single schematic can be used for drawing, while for large-scale PCB board design, hierarchical circuit design needs to be adopted. Many readers do not understand what a hierarchical schematic diagram is, and what is the difference between drawing a hierarchical schematic diagram and a single schematic diagram?

The design method of hierarchical schematic diagram is to divide the entire project into several schematic diagrams to express. In order for multiple sub schematics to be combined to represent the same design project, it is necessary to establish a certain connection relationship for these sub schematics. The parent diagram of a hierarchical schematic diagram is a schematic diagram used to express the relationships between diagrams.

As the parent diagram of the hierarchical schematic diagram, it can be seen from the diagram that in addition to various electrical connection symbols used in individual schematic diagrams such as wires, buses, and bus branch lines, there are also symbols designed for special hierarchical schematic diagrams such as block circuits and block circuit ports. A block circuit symbol represents a sub schematic, and the ports on the block circuit represent the interfaces between the sub schematic and other sub schematic connections. Each block circuit is connected by wires and buses to form a complete system diagram.

There are two ways to implement hierarchical schematic design: top-down and bottom-up. The top-down design method requires users to have a deep understanding of the system before drawing the schematic diagram, while the bottom-up method is suitable for users who are not very familiar with the entire design.