JP2000181947A - Circuit design method for multi-layer printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-layer printed wiring board design method capable of arranging a specified wiring pattern in a surface layer by a simple means without changing the program of a central processing unit. SOLUTION: Component data required for a circuit are registered in a step S.11, the data of a surface layer wiring pattern are inputted as virtual components in a step S.12, the data of a multi-layer printed board are inputted in a step S.13 and the data of a circuit diagram are inputted in a step S.14. In a step S.15, based on information inputted in the four steps, the arrangement of components and the wiring pattern is automatically designed in the central processing unit 13b. The surface layer wiring pattern is surely arranged in the surface layer since it is handled similarly to the components. A part to be corrected is pointed out in a step S.17 until a designed result is satisfying, and the processing of the step S.15 is repeatedly executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a circuit design method for a multilayer printed wiring board using a CAD system.

[0002]

2. Description of the Related Art A circuit design of a multilayer printed wiring board includes:
Conventionally, a method using a CAD system has been adopted. The conventional CAD system includes a component registration unit that stores electrical data and external shape data of components, designs an arrangement of components to be mounted on a surface layer based on the data and circuit diagram data, and includes a plurality of components. And a design processing unit for designing a wiring pattern so as to connect any one of the plurality of pins with any of a plurality of wiring layers.

In the conventional method, each data is input first, an automatic design is performed by a design processing unit, and the design result is displayed on a graphic display. The designer points out the location to be corrected using the interactive input device, and repeats the cycle of automatic design and correction until a satisfactory design result is obtained.

[0004]

However, in the above-described conventional design method, since the design processing unit side arbitrarily selects which layer of the wiring pattern is to be arranged on the multilayer printed circuit board, a plurality of wiring patterns are required. Even if there is a request to arrange a specific wiring pattern on the surface layer, this cannot be easily met unless the design processing program is changed.

Therefore, even if it is necessary to cut a specific wiring pattern due to a change in circuit design after the completion of the board, it is difficult to cut the wiring pattern if the wiring pattern is formed in an inner layer. It is necessary to redesign or to perform processing such as cutting pins of components connected to the wiring pattern.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and a specific wiring pattern can be arranged on a surface layer by a simple means without changing a program of a central processing unit. It is an object (object) to provide a method for designing a multilayer printed wiring board.

[0007]

According to the present invention, there is provided a circuit design method for a multilayer printed wiring board, comprising: a component registration unit for storing electrical data and external shape data of a component to be used; And a CAD processing system having a design processing unit for designing a wiring pattern so as to connect the pins of the plurality of components to one of the plurality of wiring layers while obtaining the arrangement of the components mounted on the surface layer based on the above. In the method, a predetermined wiring pattern is registered as a virtual component in the component registration unit, and a portion of the wiring between components where a wiring pattern is to be provided on a surface layer is a surface wiring in which the wiring between components is registered as a virtual component. It is characterized in that connection is made via a pattern.

According to the above method, the CAD system regards the wiring terminal registered as a virtual component as a component.
Even when automatic design is performed, the wiring terminal is always formed on the surface layer. The wiring connected through the surface layer can be easily cut by cutting only the surface layer by cutting the wiring terminal portion.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a circuit design method for a multilayer printed wiring board according to the present invention will be described below. FIG. 1 is a block diagram showing a CAD system for realizing the method according to the embodiment, and FIGS. 2 and 3 are flowcharts showing the method according to the embodiment.

As shown in FIG. 1, the CAD system according to the embodiment is configured to input / set data of electronic components arranged on the surface layer of a board and data of a multilayer printed board.
A board data input device 10, a virtual component input device 20 for inputting data as a virtual component using a predetermined wiring terminal,
A circuit diagram data input device 11 for inputting / setting circuit diagram data of an electronic circuit, an interactive input / output device 12, and
And an arithmetic unit 13.

The input / output device 12 includes a keyboard 12a, a mouse 12b, and a graphic display 12c. The arithmetic unit 13 includes a component registration memory 13a for registering and storing data input from the component / board data input device 10 and the virtual component input device 20, and a component on a surface layer based on the data input from each input device. And a central processing unit 13b for designing the layout of the virtual components and the wiring pattern in the multilayer printed circuit board.

The surface wiring pattern registered as a virtual component by the virtual component input device 20 is stored in the central processing unit 13b.
In the design processing in, since the components are handled in the same manner as ordinary components, they are always arranged on the surface layer of the multilayer printed wiring board. Therefore, with respect to the wiring that is to be put on the surface layer in the wiring between the normal components, the wiring passes through the surface layer at least in the part of the surface wiring pattern by interposing the surface wiring pattern in the middle of the wiring.

A design method of an embodiment using the above-described circuit design apparatus will be described with reference to the flowcharts of FIGS. In step S.11, component data necessary for the circuit is input from the component / board data input device 10 and registered in the component registration memory 13a. The registered component data is composed of circuit element data representing the electrical function / characteristics, and external data including external size, pin size, pin position, and the like. Existing data is used for components already registered in the component registration memory 13a.

In step S.12, data of the surface wiring pattern is input from the virtual component input device 20 as a virtual component. The registered virtual component data is composed of circuit element data representing its electrical characteristics and external data including external size, pin size, pin position, and the like. Existing data is used for the surface wiring pattern already registered in the component registration memory 13a. Step S.12
Consists of the steps shown in FIG. 3 in detail.
This will be described later.

In step S.13 of FIG. 2, data of the multilayer printed circuit board is input from the component / board data input device 10. The substrate data includes data such as the size of the substrate, the number of layers, and the thickness of each layer.

In step S.14, circuit diagram data indicating the electrical connection of the circuit to be designed is input from the circuit diagram data input device 11. In step S.15, based on the information input in the above four steps, the central processing unit 13b
In, the layout of the components on the surface layer, the layout of the surface layer wiring patterns as virtual components, and the wiring patterns in the multilayer printed circuit board are designed. The result of the design is the graphic display 1
2c.

When the central processing unit 13b designs a wiring pattern, it is optimized so that, for example, the overall wiring pattern is the shortest. Further, the surface wiring pattern is always disposed on the surface layer because it is treated the same as the component, but it is arbitrarily selected on the processing device side which layer of the multilayer printed circuit board is to be disposed.

If the displayed design result is satisfactory, the end of the process is selected in step S.16 to end the design. If not satisfied with the displayed design result, the keyboard 12a and the mouse 1
The point to be corrected is pointed out using 2b, and the process of S.15 is executed again. This operation is repeated until a satisfactory design result is obtained.

Next, registration of the surface wiring pattern shown in FIG. 3 will be described with reference to a display example on the screen of FIG. In step S.21, circuit element data representing electrical characteristics is input. As an example of the circuit element data, here, a cross-shaped surface wiring pattern 30 as shown in FIG.
Is assumed. It is assumed that terminals are provided at each end of the surface wiring pattern 30. These four terminals are given terminal numbers of 01, 02, 03, 04 in step S.22.

Subsequently, outline data is input on a grid indicating design coordinates on the screen. First, in step S.23, the center coordinates 32 of the surface wiring pattern to be created are input, and in step S.24, the actual shape of the conductive portion 33 of the wiring pattern is input (FIG. 4B). In step S.25,
As shown by the broken line in FIG. 4C, a square including the conductive portion 33 is input as the outer shape 34 of the virtual component. Steps
In S.26, a grid serving as a terminal of the conducting portion 33 (FIG. 4)
Assuming virtual pins on (c) and inputting the positions of the pins in the virtual part, step S.
The terminal numbers given in 22 correspond.

When the processing of FIG. 3 is completed, as shown in FIG. 4D, the surface wiring pattern 30 including the cross-shaped conductive portion 33 and the four pins and having the square outer shape 34 is stored in the component registration memory as a virtual component. 13a. The virtual part is handled in the central processing unit 13b of the CAD system in the same manner as a normal part.

FIG. 5 shows an example of a circuit design based on the above processing. In the circuit using the components 40 and 41, each component 4
Assume that the first terminals 40a and 41a of 0 and 41 are connected, and the second terminals 40b and 41b are connected. It is assumed that a wiring pattern for connecting the first terminals needs to be provided on the surface layer. At this time, when the designer first designs the circuit diagram, the first terminals 40a, 41
The surface wiring pattern 30 registered as a virtual component is arranged on the path of the wiring pattern 42 connecting the a.
The second terminals 40b and 41b are simply a wiring pattern 4.
3 are connected.

When the above-described circuit diagram data is input to the central processing unit 13b and an automatic design is executed, the result is as shown in FIG. 6, for example. FIG. 6 is a sectional view of the multilayer printed wiring board B showing the result of the automatic design. As a result of the automatic design, the components 40 and 41 and the surface wiring pattern 30 are arranged on the surface layer. Therefore, the wiring 42 connecting the first terminals 40a and 40b is connected through the surface layer at least in the part of the surface wiring pattern 30. In contrast, the second
Wiring pattern 43 connecting terminals 40b, 41b
Are arranged in the most suitable layer according to the program of the central processing unit 13b, taking into account the relationship with other wirings and the like.
In this example, the wiring pattern 43 is arranged on the third layer.

Therefore, when the wiring 42 needs to be cut due to a design change, the surface layer wiring pattern 30 can be cut easily by operating only the surface layer by cutting the portion of the surface layer wiring pattern 30.

[0025]

As described above, according to the method of the present invention, by registering a predetermined wiring pattern as a virtual component in the component registration unit, the CAD system can store the registered surface wiring pattern in a normal manner. The surface layer wiring pattern is always formed on the surface layer of the multilayer printed wiring board in order to execute the automatic design in the same manner as the component. Therefore, for wiring that may be cut later, at least part of the wiring can be placed on the surface without any program change by designing the circuit diagram to pass through the surface wiring pattern on the way. Can be arranged. Therefore,
Even if it is necessary to cut the wiring due to a design change,
It is possible to easily cope with the operation only on the surface layer.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a CAD system for realizing a design method according to an embodiment.

FIG. 2 is a flowchart illustrating a design method according to the embodiment;

FIG. 3 is a flowchart showing details of a registration step of a surface wiring pattern in FIG. 2;

FIG. 4 is an explanatory view showing a display on a screen at each stage of FIG. 3;

FIG. 5 is a circuit design diagram based on the processing of the embodiment.

6 is a cross-sectional view of a multilayer printed wiring board showing a result of automatic design based on the circuit design diagram of FIG.

[Explanation of symbols]

 Reference Signs List 10 component / board data input device 11 circuit diagram data input device 12 input / output device 13 arithmetic device 13a component registration memory 13b central processing unit 20 virtual component input device 30 surface wiring pattern 40, 41 component 40a, 41a first terminal 40b, 41b Second terminal 42 Wiring pattern 43 Wiring pattern

Claims (1)

[Claims] 1. A component registration unit for storing electrical data and external shape data of a component to be used, determining an arrangement of components to be mounted on a surface layer based on the data and circuit diagram data, In a circuit design method of a multilayer printed wiring board using a CAD system having a design processing unit for designing a wiring pattern so as to connect between pins of a component with one of a plurality of wiring layers, a predetermined wiring pattern is used as a virtual component. The parts are registered in the part registration unit, and wiring between the parts is connected via a surface wiring pattern registered as the virtual part to a part where a wiring pattern is to be provided on a surface layer among wirings between parts. Circuit design method for a multilayer printed wiring board.