JPH04291674A - Automatic parts arrangement system - Google Patents

Abstract

PURPOSE:To obtain parts arrangement capable of effectively executing auto matic wiring in respect to the automatic parts arrangement system for circuit parts on a printed board. CONSTITUTION:This automatic parts arrangement system is provided with a parts area expanding part 10 for expanding a parts area allocated to parts on the printed board and a parts arranging part 11 for finding out the proper arrangement of parts based upon the part area of respective parts allocated by the expanding part 10. The expanding part 10 calculates an arranged part area obtained by adding a wiring area required at the time of arranging parts on the board to the original part area inherent in each part and calculates an adle area on the board based upon a difference between the arrangement enabled area of the board and the sum of arrangement parts area of respective parts. The expanded parts area is calculated by expanding the arranged parts area in accordance with the size of the idle area and the parts arranging part 11 finds out the proper arrangement of parts based upon the parts area of respective parts calculated by the expanding part 10.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic component placement method for automatically determining the proper placement of circuit components on a board such as a printed circuit board. As electronic devices become more densely packaged, the placement and wiring of circuit components on boards is automated using circuit packaging design systems. ing.

[0002] When automatic wiring is performed for component placement obtained by automatic component placement, there may be cases where the placed components are not routed due to lack of wiring tracks, etc., and automatic wiring efficiency depends on the quality of component placement. It is influenced by bad things. Therefore, in order to effectively perform automatic wiring, it is necessary to find effective automatic component placement.

[0003] Automatic component placement and automatic wiring in such an automated circuit packaging design system are becoming more difficult as components become smaller and the number of pins increases. An object of the present invention is to provide an automatic component placement method that can automatically obtain component placement effective for automatic wiring.

0004

2. Description of the Related Art FIG. 8A shows a flowchart of an automated system for circuit packaging design. S1 Design the circuit using CAD, etc. S2 Perform a circuit simulation to check whether the obtained circuit satisfies the intended function.

S3: Once the circuit has been determined, circuit components to be assigned to the circuit are selected in order to embody the circuit. S
4. Find the optimal component placement by trial and error to find out how to arrange the selected circuit components on the board for efficient wiring.

S5: Perform wiring to obtain wiring data for connecting each pin of the component to a track (wiring) on the board. Conventional automatic component placement (step S4 above) calculates the wiring length (Manhattan distance) on the board based on the degree of coupling between components, the priority of connection lines, etc. The wiring distance was controlled to be the shortest.

In the figure, B shows a method of calculating the connection distance between component pins. In the figure, P and Q are component pins,
The connection distance between P and Q is expressed as the sum of the vertical distance and the horizontal distance (a+b or c+g+h). Connection distance (c+d+e+f
) is not selected because it is not the shortest distance.

In the figure, C indicates the mounting format of components on the board. A indicates a through-mount component that is inserted into a through-hole in the board and is connected to the track, and B indicates a surface-mount component that is connected to the track on the surface of the board. In the figure, D is the wiring X that facilitates cross-connections between pins.
, indicates the Y method.

Tracks on layer 1 of the substrate are routed in the X direction, and tracks on layer 2 are routed in the Y direction. The connection between layer 1 and layer 2 is then made through a through hole, as shown in Figure E. FIG. 9 is an example of a conventional automatic component placement method. There are two different methods of specifying the position of components on the board: mesh placement and grid placement.

Mesh placement is a method in which a group of parts to be placed and a grid to be placed (placement grid) are specified, and the center of the part or the first pin of the part is placed at the grid point that is the intersection of the placement grid. For the group of parts to be placed, parts of the same type or of similar size are specified. The grid spacing is determined based on the size of the parts to be wired.

[0011] Figure (a) is an example of a mesh arrangement in which the center of the part is placed at a lattice point. Figure (b) is an example in which the first pin of a component is placed at a grid point. The grid arrangement is made by reducing the grid spacing in the mesh arrangement to equal intervals, and the spacing is usually the spacing between component pins (2.54 mm).

[0012] When component placement is determined so that the wiring length is the shortest as described above, there are cases where wiring cannot be performed because there are no tracks around the component pins, resulting in unwired parts during automatic wiring. Therefore, in order to solve the above points, the present applicant has developed an automatic component that determines the area (wiring area) required when actually wiring components in the component layout, and determines the component placement by taking the wiring area into consideration. We developed an arrangement method and filed a patent application (Japanese Patent Application No. 1-150064). The present invention further improves this automatic wiring method.

In the present invention, a part-specific part area defined by the shape of the part is the original part area, and a part area obtained by adding the wiring area required when the part is placed on the board to the original part area is the placed part area. It is called. The placed parts area will be explained with reference to FIG.

In Figures (a), (b), and (c), 230 is a component, 231 is a pin of the component, and 232 is the original component area of 231, which is an area unique to the component. In Figures (b) and (c), 233 is a track, and in Figure (c), 234 is a lead wire that connects the pin and the track. , 235 is an enlarged area, which is an enlarged version of the original component area 230. The enlarged area 235 is a wiring area required for automatic wiring.

An area obtained by adding the enlarged area 235 to the original parts area 232 is defined as a placement parts area. FIG. b is an example in which the original component area is not enlarged. As shown in the figure, if the track extends in a direction perpendicular to the pin arrangement direction, the bin and track can be directly connected, so there is no need to expand the component area, and the original component area and arranged component can be directly connected. The areas will be the same.

As shown in Figure (c), when the track 233 extends parallel to the direction in which the pins are arranged, a lead line 234 is required to connect the pin and the track. Therefore, in automatic component placement, it is necessary to obtain a placement component area by adding the enlarged area 235 to the original component area 233, and perform automatic component placement based on the placement component area.

FIG. 11 shows a case where the placement component area is determined taking into account the multilayer board and the prohibited area for component placement. Figure (a)
, (b) are the placement component areas required for the first and fifth layers, respectively. (a) shows the enlarged area of the first layer.
(b) is an enlarged region of the fifth layer, and the enlarged region is formed outside the region corresponding to the placed component region arranged in the first layer.

[0018] Figure (c) shows an enlarged area when there is a prohibited area. Enlarged area A is an enlarged area when there is no prohibited area, and enlarged area B is a portion added to enlarged area A corresponding to the enlarged area that overlaps with the prohibited area and is invalidated.

Automatic component placement is determined in consideration of the placement component area determined as described above. There are various automatic component placement methods, but a typical one will be briefly explained. (1) Pair linking method This is a method of selecting and arranging a pair of a component that has already been placed and a component that is most often connected to this component.

(2) Cluster growth method This is a method in which a component that is connected the most to all the components that have already been placed is selected and placed at a position where the virtual wiring length is the shortest. (3) Considering the tension between parts connected to each other,
This is a method of arranging a part at a position (center of gravity) where the resultant vector of tension forces applied to a certain part from other parts is zero.

FIG. 12 shows an example of automatic component placement using the conventional method described above. In the figure, 250 is a substrate, 251,
252 is a connector, and 253 to 264 are parts.

[0022]

[Problem to be solved by the invention] In conventional automatic component placement, automatic wiring is no longer marked as unwired and the automatic wiring rate improves, but the distance between components is set to the shortest possible distance. As a result, component placement was concentrated in the center of the board, resulting in wasted empty space around the periphery of the board, making it impossible to arrange components in a well-balanced manner over the entire board.

An object of the present invention is to provide an automatic component placement method that allows components to be placed on a board in a well-balanced manner.

[0024]

[Means for Solving the Problems] According to the present invention, an enlarged component area is obtained by enlarging the placement component area, taking into account the vacant area of the board, and automatic component placement is performed based on the enlarged component area. The enlarged component area in the present invention will be explained with reference to FIG.

In the figure, 270 is a placement parts area, 27
1 is an enlarged component area. To find the enlarged part area,
First, the sum of the placement parts areas calculated for each component is calculated, and the free area of the board is determined as the difference between the part placement possible area of the board and the total sum of the placement parts area. Then, depending on the size of the free space, the placement parts area of each part is expanded to form an enlarged parts area.

The basic configuration of the present invention will be explained with reference to FIG. In the figure, reference numeral 10 denotes a component area enlarging unit, which calculates the placed parts area, the total sum of the placed parts areas, the empty area, and the enlarged parts area. The enlarged component area 10 also has a function to reduce the calculated enlarged component area based on the mounting rate. Reference numeral 11 denotes a component placement section that determines component placement based on the component area of each component calculated by the component area enlarging section 10. 12 is a file that stores data such as design data, component data, board data, etc. Reference numeral 15 denotes a placement component area calculation unit, which determines a wiring area based on the original component area of each component and calculates a placement component area. Reference numeral 16 denotes a placed parts area, which is used to calculate the sum of the placed parts areas of each part. Reference numeral 17 denotes an empty area calculation unit which calculates an empty area based on the difference between the component placement area of the board and the total sum of the placed component area. Reference numeral 18 denotes an enlarged parts area calculation unit, which calculates an area for enlarging the placed parts area based on the empty area, and calculates an enlarged parts area in which the enlarged area is added to the placed parts area. Reference numeral 19 denotes an enlarged parts area reduction unit, which reduces the enlarged parts area based on the enlarged parts area so as to achieve a given mounting rate. (It also has a function to enlarge the reduced component enlargement area if the mounting rate falls below a specified value.) 20 is the obtained component placement output.

[0027]

[Operation] The operation of the basic configuration shown in FIG. 1 will be explained. The placement component area calculation unit 15 calculates the shape of the original component, the direction of the pin arrangement,
The area to which the original component area is to be expanded is calculated based on the number of pins, whether or not they intersect with the prohibited area, etc. Then, an enlarged area is obtained by adding an enlarged area to the original area (the size of the area is expressed by the area, the number of grids, etc.).

The sum total calculation unit 16 of the placed parts area calculates the sum of the placed part areas of each component calculated by the placed parts area calculation unit 15. The free area calculation section 17 calculates the free space by A-B, where A is the component placement possible area of the board, and B is the calculated value of the sum total calculation section 16 of the placed component area.

The enlarged component area calculation section 18 expands the placement component area of all or some of the components based on the free area (A-B) calculated by the free area calculation section 17. for example,(
A-B) divided by the number of parts N is added to the placement parts area of each part to form an enlarged parts area.

In this case, if the placement area of each component is uniformly expanded based on the value of (A-B)/N, the mounting rate will be 10.
0%, which may result in unplaced parts. Therefore, the enlarged part area reduction unit 19 reduces the obtained enlarged part area. The component placement section 11 determines component placement based on the reduced enlarged component area of the enlarged component reduction section and obtains a component placement output. In addition, if the mounting rate falls below the specified value due to excessive reduction, the expanded component area reduction unit 19 enlarges the expanded component area that has been reduced too much, calculates the mounting rate again, and expands the expanded component area until it reaches the specified value. Repeat the reduction, and when the specified mounting rate is achieved, output the component placement.

FIG. 2 is an example of component placement obtained by the automatic component placement method of the present invention. In the figure, 30 is a board, 31 and 32 are connectors, and 33 to 44 are circuit components. 31' is an enlarged component area (reduced to a specified mounting rate) of the connector 31, and similarly, the dotted line areas around the other connectors 32 and circuit components 33 to 44 are enlarged component areas ( (reduced to the specified implementation rate).

As is clear from the comparison with the conventional component arrangement shown in FIG. 12, according to the present invention, each component is arranged in a well-balanced manner over the entire board.

[0033]

[Example] Figures 3 and 4 are flowcharts of an example of the present invention (
Figure 4 is a flow following Figure 3). Explain the flow step by step. S1 to S8 in FIG. 3 are processes in the component area enlarging unit in FIG. 1, and S9 to S13 are processes in the component placement unit.

[0034]S1 Circuit diagram data, wiring condition data,
Load design standard data, board data, component data, shape data, and wiring data. S2 Determine the order in which parts are to be placed. S3: Calculate the area where components can be placed on the board, the original component area, and the mounting rate (placement component area calculation unit).

S4: It is determined whether the mounting rate is below a specified value based on the total sum of the component placement area on the board and the original component area. If it is below the specified value, proceed to S5; if it is above the specified value, there is no room to expand the component area, so
The process proceeds to parts placement processing from S9 onwards (FIG. 4).

S5: Add an enlarged area for wiring to the original component area to obtain a placement component area (processing of the placement component area calculation unit). S6: Calculate the mounting rate by taking the total sum of the placed component areas for each component. S7: If the mounting rate is below the specified value, the process advances to S8; if it is above the specified value, there is no room for expansion, so the process proceeds to S9, where component placement processing is performed.

S8 Find the free area from the difference between the area where components can be placed on the board and the total sum of the placed parts area, divide the area by the number of parts, add the area equivalent to the placed parts area of each component, and expand the enlarged parts area. demand. Furthermore, all or part of the component is reduced, the mounting rate is calculated, and the area of the target component is expanded (or reduced) until the final mounting rate (given mounting rate) is reached (vacant area calculation unit, enlarged part processing of the area calculation unit and enlarged part area reduction unit).

S9 Select the parts to be placed. S10 Optimal placement surface (surface on multilayer board), position,
Calculate direction. S11 Determine whether placement is possible. S1 if possible
The process proceeds to step 2, and if it is not possible, the process proceeds to step S14.

S12 Since it can be placed, it is placed. S13 Determine whether processing for all parts to be placed has been completed, and if not completed, repeat the processing from S9 onwards. If it has ended, the process ends. S14 In S11, if placement is not possible, search for another placement.

[0040] S15 It is determined whether placement is possible at another location. If it is possible to arrange it, proceed to S12 and arrange it. If placement is not possible, the process advances to S16. S16 It is determined whether the search for the placement area has been completed. If the search for the placement area has not been completed, the process returns to S14;
Search for other possible placement areas. When the search for all placement areas is completed, the process advances to S17.

[0041] S17 It is determined that the item has not been placed and the process proceeds to S13. 5 and 6 are examples of the flow for determining the placed parts area and enlarged parts area in the present invention (FIG. 6 is a continuation of FIG. 5). In FIGS. 5 and 6, 100 is the process of the placement component area calculation unit, and 110 is the process regarding the enlarged component area.

[0042] This will be explained according to the steps shown in the figure. S1: Determine the automatically arrangable area on the board. S2 Find the sum of the original component areas. S3 Expanded area of the component to be placed based on wiring elements such as the original component area, the number of wiring layers, the wiring direction of each layer, which changes during component placement, the placement layer, placement direction, and intersections with prohibited areas, etc., which remain unchanged before and after component placement. Find the logical sum with the original part (to find the placement part area).

S4: Find the total sum of the placed parts area. S5 Calculate the mounting rate based on the total sum of the placed component areas. S6 Determine the implementation rate. If the mounting rate is not below the specified value, the component area cannot be expanded, so proceed to S11.
Perform parts placement. If the mounting rate is less than the specified value, the process advances to S7.

[0044] A free area is determined by S7 (area of S1 - area of S4). Next, divide the free space by the number of parts,
An area corresponding to the obtained value is added to the placed parts area of each part (calculating an enlarged parts area). S8 Specify all parts or some parts and reduce the enlarged parts area.

S9: Find the mounting rate based on the obtained component area data. If the mounting rate is not less than the specified value, the process advances to S11 to perform component placement processing. If it is less than the specified value, the process advances to S10. S10 Enlarge the reduced enlarged component area, return to S9, and calculate the mounting rate again. The processes of S8, S90 and S10 are repeated, and when the mounting rate reaches a specified value, the process proceeds to S11, where component placement is performed.

S11 Perform component placement (the flow of component placement is the same as in FIG. 4). Component placement follows conventional methods such as the pair linking method and the cluster growth method. In this example, the mounting rate due to the enlarged component area obtained in S7 of FIG. 6 is 100%, and unplaced components are likely to occur. Various methods are possible, such as uniformly reducing each component, or increasing the reduction rate from the component with the highest placement priority (increasing the enlargement rate for the placement component area).

[0047] Next, an example will be given. The enlarged part area is reduced by one of the following processes or a combination. (1) Uniformly reduce the enlarged part area by several percent. (2) The enlarged parts area is made smaller in stages starting from the one with the highest placement priority (the higher the priority of the component, the smaller the reduction rate of the enlarged part area, and the lower the priority of the part, the greater the reduction rate).

(3) The larger the number of used component pins, the larger the area to which the placed component area is expanded (the reduction rate of the enlarged component area is made smaller). (5) For 2-terminal parts and parts with through-type pins that have less than the specified number of pins, area expansion is not performed (parts are placed in the placement part area or original part area).

(6) The enlarged area is made larger for the parts placed in the center (the reduction rate of the enlarged part area is made smaller). FIG. 7 is an example of placement priority when placing components on a board according to the present invention. The higher up in the diagram, the higher the placement priority.
The lower the placement priority, the lower the placement priority.

[0050] The placement priority is determined by taking into account the size of the component, the number of pins, etc. In the figure, CN1 and CN2 are connectors, IC1 to IC5 are integrated circuits, T1 and T2 are transformers, and R1 to R3 are resistors. For example, connector C
N1 and CN2 are expanded by two grids. IC parts IC1
~IC5 is enlarged by 0.5 to 1.5 grids (the enlargement rate is adjusted depending on the number of pins and whether it is SMD or not). Transformers T1, T2 and resistors R1 to R3 are not expanded.

[0051]

According to the automatic component placement of the present invention, the component placement is determined taking into account the free space on the board, so that components can be placed on the board in a well-balanced manner. Furthermore, in the determined component placement, an area for component wiring is always secured, so that automatic wiring will not be treated as unwired, and the automatic wiring rate will be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the basic configuration of the present invention.

FIG. 2 is a diagram showing an example of the arrangement of components in the present invention.

FIG. 3 is a diagram showing the flow of an embodiment of the present invention.

FIG. 4 is a diagram showing the flow of an embodiment of the present invention (a continuation of FIG. 3).

FIG. 5 is a diagram showing a flow for determining a placed component area and an enlarged component area in the present invention.

FIG. 6 is a diagram showing a flow for determining a placed component area and an enlarged component area in the present invention (continuation of FIG. 5).

FIG. 7 is an example of placement priority in the present invention.

FIG. 8 is an explanatory diagram of a conventional technique.

FIG. 9 is a diagram showing an example of a conventional automatic component placement method.

FIG. 10 is a diagram showing a placement component area.

FIG. 11 is a diagram showing a placement component area (multilayer board and prohibited area).

FIG. 12 is a diagram showing an example of conventional automatic component placement.

FIG. 13 is an explanatory diagram of an enlarged component area in the present invention.

[Explanation of symbols]

10: Parts area expansion section 11: Parts placement section 12: File 15: Placement component area calculation unit 16: Total sum calculation unit of placed parts area 17: Free space calculation unit 18: Expanded parts area calculation section 19: Expanded parts area reduction section 20: Parts placement output

Claims (3)

[Claims] 1. A method for automatically arranging circuit components on a board includes a component area enlarging unit (10) for enlarging the component area to which components are allocated on the board;
Based on the part area of each part assigned by 0),
a parts placement unit (11) for determining proper placement of parts;
The component area expansion unit (10) calculates a placement component area by adding the wiring area required when placing the component on the board, to the original component area based on the unique shape of the component, and also calculates the placement part area by adding the wiring area required when placing the component on the board. The free area of the board is calculated based on the difference between the possible area and the sum of the placed parts area of each component, and the enlarged parts area is calculated by expanding the placed parts area of all or some parts according to the size of the free area. An automatic component placement method characterized in that the component placement section calculates the appropriate placement of the components based on the component area of each component calculated by the component area expansion section. [Claim 2] In Claim 1, the component area enlarging portion (
10) is (A-B)/N for the placement area A of the board, the sum B of the placement parts area of each component, and the number N of components.
The expanded component area of each component is calculated by calculating and adding the calculated value to the placed component area of each component, and it is possible to reduce all or part of the expanded component area to obtain a specified mounting rate. The automatic component placement method according to claim 1. 3. The automatic component placement method according to claim 1, wherein the size of the enlarged component area is made different for each component based on the placement order.