JP3082737B2 - System and method for simulating measured waveform of printed circuit board - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring a printed circuit board, and more particularly to a system and method for simulating a measured waveform of a printed circuit board using a circuit simulator.

[0002]

2. Description of the Related Art As a conventional circuit simulation system for printed circuit boards, for example, Japanese Patent Application Laid-Open No. 9-218884 discloses a configuration as shown in FIG.

Referring to FIG. 9, this conventional circuit simulation system for a printed circuit board includes a board layout tool 1, a simulation data file 4,
A netlist generation tool 6, a circuit simulator 9,
It is composed of

A circuit simulation is performed using a circuit simulator 9 on a partial circuit including a measurement point set on a substrate layout by a measurement point setting means of the substrate layout tool 1, and an electric waveform in the partial circuit can be obtained.

[0005]

However, in this conventional simulation system, a simulation result different from a waveform obtained when an actual printed circuit board is actually measured by a measuring instrument is obtained.

The reason is that, in the conventional simulation method, the measuring instrument and the probe are ideal, and the circuit simulation is performed without including the electrical characteristics of the measuring instrument and the probe.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above problems, and has as its object to provide a simulation system and method capable of obtaining an accurate circuit simulation result of a measured waveform of a substrate. It is in.

[0008]

In order to achieve the above object, according to the present invention, a board layout means for creating board layout information sets a measurement point at a place where a probe of a measuring instrument is connected at the time of actual measurement. Setting means, and
Using the board layout information in which the measurement points are set, the model information of the circuit simulation parts and wiring stored in advance in the storage means, and the information defining the electrical characteristics of the measuring device and the probe. A netlist generating means for generating netlist information of a circuit to be measured in a state where an equivalent circuit of the measuring device and the probe is added, and including an electrical characteristic of the measuring device from the generated netlist information. Circuit simulation means for performing a circuit simulation and outputting a simulation result.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides a configuration capable of calculating a waveform in consideration of the influence of a measuring instrument, a probe and a measuring point in an actual measurement in a circuit simulation of a printed circuit board.

In a preferred embodiment of the system of the present invention, device layout information is created using a board layout tool (1) in FIG. Then, in the board layout tool (1), a measurement point (11) is set by a measurement point setting means (2) at a location to which a probe of a measuring instrument is connected at the time of actual measurement.

The net generation tool (6) uses the board layout information in which measurement points are set, the simulation model data file (4), and the measurement device and probe characteristic data file (5) to electrically connect the measurement device and the probe. A netlist file (8) of the circuit under test including the equivalent circuit is generated.

From the netlist file (8) generated in this way, it is possible to calculate a simulation waveform (10) including the electrical characteristics of the measuring instrument by the circuit simulator (9). Hereinafter, the present invention will be described in detail with reference to examples.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory diagram for explaining the configuration of one embodiment of the present invention. Referring to FIG. 1, an embodiment of an actually measured waveform simulation system for a printed circuit board according to the present invention includes a board layout tool 1, a simulation model data file 4, a measuring instrument and probe characteristic data file 5, a net generation tool 6 and a circuit simulator 9.

The board layout tool 1 includes a measuring point setting means 2 for designating a point to which a probe of a measuring instrument is connected in actual measurement.

Measurement device and probe characteristic data file 5
Contains electrical equivalent circuit information of a measuring instrument and a probe that can be simulated by the circuit simulator 9.

The net generation tool 6 converts the circuit to be measured specified by the measurement point setting means 2, the simulation model data file 4, the measuring device and the probe characteristic data file 5 from the data of the board layout tool 1 into a measuring device. And a netlist 8 including an electrical equivalent circuit of the probe.

The circuit simulator 9 simulates the netlist file 8 and calculates a simulation waveform 10 taking into account the electrical characteristics of the measuring instrument and the probe.

The operation of one embodiment of the present invention will be described. FIG. 2 is a perspective view showing how the substrate is actually measured. FIG. 3 is a flowchart for explaining the processing flow of one embodiment of the present invention. FIG. 4 is a diagram showing an example of a circuit for specifically describing one embodiment of the present invention.

First, in the data in which the components have been arranged on the board layout tool 1, using the measurement point setting means 2,
On the printed circuit board 53, a measurement point 11 for calculating a waveform is set at a point corresponding to the measurement point 54 to which the probe 52 of the measuring instrument 51 is connected at the time of actual measurement (step A1 in FIG. 3).

Next, the measurement point 11 is
Is extracted (Step A2 in FIG. 3).

Further, the net creation tool 6 uses the simulation model data file 4 from the extracted circuit portion to execute a simulation netlist file 7.
Is generated (step A3 in FIG. 3).

Next, the net creation tool 6 stores the measurement points 11 in the simulation netlist file 7.
A simulation netlist file 8 is generated by adding an electrical equivalent circuit 42 (see FIG. 4) of the measuring device and the probe from the measuring device and probe characteristic data file 5 to a point 41 (see FIG. 4) (see FIG. 3). Step A4).

Finally, the circuit simulator 9 receives the simulation netlist file 8 including the electrical equivalent circuit of the measuring instrument and the probe and calculates the simulation waveform 10 (step A5 in FIG. 3).

Next, a specific example will be described.

In step A2 in FIG. 3, a circuit under test C1 (see FIG. 4) including the measurement points 11 set by the measurement point setting means 2 in FIG. 1 is generated by the net creation tool 6 in step A1. .

Then, in step A3, a simulation netlist corresponding to the simulation circuit C1 is obtained from the simulation model data file 4 by using the simulation model of the driver 31, the wiring 32, the resistor 33, the wiring 34, and the receiver 35. File)
7 is generated.

In step A4, the net creation tool 6 sets the measuring device 51 and the probe to the point 41 corresponding to the point 54 where the probe 52 of the measuring device 51 is connected to the printed circuit board 53 from the net list file 7 of the circuit to be measured. A net list 8 corresponding to the simulation circuit C2 (see FIG. 4) to which the electrical equivalent circuit 52 is added is generated.

Thereafter, the circuit simulator 9 performs a circuit simulation (excessive analysis is performed) using the netlist 8 as an input, and the circuit under test, the measuring instrument and the probe 52 are analyzed.
A simulation waveform 10 is calculated in consideration of the electrical characteristics of.

Next, another embodiment of the present invention will be described. FIG. 5 is an explanatory diagram for explaining the configuration of the second embodiment of the present invention. FIG. 6 is a perspective view showing how a substrate is actually measured in the second embodiment of the present invention.
FIG. 7 is a flowchart for explaining the processing flow of the second embodiment of the present invention. FIG. 8 is a diagram showing an example of a circuit for specifically explaining the second embodiment of the present invention.

Referring to FIG. 5, a second embodiment of the present invention has a ground point setting means 3 in addition to the measurement point setting means 2 of the embodiment shown in FIG. ,
In the second embodiment of the present invention, in addition to the processing flow of the above-described embodiment shown in FIG.
0) and a ground point connection net modeling process (step A11).

The ground point setting means 3 designates a point 12 corresponding to a point at which the ground terminal of the probe 52 of the measuring instrument 51 is connected on the printed circuit board 53 of FIG.

In the ground point connection net modeling process (step A10), a model of wiring and components from the point 12 set by the ground point setting means 3 to the circuit to be simulated is added.

Next, the overall operation of the second embodiment of the present invention will be described in detail with reference to FIGS.

First, a measurement point 11 corresponding to a point 54 to which the probe 52 of the measuring instrument 51 is connected at the time of actual measurement is measured on the printed circuit board 53 by using the measurement point setting means 2 in the data of the components arranged on the board layout tool 1. Is set at step (A1 in FIG. 7).

Next, on the printed circuit board 53, a ground point is set to the ground point 12 corresponding to the point 55 connecting the ground terminal of the probe 52 of the measuring instrument 51 at the time of actual measurement (Step 10 in FIG. 7).

The circuit part to be simulated including the measurement point 11 and the ground point 12 is extracted by the net creation tool 6 (step A2 in FIG. 7).

Further, the net creation tool 6 uses the simulation model data file 4 from the extracted circuit portion to
Is generated (step A3 in FIG. 7).

Next, the net creation tool 6 stores the measurement points 11 in the simulation netlist file 7.
Then, a simulation netlist file 8 to which an electrical equivalent circuit of the measuring instrument and the probe is added is generated from the measuring instrument and the probe characteristic data file 5 between the point corresponding to and the ground point 12 (step A4 in FIG. 7).

Finally, the circuit simulator 9 calculates a simulation waveform 10 by inputting the simulation netlist file 8 including the electrical equivalent circuit of the measuring instrument and the probe (step A5 in FIG. 7).

Next, a description will be given using a specific example shown in FIG.

In the board layout tool 1, a measurement point 11 corresponding to the measurement point 54 to which the probe 52 of the measuring instrument 51 is connected at the time of actual measurement is set. Subsequently, the ground point 12 corresponding to the ground point 55 connecting the ground terminal of the probe 52 of the measuring instrument 51 is set.

In step A2 in FIG. 7, the circuit C11 (see FIG. 8) including the measurement point 11 set by the measurement point setting means 2 in FIG. 5 is extracted by the net creation tool 6 in step A1. .

Then, in step A3, the net creation tool 6 uses the simulation model of the driver 31, the wiring 32, the resistor 33, the wiring 34, and the receiver 35 from the simulation model data file, and corresponds to the simulation circuit C11. A simulation netlist 7 is generated.

Next, in step A11, the ground point 12 and the wiring 44 related to the circuit under test C11 are extracted from the data of the board layout tool 1, and a wiring simulation model is added from the simulation data file.

In step A4, the net creation tool 6 determines the points 41 and 52 corresponding to the points 54 connecting the probe 52 of the measuring instrument 51 to the printed circuit board 53 in the netlist file 7 and the wiring model 44 of the circuit to be measured. A netlist 13 corresponding to a simulation circuit C12 (see FIG. 8) in which 42 which is an electric equivalent circuit of the measuring instrument 51 and the probe 52 is added between points 43 corresponding to points 55 connecting the ground points I do.

Thereafter, the circuit simulator 9 performs a simulation by using the netlist 13 as an input, and calculates a simulation waveform 14 in consideration of the electrical characteristics of the circuit under test, the measuring instrument, the probe 52 and the ground point.

[0047]

As described above, according to the present invention,
There is an effect that the waveform actually measured by the measuring instrument can be compared with the waveform of the simulation. The reason is that the simulation is performed using a netlist including the electrical characteristics of the measuring instrument and the probe.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram schematically showing a configuration of one embodiment of the present invention.

FIG. 2 is a diagram for explaining one embodiment of the present invention;
It is a figure which shows the mode of a board | substrate measurement.

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

FIG. 4 is a diagram showing a specific circuit for explaining one embodiment of the present invention.

FIG. 5 is an explanatory diagram schematically showing a configuration of a second embodiment of the present invention.

FIG. 6 is a view for explaining a second embodiment of the present invention, and is a view showing a state of substrate measurement.

FIG. 7 is a flowchart showing a processing flow of a second embodiment of the present invention.

FIG. 8 is a diagram showing a specific circuit for explaining a second embodiment of the present invention.

FIG. 9 is a diagram showing a configuration of a conventional simulation system.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Board layout tool 2 Measurement point setting means 3 Ground point setting means 4 Model data file for simulation 5 Measuring instrument and probe characteristic data file 6 Net generation tool 7 Netlist file of circuit under test 8 Circuit under test, measuring instrument and probe Netlist file including equivalent circuit 9 Circuit simulator 10 Simulation result 11 Measurement point 12 Ground point 21, 22, 23 Electronic device (chip) 31 Driver 32, 34 Wiring 33 Resistance 35 Receiver 41 Measurement point 42 Probe and measuring instrument 51 Measurement Instrument 52 Probe 53 Printed circuit board 54 Measurement point 55 Ground point

Claims (4)

(57) [Claims] (A) A netlist for simulation by adding an equivalent circuit of a probe and a measuring device to a position corresponding to a position where a probe of a measuring device is actually placed on a substrate with respect to layout information of the substrate. And (b) performing a circuit simulation based on the generated netlist information. 2. A circuit simulation in which connection information of a ground terminal of the probe is added to the layout information, and connection of the measuring device and the probe to a ground point is taken into consideration. A method for simulating an actually measured waveform of a printed circuit board as described above. 3. A board layout means for creating board layout information, comprising: setting means for setting a measurement point at a location to which a probe of a measuring instrument is connected at the time of actual measurement, further comprising: a board on which the measurement point is set. Using the layout information, the model information of the parts and wiring for circuit simulation stored in the storage means in advance, and the information defining the electrical characteristics of the measuring instrument and the probe, the measuring instrument and the probe A netlist generating means for generating netlist information of the circuit to be measured in a state where an electrical equivalent circuit of the above is added; and performing a circuit simulation including the electrical characteristics of the measuring device from the generated netlist information. And circuit simulation means for outputting a simulation result as a waveform. Simulation system. 4. A board layout means for creating layout information of a board, comprising: a setting means for setting a measurement point at a place where a probe of a measuring instrument is connected in actual measurement; and a ground point for connecting a ground terminal of the probe. Ground point setting means for setting, furthermore, board layout information in which the measurement points and ground points are set, model information such as a device for circuit simulation stored in a storage means in advance, and the measuring instrument And information defining the electrical characteristics of the probe, and generating netlist information of a circuit to be measured in a state where an electrical equivalent circuit of the measuring device and the probe is added between the measurement point and a ground point. Netlist generating means for connecting the measuring device and the probe to the ground point from the generated netlist information. A circuit simulation means for outputting a simulation result performed circuit simulation taking into as a waveform, characterized in that it comprises a printed circuit board measured waveform simulation system.