JPH0476583B2 - - Google Patents

Description

[Detailed Description of the Invention] [Summary] When soldering a printed circuit board on which electronic components are mounted, power of a prescribed potential is supplied to a prescribed pattern of the printed circuit board, and the potential of the terminal end of the wiring material is measured. This system is designed to prevent erroneous connections of wiring materials by detecting this with a device.

[Industrial Application Field] The present invention relates to a miswiring detection device for wiring a printed circuit board on which electronic components are mounted.
In particular, the present invention relates to a miswiring detection device that detects miswiring by applying a potential to a predetermined pattern on a printed circuit board and measuring changes in the potential from the wiring material side.

There are cases where a printed circuit board on which electronic components such as LSI elements are mounted is modified to add functions, etc. In such cases, wiring using wiring material is required, and such wiring is generally A device is used that automatically joins the wiring material to the pad by moving the bonding chip to be connected to a predetermined pad and supplying the wiring material.

A pair of wires is used for such a wiring material, and wiring is performed by joining one wire to a signal pattern and the other to a ground pattern.

Therefore, in such wiring, erroneous wiring occurs, such as connecting a wire that should be connected to a signal pattern to a ground pattern, or conversely connecting a wire that should be connected to a ground pattern to a signal pattern.

Therefore, in order to prevent such erroneous wiring from occurring, when joining wiring materials, the wiring material is formed in such a way that it can be detected that the wire material to be connected to the signal pattern has been reliably joined to the signal pattern. There is.

[Problems to be solved by conventional technology and invention]

Conventionally, the configuration was as shown in the conventional explanatory diagram of FIG. In FIG. 3, a is a configuration diagram, and b1 and b2 are connection diagrams.

As shown in FIG. 3a, the wiring material 4 wound around the bobbin 5 is supplied to the wiring pad of the printed circuit board 1 on which the electronic component 3 is mounted, and the bonding chip 6 is lowered. Soldering is performed, and after soldering, a resistance measuring device 20 is connected to the pattern 2 of the printed circuit board 1 and the terminal end of the wiring material 4 wound around the bobbin 5, and the resistance value is measured by the resistance measuring device 20. It was composed of

Measurement by such a resistance measuring device 20 is performed by b1
As shown in , when the wiring material 4 is connected to the pad 7-1 connected to the signal pattern 22, the resistor is connected via the mounted LSI element 3-1, R package 3-2, etc. The value will be measured.

In addition, as shown in b2, the wiring material 4 is connected to the pad 7-2 connected to the ground pattern 23.
If the measurement is carried out at the same time, the resistance value of the wiring material 4 will be measured.

In this case, it is connected to the signal pattern 22.
Since the LSI element 3-1 has a resistance value of 10KΩ, it is connected to the ground G through the 10KΩ resistance, and the capacitance shown in C is formed between the signal pattern 22 and the ground pattern 23. .

The resistance value of this wiring material 4 is variable depending on the length of the wiring material 4 wound on the bobbin 5, but it is usually 6KΩ.
It is as follows.

Therefore, the connection to the ground pattern 23 can be confirmed by checking that the resistance value is 6KΩ or less.

However, since the electronic component 3 is mounted, the connection to the signal pattern 22 is
If the unit of resistance value is large, the connection can be confirmed by the change in resistance value, but as mentioned above, when R package 3-2 is mounted, the resistance value is about 65Ω, so the resistance value The change in is within the range of measurement error.

Therefore, in such a configuration, when the electronic component 3 is mounted, especially when the R package 3-2 with a small resistance value is mounted, it is difficult to connect the wiring material 4 to the pad 7-1. I had a problem where I couldn't confirm.

[Means for solving problems]

FIG. 1 is a block diagram of the principle of the present invention.

As shown in FIG. 1, the measuring instrument 10 includes a low constant voltage generation circuit 11 that outputs power at a predetermined potential, an output cutoff circuit 12 that supplies and disconnects the power to the pattern 2, and a supply potential of the power source. a supply voltage abnormality detection unit 13 that monitors V1 and instructs the output cutoff circuit 12 to disconnect when an abnormal potential occurs;
and a detected potential V2 at the end of the wiring material, and a potential difference detection circuit 14 that detects incorrect wiring based on an output signal S as a result of the comparison, and is configured to form the supply potential V1 to a negative potential. This is what I did.

With this configuration, the above-mentioned problems can be solved.

[Effect]

That is, a low constant voltage generation circuit applies a potential to a predetermined pattern, and a potential difference detection circuit detects a change in the potential of the pad where the wiring material is to be bonded, thereby confirming the connection location. In addition, a negative potential is used as the potential to be applied, and if an abnormality occurs, it is monitored by the supply voltage abnormality detection unit to prevent damage to the mounted electronic components. The output is immediately disconnected by the output cutoff circuit.

Therefore, it is now possible to confirm the bonded pads of wiring materials by checking the change in resistance as in the past, which could not be done when electronic components with low resistance are mounted. can do.

〔Example〕

The present invention will be explained in detail below with reference to FIG.
FIG. 2 is an explanatory diagram of an embodiment according to the present invention.
The same reference numerals indicate the same objects throughout the figures.

As shown in FIG. 2, the measuring instrument 10 is formed by a low constant voltage generation circuit 11, an output cutoff circuit 12, a supply voltage abnormality detection section 13, and a potential difference detection circuit 14. The rest of the configuration is the same as described above.

Therefore, pads 7-1 and 7 to which wiring materials are to be joined
The power supply of the potential V1 outputted by the low constant voltage generation circuit 11 is supplied to the signal pattern 22 or the ground pattern 23 connected to the signal pattern 22 or the ground pattern 23 via the output cutoff circuit 12, and the potential V1 of the supply voltage and the bobbin 4 A potential difference detection circuit 14 compares the potential V2 at the terminal end of the wiring material 4 wound around the wire.

Further, the potential V1 of this power supply is always monitored by the supply voltage abnormality detection unit 13, and an alarm is further set so that the power supply is immediately cut off by the output cutoff circuit 12 if an abnormality occurs. It is configured to notify by the output of AL.

Therefore, care is taken to prevent damage to the LSI element 3-1, which is a mounted electronic component, due to an abnormality in the potential V1.

This signal pattern 22 has -2V during normal driving.
Therefore, if a potential of -0.3V is supplied during measurement, when the wiring material 4 is connected to the pad 7-1 connected to the signal pattern 22, the detected potential V2 is -0.30V. is detected.

Furthermore, when the wiring material 4 is connected to the pad 7-2 connected to the ground pattern 23 as shown by the dotted line, the detection potential V2 has an output impedance of 1Ω on the power supply side and an output impedance on the detection side. If is 5.1KΩ, the value is shown in the following equation (1).

V2 = -0.39/5.1 + (0 to 6) x (0 to 6) = 0 to 0.21V ... (1) Therefore, when the potential V2 detected by the potential difference detection circuit 14 is -0.30V, Signal pattern 22
This means that the bond was made to the pad 7-1 connected to the ground pattern 23 when the voltage was 0 to 0.21V.
This means that the bonding has been performed on the pad 7-1 connected to the wiring material 4, and the bonding pad of the wiring material 4 can be easily determined based on whether the potential is the same or lower than the supply potential V1. can.

Therefore, by outputting the signal S from the potential difference detection circuit 14 based on the result of comparing the potential differences, it is possible to detect incorrect wiring of the wiring material 4 using the signal S.

〔Effect of the invention〕

As described above, according to the present invention, it can be determined based on the detected potential difference whether the pad to which the wiring material is bonded is connected to a predetermined signal pattern or ground pattern.

Therefore, it is possible to prevent incorrect wiring such as the wiring material that should be bonded to the signal pattern being connected to the ground pattern, and it is also possible to detect incomplete bonding, thereby increasing the reliability of the bonding of the wiring materials. The practical effect is great.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the present invention, FIG. 2 is an explanatory diagram of an embodiment according to the present invention, and FIG. 3 is an explanatory diagram of a conventional system, where a shows a configuration diagram and b1 and b2 show connection diagrams. In the figure, 1 is a printed circuit board, 2 is a pattern, 3 is an electronic component, 4 is a wiring material, 5 is a bobbin, 6
1 is a bonding chip, 7 is a pad, 10 is a measuring device, 11 is a low constant voltage generating circuit, 12 is an output cutoff circuit, 13 is a supply voltage abnormality detection section, and 14 is a potential difference detection circuit.

Claims (1)

[Claims] 1. A printed circuit board 1 on which an electronic component 3 is mounted;
A wiring material 4 wound around a bobbin 5, a bonding chip 6 for soldering the wiring material 4 to a predetermined pad 7 of the printed circuit board 1, and a terminal end of the wiring material 4 and a predetermined pattern 2 of the printed circuit board 1. and a measuring device 10 for measuring the conductive path between the wiring member 4 and the wiring member 4. A low constant voltage generation circuit 11 that outputs power at a predetermined potential, an output cutoff circuit 12 that supplies and disconnects the power to the pattern 2, and monitors the supply potential V1 of the power supply, and when an abnormal potential occurs, A supply voltage abnormality detection unit 13 that instructs the output cutoff circuit 12 to disconnect, and a potential difference detection unit that compares the supply potential V1 and the detection potential V2 of the termination and detects incorrect wiring based on the output signal S of the comparison result. circuit 14
What is claimed is: 1. A miswiring detection device comprising the following: and forming the supply potential V1 to a negative potential.