JP2004245709A - Failure diagnosis method, failure diagnosis system, and failure diagnosis device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To actualize an easy-to-use failure diagnosis scheme at a low cost with respect to a system for diagnosing failure of a circuit board. <P>SOLUTION: For every function block and wiring pattern on the circuit board 10, a coil 32 and a capacitor 33 are formed in patterns at corresponding positions on a support substrate 4, the coil 32 and capacitor 33 constituting a signal change detection part 30 for detecting induced electromotive force among them. A failure diagnosis part 90 is connected to the open end side of the coil 32 and the capacitor 33. The diagnosis part 90 detects an electrical signal corresponding to a change in a signal induced in the coil 32, etc. by electromagnetic coupling or capacitive coupling with the coil 32, etc. owing to the actuation of a circuit member 20 with the circuit board 10 supplied with power. Further, the signals are frequency-converted, frequency spectra are analyzed, and they are compared with a previously measured normal state, thereby diagnosing whether or not any failure exists in the circuit member 20. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention predicts the operation, performance abnormality, or failure of a circuit member in a device having a circuit board on which a circuit member is mounted, for example, a printer device, a facsimile device, or a device such as a multifunction peripheral having those functions. The present invention relates to a method of performing a fault diagnosis (hereinafter collectively referred to as a fault diagnosis), a fault diagnosis system for implementing the fault diagnosis method, and a device used in the fault diagnosis system.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as electronic devices such as personal computers and copiers have been improved in performance and functions, analog and digital electronic circuits for various applications for realizing them have been increasingly stored in the form of printed circuit boards. .
[0003]
The environment in which the device on which such a board is mounted is used is usually in an office or a house, but it may be used in other harsh environments, and it is very diverse. Over. In particular, when the use environment is poor, various abnormalities and failures that are difficult to detect occur even if the device is used in a normal manner, and a great deal of labor is required to repair the abnormalities and failures.
[0004]
In addition, even when the electronic circuit is used in a normal use environment, an abnormality or a failure of the electronic circuit occurs, the frequency of the abnormality is not always low, and the detection location cannot often be specified. Further, when an abnormality occurs in the electronic circuit board, it is necessary to take an urgent action in terms of safety and cost.
[0005]
As a general method of fault diagnosis, a fault location is identified while monitoring (monitoring) the voltage and signal waveform of a main location using a measuring device such as a tester. For example, based on the design information of the electronic circuit, the signal input / output characteristics to the electronic circuit board are inspected, and according to the inspection result, the wiring and the terminals in the electronic circuit board are probed while following the circuit diagram to determine the failure location. After the identification, the user replaces the failed component.
[0006]
For example, Patent Document 1 discloses a technology for detecting a magnetic field generated by a current flowing through an electronic circuit. In the technique proposed in Patent Document 1, in a circuit wiring such as a printed circuit board or an LSI, the influence of an adjacent wiring is suppressed, and a magnetic field due to a current of only one wiring is measured with high resolution and in a non-contact manner. If this technology is used, it is possible to specify a fault location while monitoring the operation of the electronic circuit.
[0007]
[Patent Document 1]
JP-A-11-38111
[0008]
Further, Patent Document 2 discloses a technique for extracting an electric characteristic amount using a small and simple coil component suitable for applications such as high-precision extraction of electric characteristics of an electric wire. In this technology, a coil body is presented as a coil component in which the center of each turn gradually shifts on the same straight line or the same curve, and the whole is flat.
[0009]
[Patent Document 2]
JP 2002-237413 A
[0010]
[Problems to be solved by the invention]
However, since the operation of electronic circuits is becoming more and more complicated with the improvement of performance and functions in recent years, probing of wirings and terminals in an electronic circuit board becomes difficult, and high circuit knowledge is required. The technique described in Patent Literature 1 has a problem in that the cost of identifying and repairing a fault location is increased. In addition, although it is possible to probe a magnetic field generated from the state of a signal line or a current on a circuit board with high accuracy without contact, a dedicated probe used as a means for sensing a magnetic field is expensive and large. There is a problem that it is difficult to perform a failure diagnosis and a failure location with the electronic circuit board incorporated in the system.
[0011]
Further, the technique described in Patent Document 2 is an invention effective for detecting an abnormality in a power supply line of a power plug, a current transformer, a power supply line of a transformer, and the like. When constructing a fault diagnosis system that takes out the current flowing on the board using a coil and specifies the fault location for the complicated circuit configuration of the above, there is no mention of the coil arrangement or signal processing method . Since the arrangement of the coils and the signal processing greatly affect the failure diagnosis accuracy, accurate failure diagnosis cannot always be performed.
[0012]
As described above, the conventional failure diagnosis method is not always sufficient in terms of cost, accuracy, or usability.
[0013]
The present invention has been made in view of the above circumstances, has a low cost, can be incorporated in a system, and can perform a failure diagnosis and specify a failure location while monitoring circuit operation. It is an object of the present invention to provide a failure diagnosis system and device for implementing the failure diagnosis method of the present invention.
[0014]
[Means for Solving the Problems]
That is, the failure diagnosis method according to the present invention is a failure diagnosis method for diagnosing the presence or absence of a failure in a diagnosis target portion such as a wiring or a mounted component of a circuit board. A signal at a diagnosis target portion which is arranged in a non-contact and fixed manner with respect to the diagnosis target portion and is induced in the signal change detection portion by electrostatic coupling or electromagnetic coupling between the diagnosis target portion and the signal change detection portion. The electrical signal corresponding to the change is detected, and the detected electrical signal and the electrical signal corresponding to the signal change at the time of normality or abnormality of the diagnostic target part obtained in advance are subjected to frequency analysis to thereby determine the diagnostic target part. It was decided to diagnose the failure.
[0015]
The failure diagnosis system according to the present invention is a system that performs the failure diagnosis method according to the present invention, and includes a signal change detection unit that is non-contact and fixedly disposed near the diagnosis target part in the vicinity of the diagnosis target part. Detecting an electrical signal corresponding to a signal change in the diagnosis target portion induced in the signal change detection portion by electrostatic coupling or electromagnetic coupling between the diagnosis target portion and the signal change detection portion, and detecting the detected electric signal. A failure diagnosis unit that diagnoses the presence or absence of a failure in a diagnosis target portion by frequency-analyzing a signal and an electric signal corresponding to a signal change in a normal or abnormal time of a diagnosis target portion acquired in advance, And
[0016]
The dependent claims define further advantageous specific examples of the fault diagnosis system according to the present invention. For example, the signal change detection unit is formed of a capacitive reactance component that forms an electrostatic coupling with a diagnosis target portion, or an inductive reactance component that forms an electromagnetic coupling with a diagnosis target portion. It is good to be formed. These may be patterned on a flexible printed circuit board or the like.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0018]
FIG. 1 is a diagram illustrating a basic configuration for realizing the present invention. FIG. 1 shows an example of a layout of a circuit board to be diagnosed and an outline of a failure diagnosis system for the circuit board.
[0019]
As shown in FIG. 1, a circuit board (an example of an electronic circuit system) 10 provided in an electronic circuit system to be diagnosed by the failure diagnosis system 1 has a printed wiring pattern (hereinafter simply referred to as a pattern) not shown. The circuit member 20 is formed and mounted at a predetermined corresponding position. The circuit member 20 may be a passive component such as a resistive element, an inductive element, or a capacitive element, or may be an active component such as a transistor or an IC (Integrated Circuit).
[0020]
The failure diagnosis system 1 is for inspecting the operation of a circuit board 10 on which a predetermined circuit member 20 and a wiring pattern are formed, and a failure diagnosis target site such as the circuit member 20 or the wiring on the circuit board 10. A signal change detection unit (sensor unit) 30 functioning as a detection probe that is non-contact and fixedly disposed with respect to the sensor, an electric signal detected by the signal change detection unit 30, and an electronic circuit acquired in advance. A failure for diagnosing whether or not the electronic circuit system (specifically, the circuit board 10) is normal (the presence or absence of a failure) by comparing the signal with an electric signal corresponding to a signal change when the system is normal or abnormal. And a failure diagnosis unit 90 as a diagnosis device.
[0021]
The failure diagnosing unit 90 receives a signal change by electromagnetic coupling or electrostatic coupling between the signal change detection unit 30 and the circuit member 20 or the wiring pattern when the circuit member 20 is operated by supplying power to the circuit board 10. An electric signal corresponding to a signal change induced by the detection unit 30 is detected. In addition, the frequency of the signal is converted, the frequency spectrum is analyzed, and the presence or absence of a failure of the circuit member 20 is diagnosed by comparing the frequency spectrum with the frequency spectrum intensity distribution in a normal state measured in advance. Further, by comparing the previously measured circuit components and wiring patterns with the frequency spectrum intensity distribution in the abnormal state, it is diagnosed which circuit member 20 has a failure.
[0022]
The signal change detection unit 30 is configured to use a reactance component in order to perform a non-contact test on a diagnostic location. That is, a configuration that detects an electric signal (induced electromotive force) corresponding to a signal change of a signal line induced in a reactance component by electrostatic or electromagnetic coupling between a diagnosis target portion and a reactance component. I do. For example, an inductive reactance component (coil) that generates an induced electromotive force by electromagnetically coupling with a magnetic field generated by a current flowing through a circuit component or a wiring is used. Further, a capacitive reactance component (capacitor) that generates an induced voltage (coupling voltage) by electrostatic coupling (electrostatic coupling) with the signal wiring is used.
[0023]
The signal change detection unit 30 is configured to detect a diagnosis target on the support substrate 4 in a state where the support substrate 4 is disposed substantially in parallel with the circuit board 10 on the support substrate 4 disposed substantially in parallel with the component mounting surface of the circuit board 10. It is provided at a position facing the site.
[0024]
In FIG. 1A, a coil 32a is arranged on the support substrate 4 so as to surround the periphery of the connector 22 arranged on the circuit board 10, and a coil 32b is arranged so as to surround the outer periphery of the circuit board 10. Have been. Further, a coil 32c is arranged so as to surround a specific component (for example, the integrated circuit 24). Further, a configuration (for example, a capacitor 33a) that functions as a capacitance component is arranged so as to be orthogonal to the input / output wiring group 23a connected to the specific connector 23. Although not described, the coils 32d and 32e and the capacitor 33b are arranged so as to face other diagnosis target parts. Hereinafter, each coil constituting the signal change detection unit 30 is collectively referred to as a coil 32, and each capacitor is collectively referred to as a capacitor 33.
[0025]
The support substrate 4 has substantially the same size in the vertical and horizontal directions as the circuit board 10 to be applied. When the circuit board 10 and the support substrate 4 are superimposed substantially in parallel, the coil 32 and the capacitor 33 formed on the support substrate 4 , So that it comes to a position just addressed to the desired location. In addition, the circuit board 10 and the support board 4 are arranged so as to be electrically non-contact and close to each other (to be extremely close to each other). In this way, the electrical signals from the arranged parts are connected to the signal extracting unit 7 and are extracted therefrom to the failure diagnosis unit 90 arranged outside the electronic circuit system (for example, a copying apparatus). To By providing the failure diagnosis unit 90 on the support substrate 4, a self-diagnosis system in which the apparatus itself diagnoses the substrate at the time of starting the copying apparatus or the like may be constructed.
[0026]
The coil 32 forming the signal change detection unit 30 may be a one-turn coil or a plural-turn flat surface so as to surround a predetermined range on the support substrate 4 according to a failure diagnosis target portion (diagnosis target portion). By forming a coil, an electric field is induced in the coil 32 by a magnetic field in a direction perpendicular to the circuit board 10 (a depth direction in the drawing), which is generated when power is supplied to the circuit board 10 and the circuit member 20 operates. It functions as a magnetic field sensing unit for detecting electric power. By arranging the coil windings (wiring forming the coil) along the outer circumference of the diagnosis target portion, it is possible to diagnose a failure in the target portion without being conscious of a specific wiring or terminal.
[0027]
Here, specific examples of the “predetermined range according to the target part of the failure diagnosis” include, for example, the outer periphery of a circuit board on which the target part of the failure diagnosis is mounted, the outer periphery of the target part itself of the failure diagnosis, The outer periphery of the terminal of the site may be considered. Further, when a failure diagnosis is to be performed for each functional block of a circuit, the circuit member 20 is enclosed so as to include more (preferably all) of the circuit members 20 constituting the functional block. When the present invention is applied to an apparatus having a plurality of boards, the outer circumference of an input / output connector for providing a signal interface between a plurality of circuit boards and the outer circumference of a plurality of circuit boards integrated with each other are surrounded. You may make it.
[0028]
Even if the position of the coil as the sensing probe is fixed, the detection range can be set by setting the range surrounded by the coil winding. Conversely, the range surrounded by the coil windings can be set according to the desired range of the failure diagnosis, and the detection range can be freely widened, improving the usability. In the conventional sensing probe, when the probe position is fixed, only the range near the fixed probe position can be detected, which is greatly different from the fact that the detection range has become extremely narrow. The wiring forming the coil is fixedly arranged on the support substrate 4. In order to dispose them fixedly, it is preferable to print them on the support substrate 4. Or you may fix using a taping member or an adhesive member.
[0029]
In addition, as the capacitor 33 constituting the signal change detecting unit 30, a flat metal member is arranged so as to be in non-contact with and intersect with the wiring pattern of the part to be diagnosed so as to function as an electric field sensing unit. I do. The wiring pattern may be sandwiched between two metal plates, or one metal plate may be provided on the wiring pattern. In any case, the metal member is fixedly arranged on the pattern. In order to dispose them fixedly, it is preferable to print them on the support substrate 4. Or you may fix using a taping member or an adhesive member.
[0030]
When the coil 32 and the capacitor 33 are printed on the support substrate 4, the support substrate 4 is, for example, a flexible (flexible) printed circuit board (FPC board) which is a planar insulating plate. Good to use. This is because there is a certain degree of flexibility, which makes it electrically non-contact and is convenient for disposing them close to each other.
[0031]
When there are a plurality of signal change detection units 30 each including the printed coil 32 and the capacitor 33, one terminal of each of the coils 32 and the capacitor 33 may be commonly connected at the end of the support substrate 4. Further, the commonly connected terminals may be grounded outside the support substrate 4. Further, the wiring of each coil 32 and the capacitor 33 is arranged substantially parallel in a state of being close to each other, and the support substrate 4 is routed. Such wiring makes it possible to accurately detect a signal change caused by the coil 32 and the capacitor 33.
[0032]
That is, if the coil 32 and the capacitor 33 forming the signal change detecting unit 30 are formed by the printed wiring pattern, the signal change detecting unit 30 functioning as the sensing unit and the diagnostic object on the circuit board 10 can be used without using a special fixing member. The physical positional relationship with the part can be fixed. Thereby, the state of the induced electromotive force at the time of obtaining the expected value (at the time of normal operation) and during the failure diagnosis can be reliably stabilized. That is, the induced electromotive force, which is a judgment index for failure diagnosis, can be obtained with high accuracy, and the diagnostic performance is also improved. When the circuit board 10 is manufactured, the coil 32 and the capacitor 33 forming the signal change detection unit 30 are patterned at corresponding positions on the support substrate 4 in accordance with the diagnosis target site (in each of a plurality of cases). It should be left.
[0033]
In addition, if a method of arranging the signal change detection unit 30 at a position corresponding to the circuit member 20 component or the wiring pattern on the circuit board 10 on the support substrate 4 is adopted, the support substrate 4 on which the signal change detection unit 30 is arranged can be used. By arranging substantially in parallel with the circuit board 10, the position of the signal change detection unit 30 is aligned with the circuit member 20 or the wiring pattern, and the inspection of the circuit member 20 and the wiring pattern mounted on the circuit board 10 can be performed easily and accurately. Will be able to do it. In addition, since it is not necessary to incorporate the signal change detection unit 30 in the circuit board 10 in advance, and since the signal change detection unit 30 is arranged on the support substrate 4, the signal change detection is performed later according to the component layout of the circuit board 10 to be inspected. It is possible to provide the support substrate 4 on which the unit 30 is arranged, and it is possible to cope with the existing circuit board 10.
[0034]
In addition, since the coil 32 and the capacitor 33 are fixedly arranged by the printed wiring pattern, it is needless to say that no mechanical means is required for bringing the probe closer to the diagnostic location for observation or for bringing the probe closer to the target portion. . This makes it possible to incorporate the sensing unit into the system at low cost without adding a complicated failure diagnosis circuit to the electronic circuit even when monitoring the circuit operation in an arbitrary plurality of ranges, and to perform the circuit operation with high accuracy. A failure diagnosis system that can be monitored can be provided.
[0035]
Whether to use the electromagnetic coupling or the electrostatic coupling (capacitive coupling) when forming the signal change detection unit 30 depends on the frequency components of the current and voltage fluctuations of the signal line. It is good to decide from such a viewpoint. In the form using the electrostatic coupling, it is considered that as the frequency increases, the impedance decreases and the detection sensitivity tends to decrease. On the other hand, in the form using electromagnetic coupling, it is considered that the lower the frequency, the lower the impedance and the lower the detection sensitivity. Therefore, in order to perform accurate detection, electrostatic coupling may be used when the frequency component of the voltage fluctuation of the signal line is mainly low frequency, and electromagnetic coupling may be mainly used when the frequency component is high frequency.
[0036]
However, in the form using the electrostatic coupling, the degree of freedom of the sensitivity adjustment is smaller than that in the electromagnetic coupling. For example, in order to increase the sensitivity, the electrode area must be increased or the distance between the electrode and the diagnosis target must be reduced. The technique of increasing the electrode area cannot be realized unless there is a margin between adjacent parts. In addition, in the technique of reducing the distance between the diagnosis target portion and the target, the distance between the support substrate 4 and the circuit board 10 must be adjusted, and there is a limit in practice. On the other hand, in a mode using electromagnetic coupling, the sensitivity can be adjusted by greatly changing the number of windings, and this method has a certain degree of freedom in pattern formation. Therefore, when considered in total, the signal change detection unit 30 may use the electrostatic coupling regardless of the operating frequency of the diagnosis target part. In practice, this is not always the case, and it is better to decide by cut and try (trial and error).
[0037]
If there is a part of the support substrate 4 where the signal change detection unit 30 is not disposed and there is a component that interferes when the support substrate 4 is brought close to the circuit board 10, a hole is provided at the position of the support substrate 4 corresponding to the component. (Not shown) may be provided so that the component does not contact the support substrate 4.
[0038]
FIG. 1B shows an example of the support substrate 4 in an enlarged manner. Here, two 4-turn coils 32 and two capacitors 33 of the illustrated size are formed in a printed pattern. I have. The support substrate 4 is provided with an insulating layer 4a at the center in the thickness direction d, as shown in the cross-sectional view at the top in the figure, and a pattern 4b forming a coil 32 and a capacitor 33 formed on both surfaces thereof. A structure in which a layer is provided is adopted. Further, a laminate layer 4c in which a signal layer is coated with an insulating resin or the like is provided so as to avoid electrical contact with the outside. The laminate layer 4c is preferably provided on both sides of the support substrate 4, but may be provided on only one side. However, in this example, it is preferable to provide at least on the circuit board 10 side.
[0039]
The coil 32 is formed by spirally wiring both signal layers. In the illustrated example, the two layers are formed so as to rotate in the same direction by two turns, and the both layers are connected by through holes 34. Therefore, in FIG. 1 (B), the two-turn coil formed on the layer on the opposite side of the layer on which the two-turn coil wiring is formed (one-point oblique line in the figure) is passed from the two-turn coil indicated by the solid line to the through-hole. The connection is made via a hole 34.
[0040]
Then, when the coil makes two rotations, it is again guided to the surface layer through the through hole 34. Wirings 36 connected to both ends of the coil 32 are wired in parallel to the vicinity of the signal extraction unit 7 in two pairs, and one of the wirings moves to another layer again through the through hole 34, where it is formed. It is connected to one of the wires of the other signal line pair, and is led to the failure diagnosis unit 90 via the signal extraction unit 7. The other wires are independently guided from the signal extracting unit 7 to the failure diagnosis unit 90.
[0041]
Similarly, in the capacitor 33, a wiring 37 is connected to each of the electrode pairs formed on the front and back surfaces of the support substrate 4, and one of the wirings is guided to the opposite layer via the through hole 34. Then, these wirings 37 are wired in parallel to the vicinity of the signal extraction portion 7 so as to form two pairs, and one of the wirings is moved to another layer again through the through hole 34, where the other signal line pair is connected. It is connected to one of the wires, and is guided to the failure diagnosis unit 90 via the signal extraction unit 7.
[0042]
FIG. 2 is a block diagram showing a configuration example of a failure diagnosis unit 90 that analyzes a signal extracted through the signal extraction unit 7 of the support substrate 4 and diagnoses whether an abnormality has occurred in the circuit board 10. is there.
[0043]
As shown in FIG. 2, the failure diagnosis unit 90 includes an analog multiplexer 91 so as to correspond to a plurality of wiring patterns and circuit members 20 as inspection target parts. Further, the failure diagnosis unit 90 is connected to the coil 32 and the capacitor 33 selected by the analog multiplexer 91, detects a induced electromotive force induced in the coil 32 and the capacitor 33, and amplifies the buffer to a predetermined level. A shaping circuit 93 for shaping an analog signal output from the buffer 92; and an A / D (Analog to Digital) converter 94 for converting the shaped analog signal into digital data.
[0044]
Further, the failure diagnosis unit 90 digitally Fourier-transforms (frequency-converts) the acquired operation signal waveform (induced electromotive force waveform) based on the data digitized by the A / D conversion unit 94, A frequency analysis unit 95 for analyzing a frequency component included in the signal component, and a result of frequency analysis of the induced electromotive force induced in the coil 32 and the capacitor 33 when the circuit board 10 is normal by the frequency analysis unit 95 are stored as expected values. And a storage unit 96 such as a semiconductor memory to be compared with the expected value stored in the storage unit 96 and the result of frequency analysis of the induced electromotive force in the working state by the frequency analysis unit 95 to determine whether there is a failure. And a control unit 99 for controlling the entirety of the failure diagnosis system 1. The control unit 99 controls, for example, switching of the analog multiplexer 91 and the sampling frequency ADCK of the A / D conversion unit 94.
[0045]
As described above, one wiring of each of the coils 32 and the capacitors 33 is commonly connected, guided to the failure diagnosis unit 90, and connected to the ground of the failure diagnosis unit 90. The other wires are individually connected to corresponding input terminals of the analog multiplexer 91 as signal lines. The selection operation of the analog multiplexer 91 is controlled by a control signal MPX from the control unit 99.
[0046]
In the shaping circuit 93, as shown in FIG. 2B, an integrating circuit 93a for integrating the induced electromotive force signal detected by the coil 32 forming a signal change detecting section, and a filter circuit 93b for adjusting a frequency component. Is provided. The integration circuit 93a is provided for returning to the original current waveform because the induced electromotive force signal is a differential waveform of the current flowing through the circuit. That is, the induced electromotive force of the coil is proportional to the change (differential) of the current flowing through the circuit. Therefore, the induced electromotive force is integrated by the integrator, converted into the original current waveform, then A / D converted, and the frequency analysis unit 95 performs frequency conversion.
[0047]
The filter circuit 93b is used to remove unnecessary components in signal analysis, and a low-pass characteristic, a high-pass characteristic, a band-pass characteristic or a band elimination characteristic alone or an arbitrary combination thereof is used. You. The through characteristics may be selectable as needed. For example, in order to prevent the problem of the aliasing distortion component at the time of A / D conversion, it is preferable that the A / D converter 94 has a characteristic of removing a component equal to or more than １ ／ of the sampling frequency.
[0048]
As described later, in the configuration of the present embodiment, the coil 32 forming the signal change detection unit 30 is provided according to the operating frequency of each functional block on the circuit board 10, and an analog multiplexer according to the coil 32 to be diagnosed The sampling frequency of the A / D conversion unit 94 is switched with the sampling frequency of the A / D conversion unit 94. Therefore, it is preferable that the filter circuit 93b has a configuration in which the cutoff characteristic is switched in synchronization with the sampling frequency in the A / D converter 94.
[0049]
The frequency analysis unit 95 checks the frequency value at which a peak occurs by performing a Fourier transform (not shown) on the read waveform instead of simply performing a failure diagnosis by comparing the waveforms. It is provided to analyze whether an abnormality has occurred.
[0050]
In failure diagnosis by waveform analysis, it is necessary to synchronize at the time of signal acquisition in order to compare a waveform pattern in a normal state with a waveform pattern in an actual operation, that is, to acquire an operation waveform at the same time in circuit operation timing. However, this synchronization work is actually difficult, although it depends on the site to be verified. On the other hand, in the failure diagnosis based on the frequency analysis, such a synchronization process is not required, and the operation of acquiring a waveform is greatly facilitated.
[0051]
For example, the frequency analysis unit 95 extracts a frequency spectrum (frequency) of an operation signal waveform of the circuit member 20 in the circuit board 10 as a feature amount. For example, the frequency analysis unit 95 extracts a fundamental frequency component included in the operation signal waveform obtained via the signal change detection unit 30 and a harmonic component thereof. Note that the frequency analysis unit 95 may extract one frequency. There may be more than one. The specific frequency component included in the induced electromotive force signal from the coil 32 and the like varies depending on the circuit, but each functional block has a characteristic frequency component. To identify. In addition, since the characteristic frequency component has a wide frequency range depending on the circuit, the control unit 99 switches the AD conversion sampling frequency, and performs sampling in, for example, a low frequency region and a high frequency region separately.
[0052]
For example, signals from a plurality of planar coils (not shown) 32 and capacitors 33 arranged in functional blocks of the circuit are input to an analog multiplexer 91 and amplified by a buffer 92 having an amplifying function to a predetermined level, and then integrated. The signal is input to the circuit 93a and is converted into digital data by the A / D converter 94. The control unit 99 fetches the induced electromotive force signal of the coil 32 during normal operation, converts the frequency by the frequency analysis unit 95, and stores the normal frequency data in the storage unit 96. Note that feature extraction may be performed as an expected value based on frequency data of the induced electromotive force signal obtained by one measurement, or average data detected a plurality of times may be an expected value.
[0053]
At the time of failure diagnosis, the comparison / determination section 98 operates the circuit, always captures the induced electromotive force signal of the coil 32, and operates under the normal frequency stored in the storage section 96 in accordance with the instruction of the control section 99. The data is always compared with the data (actual data) of the diagnostic sample, which is frequency-converted by the frequency analysis unit 95 for the induced electromotive force signal that is constantly captured, and when there is a difference in the data, the wiring of the circuit board 10 It is determined that a failure has occurred in the mounted component. That is, by diagnosing whether or not the extracted difference is in the same range as compared with the normal state, it is diagnosed whether or not the functional block targeted by the coil 32 and the capacitor 33 is operating normally. Further, by analyzing the state of the read frequency spectrum in detail, it is possible to further identify the details of the failure.
[0054]
When a failure is detected, an alarm unit (not shown) issues an alarm (alarm) or notifies the user of the failure. The alarm unit may be provided inside the device having the failure diagnosis unit 90, or when the failure diagnosis unit 90 is located far away from the device to be diagnosed, the status of the device may be changed via a telephone line or the Internet. May be installed in a place where centralized management is performed, and an alarm may be issued there.
[0055]
<Example of switching power supply circuit>
Next, a switching power supply circuit (switching regulator) as a failure diagnosis target circuit will be described. FIG. 3 is a functional block diagram showing a basic configuration of the switching power supply circuit. The switching power supply circuit 200 includes a primary transformer (input system) 200a on the left side in the figure and a secondary system (output system) on the right side in the figure by a switching transformer 210 having a primary winding 210a and a secondary winding 210b. ) 200b and a control system 200c for drive-controlling the switching transformer 210.
[0056]
The primary system 200a includes, for example, a noise filter 202 provided for an alternating current (Alternating Current) of 100 to 120 V at 50 Hz or 60 Hz, an inrush current limiting circuit 204 for limiting an inrush current during a switching operation, and a rectifier (not shown). An input rectifying / smoothing circuit 206 including an element (such as a diode) and a smoothing capacitor for rectifying and smoothing an AC input to obtain a DC voltage of a predetermined voltage; a switching circuit 208 for switchingly driving a primary winding 210a of a switching transformer 210; Is provided.
[0057]
The secondary system 200a rectifies and smoothes the output of the secondary winding 210b of the switching transformer (transformer) 210 to obtain a predetermined DC voltage, and first and second output rectifying and smoothing circuits 222 and 224; And a control circuit 226 for controlling the second output rectifying / smoothing circuit 222. The first output rectifying / smoothing circuit 222 includes a rectifying element (such as a diode) (not shown) and a smoothing capacitor, and obtains, for example, DC 24 V as an output voltage. The second output rectifying / smoothing circuit 224 includes a switching element (not shown), a rectifying element (such as a diode), a smoothing capacitor, and the like, and obtains, for example, 5 V DC as an output voltage by a switching operation. The drive center frequency of the output rectifying / smoothing circuit 224 by the control circuit 226 is set to several tens kHz to several hundred kHz. For example, it is set to 50 kHz.
[0058]
The control system 200c includes a feedback circuit 232 for monitoring the output voltage of the output rectifying / smoothing circuit 222, and a switching transformer 210 via a switching circuit 208 such that a voltage corresponding to the output voltage obtained by the feedback circuit 232 maintains a constant value. , And an overcurrent protection circuit 236 that protects the switching circuit 208 and the switching transformer 210 from excess current during circuit operation.
[0059]
There are various methods of the switching circuit 208. The driving center frequency of the switching circuit 208 by the control circuit 234 is set to several tens kHz to several hundred kHz. For example, it is set to 120 kHz.
[0060]
The overcurrent protection circuit 236 transmits a monitor voltage reflecting the operation current to the control circuit 234. The control circuit 234 stops the operation of the switching circuit 208 when the monitoring voltage goes out of the predetermined range, and prevents the circuit from being broken. Note that the control system 200c is not limited to the overcurrent protection function, and when the voltage corresponding to the output voltage obtained by the feedback circuit 232 is out of the predetermined range, the operation of the switching circuit 208 is stopped so that the circuit is destroyed. It also has an overvoltage protection function to prevent power failure.
[0061]
FIG. 4 is a diagram showing an example of a component layout of the switching power supply circuit 200 shown in FIG. 3 and an embodiment in which a failure diagnosis support substrate 4 is arranged in the switching power supply circuit 200. Here, FIG. 4A is a side view of the switching power supply circuit 200 and the support substrate 4 arranged on the circuit board 10, and FIG. 4B is a view showing a coil 32 as a detection probe provided on the support substrate 4. It is a top view which shows the arrangement | positioning outline | summary. Although an example in which only the coil 32 is used as the print coil 30 is shown, it goes without saying that a capacitor 33 can be used.
[0062]
As shown in FIG. 1, the coil 32 as the detection probe is formed by spirally wiring the FPC board as the support board 4. For example, for each functional block in the block diagram shown in FIG. 3, the coil 32 is formed by arranging a winding in a printed wiring pattern so as to surround an area where components constituting the functional block are arranged. . Although it is not possible to clearly divide the circuit in functional block units due to the restrictions on the arrangement of components and the restrictions on the printed wiring, it is only necessary that the circuits be roughly surrounded in functional block units.
[0063]
The (planar) coil 32 is arranged on the circuit board 10 of the switching power supply circuit 200 as shown in FIG. The distance between the coil and the printed circuit board should be as close as possible. Only in this way, it is possible to detect a current waveform for each circuit functional block without adding any circuit to the circuit to be diagnosed.
[0064]
For example, as shown in FIG. 3, the circuit board 10 on which the switching power supply circuit 200 of the forward converter type is divided into 11 functional blocks (a noise filter 202, an inrush current limiting circuit 204, an input rectifying and smoothing circuit). 206, switching circuit 208, switching transformer 210, etc.). Since a circuit is usually arranged according to a circuit diagram, it is possible to roughly surround a functional block. The FPC board shown in FIG. 4B in which the coil 32 is formed at a position corresponding to the functional block is placed in parallel and close to the circuit board 10 of the switching power supply circuit 200 as shown in FIG. 4A.
[0065]
<Basic principle of frequency analysis>
FIG. 5 is a conceptual diagram illustrating a method of performing a frequency analysis on the induced electromotive force signal of the coil 32 and performing a failure diagnosis. Here, a diagnosis case for the switching power supply circuit 200 shown in FIG. 4 will be described. FIGS. 5A to 5D show frequency data (frequency spectrum) of a coil signal for the switching power supply circuit 200.
[0066]
The A / D converter 94 enables sampling in two bands, a low frequency region and a high frequency region. In the low frequency region, a frequency spectrum can be obtained around the commercial frequency (50 Hz). The high frequency region is set to be centered on the switching frequency (for example, 100 kHz). That is, in the switching power supply circuit 200, since the AC input is 50 Hz and the switching frequency is wide, for example, several tens Hz to several hundreds kHz, the A / D converter 94 performs sampling in two regions of a low frequency region and a high frequency region. The frequency is converted by the frequency analysis unit 95.
[0067]
The low frequency region includes harmonic components such as 100 Hz and 200 Hz, including 50 Hz which is the fundamental frequency of AC input. Similarly, the high-frequency region includes 50 kHz and 120 kHz, which are the fundamental frequencies of the two switching frequencies, and harmonic components thereof. FIG. 5A shows an example of a frequency spectrum when the switching power supply circuit 200 is in a normal state.
[0068]
Here, for example, if a failure occurs in the noise filter 202 portion (AC input portion), the entire circuit does not operate. Therefore, as shown in FIG. 50 kHz is not detected. Therefore, when such a comparison result is obtained as compared with the normal state, it can be diagnosed that the AC input unit has failed.
[0069]
Further, when the control circuit 234 of the first output system (output rectifying / smoothing circuit 222) fails, as shown in FIG. 5C, the current due to the AC input reaches the primary side of the switching transformer 210. Because of the flow, 50 Hz or the like is detected in the low frequency region, but 120 kHz or the like, which is the switching frequency of the first output system, is not detected in the high frequency region. Further, since the second output system (output rectifying / smoothing circuit 224) is generated from the first output system, 50 kHz which is the switching frequency of the second output system is not detected. Therefore, when such a comparison result is obtained as compared with the normal state, it can be diagnosed that the control circuit 234 of the first output system has failed.
[0070]
When only the control circuit 236 of the second output system (output rectifying / smoothing circuit 224) fails, as shown in FIG. 5D, only the switching frequency of 50 kHz is not detected, and the others are normal. The detection is the same as at the time. Therefore, when such a comparison result is obtained as compared with the normal state, it can be diagnosed that the control circuit 226 of the second output system has failed.
[0071]
In this way, by comparing the fluctuation of the frequency component corresponding to the operation of the circuit function block with the normal state, a malfunctioning function block can be specified. Further, in a case where the failure is not a complete failure (defective state), there is a spectrum of each frequency component, but there may be a case where the intensity is different from that in the normal state. In such a case, by analyzing the intensity pattern, it is possible to specify a functional block in a defective state. That is, since the spectrum intensity distribution differs between the normal state and the abnormal state, the presence or absence of an abnormality and the state of the abnormality can be determined by analyzing the difference.
[0072]
Since the basic frequency of operation of the switching power supply circuit 200 is relatively clearly divided according to the functional blocks, it is convenient for judging the presence or absence of a failure by frequency analysis. However, the applicable range of the method of performing a failure diagnosis by frequency analysis as in the present embodiment is not necessarily limited to the switching power supply circuit.
[0073]
In addition, by referring to not only the fundamental frequency but also the state of its harmonics, it is possible to make a more detailed comparison, which is advantageous for determining an abnormal state. For example, focusing on the frequency spectrum of an integral multiple of 50 Hz, if this frequency spectrum is not observed from the coil arranged in the vicinity of the AC input to the input rectification smoothing circuit 206 to the switching transformer 210, it is diagnosed as a failure immediately after the AC input. Similarly, if no switching frequency spectrum is observed from the coil near the control circuit 234, it is diagnosed that the control circuit 234 has failed. By combining a signal of a plurality of coils with a combination of low frequency / high frequency, spectrum, presence / absence of load, etc., a more accurate failure diagnosis can be performed.
[0074]
<Example of frequency analysis for switching power supply circuit>
Next, an embodiment of frequency analysis for a switching power supply circuit will be described. FIG. 6 is a schematic circuit diagram of the switching power supply circuit 200 targeted in the present embodiment. Functional parts equivalent to the functional blocks shown in FIG. 3 are denoted by the same reference numerals.
[0075]
As shown in FIG. 6B, a control integrated circuit (model number M51195P) manufactured by Mitsubishi Electric Corporation was used as the control circuit 234. Its peripheral components are equivalent to the standard application of this integrated circuit. Note that, unlike the switching power supply circuit 200 shown in FIG. 3, only one output system is provided. The details of the other circuits are omitted.
[0076]
In each functional block, a failure diagnosis coil 32 is provided so as to surround the periphery of each functional block. Here, the first coil 32 (hereinafter referred to as the coil # with the number ＠) for the noise filter 202, the coil 2 for the inrush current limiting circuit 204, and the input rectifying / smoothing circuit 206 The coil 3 is provided for the overcurrent protection circuit 236, and the coil 5 is provided for the switching circuit 208. Further, a coil 6 is provided for the control circuit 234, a coil 7 for the switching transformer 210, a coil 8 for the output rectifying and smoothing circuit 222, and a coil 9 for the feedback circuit 232.
[0077]
FIG. 7 shows a frequency spectrum showing the result of frequency analysis after integrating the induced electromotive force signal of the coil 1 provided in the noise filter 202 of the switching power supply circuit 200 shown in FIG. The noise filter 202 is a member of an AC input system, and when the circuit is normal, as shown by a circle in FIG. 7A, exhibits relatively high-intensity FFT power at 50 Hz and 100 Hz. Also, a large number of third-order or higher harmonic components of 50 Hz can be found. On the other hand, FIG. 7B shows a state in which the circuit has failed. As can be seen from the figure, not only 50 Hz and 100 Hz but also 50 Hz or higher harmonic components have almost no FFT power.
[0078]
FIG. 8 shows a frequency spectrum showing the result of frequency analysis after integrating the induced electromotive force signal of the coil 6 provided in the control circuit 234 of the switching power supply circuit 200 shown in FIG. When the circuit is normal, as shown by a circle in FIG. 8A, relatively high-intensity FFT power is exhibited at a portion of 120 kHz. On the other hand, FIG. 8B shows a state where the same failure as in FIG. 7B has occurred. As can be seen from the figure, the FFT power almost disappears in the 120 kHz portion.
[0079]
From the diagnosis results of FIGS. 7 and 8, at the time of this failure, since the switching frequency is not detected not only in the low frequency side of 50 Hz, but also in the high frequency region, it can be diagnosed that the noise filter 202 has failed.
[0080]
As described above, as in the above-described embodiment, the frequency of the operation signal of the circuit obtained by the signal change detection unit 30 is analyzed (the signal is frequency-converted and the frequency spectrum is analyzed), so that the circuit member 20 is analyzed. It is possible to diagnose the presence or absence of a failure. A simple and low-cost configuration in which a capacitance component or an inductance component, which is an example of a reactance component provided as the signal change detection unit 30, is fixedly provided using a taping member, an adhesive member, a printed wiring pattern, or the like. The functioning reactance component and the physical positional relationship between the circuit board and the cable can be fixed. Thus, the state of the detection signal during the failure diagnosis can be reliably stabilized. That is, it is possible to accurately acquire a signal induced in a reactance component serving as a determination index for failure diagnosis, and to improve diagnostic performance.
[0081]
In addition, instead of comparing the induced electromotive force waveform itself during normal operation and actual operation, the waveform is frequency-analyzed, so that, for example, diagnosis is divided into low frequency and high frequency, and the combination of spectrum intensities is diagnosed in detail. It is also possible to perform a diagnosis by combining operation verification with and without a load or the like, thereby enabling more accurate failure diagnosis. Although the number of circuit elements in the frequency analysis part increases for the waveform diagnosis, the circuit configuration of the waveform diagnosis can be used for other cases. Therefore, it is possible to provide a failure diagnosis system that can be incorporated into a system at low cost and that can monitor circuit operation with high accuracy without adding a complicated failure diagnosis circuit.
[0082]
In addition, at the time of diagnosis, the reactance component is fixedly arranged with respect to the diagnosis target site.Therefore, it is necessary to provide a mechanical means for bringing the probe closer to the diagnosis site for observation or for bringing the probe closer to the target site. do not do. Even if a reactance component having a simple structure composed of a coil winding, a plate electrode, and the like is provided at each location according to a diagnosis target portion, the cost does not increase significantly.
[0083]
As a result, it is possible to provide a user-friendly failure diagnosis mechanism in terms of cost and flexibility in setting a target part for failure diagnosis.
[0084]
<Another configuration example of coil>
FIG. 9 is a diagram showing another configuration example of the coil 32 forming the detection probe. The winding of the coil 32 shown in the above embodiment surrounds the detection target portion so as to detect a magnetic field in a direction perpendicular to the circuit board 10 generated from the circuit member 20 and the wiring pattern of the circuit board 10, A pattern is formed in a plane on the support substrate 4 to form a planar coil. On the other hand, this modified example detects a magnetic field generated in parallel with the circuit board 10 from the circuit member 20 or the wiring pattern of the circuit board 10, for example, a spiral coil (spiral coil) adjacent to the wiring pattern 80. A coil-shaped inductor) 70 is disposed.
[0085]
Although the wiring patterns 80a and 80b are mainly microstrip lines, a magnetic field shown in FIG. 9A is generated by a current flowing through the wiring. As shown in FIG. 9A, a spiral coil 70 having a magnetic path length LEN substantially equal to the width PW of the wiring pattern is brought into close proximity to the wiring pattern 80a to be inspected and flows through the wiring pattern 80a. It is arranged perpendicular to the current direction.
[0086]
In this case, only the weak magnetic field of the other wiring pattern 26b adjacent to the wiring pattern 80a to be inspected passes through the spiral coil 70 having the coil diameter W because of the distance, and one of the wirings to be inspected. Only the magnetic field caused by the current of the pattern 80a efficiently passes through the spiral coil 70. Then, the change in current of only the wiring pattern 80a to be inspected can be monitored by the induced electromotive force of the spiral coil 70. This makes it possible to diagnose a failure not in units of functional blocks but in units of wiring patterns.
[0087]
For example, assuming that a magnetic flux generated by the current flowing through the wiring pattern 80 and passing through the spiral coil 70 is Φ, the induced electromotive voltage V induced at both ends of the spiral coil 70 is obtained by Expression (1).
[0088]
V = dΦ / dt (1)
Note that any device may be used as long as it can read the induced electromotive force generated in the spiral coil 70 as the magnetic field sensing unit, and is not limited to a mode in which the induced electromotive voltage generated at the open end of the spiral coil 70 is read as shown in Expression (1). Instead, the current flowing through the spiral coil 70 may be read.
[0089]
In order to reduce the influence of the adjacent wiring, it is preferable to prevent the magnetic field from the wiring pattern 80b adjacent to the wiring pattern 80a to be inspected from passing through the spiral coil 70 as much as possible. For this purpose, it is preferable that the magnetic path length of the spiral coil 70 is substantially equal to or less than the width of a predetermined wiring pattern corresponding to a target part of the circuit board for failure diagnosis.
[0090]
In order to perform an accurate inspection, it is desirable to fix the physical positional relationship between the wiring pattern 80a to be inspected and the spiral coil 70. When arranging the spiral coil 70 in a fixed manner with respect to a predetermined wiring pattern corresponding to the target part of the failure diagnosis, it is preferable to form a printed wiring pattern on an outer layer (front or back surface) or an inner layer on the circuit board.
[0091]
Alternatively, a coil formed in advance by winding may be fixed substantially closely using a fixing member such as a taping member so as to be electrically non-contact. In this case, for example, after forming a coil in which the cross section of the opening of the magnetic path is substantially circular or elliptical, the coil is flattened, and the wiring pattern of the diagnosis target portion is placed at a position corresponding to the diagnosis target portion. And the flat surface of the coil may be fixedly arranged so as to face each other.
[0092]
For example, as shown in FIG. 9B, the circuit board 10 has two insulators 87 laminated, and a wiring pattern 80 is printed on the surface of one (the right side in the figure) of the insulator 87a. I have. The spiral coil 70 is formed by printed wiring patterns formed on both sides of the insulator 87b on the opposite side (the left side in the figure) opposite to the wiring pattern 26 with the insulator 87a interposed therebetween. That is, the spiral coil 70 is formed on the same substrate as the circuit board (printed wiring board) 10 that constitutes the circuit.
[0093]
Specifically, the spiral coil 70 passes through a plurality of conductors (a plurality of first conductors 134 and a plurality of second conductors 135, each of which is formed by cutting out a part of two conductor layers facing each other) through holes (a plurality of conductors). Via holes 136 are used for connection in a predetermined order (to form a winding). An insulator 137c similar to the insulator 87b is arranged between the through holes 136. This improves the stability of the arrangement.
[0094]
Further, as shown in FIG. 9C, similarly to the above-described embodiment, the wiring pattern of the diagnosis target portion and the flat surface of the coil are opposed to each other on the support substrate 4 different from the circuit substrate 10. May be arranged in close proximity to each other.
[0095]
When forming the spiral coil, a structure may be employed in which the outside of the insulator 137c or the through hole 136 disposed between the through holes 136 in the insulator 37b is replaced with an insulating magnetic material layer. That is, a structure in which an insulating magnetic material is arranged in a layer at a part between two opposing conductor layers (coil layers) used to configure the spiral coil 70 may be used.
[0096]
As a technique for arranging an insulating magnetic material in layers between two conductor layers, for example, a technique described in Japanese Patent Application Laid-Open No. 11-40915 may be used. For example, an insulating magnetic material may be used as a magnetic material for forming the insulating magnetic material layer. As the insulating magnetic material, for example, a mixture of Ni-Zn based ferrite fine powder, Mn-Zn based ferrite fine powder, Sendust fine powder, or Li based ferrite fine powder and an insulating solvent may be used. The insulating solvent includes an epoxy-based insulating solvent.
[0097]
As an insulating magnetic body disposed between two coil layers, a metal foil having an insulating coating on both surfaces may be used. Metal foils with an insulating coating on both sides include an amorphous magnetic foil multilayer strip.
[0098]
Further, the entire insulating layer 137b may be replaced with an insulating magnetic layer, not limited to the portion of the insulator 137c disposed between the through holes 136 in the insulating layer 137b. In other words, a structure in which an insulating magnetic material is disposed in a layered manner over the entire area between two opposing conductor layers (coil layers) used to configure the spiral coil 70 may be used.
[0099]
As described above, the inductance of the spiral coil 70 is reduced by arranging the insulating magnetic material in a part or the entire area between the two opposing conductor layers (coil layers) used to configure the spiral coil 70. Since it can be increased, the detection sensitivity of the spiral coil 70 can be improved, and a more accurate failure diagnosis system can be constructed.
[0100]
The above-described series of failure diagnosis processes can be executed by hardware, but can also be executed by software. When a series of failure diagnosis processing is executed by software, a program constituting the software is implemented by a computer (such as an embedded microcomputer) built into dedicated hardware, or a function such as a CPU, a logic circuit, or a storage device. (System On A Chip: System On Chip) that realizes a desired system by mounting the on a single chip, or a general-purpose personal computer that can execute various functions by installing various programs It is installed from a recording medium in a computer or the like.
[0101]
This recording medium causes a reading device provided in a hardware resource of a computer to change the state of energy, such as magnetism, light, or electricity, in accordance with the description content of the program, and a signal format corresponding thereto. Thus, the program description can be transmitted to the reading device. For example, separately from a computer, a magnetic disk (including a flexible disk) on which a program is recorded, an optical disk (CD-ROM (Compact Disc-Read Only Memory), a DVD ( Digital Versatile Disc), a magneto-optical disc (including an MD (Mini Disc)), or a package medium (portable storage medium) such as a semiconductor memory, as well as being pre-installed in a computer. It may be constituted by a ROM or a hard disk in which a program is provided and provided to the user in a state. Alternatively, a program constituting software may be provided through a wired or wireless communication network.
[0102]
FIG. 10 is a diagram illustrating an example of a hardware configuration when a failure diagnosis system is configured as software using a CPU and a memory, that is, when a failure diagnosis system is configured using an electronic computer such as a personal computer. is there.
[0103]
The computer system 900 constituting the failure diagnosis unit 90 includes a CPU 902, a ROM (Read Only Memory) 904, a RAM 906, and a communication I / F (interface) 908. The RAM 906 includes an area for storing captured image data.
[0104]
Further, for example, recording / reading for reading / recording data from / to a storage medium such as a memory reading unit 907, a hard disk device 914, a flexible disk (FD) drive 916, or a CD-ROM (Compact Disk ROM) drive 918. An apparatus may be provided. Data is exchanged between each hardware through a data bus.
[0105]
The hard disk device 914, the FD drive 916, or the CD-ROM drive 918 is used, for example, for registering program data for causing the CPU 902 to execute processing such as frequency conversion and frequency analysis by software. Further, the hard disk device 914 includes an area for storing processing target data.
[0106]
The communication I / F 908 mediates the exchange of communication data with a communication network such as the Internet. Further, the computer system 900 includes an I / F unit 930 that functions as an interface with the circuit board 10.
[0107]
It should be noted that not all the processing of each functional part (particularly, the comparing and judging part 98) of the failure diagnosis unit 90 shown in the above embodiment is performed by software, but a processing circuit 940 that performs a part of these functional parts by hardware. May be provided.
[0108]
On the circuit board 10, an analog multiplexer 950, a buffer circuit 952, and an A / D converter 954 are arranged as the circuit member 20 constituting a part of the failure diagnosis unit 90. For example, an analog multiplexer 950 is provided so as to correspond to a plurality of wiring patterns 80 as inspection target parts. The above-described signal change detection unit 30 (for example, the coil 32 or the capacitor 33; only the coil is shown in the drawing) is disposed on each of the wiring patterns 80 to be inspected on the circuit board 10.
[0109]
One terminal of each signal change detection unit 30 is commonly connected to the ground, and the other terminal is individually connected to a corresponding input terminal of the analog multiplexer 950. The selection operation of the analog multiplexer 950 is controlled by a control signal MPX from the I / F unit 930 on the computer system 900 side.
[0110]
An output signal of the analog multiplexer 950 is converted into digital data by an A / D converter 954 via a buffer circuit 952. The digital detection data output from the A / D conversion unit 954 is input to the I / F unit 930 of the computer system 900 via an output buffer (not shown).
[0111]
The computer system 900 having such a configuration can be the same as the basic configuration and operation of the failure diagnosis unit 90 shown in the above embodiment. Further, a program for causing a computer to execute the above-described processing is distributed through a recording medium such as a CD-ROM 922. Alternatively, the program may be stored in FD 920 instead of CD-ROM 922. Further, an MO drive may be provided, and the program may be stored in the MO, or the program may be stored in another recording medium such as a nonvolatile semiconductor memory card 924 such as a flash memory.
[0112]
Further, the program may be downloaded from another server or the like via a communication network such as the Internet, acquired, or updated. As a recording medium, in addition to the FD 920 and the CD-ROM 922, an optical recording medium such as a DVD, a magnetic recording medium such as an MD, a magneto-optical recording medium such as a PD, a tape medium, a magnetic recording medium, an IC card, A semiconductor memory such as a miniature card can be used.
[0113]
The FD 920, the CD-ROM 922, or the like as an example of the recording medium can store some or all of the functions of the processing in the failure diagnosis unit 90 described in the above embodiment. That is, the software installed in the RAM 906 or the like includes a functional unit such as the comparison / determination unit 98, the feature amount extraction unit, or the frequency analysis unit as software, like the failure diagnosis unit 90 described in the above embodiment. Such software may be stored in a portable storage medium such as a CD-ROM or FD as application software for failure monitoring, or distributed via a network.
[0114]
When the failure diagnosis unit 90 is configured by a computer, the CD-ROM drive 918 reads data or a program from the CD-ROM 922 and passes it to the CPU 902. Then, the software is installed from the CD-ROM 922 to the hard disk device 914. The hard disk device 914 stores data or a program read by the FD drive 916 or the CD-ROM drive 918, data created by the CPU 902 executing the program, and reads the stored data or program to read the CPU 902. Pass to.
[0115]
The software stored in the hard disk device 914 is read by the RAM 906 and executed by the CPU 902. For example, the CPU 902 executes the above processing based on programs stored in the ROM 904 and the RAM 906, which are examples of a recording medium. For example, first, during normal operation, the induced electromotive force signal of the signal change detection unit 30 is fetched while being switched by the analog multiplexer 950, and stored in a storage device such as the hard disk device 914. Next, while the circuit is actually operated and the signal of the signal change detection unit 30 is constantly captured, the normal waveform stored in the hard disk device 914 or the like and the constantly captured waveform are read in accordance with the instruction of the CPU 902. The frequency is always compared or the waveform is converted, and when a difference occurs between the actual operation and the normal operation, a failure is determined and an alarm is issued or the details of the failure are notified. Further, by analyzing in detail the change state of the waveform and the state of the frequency spectrum at the time of the failure, the details of the failure are identified in more detail.
[0116]
As described above, the present invention has been described using the embodiment. However, the technical scope of the present invention is not limited to the scope described in the embodiment. Various changes or improvements can be made to the above-described embodiment without departing from the spirit of the invention, and embodiments with such changes or improvements are also included in the technical scope of the present invention.
[0117]
Further, the above embodiments do not limit the invention according to the claims (claims), and all combinations of the features described in the embodiments are not necessarily essential to the means for solving the invention. Absent. The embodiments described above include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent features. Even if some components are deleted from all the components shown in the embodiment, as long as the effect is obtained, a configuration from which some components are deleted can be extracted as an invention.
[0118]
For example, in the coil (including the spiral coil) and the capacitor described in the above-described embodiment, a mode in which they are formed on a printed circuit board so as to correspond to a diagnosis target portion has been described. It may be formed by. For example, a coil formed in advance by winding may be fixed using a fixing member such as a taping member so as to be electrically non-contact.
[0119]
In the above-described embodiment, the coil and capacitor to be sensed are arranged so as to be located around the circuit portion when the flexible board is brought close to the circuit board. However, this is installed at a position where the most necessary information can be sensed. Means that.
[0120]
Further, in the above-described embodiment, it is suggested that a member forming a coil or a capacitor be a flexible substrate and fixed to a circuit substrate, a cable, or the like. The circuit board or the cable to be inspected may be housed in a box assembled and inspected.
[0121]
【The invention's effect】
As described above, according to the present invention, the signal change detection unit is disposed in a non-contact and fixed manner with respect to the diagnosis target portion in the vicinity of the diagnosis target portion, and is disposed between the diagnosis target portion and the signal change detection unit. Detects an electrical signal corresponding to a signal change in the diagnosis target site induced by the signal change detection unit due to the combination of the signal change detection unit, and detects the detected electrical signal and the signal change in the normal or abnormal state of the diagnosis target site acquired in advance. The frequency of an electric signal corresponding to the above is analyzed to determine whether or not a failure has occurred in a diagnosis target portion.
[0122]
Therefore, synchronization is performed at the time of signal acquisition in order to compare the frequency pattern in the normal state with the frequency pattern in the actual operation, that is, there is no need to acquire operation waveforms at the same time in the timing of circuit operation, and the task of waveform acquisition becomes easy. Become. In addition, the failure state can be diagnosed in detail by frequency analysis.
[0123]
In addition, since the signal change detection unit is fixedly arranged, there is no need for a mechanical means for bringing the probe closer to the diagnostic location for observation or for bringing the probe closer to the target part. Even if a signal change detection unit having a simple structure using a method such as pattern formation is provided at each location in accordance with the diagnosis target site, the cost does not increase much.
[0124]
As a result, it is possible to provide a user-friendly failure diagnosis mechanism in terms of cost and flexibility in setting a target part for failure diagnosis.
[0125]
Therefore, in the failure diagnosis of the electronic circuit board, it is possible to construct a failure diagnosis system that can be incorporated into the system at low cost and that can monitor the circuit operation with high accuracy without adding a complicated failure diagnosis circuit.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a basic configuration for realizing the present invention.
FIG. 2 is a block diagram illustrating a configuration example of a failure diagnosis unit.
FIG. 3 is a functional block diagram illustrating a basic configuration of a switching power supply circuit.
4 is a diagram showing an example of a component layout of the switching power supply circuit shown in FIG. 3 and a form in which a support substrate is arranged on a circuit board.
FIG. 5 is a conceptual diagram illustrating a method of performing a failure diagnosis by frequency-analyzing an induced electromotive force signal of a coil.
FIG. 6 is a schematic circuit diagram of a switching power supply circuit targeted in the present embodiment.
7 is a diagram illustrating a frequency spectrum of a coil provided in a noise filter of the switching power supply circuit illustrated in FIG. 6;
8 is a diagram showing a frequency spectrum of a coil provided in a control circuit of the switching power supply circuit shown in FIG.
FIG. 9 is a diagram showing another configuration example of the coil forming the detection probe.
FIG. 10 is a diagram illustrating an example of a hardware configuration when a failure diagnosis system is constructed using an electronic computer.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Fault diagnosis system, 4 ... Support board, 10 ... Circuit board, 20 ... Circuit member, 30 ... Signal change detection part, 32 ... Coil, 33 ... Capacitor, 70 ... Spiral coil, 90 ... Fault diagnosis part, 91 ... Analog Multiplexer, 92, buffer, 93, waveform shaping unit, 93a, integrating circuit, 93b, filter circuit, 94, A / D conversion unit, 95, frequency analysis unit, 96, storage unit, 98, comparison and judgment unit, 99, control Department

Claims (16)

A failure diagnosis method for diagnosing the presence or absence of a failure in a diagnostic target portion such as a circuit board wiring or a mounted component,
In the vicinity of the diagnosis target portion, a signal change detection unit is disposed in a non-contact and fixed manner with respect to the diagnosis target portion,
Detecting an electrical signal corresponding to a signal change in the diagnosis target portion induced in the signal change detection portion by coupling between the diagnosis target portion and the signal change detection portion,
A frequency analysis is performed on the detected electric signal and an electric signal corresponding to the signal change at the time of normality or abnormality of the diagnosis target portion which has been obtained in advance, thereby diagnosing the failure of the diagnosis target portion. A failure diagnosis method characterized by the above-mentioned. A failure diagnosis system for diagnosing the presence or absence of a failure in a diagnosis target portion such as a wiring of a circuit board or a mounted component,
A signal change detection unit non-contact and fixedly arranged with respect to the diagnosis target site in the vicinity of the diagnosis target site,
Detecting an electrical signal corresponding to a signal change of the diagnosis target portion induced by the signal change detection portion by coupling between the diagnosis target portion and the signal change detection portion, and detecting the detected electrical signal; A failure diagnosis unit that diagnoses the presence or absence of a failure in the diagnosis target portion by frequency-analyzing an acquired electric signal corresponding to the signal change at the time of normality or abnormality of the diagnosis target portion. A failure diagnosis system characterized by the above. The failure diagnosis system according to claim 2, wherein the signal change detection unit is formed of a capacitive reactance component that forms an electrostatic coupling with the diagnosis target part. The failure diagnosis system according to claim 2, wherein the signal change detection unit is formed of an inductive reactance component that forms an electromagnetic coupling with the diagnosis target part. The failure diagnosis system according to claim 3, wherein the reactance component is formed by a printed wiring pattern on a circuit board. The signal change detection unit is a coil that forms the inductive reactance component, and a winding is disposed so as to surround most of the functional block for each functional block of a circuit as the diagnosis target portion. The failure diagnosis system according to claim 4, wherein: The signal change detection unit is a coil that forms the inductive reactance component, and the magnetic path length of the coil is substantially the same as or less than the width of the diagnosis target portion, and the coil further faces the target. The failure diagnosis system according to claim 4, wherein the failure diagnosis system is formed by a spiral coil that is arranged perpendicularly and fixedly to a direction of a current flowing through a part. The spiral coil vertically connects a plurality of conductors formed by cutting out a part of two opposing conductor layers formed by a printed wiring pattern on a predetermined circuit board, and each of the plurality of conductors. It is composed of through holes,
8. The failure diagnosis system according to claim 7, wherein a magnetic path length of the spiral coil is set to be substantially equal to or less than a predetermined wiring pattern corresponding to the diagnosis target part. The predetermined circuit board on which the spiral coil is formed and the circuit board on which the diagnosis target portion is mounted are each configured integrally, and are multilayer boards formed by stacking a plurality of boards.
9. The failure diagnosis system according to claim 8, wherein the spiral coil is formed by a printed wiring pattern of two layers of the multilayer board. The signal change detection unit is formed on a printed wiring board different from a circuit board on which the diagnosis target portion is mounted,
The printed circuit board on which the signal change detection unit is formed is electrically non-contact and close to the circuit board on which the diagnosis target portion is mounted such that the signal change detection unit faces the diagnosis target portion. 3. The failure diagnosis system according to claim 2, wherein the failure diagnosis system is arranged in a manner to be arranged. The failure diagnosis system according to claim 10, wherein the printed wiring board on which the signal change detection unit is formed is a flexible wiring board. The failure diagnosis unit, an integration unit that integrates the induced electromotive force signal detected by the signal change detection unit,
A conversion unit that converts the induced electromotive force signal integrated by the integration unit into a digital value with different sampling clocks in a high frequency region and a low frequency region,
The failure diagnosis system according to claim 2, further comprising: a frequency conversion unit configured to convert a frequency of the induced electromotive force signal digitized by the conversion unit. A failure diagnosis system for diagnosing the presence or absence of a failure in a diagnosis target portion such as a wiring of a switching power supply circuit or a mounted component,
A coil disposed in a non-contact and fixed manner near the diagnosis target site in the vicinity of the diagnosis target site,
An electrical signal corresponding to a signal change of the diagnostic target portion induced in the coil by electromagnetic coupling between the diagnostic target portion and the coil is detected, and the detected electrical signal is acquired in advance. A failure diagnosis unit for performing frequency analysis of an electrical signal corresponding to the signal change when the diagnosis target portion is normal at the time of diagnosis to determine whether there is a failure in the diagnosis target portion. system. The coil is formed on a printed wiring board different from the circuit board on which the diagnosis target portion is mounted,
The printed wiring board on which the coil is formed is electrically non-contact and disposed close to the circuit board on which the diagnosis target portion is mounted so that the coil faces the diagnosis target portion. The failure diagnosis system according to claim 13, wherein: The failure diagnosis system according to claim 14, wherein the printed wiring board on which the coil is formed is a flexible wiring board. A failure diagnostic device for diagnosing the presence or absence of a failure in a diagnostic target portion such as a wiring of a circuit board or a mounted component,
A signal from a signal change detection unit that is arranged in a non-contact and fixed manner in the vicinity of the diagnosis target region in a non-contact manner with respect to the diagnosis target region, and is coupled between the diagnosis target region and the signal change detection unit. A buffer that receives an electric signal corresponding to a signal change of the diagnosis target portion induced in the signal change detection unit,
By comparing the electrical signal received by the buffer and the previously acquired electrical signal corresponding to the signal change at the time of normality or abnormality of the diagnosis target portion with frequency analysis and comparison, the failure of the diagnosis target portion is performed. A failure diagnosis unit for diagnosing presence / absence of a failure.

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