JP4036112B2 - Fault diagnosis system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention predicts an operation, performance abnormality, or failure of a circuit member in a device including a circuit board on which the circuit member is mounted, such as a printer device, a facsimile device, or a multifunction device having these functions. (Hereinafter collectively referred to as failure diagnosis)LateFault diagnosis system for implementing fault diagnosis methodToRelated.
[0002]
[Prior art]
In recent years, as electronic devices such as personal computers and copying machines have been improved in performance and functions, analog and digital electronic circuits for various purposes for realizing them have been increasingly stored in the form of printed circuit boards. .
[0003]
The environment in which such a board-mounted device is used is usually in an office or a house, but may be used in other harsh environments. Over. In particular, when the usage environment is inferior, even if it is used by a normal method, various abnormalities and failures that are difficult to detect occur, and a great deal of labor is required for the repair.
[0004]
Even when used in a normal use environment, an abnormality or failure of the electronic circuit has occurred, and the frequency is not necessarily low, and the detection location cannot often be specified. Furthermore, when an abnormality occurs in the electronic circuit board, it is necessary to take immediate measures in terms of safety and cost.
[0005]
As a general method of fault diagnosis, a fault location is specified 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, while tracing the circuit diagram, probing the wiring and terminals in the electronic circuit board to identify the failure location After identifying, replace the failed part.
[0006]
For example, Patent Document 1 discloses a technique for detecting a magnetic field generated by a current flowing through an electronic circuit. In the technique proposed in this Patent Document 1, in a circuit wiring such as a printed circuit board or LSI, the magnetic field due to the current of only one wiring is measured with high resolution and in a non-contact manner while suppressing the influence of adjacent wiring. If this technology is used, it is possible to identify a failure location while monitoring the operation of the electronic circuit.
[0007]
[Patent Document 1]
JP-A-11-38111
[0008]
Patent Document 2 discloses a technique for extracting an electrical characteristic amount by using a small and simple coil component suitable for an application such as high-accuracy extraction of electrical characteristics of an electric wire. In this technique, as a coil component, a coil body that is flattened so that the center of each turn gradually shifts on the same straight line or the same curve is presented.
[0009]
[Patent Document 2]
JP 2002-237413 A
[0010]
[Problems to be solved by the invention]
However, since the operation of electronic circuits has become more and more complicated with recent improvements in performance and functions, it becomes difficult to probe wiring and terminals in an electronic circuit board, and high circuit knowledge is required. In the technique described in Patent Document 1, there is a problem that the cost of specifying and repairing a failure location increases. In addition, although it is possible to probe the magnetic field generated from the state of the signal line on the circuit board and the current with high accuracy without contact, the dedicated probe used as a means for sensing the magnetic field is expensive and large, There is a problem that it is difficult to perform fault diagnosis and specify a fault location in a state where an electronic circuit board is incorporated in the system.
[0011]
The technique described in Patent Document 2 is an effective invention for detecting an abnormality in a power supply line, a current transformer, a power supply line of a transformer, etc. in a power plug. In the case of constructing a fault diagnosis system that uses a coil to extract the current flowing on the board and identifies the fault location for the complicated circuit configuration of the above, the arrangement of the coil and the signal processing method are not mentioned . Since the coil arrangement and signal processing greatly affect the fault diagnosis accuracy, accurate fault diagnosis cannot always be performed.
[0012]
As described above, the conventional failure diagnosis methods are not always sufficient in terms of cost, accuracy, and usability.
[0013]
  The present invention has been made in view of the above circumstances, is low in cost, can be incorporated into a system, and is capable of fault diagnosis and fault location identification while monitoring circuit operation.The lawFault diagnosis system to be implementedTheThe purpose is to provide.
[0015]
  The fault diagnosis system according to the present invention is, DiagnosisA signal change detection unit arranged in a non-contact and fixed manner with respect to the diagnosis target part in the vicinity of the disconnection target part, and a signal by electrostatic coupling or electromagnetic coupling between the diagnosis target part and the signal change detection unit An electrical signal corresponding to the signal change of the diagnosis target part induced in the change detection unit is detected, and the detected electric signal and the signal change at the normal time or abnormality of the diagnosis target part acquired in advance are supported. A failure diagnosis unit for diagnosing the presence or absence of a failure in the diagnosis target part by performing frequency analysis of the electrical signal is provided.
[0016]
TrustThe signal change detector, DiagnosisIt is good to be formed with the inductive reactance component which makes an electromagnetic coupling with the cutting | disconnection object site | part.In particular, it is a coil that forms an inductive reactance component, and is perpendicular to the direction of the current that flows through the target part, facing the part to be diagnosed and having a magnetic path length that is substantially the same as or less than the width of the part to be diagnosed. It is good to be formed with the spiral coil arrange | positioned fixedly.
[0017]
DETAILED DESCRIPTION OF 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. Here, FIG. 1 shows a layout example 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 resistance 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 target part for failure diagnosis such as a circuit member 20 or wiring on the circuit board 10. Signal change detection unit (sensor unit) 30 that functions as a detection probe arranged in a non-contact and fixed manner, an electrical signal detected by the signal change detection unit 30, and an electronic circuit acquired in advance A failure that diagnoses whether or not the electronic circuit system (specifically, the circuit board 10) is normal (the presence or absence of a failure) by comparing with an electric signal corresponding to a signal change at the time of normal or abnormal system A failure diagnosis unit 90 as a diagnosis device is provided.
[0021]
The failure diagnosis unit 90 is configured to change the signal by electromagnetic coupling or electrostatic coupling between the signal change detection unit 30 and the circuit member 20 or the wiring pattern by supplying power to the circuit board 10 and operating the circuit member 20. An electrical signal corresponding to a signal change induced in the detection unit 30 is detected. Further, the frequency of the signal is converted, the frequency spectrum is analyzed, and the frequency spectrum intensity distribution in a normal state measured in advance is compared to diagnose whether or not the circuit member 20 has a failure. Further, it is diagnosed which of the circuit members 20 is faulty by comparing circuit components and wiring patterns measured in advance with the frequency spectrum intensity distribution in an abnormal state.
[0022]
The signal change detection unit 30 is configured to use a reactance component so as to perform a non-contact inspection on a diagnosis location. That is, a configuration for detecting an electrical signal (inductive electromotive force) corresponding to a signal change of a signal line induced by a reactance component by electrostatic coupling or electromagnetic coupling between a diagnosis target site and the reactance component To 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 wiring is used. Also, 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 a diagnostic object on the support board 4 in a state where the support board 4 is arranged substantially parallel to the circuit board 10 on the support board 4 arranged substantially parallel to the component mounting surface of the circuit board 10. Provided at a position facing the part.
[0024]
In FIG. 1A, a coil 32 a is disposed on the support substrate 4 so as to surround the periphery of the connector 22 disposed on the circuit board 10, and a coil 32 b is disposed so as to surround the outer periphery of the circuit board 10. Has been. A coil 32c is arranged so as to surround a specific part (for example, the integrated circuit 24). In addition, 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 the description is omitted, the coils 32d and 32e and the capacitor 33b are arranged so as to face other parts to be diagnosed. Hereinafter, the coils forming the signal change detection unit 30 are collectively referred to as a coil 32, and the capacitors are collectively referred to as a capacitor 33.
[0025]
The support substrate 4 is substantially the same size as the circuit board 10 to be applied, and when the circuit board 10 and the support substrate 4 are stacked substantially in parallel, the coil 32 and the capacitor 33 formed on the support substrate 4 are formed. , So that it is positioned so as to be addressed to the desired location. Further, the circuit board 10 and the support board 4 are arranged in a non-contact and close proximity (very close) electrically. In this way, the electrical signals from the respective units arranged are connected to the signal extraction unit 7 and are extracted therefrom to the failure diagnosis unit 90 arranged outside the electronic circuit system (for example, a copying machine). To. In addition, by providing the failure diagnosis unit 90 on the support substrate 4, a self-diagnosis system in which the device 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 is a one-turn coil or a plurality of winding planes on the support substrate 4 so as to surround a predetermined range corresponding to a target part (diagnosis target part) for failure diagnosis. By forming the coil, induction is induced in the coil 32 by a magnetic field perpendicular to the circuit board 10 (in the depth direction in the figure) generated when power is supplied to the circuit board 10 and the circuit member 20 operates. Functions as a magnetic field sensing unit for detecting electric power. By arranging coil windings (wirings forming a coil) along the outer periphery of the diagnosis target part, it is possible to diagnose a failure of the target part without being aware of specific wiring or terminals.
[0027]
Here, specific embodiments of the “predetermined range according to the target part of failure diagnosis” include, for example, the outer periphery of the circuit board on which the target part of failure diagnosis is mounted, the outer periphery of the target part of failure diagnosis itself, the target The outer periphery of the terminal of the part can be considered. Moreover, when it is set as the object of a fault diagnosis in the functional block unit of a circuit, it encloses so that more things (preferably all) of the circuit members 20 which comprise the functional block may be included. In addition, when applied to an apparatus having a plurality of substrates, the outer periphery of the input / output connector for taking a signal interface between the plurality of circuit boards, the outer periphery of the plurality of circuit boards integrated, and the like are enclosed. You may make it do.
[0028]
Even if the coil position as a sensing probe is fixed, the detection range can be set by setting the range surrounded by the coil winding. In other words, the range surrounded by the coil windings can be set according to the desired range of the fault diagnosis, and the detection range can be freely widened, which improves usability. In the conventional sensing probe, when the probe position is fixed, only the range in the vicinity of the fixed probe position can be detected, which is greatly different from the detection range becoming very narrow. The wiring forming the coil is fixedly arranged on the support substrate 4. For fixed placement, it is preferable to print on the support substrate 4. Or you may fix using a taping member, an adhesive member, etc.
[0029]
Moreover, as the capacitor | condenser 33 which comprises the signal change detection part 30, it arrange | positions so that a flat metal member may be non-contactingly cross | intersected with respect to the wiring pattern of a diagnostic object part, and may function as an electric field sensing part. To do. A configuration in which the wiring pattern is sandwiched between two metal plates may be used, or a configuration in which one metal plate is provided on the wiring pattern. In either case, the metal member is fixedly arranged on the pattern. For fixed placement, it is preferable to print on the support substrate 4. Or you may fix using a taping member, an adhesive member, etc.
[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 printed circuit board (FPC substrate) that is a planar insulating plate. It is good to use. This is because there is a certain degree of flexibility, so that it is electrically non-contact and convenient for placement close to each other.
[0031]
In addition, when there are a plurality of signal change detection units 30 including printed coils 32 and capacitors 33, one terminal of each coil 32 or 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 wirings of the coils 32 and the capacitors 33 are arranged substantially parallel to each other so as to route the support substrate 4. Such wiring makes it possible to accurately capture signal changes caused by the coil 32 and the capacitor 33.
[0032]
That is, if the coil 32 and the capacitor 33 that form the signal change detection unit 30 are formed by a printed wiring pattern, the signal change detection unit 30 that functions as a sensing unit and the diagnosis target on the circuit board 10 without using a special fixing member. The physical positional relationship with the site can be fixed. As a result, the state of the induced electromotive force during expected value acquisition (normal time) or during failure diagnosis can be reliably stabilized. That is, an induced electromotive force that is a determination index for failure diagnosis can be obtained with high accuracy, and diagnostic performance is also improved. When the circuit board 10 is formed, the coil 32 and the capacitor 33 forming the signal change detection unit 30 are patterned at corresponding positions on the support board 4 in accordance with the diagnosis target site (in the case of a plurality of cases). Just keep it.
[0033]
Further, if a method of arranging the signal change detection unit 30 at a position corresponding to the circuit member 20 component or wiring pattern on the circuit board 10 in the support substrate 4 is adopted, the support substrate 4 on which the signal change detection unit 30 is arranged is arranged. The signal change detection unit 30 is positioned corresponding to the circuit member 20 or the wiring pattern by arranging it substantially parallel to the circuit board 10, and the inspection of the circuit member 20 and the wiring pattern mounted on the circuit board 10 can be easily and accurately performed. Will be able to do it. Further, since it is not necessary to previously incorporate the signal change detection unit 30 in the circuit board 10 and 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. The support substrate 4 in which the part 30 is arranged can be provided, and the correspondence to the existing circuit board 10 is also possible.
[0034]
Further, since the coil 32 and the capacitor 33 are fixedly arranged by the printed wiring pattern, naturally, no mechanical means for observing the probe close to the diagnosis location or for bringing the probe close to the target portion is required. . This makes it possible to incorporate a sensing unit into a system at a low cost without adding a complicated fault diagnosis circuit to an electronic circuit, even when monitoring circuit operations in any of a plurality of ranges. It becomes possible to provide a fault diagnosis system that can be monitored.
[0035]
Whether to use electromagnetic coupling or electrostatic coupling (capacitive coupling) when forming the signal change detection unit 30 depends on the frequency components of signal line current and voltage fluctuations. It is good to decide from such a viewpoint. In the form using electrostatic coupling, it is considered that the higher the frequency, the lower the impedance and the lower the detection sensitivity. On the other hand, in the form using electromagnetic coupling, it is considered that as the frequency becomes lower, the impedance becomes lower and the detection sensitivity tends to decrease. 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 used when the frequency component is mainly high frequency.
[0036]
However, in the form using electrostatic coupling, the degree of freedom of sensitivity adjustment is less than that of electromagnetic coupling. For example, to increase the sensitivity, the electrode area must be increased or the distance from the diagnosis target site must be decreased. The method of increasing the electrode area cannot be realized unless there is a margin between adjacent parts. Further, in the method of reducing the distance to the diagnosis target site, there is no choice but to adjust the distance between the support substrate 4 and the circuit board 10, and there is a limit in practice. On the other hand, in the form 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 be configured to use electrostatic coupling regardless of the operating frequency of the diagnosis target part. Actually, this is not always the case, and it is better to decide by cut and try (trial and error).
[0037]
In addition, when there is a component that interferes when the support substrate 4 is brought close to the circuit board 10 in a portion where the signal change detection unit 30 is not disposed in the support substrate 4, a hole is formed at the position of the support substrate 4 corresponding to the component. (Not shown) may be provided so that the component and the support substrate 4 do not contact each other.
[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 size shown are formed in a printed pattern. Yes. As shown in the cross-sectional view at the top of the figure, the support substrate 4 is provided with an insulating layer 4a at the center in the thickness direction d, and a signal on which patterns 4b forming the coil 32 and the capacitor 33 are formed on both surfaces. A layer is provided. In addition, a laminate layer 4c in which the 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 it may be provided on only one side. However, in this example, it is preferably provided at least on the circuit board 10 side.
[0039]
The coil 32 is produced by wiring in a spiral shape on both signal layers. In the illustrated example, two turns are formed so as to rotate in the same direction, and the two layers are connected by a through hole 34. Accordingly, in FIG. 1 (B), a through-turn from a two-turn coil indicated by a solid line to a two-turn coil formed on the layer opposite to the layer on which the two-turn coil wiring is formed (indicated by a diagonal line in the figure) Connection is made through a hole 34.
[0040]
Then, when the coil rotates twice, it is led again to the surface layer through the through hole 34. The wirings 36 connected to both ends of the coil 32 are wired in parallel to the vicinity of the signal extraction section 7 in two pairs, and one wiring again moves to another layer through the through-hole 34, where It is connected to one wiring of another signal line pair so that it is guided to the failure diagnosis unit 90 via the signal extraction unit 7. The other wiring is led independently from the signal extraction unit 7 to the failure diagnosis unit 90.
[0041]
Similarly, in the capacitor 33, wirings 37 are respectively connected to the electrode pairs formed on the front and back of the support substrate 4, and one wiring is led to the opposite layer through the through hole 34. Then, the wirings 37 are wired in parallel to the vicinity of the signal extraction portion 7 so as to form two pairs, and one wiring again moves to another layer through the through hole 34, where the other signal line pairs It is connected to one of the wirings so that it is guided to the failure diagnosis unit 90 via the signal extraction unit 7.
[0042]
FIG. 2 is a block diagram illustrating a configuration example of a failure diagnosis unit 90 that analyzes a signal extracted via 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. The fault 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 by them, and a buffer 92 formed of a differential amplifier that amplifies to a predetermined level. And a shaping circuit 93 for shaping the 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 conversion) the acquired operation signal waveform (induced electromotive force waveform) based on the data digitized by the A / D conversion unit 94, The frequency analysis unit 95 that analyzes the frequency component included in the signal component, and the 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 is stored as an expected value. A comparison unit that compares the expected value stored in the storage unit 96 with the result of frequency analysis of the induced electromotive force in the working state by the frequency analysis unit 95 to determine the presence or absence of a failure. Unit 98 and a control unit 99 that controls the entire failure diagnosis system 1. For example, the control unit 99 controls 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 coil 32 and capacitor 33 is connected in common, led to the failure diagnosis unit 90, and connected to the ground of the failure diagnosis unit 90. The other wiring is individually connected to the corresponding input terminal of the analog multiplexer 91 as a signal line. 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 integration circuit 93a for integrating the induced electromotive force signal detected by the coil 32 forming the signal change detection unit, and a filter circuit 93b for adjusting the frequency component. Is provided. Since the induced electromotive force signal is a differential waveform of the current flowing through the circuit, the integrating circuit 93a is provided to restore the original current waveform. That is, the induced electromotive force of the coil is proportional to the change (differentiation) of the current flowing through the circuit. Therefore, the induced electromotive force is integrated by an integrator and converted to the original current waveform, then AD conversion is performed, and the frequency analysis unit 95 performs frequency conversion.
[0047]
The filter circuit 93b is used to remove unnecessary components in signal analysis, and low-pass characteristics, high-pass characteristics, band-pass characteristics and band-elimination characteristics, respectively, or any combination thereof are used. The The through characteristics may be selectable as necessary. For example, in order to prevent the problem of aliasing distortion components at the time of A / D conversion, it is preferable to exhibit a characteristic of removing a component of 1/2 or more of the sampling frequency in the A / D conversion unit 94.
[0048]
As will be 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. 91 and the sampling frequency of the A / D converter 94 are switched. Therefore, the filter circuit 93b may be configured such that its cut-off characteristic is switched in conjunction with the sampling frequency in the A / D converter 94.
[0049]
The frequency analysis unit 95 does not perform failure diagnosis by simple waveform comparison, but performs a Fourier transform (not shown) of the read waveform to check the frequency value at which the peak is generated, so that the circuit board 10 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 the waveform pattern at normal time and the waveform pattern at actual operation, that is, to acquire operation waveforms at the same time at the timing of circuit operation. However, this synchronization is actually difficult although it depends on the verification target part. On the other hand, failure diagnosis by frequency analysis does not require such synchronization processing, and the waveform acquisition operation becomes very easy.
[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 and a harmonic component thereof included in the operation signal waveform obtained through the signal change detection unit 30. Note that the frequency analyzing 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 since there is a characteristic frequency component for each functional block, the fault location is broken down by functional block using this. Is identified. Since characteristic frequency components have a wide frequency range depending on the circuit, the sampling frequency of AD conversion is switched by the control unit 99, for example, sampling is performed separately in a low frequency region and a high frequency region.
[0052]
For example, signals from a plurality of planar coils (not shown) 32 and capacitors 33 arranged separately in functional blocks of the circuit are input to the analog multiplexer 91 and integrated after being amplified to a predetermined level by a buffer 92 having an amplification function. The signal is input to the circuit 93 a and converted into digital data by the A / D converter 94. The control unit 99 captures the induced electromotive force signal of the coil 32 during normal operation, performs frequency conversion by the frequency analysis unit 95, and stores the normal frequency data in the storage unit 96. Note that feature extraction may be performed based on frequency data of the induced electromotive force signal obtained by one measurement to obtain an expected value, or average data detected a plurality of times may be expected.
[0053]
At the time of failure diagnosis, the comparison / determination unit 98 actually operates the circuit and constantly captures the induced electromotive force signal of the coil 32, and stores the normal frequency stored in the storage unit 96 according to the instruction of the control unit 99. The data is always compared with the data (actual data) of the diagnostic sample frequency-converted by the frequency analysis unit 95 for the induced electromotive force signal that is always taken in. When a difference occurs in the data, the wiring of the circuit board 10 It is determined that a failure has occurred in the mounted component. That is, it is diagnosed whether the functional block targeted by the coil 32 or the capacitor 33 is operating normally by diagnosing whether the extracted difference is in the same range as compared with the normal state. Further, the details of the failure can be further identified by analyzing the read state of the frequency spectrum in detail.
[0054]
When a failure is detected, an alarm unit (not shown) issues an alarm (alarm) or notifies the details 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 diagnosis target device, the state of the device via a telephone line or the Internet May be installed in a centrally managed place and an alarm may be issued there.
[0055]
<Examples for switching power supply circuits>
Next, a switching power supply circuit (switching regulator) as a circuit for failure diagnosis 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 driving the switching transformer 210.
[0056]
The primary system 200a includes, for example, a noise filter 202 provided for an AC input (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 switching operation, and a rectification (not shown) An input rectifying / smoothing circuit 206 that includes an element (such as a diode) and a smoothing capacitor to rectify and smooth an AC input to obtain a predetermined DC voltage, and a switching circuit 208 that drives the primary winding 210a of the switching transformer 210 to switch. Is provided.
[0057]
The secondary system 200a rectifies and smoothes the output of the secondary winding 210b of the switching transformer (transformer) 210, and obtains 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 24V as an output voltage. The second output rectifying / smoothing circuit 224 includes a switching element, a rectifying element (such as a diode), a smoothing capacitor, etc. (not shown), and obtains, for example, DC 5V 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 hundreds kHz. For example, 50 kHz.
[0058]
The control system 200c includes a feedback circuit 232 that monitors the output voltage of the output rectifying and smoothing circuit 222, and a switching transformer 210 via the switching circuit 208 so that the voltage corresponding to the output voltage obtained by the feedback circuit 232 maintains a constant value. And an overcurrent protection circuit 236 that protects an excessive current from flowing to the switching circuit 208 and the switching transformer 210 during circuit operation.
[0059]
There are various methods for the switching circuit 208. The driving center frequency of the switching circuit 208 by the control circuit 234 is several tens kHz to several hundreds kHz. For example, 120 kHz.
[0060]
The overcurrent protection circuit 236 transmits a monitoring voltage reflecting the operating current to the control circuit 234. The control circuit 234 stops the operation of the switching circuit 208 to prevent the circuit from being destroyed when the monitoring voltage is out of the predetermined range. 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 this.
[0061]
FIG. 4 is a diagram showing a component layout example of the switching power supply circuit 200 shown in FIG. 3 and a form in which the failure diagnosis support substrate 4 is arranged in the switching power supply circuit 200. 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 coil 32 as a detection probe provided on the support board 4. FIG. 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 printed coil 30 is shown, it goes without saying that a capacitor 33 can also be used.
[0062]
As shown in FIG. 1, the coil 32 as a detection probe is produced by wiring in a spiral shape on an FPC board as the support substrate 4. For example, in each functional block unit of the block diagram shown in FIG. 3, the coil 32 is formed by arranging the windings in the printed wiring pattern so as to surround the area where the components constituting the functional block are arranged. . Although it is not possible to clearly divide the circuit in units of functional blocks due to component placement restrictions or restrictions on printed wiring, it is only necessary to enclose them roughly in units of functional blocks.
[0063]
This (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 is as close as possible. By simply doing this, it is possible to detect the current waveform in units of circuit function blocks without adding any circuit to the circuit to be diagnosed.
[0064]
For example, as shown in FIG. 3, the circuit board 10 in which the switching power supply circuit 200 of the forward converter system is divided into 11 functional blocks (noise filter 202, inrush current limiting circuit 204, input rectifying smoothing circuit 206, switching circuit 208, switching transformer 210, etc.). Since the circuit is usually arranged with components along the circuit diagram, it is possible to enclose the functional block roughly. The FPC board shown in FIG. 4B in which the coil 32 is manufactured at a position corresponding to the functional block is installed in parallel with 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 for explaining a technique for performing failure diagnosis by analyzing the frequency of the induced electromotive force signal of the coil 32. Here, a diagnosis example for the switching power supply circuit 200 shown in FIG. 4 will be described. 5A to 5D show frequency data (frequency spectrum) of a coil signal for the switching power supply circuit 200. FIG.
[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 is set around a commercial frequency (50 Hz). The high frequency region should be centered around the switching frequency (for example, 100 kHz). That is, in the switching power supply circuit 200, for example, since the AC input is 50 Hz and the switching frequency is several tens Hz to several hundred kHz and the frequency range is wide, the A / D converter 94 performs sampling in two regions, a low frequency region and a high frequency region. The frequency analysis unit 95 performs frequency conversion.
[0067]
The low frequency region includes harmonic components such as 100 Hz and 200 Hz as well as 50 Hz which is the fundamental frequency of AC input. Similarly, in the high frequency region, the harmonic components including 50 kHz and 120 kHz which are the fundamental frequencies of the two switching frequencies are included. 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 part (AC input part), the entire circuit does not operate. Therefore, as shown in FIG. 50 kHz etc. are not detected. Therefore, when such a comparison result is obtained as compared with the normal time, it is possible to diagnose a failure of the AC input unit.
[0069]
In addition, when the control circuit 234 of the first output system (output rectifying and smoothing circuit 222) fails, as shown in FIG. 5C, the current caused by the AC input is supplied to the primary side of the switching transformer 210. Since it flows, 50 Hz or the like is detected in the low frequency region, but 120 kHz that 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 time, it is possible to diagnose a failure of the control circuit 234 of the first output system.
[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. Detection is similar to time. Therefore, when such a comparison result is obtained as compared with the normal time, it is possible to diagnose a failure of the control circuit 226 of the second output system.
[0071]
In this manner, the failure functional block can be identified by comparing the fluctuation of the frequency component corresponding to the operation of the circuit functional block with that in the normal state. In a case where the failure is not complete (defective state), there is a case where there is a spectrum of each frequency component but the intensity is different from that in the normal state. In such a case, it is possible to identify a functional block in a defective state by analyzing the intensity pattern. That is, since the spectrum intensity distribution is different between the normal state and the abnormal state, the presence / absence of the abnormality and the abnormal state can be determined by analyzing the difference.
[0072]
Since the basic frequency of the operation of the switching power supply circuit 200 is relatively clearly divided by functional blocks, it is convenient for determining the presence or absence of a failure by frequency analysis. However, the application range of the technique for diagnosing faults by frequency analysis as in this embodiment is not necessarily limited to the switching power supply circuit.
[0073]
In addition, since it is possible to make a more detailed comparison by referring to not only the fundamental frequency but also the state of its harmonics, it is advantageous for determining an abnormal state. For example, paying attention to a frequency spectrum that is an integral multiple of 50 Hz, if this frequency spectrum is not observed from coils arranged in the vicinity of AC input to input rectifying and smoothing circuit 206 to switching transformer 210, a failure immediately after AC input is diagnosed. Similarly, when the switching frequency spectrum is not observed from the coil in the vicinity of the control circuit 234, a failure of the control circuit 234 is diagnosed. Combining a plurality of coil signals with low / high frequency, spectrum combination, presence / absence of load, etc. makes it possible to perform fault diagnosis with higher accuracy.
[0074]
<Example of frequency analysis for switching power supply circuit>
Next, an example of frequency analysis for a switching power supply circuit will be shown. FIG. 6 is a schematic circuit diagram of the switching power supply circuit 200 targeted in this embodiment. Functional portions equivalent to the functional blocks shown in FIG. 3 are denoted by the same reference numerals.
[0075]
As the control circuit 234, as shown in FIG. 6B, a control integrated circuit (model number M51195P) manufactured by Mitsubishi Electric Corporation was used. Its peripheral members 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 will not be described.
[0076]
Each functional block is provided with a failure diagnosis coil 32 so as to surround each functional block. Here, for the noise filter 202, the first coil 32 (hereinafter referred to as the coil @), the coil 2 for the inrush current limiting circuit 204, and the input rectifying and smoothing circuit 206 Coil 4 is provided for coil 3 and overcurrent protection circuit 236, and coil 5 is provided for switching circuit 208. Further, a coil 6 is provided for the control circuit 234, a coil 7 is provided for the switching transformer 210, a coil 8 is provided for the output rectifying / smoothing circuit 222, and a coil 9 is provided for the feedback circuit 232.
[0077]
FIG. 7 shows a frequency spectrum showing a 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 exhibits a relatively high FFT power at 50 Hz or 100 Hz as indicated by a circle in FIG. 7A when the circuit is normal. In addition, a large number of third-order or higher harmonic components of 50 Hz can be seen. On the other hand, FIG. 7B shows a state where the circuit has failed. As can be seen from the figure, not only 50 Hz and 100 Hz, but also the third-order and higher harmonic components of 50 Hz 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, a relatively high intensity FFT power is exhibited at the 120 kHz portion. On the other hand, FIG. 8B shows a state in which the same failure as that in FIG. 7B occurs. As can be seen from the figure, the FFT power almost disappears at 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 in the high frequency region as well as 50 Hz on the low frequency side, it can be diagnosed that the noise filter 202 has failed.
[0080]
As described above, as in the above-described embodiment, the circuit operation signal obtained by the signal change detection unit 30 is frequency-analyzed (the signal is frequency-converted and the frequency spectrum is analyzed). It becomes possible to diagnose the presence or absence of a failure. Capacitance component and inductance component, which are examples of reactance components provided as the signal change detection unit 30, can be provided as a sensing unit with a simple and low-cost configuration by using a taping member, an adhesive member, or a printed wiring pattern. It is possible to fix the physical positional relationship between the functional reactance component and the circuit board or cable. As a result, the state of the detection signal during failure diagnosis can be reliably stabilized. That is, a signal induced in a reactance component that is a determination index for failure diagnosis can be obtained with high accuracy, and diagnostic performance is also improved.
[0081]
In addition, instead of comparing the induced electromotive force waveform itself between normal operation and actual operation, the waveform is analyzed for frequency, so for example, diagnosis is divided into low frequency and high frequency, and the combination of spectrum intensity is diagnosed finely. Diagnosis can also be made by combining operations such as verifying operation with and without a load, enabling more accurate fault diagnosis. Although the number of circuit elements in the frequency analysis portion increases with respect to the waveform diagnosis, the circuit configuration for waveform diagnosis can be diverted otherwise. Therefore, it is possible to provide a failure diagnosis system that can be incorporated into the system at a low cost without adding a complicated failure diagnosis circuit and can monitor the circuit operation with high accuracy.
[0082]
Further, since the reactance component is fixedly arranged with respect to the diagnosis target part at the time of diagnosis, a mechanical means for observing the probe close to the diagnosis part or bringing the probe close to the target part is necessary. do not do. Even if a reactance component having a simple structure composed of a coil winding, a flat plate electrode, or the like is provided at each location according to the diagnosis target portion, the cost does not increase much.
[0083]
As a result, it has become possible to provide a user-friendly failure diagnosis mechanism in terms of cost and the degree of freedom in setting the target site for failure diagnosis.
[0084]
<Other configuration examples of the coil>
FIG. 9 is a diagram illustrating another configuration example of the coil 32 that forms the detection probe. The winding of the coil 32 shown in the above embodiment surrounds a detection target part 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 planar coil was formed by forming a pattern in a plane on the support substrate 4. On the other hand, in this modification, in order to detect a magnetic field generated in parallel to the circuit board 10 from the circuit member 20 or the wiring pattern of the circuit board 10, for example, a spiral coil (spiral) is provided adjacent to the wiring pattern 80. A coiled inductor) 70 is disposed.
[0085]
The wiring patterns 80a and 80b are mainly microstrip lines, but a magnetic field shown in FIG. 9A is generated by a current flowing through the wiring. As shown in FIG. 9A, the spiral coil 70 whose magnetic path length LEN is substantially the same as the width PW of the wiring pattern is brought close to the inspection target wiring pattern 80a in a non-contact manner and flows through the wiring pattern 80a. Arranged perpendicular to the current direction.
[0086]
In this way, the magnetic field generated by the other wiring pattern 26b adjacent to the wiring pattern 80a to be inspected passes only a weak magnetic field through the spiral coil 70 having the coil diameter W because the distance is increased. Only the magnetic field generated by the current of the pattern 80a efficiently passes through the spiral coil 70. Then, the current change of only the wiring pattern 80a to be inspected can be monitored by the induced electromotive force of the spiral coil 70. As a result, it is possible to diagnose a failure not in units of functional blocks but in units of wiring patterns.
[0087]
For example, if the magnetic flux passing through the spiral coil 70 generated by the current flowing through the wiring pattern 80 is Φ, the induced electromotive voltage V induced at both ends of the spiral coil 70 can be obtained by Expression (1).
[0088]
V = dΦ / dt (1)
Note that it is only necessary to read the induced electromotive force generated in the spiral coil 70 as the magnetic field sensing unit, and is not limited to the mode in which the induced electromotive voltage generated at the open end of the spiral coil 70 is read as shown in the equation (1). Alternatively, the current flowing in 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 the same as or less than the width of the predetermined wiring pattern corresponding to the target part of the circuit board for failure diagnosis.
[0090]
In addition, in order to perform inspection with high accuracy, it is desirable to fix the physical positional relationship between the wiring pattern 80a to be inspected and the spiral coil 70. When the spiral coil 70 is fixedly arranged with respect to a predetermined wiring pattern corresponding to the target site of the failure diagnosis, it is preferable to form a printed wiring pattern on the outer layer (front surface or back surface) or inner layer on the circuit board.
[0091]
Further, a coil formed by winding in advance may be fixed in close contact with each other by using a fixing member such as a taping member so as to be electrically non-contact. In this case, for example, after the coil is formed so that the cross section of the opening of the magnetic path is substantially circular or elliptical, the coil is flattened, and then the wiring pattern of the diagnostic target part is located at a position corresponding to the diagnostic target part. And the coil flat surface may be fixedly disposed.
[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 (right side in the figure) insulator 87a. Yes. Then, the spiral coil 70 is formed by a printed wiring pattern formed on both surfaces of the insulator 87b on the opposite side (left side in the figure) opposite to the wiring pattern 26 sandwiching the insulator 87a. That is, the spiral coil 70 is configured on the same substrate as the circuit substrate (printed wiring substrate) 10 constituting 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 a part of two opposing conductor layers) through holes ( Via holes) 136 are connected in a predetermined order (so as to form a winding). An insulator 137c similar to the insulator 87b is disposed between the through holes 136. By doing so, the stability of the arrangement is improved.
[0094]
Further, as shown in FIG. 9C, similarly to the embodiment described above, the wiring pattern of the diagnosis target portion and the flat surface of the coil face each other on the support substrate 4 different from the circuit substrate 10. The positions may be close to each other.
[0095]
When forming the spiral coil, the insulator 137c or the outside of the through hole 136 disposed between the through holes 136 in the insulator 37b may be replaced with an insulating magnetic layer. That is, a structure in which an insulating magnetic material is arranged in a layer between a part of two opposing conductor layers (coil layers) used to configure the spiral coil 70 may be adopted.
[0096]
As a technique for arranging an insulating magnetic material in layers between two conductor layers, for example, a technique described in JP-A-11-40915 is preferably used. For example, an insulating magnetic material may be used as the magnetic material constituting the insulating magnetic material layer. As the insulating magnetic body, for example, a mixture of Ni—Zn ferrite fine powder, Mn—Zn ferrite fine powder, Sendust fine powder, Li-based ferrite fine powder and an insulating solvent may be used. The insulating solvent includes an epoxy insulating solvent.
[0097]
As an insulating magnetic material disposed between two coil layers, a metal foil having an insulating coating on both surfaces may be used. A metal foil having an insulating coating on both sides includes an amorphous magnetic foil multilayer strip.
[0098]
Furthermore, not only the portion of the insulator 137c disposed between the through holes 136 in the insulating layer 137b, but the entire insulating layer 137b may be replaced with an insulating magnetic layer. That is, a structure in which an insulating magnetic material is arranged in a layered manner on the entire area between two opposing conductor layers (coil layers) used to configure the spiral coil 70 may be adopted.
[0099]
In this way, by disposing an insulating magnetic material on a part or the entire surface region between two opposing conductor layers (coil layers) used to configure the spiral coil 70, the inductance of the spiral coil 70 can be reduced. Since it can increase, the detection sensitivity by the spiral coil 70 can be improved, and a more accurate fault diagnosis system can be constructed.
[0100]
The series of failure diagnosis processes described above can be executed by hardware, but can also be executed by software. When a series of fault diagnosis processes are executed by software, a program (such as an embedded microcomputer) in which a program constituting the software is incorporated in dedicated hardware, or a function of a CPU, logic circuit, storage device, etc. System-on-a-chip (SOC) that implements a desired system by mounting on a single chip, or a general-purpose personal that can execute various functions by installing various programs It is installed from a recording medium on a computer or the like.
[0101]
This recording medium causes a change state of energy such as magnetism, light, electricity, etc. to a reading device provided in the hardware resource of a computer in accordance with the description contents of the program, and a corresponding signal format. Thus, the description content of the program can be transmitted to the reading device. For example, a magnetic disc (including a flexible disc), an optical disc (CD-ROM (Compact Disc-Read Only Memory)), a DVD (which is distributed to provide a program to a user separately from a computer, (Including Digital Versatile Disc), magneto-optical disc (including MD (Mini Disc)), or package media (portable storage media) made of semiconductor memory, etc. It may be configured by a ROM, a hard disk, or the like in which a program is recorded that is provided to the user in a state. Or the program which comprises software may be provided via communication networks, such as a wire communication or radio | wireless.
[0102]
FIG. 10 is a diagram showing an example of a hardware configuration when a fault diagnosis system is configured by software using a CPU and a memory, that is, when a fault diagnosis system is constructed using an electronic computer such as a personal computer. is there.
[0103]
A 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, a recording / reading for reading and recording data from a storage medium such as the memory reading unit 907, the hard disk device 914, the flexible disk (FD) drive 916, or the CD-ROM (Compact Disk ROM) drive 918. An apparatus may be provided. Data is exchanged between the hardware units via a data bus.
[0105]
The hard disk device 914, the FD drive 916, or the CD-ROM drive 918 is used for registering program data for causing the CPU 902 to execute processing such as frequency conversion and frequency analysis by software. The hard disk device 914 includes an area for storing processing target data.
[0106]
The communication I / F 908 mediates transfer of communication data with a communication network such as the Internet. The computer system 900 also includes an I / F unit 930 that functions as an interface with the circuit board 10.
[0107]
It should be noted that the processing circuit 940 that does not perform all processing of each functional part (particularly, the comparison determination unit 98) of the failure diagnosis unit 90 shown in the above embodiment by software, but performs a part of these functional parts by hardware. You may provide as.
[0108]
On the circuit board 10, an analog multiplexer 950, a buffer circuit 952, and an A / D conversion unit 954 are arranged as circuit members 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. Each wiring pattern 80 to be inspected on the circuit board 10 is provided with the signal change detection unit 30 (for example, the coil 32 and the capacitor 33; only the coil is shown in the figure).
[0109]
Each signal change detection unit 30 has one terminal commonly connected to the ground, and the other terminal 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]
The output signal of the analog multiplexer 950 is converted into digital data by the A / D converter 954 via the buffer circuit 952. Digital detection data output from the A / D conversion unit 954 is input to the I / F unit 930 on the computer system 900 side 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. A program that causes 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 the FD 920 instead of the CD-ROM 922. An MO drive may be provided to store the program 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 and acquired from another server or the like via a communication network such as the Internet, or may be updated. In addition to the FD 920 and the CD-ROM 922, the recording medium includes 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]
An FD 920, a CD-ROM 922, or the like as an example of a recording medium can store a part 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 functional units such as a comparison / determination unit 98, a feature amount extraction unit, or a 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. 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 and data created by the CPU 902 executing the program, and reads the stored data or program to read the CPU 902. To pass.
[0115]
The software stored in the hard disk device 914 is read by the RAM 906 and then 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 that are examples of the recording medium. For example, first, during normal operation, the induced electromotive force signal of the signal change detection unit 30 is captured while being switched by the analog multiplexer 950 and stored in a storage device such as the hard disk device 914. Next, the circuit is actually operated, and the normal waveform stored in the hard disk device 914 or the like and the waveform that is always captured are in accordance with instructions from the CPU 902 while constantly capturing the signal of the signal change detection unit 30. When the difference is generated between the normal operation and the normal operation, the comparison is always performed, or the waveform is frequency-converted, and it is determined that there is a failure and an alarm is issued or the failure content is notified. Further, by analyzing in detail the waveform change state and frequency spectrum state at the time of failure, the failure content is further identified in detail.
[0116]
As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. Various changes or improvements can be added to the above-described embodiment without departing from the gist of the invention, and embodiments to which such changes or improvements are added 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 features described in the embodiments are not necessarily essential to the solution means of 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 elements. Even if some constituent requirements are deleted from all the constituent requirements shown in the embodiment, as long as an effect is obtained, a configuration from which these some constituent requirements are deleted can be extracted as an invention.
[0118]
For example, in the coils (including spiral coils) and capacitors shown in the above-described embodiment, the pattern is formed on the printed circuit board so as to correspond to the diagnosis target portion. However, these are methods other than pattern formation. It does not matter if it is formed. For example, a coil previously formed 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 embodiment, the coil and capacitor to be sensed are arranged so that they are located around the circuit part when the flexible board is brought close to the circuit board, but this is installed at a position where the most necessary information can be sensed. It means that.
[0120]
In the above embodiment, it is suggested that a coil or a capacitor is formed as a flexible board and fixed to a circuit board, a cable, or the like, but the flexible board to be the support board 4 can be assembled into a box body, The circuit board or cable to be inspected may be housed in a box assembly and inspected.
[0121]
【The invention's effect】
As described above, according to the present invention, the signal change detection unit is arranged in a non-contact and fixed manner with respect to the diagnosis target part in the vicinity of the diagnosis target part, and between the diagnosis target part and the signal change detection part. The electric signal corresponding to the signal change in the diagnosis target part induced by the signal change detection unit by the combination of the signal is detected, and the detected electric signal and the signal change when the diagnosis target part acquired in advance are normal or abnormal The presence or absence of a failure in the diagnosis target part is diagnosed by frequency analysis of the electrical signal corresponding to the.
[0122]
For this reason, it is not necessary to synchronize at the time of signal acquisition in order to compare the frequency pattern at normal time and the frequency pattern at actual operation, that is, it is not necessary to acquire the operation waveform at the same time at the timing of circuit operation, and the work of waveform acquisition is easy Become. In addition, it is possible to make a detailed diagnosis of the failure state by frequency analysis.
[0123]
Further, since the signal change detection unit is fixedly arranged, there is no need for a mechanical means for observing the probe close to the diagnosis location or for bringing the probe close to the target site. Even if a signal change detection unit having a simple structure using a technique such as pattern formation is provided at each location in accordance with the site to be diagnosed, the cost does not increase much.
[0124]
As a result, it has become possible to provide a user-friendly failure diagnosis mechanism in terms of cost and the degree of freedom in setting the target site 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 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 showing 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.
FIG. 5 is a conceptual diagram illustrating a technique for performing a failure diagnosis by analyzing the frequency of 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 showing a frequency spectrum of a coil provided in a noise filter of the switching power supply circuit shown in FIG. 6;
8 is a diagram showing a frequency spectrum of a coil provided in the control circuit of the switching power supply circuit shown in FIG.
FIG. 9 is a diagram showing another configuration example of a coil that forms a 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 ... Integration circuit, 93b ... Filter circuit, 94 ... A / D conversion unit, 95 ... Frequency analysis unit, 96 ... Storage unit, 98 ... Comparison determination unit, 99 ... Control Part

Claims (3)

A fault diagnosis system for diagnosing the presence or absence of a fault in a part to be diagnosed, such as circuit board wiring and mounted parts,
A signal change detection unit arranged in a non-contact and fixed manner with respect to the diagnosis target part in the vicinity of the diagnosis target part;
An electrical signal corresponding to a signal change of the diagnostic target part induced in the signal change detection unit by coupling between the diagnostic target part and the signal change detection unit is detected, and the detected electrical signal is and an electrical signal corresponding to the signal change at the normal state or abnormal in had been acquired the diagnosis target site by frequency analysis, and a fault diagnosis unit for diagnosing the presence or absence of a failure of the diagnosis target site,
The signal change detection unit is a coil that forms an inductive reactance component that forms an electromagnetic coupling with the diagnosis target part, and is opposed to the diagnosis target part, and a magnetic path length of the coil is the diagnosis target A fault diagnosis system, characterized in that it is formed of a spiral coil that is substantially the same as or less than the width of the part and is arranged perpendicularly and fixedly to the direction of current flowing through the target part . The spiral coil vertically connects between a plurality of conductors formed by cutting 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,
Furthermore, the failure diagnosis system of claim 1 in which the magnetic path length of spiral coil, characterized in that it is set a predetermined substantially the same or less and the wiring pattern corresponding to the diagnosis target site. The predetermined circuit board on which the spiral coil is formed and the circuit board on which the diagnosis target site is mounted are each a multilayer board formed by laminating a plurality of boards, each integrally configured,
The spiral coils, a fault diagnosis system according to claim 2, characterized in that it is formed by printed wiring pattern of the second layer of the multilayer substrate.

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