JP4892876B2 - Failure diagnosis apparatus and method - Google Patents

Description

  The present invention relates to a fault diagnosis apparatus and method, and more particularly to a fault diagnosis apparatus and method for diagnosing a fault in an electronic circuit.

  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. .

  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.

  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.

  In addition, the sound insulation performance in the office or home where the equipment is installed has been improved, so even though the operation is normal, unpleasant noise (abnormal noise) generated from the internal power supply circuit in the standby state has become a problem. .

  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.

  The following technologies are shown.

  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.

  Patent Document 2 discloses a technique for extracting an electric characteristic amount (current) using a small and simple coil component suitable for applications such as high-accuracy extraction of electric characteristics of an electric wire. .

Furthermore, Patent Document 3 discloses a technique for detecting abnormal noise. In the technique proposed in Patent Document 3, two microphones are provided, ambient noise is canceled by a differential means and output to a headset, and an inspector can hear only abnormal noise, thereby allowing ambient noise to be heard. In a production line having a large size, an abnormal sound is detected without requiring a soundproof room.
JP-A-11-38111 JP 2002-237413 A Japanese Patent Laid-Open No. 10-19656

  However, Patent Documents 1 and 2 are not limited to detecting a magnetic field or current, and are not disclosed in terms of how the detected magnetic field is used for failure determination.

  On the other hand, in Japanese Patent Application Laid-Open No. H10-260260, it is possible to easily detect abnormal noise. However, for this purpose, the apparatus configuration and processing are complicated, such as providing two microphones and canceling ambient noise by differential means. In addition, it is not possible to identify the cause of abnormal noise, and only replace the parts and units that are the source of generation, for example, the power circuit unit that generates abnormal noise. It was impossible to replace the deteriorated parts and repair them, resulting in waste. Furthermore, it is impossible to incorporate in equipment, and abnormal noise inspection is still performed by an inspector using a headset, so it is difficult to automate abnormal noise detection.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a failure diagnosis apparatus and method capable of determining a failure with a simple configuration and easily determining a failure location.

In order to achieve the above object, the invention according to claim 1 is a signal detection means for detecting a signal flowing in an electronic circuit, a conversion means for converting the detected signal into a frequency component, and the converted frequency component. From the calculation means for calculating an abnormal sound index, which is a physical quantity representing the magnitude of the abnormal sound generated due to the change in the signal, and a failure occurs in the electronic circuit based on the calculated abnormal sound index Bei example and a determining means for determining whether or not said calculation means, the values of the frequency components in advance according to the frequency for correcting the value corresponding to the sensitivity of the different human hearing by the frequency The abnormal noise index is calculated by correcting with a predetermined correction value and integrating the corrected value of the frequency component within a predetermined frequency range as abnormal noise is generated. and wherein

According to a second aspect of the present invention, there is provided a signal detection means for detecting a signal flowing through an electronic circuit, a conversion means for converting the detected signal into a frequency component, and a change in the signal from the converted frequency component. Calculation means for calculating an abnormal sound index, which is a physical quantity representing the magnitude of the abnormal sound generated due to it , peak frequency and intensity of the converted frequency component, and dispersion and standard deviation in the calculated frequency range Detection means for detecting, determination means for determining a fault location of the electronic circuit based on the calculated abnormal sound index, the peak frequency of the detected frequency component and its intensity, and variance and standard deviation ; The calculation means corrects the value of the frequency component with a correction value determined in advance according to a frequency for correcting the value of the frequency component to a value corresponding to the sensitivity of human hearing depending on the frequency, and The value of Tadashisa the said frequency components, by integrating within a predetermined frequency as abnormal noise, and calculates the abnormal noise index.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the determination unit further determines an electrical failure based on the converted frequency component .

According to a fourth aspect of the present invention, in the invention according to any one of the first to third aspects, the signal detecting unit detects the signal in a non-contact manner with respect to the electronic circuit. .

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, the signal detection means is formed of a passive element .

The invention according to claim 6 is the invention according to claim 5, wherein the passive element is a capacitive reactance element that forms electrostatic coupling or an inductive reactance element that forms electromagnetic coupling. And

The invention described in claim 7 is the invention described in claim 6, wherein the reactance element is formed on the circuit board by a wiring pattern .

The invention according to claim 8 is the invention according to claim 6 or 7, wherein the reactance element is a coil composed of windings arranged so as to surround the functional block of the electronic circuit. It is characterized by .

The invention according to claim 9 is the invention according to claim 6 or claim 7, wherein the reactance element is opposed to a diagnosis target part in the electronic circuit, and a magnetic path length is substantially equal to a width of the diagnosis target part. Spiral coils that are the same or less than the width and are arranged perpendicularly and fixedly with respect to the direction of a signal flowing through the diagnosis target region .

The invention according to claim 10 is the invention according to claim 9, wherein the spiral coil is formed by cutting off a part of two opposing conductor layers formed by a printed wiring pattern on a predetermined circuit board. a plurality of conductors, as well as supporting the conductive layer, a support layer through holes are formed for connecting vertically between each of the plurality of conductors, provided with a magnetic path length of the spiral coil, the It is characterized in that it is set to be substantially the same as or less than the predetermined wiring pattern corresponding to the diagnosis target part.

The invention according to claim 11 is the invention according to any one of claims 1 to 10, wherein the integration means for integrating the detected signal, and the integrated signal is reduced to a high frequency region. And a digital conversion unit that converts the digital value into a digital value using a sampling clock that is different from each other in the frequency domain, wherein the conversion unit converts the digital value into a frequency component .

According to a twelfth aspect of the present invention, there is provided a step of detecting a signal flowing through an electronic circuit, a step of converting the detected signal into a frequency component, and a change in the signal from the converted frequency component. Calculating an abnormal sound index that is a physical quantity representing the magnitude of the generated abnormal sound; determining whether or not a failure has occurred in the electronic circuit based on the calculated abnormal sound index; In the calculating step, the value of the frequency component is corrected with a correction value determined in advance according to the frequency for correcting the value of the frequency component to a value corresponding to the sensitivity of human hearing depending on the frequency, and the correction is performed. Further, the abnormal sound index is calculated by integrating the value of the frequency component within a predetermined frequency range in which abnormal sound is generated.
It is characterized by that .

According to a thirteenth aspect of the present invention, there is provided a step of detecting a signal flowing through an electronic circuit, a step of converting the detected signal into a frequency component, and a change in the signal from the converted frequency component. A step of calculating an abnormal sound index that is a physical quantity representing the magnitude of the generated abnormal sound, a step of detecting a peak frequency and intensity of the converted frequency component, and a variance and a standard deviation in the calculated frequency range ; Determining the failure location of the electronic circuit based on the calculated abnormal index, the peak frequency of the detected frequency component, its intensity, variance and standard deviation, and calculating In the step, the value of the frequency component is corrected with a correction value determined in advance according to the frequency for correcting the value to a value corresponding to the sensitivity of human hearing depending on the frequency. One the correction values of the frequency components by integrating within a predetermined frequency as abnormal noise, and calculates the abnormal noise index.

  As described above, the present invention detects a signal flowing in an electronic circuit, converts it to a frequency component, calculates an abnormal sound index from the converted frequency component, and breaks down the electronic circuit based on the abnormal sound index. Therefore, the failure can be determined with a simple configuration.

  Further, according to the present invention, since a signal flowing through the electronic circuit is detected and processed to determine the failure location of the electronic circuit, the failure location can be easily determined.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  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.

  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 (see 22, 23, 24... In FIG. 1A) may be a passive component such as a resistive element, an inductive element, or a capacitive element, or may be a transistor or an IC (Integrated). An active component such as a circuit) may be used.

  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. The signal change detecting unit (sensor unit) 30 (in FIG. 1 (A), 32a, 32b, 32c,. Reference) and the electric signal detected by the signal change detection unit 30 and the electric signal corresponding to the signal change at the normal time or abnormal time of the electronic circuit system acquired in advance are compared with each other. Specifically, the circuit board 10 includes a failure diagnosis unit 90 as a failure diagnosis device for diagnosing whether or not the circuit board 10) is normal (whether or not there is a failure).

  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.

  The signal change detection unit 30 is a passive element having a configuration using 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.

  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.

  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.

  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.

  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.

  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 a part etc. 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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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).

  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.

  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.

  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.

  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.

  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.

  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 or not an abnormality has occurred in the circuit board 10. It is.

  As shown in FIG. 2, the failure diagnosis unit 90 includes an analog multiplexer 40 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 40, detects a induced electromotive force induced by them, and a buffer 41 formed of a differential amplifier that amplifies to a predetermined level. A shaping circuit 42 that shapes the analog signal output from the buffer 41, and an A / D (Analog to Digital) converter 43 that converts the shaped analog signal into digital data.

  Further, the failure diagnosis unit 90 digitally performs a Fourier transform (frequency conversion) on the acquired operation signal waveform (induced electromotive force waveform) based on the data digitized by the A / D conversion unit 43. Unit 44, an allophone index calculation unit 45 that calculates an allophone index to be described later from the converted frequency components, a statistical processing unit that statistically processes (determines a feature value) the frequency components that have been frequency converted, and an allophone index An abnormal noise determination unit 47 that inputs the result from the calculation unit 45 and the result from the statistical processing unit 46 and determines the occurrence of abnormal noise and the determination of the failure location is provided, and is converted by the frequency conversion unit 44. The frequency analysis unit 48 that analyzes the frequency component included in the signal component that has been generated, and the frequency analysis unit 48 that performs frequency analysis of the induced electromotive force induced in the coil 32 and the capacitor 33 when the circuit board 10 is normal. The storage unit 49 such as a semiconductor memory that stores the expected value as an expected value, and the expected value stored in the storage unit and the result of frequency analysis of the induced electromotive force signal in the working state by the frequency analysis unit are compared. A comparison / determination unit that determines presence / absence and a control unit 51 that controls the entire failure diagnosis system 1 are provided. The control unit 51 controls, for example, the switching of the analog multiplexer 41 and the sampling frequency ADCK of the A / D conversion unit 43.

  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 a corresponding input terminal of the analog multiplexer 40 as a signal line. The selection operation of the analog multiplexer 40 is controlled by a control signal MPX from the control unit 51.

  In the shaping circuit 42, as shown in FIG. 2B, an integration circuit 52 for integrating the induced electromotive force signal detected by the coil 32 as a signal change detection means, and a filter circuit 53 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 integration circuit 52 is provided to return the waveform to 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 the integration circuit 52 and converted into the original current waveform, and then A / D conversion is performed by the A / D conversion unit 43, and frequency conversion is performed by the frequency conversion unit 44.

  The filter circuit 53 is used to remove unnecessary components in signal analysis, and low-pass characteristics, high-pass characteristics, or band-pass characteristics and band elimination characteristics are used alone or in any combination thereof. 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 43.

  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 analog according to the coil 32 to be diagnosed. The sampling frequencies of the multiplexer 40 and the A / D converter 43 are switched. Therefore, the filter circuit 53 may be configured such that its cut-off characteristic is switched in conjunction with the sampling frequency in the A / D converter 43.

  The frequency conversion unit 44 does not perform failure diagnosis by simple waveform comparison, but performs a Fourier transform (not shown) of the read waveform to confirm the frequency value at which the peak occurs, It is provided to analyze whether or not an abnormality has occurred in the circuit board 10 by calculating a statistical value and determining an abnormal sound pattern.

  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.

  For example, the abnormal sound index calculation unit 45 extracts the frequency spectrum (frequency) of the operation signal waveform of the circuit member 20 in the circuit board 10 as a feature amount. For example, a frequency spectrum is extracted in a range such as a human audible frequency range (20 Hz to 20 kHz), corrected for each frequency by the correction unit 55, integrated by the integration unit 56, and calculated as an abnormal sound index. Then, the statistical processing unit 46 calculates a statistic representing the characteristic amount of the frequency spectrum, and the abnormal noise determination unit 47 determines to identify a circuit member that causes a failure of the generated abnormal noise.

  For example, the frequency analysis unit 48 extracts the frequency spectrum (frequency) of the operation signal waveform of the circuit member 20 in the circuit board 10 as a feature amount. For example, the frequency analysis unit 48 extracts a fundamental frequency component and its harmonic component included in the operation signal waveform obtained via the signal change detection unit 30. Note that the frequency analyzing unit 48 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.

  In addition, since characteristic frequency components have a wide frequency range depending on the circuit, the control unit 51 switches the sampling frequency of the A / D conversion, for example, separates sampling into a low frequency region and a high frequency region.

  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 40 and amplified after being amplified to a predetermined level by a buffer 41 having an amplification function. The signal is input to the circuit 52 and converted into digital data by the A / D converter 43. The control unit 51 captures the induced electromotive force signal of the coil 32 during normal operation, performs frequency conversion by the frequency conversion unit 44, and stores normal frequency data in the storage unit 49 through the frequency analysis unit 48. 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.

  At the time of failure diagnosis, the comparison / determination unit 50 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 49 according to the instruction of the control unit 51. The data is always compared with the frequency-converted diagnostic sample data (actual data) for the induced electromotive force signal that is constantly captured, and when there is a difference in the data, an electrical failure occurs in the wiring of the circuit board 10 and the mounted components. Is determined to have occurred. 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.

  When a failure is detected, an alarm unit (not shown) issues an alarm (alarm) or notifies the content 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.

<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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

<Basic principle of abnormal noise detection and fault diagnosis>
Next, a method for detecting an abnormal sound and calculating an abnormal sound index according to the present embodiment will be described. The switching power supply circuit shown in FIG. 3 is taken as an example. For example, if the smoothing performance deteriorates due to a component failure of the rectifying capacitor (not shown) of the input rectifying / smoothing circuit 206, the output rectifying / smoothing circuit 222, or the output rectifying / smoothing circuit 224 due to performance deterioration due to aging, feedback is performed through the feedback circuit 232. Becomes unstable, sometimes causes intermittent oscillation, fluctuates internal current, and vibrates components such as transformers and choke coils. The fluctuation frequency varies, but when it occurs in a human audible frequency range, particularly about 7000 Hz to 15000 Hz, vibrations of components such as a transformer and a choke coil become abnormal sounds and can be heard by the human ear. Therefore, the frequency characteristic corresponding to the generated abnormal noise can be detected by detecting the current fluctuation in the circuit in the vicinity of the transformer and the choke coil with the coil as the detection unit and performing frequency conversion. In addition, since the sound is not detected as in the microphone, but an electrical signal is detected, it is possible to detect the frequency characteristic of only the abnormal sound without affecting the noise in the inspection environment. FIG. 5A shows an example of the detected abnormal sound. In this example, a peak occurs in the vicinity of 13000 Hz, and high-frequency abnormal noise is observed. For reference, the frequency characteristics of abnormal noise measured with a microphone are shown in FIG. Exactly the same characteristics are obtained, which shows that the present invention can detect abnormal sounds.

Next, the abnormal sound index obtained by the present invention will be described as a reference for determining by abnormal sound inspection or the like. Human hearing has different sensitivities depending on frequency, and feels the loudness as an integral value in the audible range. For this reason, the exponent obtained by correcting and integrating the frequency characteristics of the abnormal noise obtained in the present invention objectively represents the magnitude of the abnormal noise. This is the abnormal sound index. Therefore, the correction unit 55 of the abnormal sound index calculation unit 45 corrects the difference in sensitivity for each frequency. Specifically, an A characteristic (see FIG. 6) known as a curve for correcting an equal loudness curve is multiplied for each frequency as an example. There are various other correction curves, which can be selected as appropriate. Next, the integrating unit 56 integrates the frequency characteristics corrected particularly in a frequency range (such as 6000 Hz to 17000 Hz) where abnormal noise occurs. That is, the abnormal sound index is calculated by performing the calculation shown in Equation 1.

  The frequency range may be selected as appropriate in accordance with the frequency at which abnormal noise occurs and the degree of generation of AC harmonics generated in the switching power supply circuit.

  FIG. 7 is a diagram illustrating a frequency pattern of abnormal noise generated according to a failure state. There may be a single sound with a steep peak as shown in FIG. 7A, or a broad frequency spectrum without a clear peak as shown in FIG. 7B. FIG. 8A shows an example of an abnormal sound index and a statistic calculated when performing an abnormal sound failure diagnosis. Case 1 is a case of a frequency spectrum having a steep peak, and Case 2 is a case of a broad frequency spectrum. Both sounds as an unpleasant noise to the human ear. As the statistics to be calculated, for example, a list of peak frequencies and their intensities, and variances and standard deviations in the frequency range to be calculated are calculated. Since the value of the variance or standard deviation is small when the peak is steep, and large when it is broad, this statistic is a characteristic amount that reflects the shape of the frequency spectrum.

  FIG. 8B is a diagnosis table for performing failure diagnosis of abnormal noise. Diagnosis No. 1 is a criterion for judging an abnormal sound having a steep peak. 2 is a criterion for judging a broad abnormal sound. The failure location may be specified in advance by associating the relationship between the shape of the frequency spectrum and the failure location by experiments or by circuit simulation. A table in which abnormal noise patterns and failure locations are associated is held in the abnormal noise determination unit, and abnormal noise determination is performed while sequentially referring to the table.

<Basic principle of frequency analysis>
FIG. 9 is a conceptual diagram for explaining a method of performing a fault 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. 9A to 9D show frequency data (frequency spectrum) of a coil signal for the switching power supply circuit 200. FIG.

  The A / D converter 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. Frequency conversion is performed in the frequency analysis unit.

  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. 9A shows an example of a frequency spectrum when the switching power supply circuit 200 is in a normal state.

  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. 9B, not only 50 Hz on the low frequency side but also the high frequency region. 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.

  In addition, when the control circuit 234 of the first output system (output rectifying and smoothing circuit 222) fails, as shown in FIG. 9C, 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.

  When only the control circuit 236 of the second output system (output rectifying / smoothing circuit 224) fails, only the switching frequency of 50 kHz is not detected as shown in FIG. 9D, 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.

  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.

  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 the present embodiment is not necessarily limited to the switching power supply circuit.

  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.

<Embodiment of frequency analysis for switching power supply circuit>
Next, an embodiment of frequency analysis for a switching power supply circuit will be described. FIG. 10 is a schematic circuit diagram of the switching power supply circuit 200 targeted in the present embodiment. Functional portions equivalent to the functional blocks shown in FIG. 3 are denoted by the same reference numerals.

  As the control circuit 234, as shown in FIG. 10B, 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.

  Each functional block is provided with a failure diagnosis coil 32 so as to surround each functional block. Here, the first coil 31 for the noise filter 202, the coil 2 for the inrush current limiting circuit 204, the coil 3 for the input rectifying and smoothing circuit 206, the coil 4 for the overcurrent protection circuit 236, and switching. The coil 5 is provided for the 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.

  FIG. 11 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 strength FFT power at 50 Hz or 100 Hz as indicated by a circle in FIG. 11A 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. 11B shows a state where the circuit has failed. As can be seen from FIGS. 11A and 11B, not only 50 Hz and 100 Hz, but also third-order or higher harmonic components of 50 Hz have almost no FFT power.

  FIG. 12 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. 12A, a relatively high strength FFT power is exhibited at the 120 kHz portion. On the other hand, FIG. 12B shows a state in which the same failure as in FIG. 11B occurs. As can be seen from FIGS. 12A and 12B, the FFT power almost disappears at the 120 kHz portion.

  From the diagnosis results of FIGS. 11 and 12, 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.

  As described above, the circuit member 20 is analyzed by frequency analysis of the operation signal of the circuit obtained by the signal change detection unit 30 (frequency conversion of the signal and analysis of the frequency spectrum) as in the above embodiment. It is 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.

  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.

  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.

  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.

<Other configuration examples of the coil>
FIG. 13 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. Then, a planar coil was formed by forming a pattern on the support substrate 4 in a planar manner. 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.

  The wiring patterns 80a and 80b are mainly microstrip lines, but a magnetic field shown in FIG. 13A is generated by a current flowing through the wiring. As shown in FIG. 13A, a 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.

  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.

  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 (2).

  It should be noted that any device can 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 it 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 (2). Alternatively, the current flowing in the spiral coil 70 may be read.

  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.

  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.

  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.

  For example, as shown in FIG. 13B, 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.

  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.

  Further, as shown in FIG. 13C, similarly to the above-described embodiment, 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. As described above, the positions may be close to each other.

  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.

  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.

  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.

  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.

  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.

  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.

  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.

  FIG. 14 is a diagram showing an example of a hardware configuration in which a fault diagnosis system is configured by software using a CPU and a memory, that is, a fault diagnosis system is constructed using an electronic computer such as a personal computer. is there.

  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.

  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.

  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.

  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.

  It should be noted that the processing circuit 940 that does not perform all the processing of each functional part (particularly the comparison / determination unit) 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.

  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).

  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.

  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).

  The computer system 900 having such a configuration can be the same as the basic configuration and operation of the failure diagnosis unit 90 described 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.

  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.

  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.

  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.

  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.

  As mentioned above, although this invention was demonstrated using the said 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.

  The above embodiments do not limit the invention according to the claims (claims), and all the combinations of features described in the embodiments are essential for the solution of the invention. Is not limited. 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.

  For example, in the coil (including the spiral coil) and the capacitor shown in the above embodiment, the pattern is formed on the printed circuit board so as to correspond to the diagnosis target part. You may form by the method. 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.

  In the above embodiment, the coil and capacitor to be sensed are placed so that they come around the circuit when the flexible board is close to the circuit board. However, this is installed at a position where the most necessary information can be sensed. Is meant to do.

  Further, in the above embodiment, it has been suggested that a coil or a capacitor is formed as a flexible board and fixed to a circuit board or a cable. However, the flexible board to be the support board 4 can be assembled in a box. The circuit board or cable to be inspected may be housed in a box assembly and inspected.

  As described above, in this embodiment, there is a failure diagnosis method for diagnosing the presence or absence of a failure in a diagnosis target part such as a circuit board wiring or a mounted component from an abnormal sound emitted from an electronic circuit. The signal change detection unit is arranged in a non-contact and fixed manner with respect to the diagnosis target part, and is induced in the signal change detection part by electrostatic coupling or electromagnetic coupling between the diagnosis target part and the signal change detection unit. The electrical signal corresponding to the signal change in the diagnosis target part to be detected is detected, the detected electrical signal is frequency-converted, corrected in a predetermined frequency range, integrated, and the frequency characteristic is also in the predetermined frequency range. In addition to diagnosing the presence or absence of a failure in the diagnostic target part that causes abnormal noise, analyze the statistic calculated in step 1. And an electrical signal corresponding to the signal change at the normal state or abnormal diagnosis target site by frequency analysis, so as to diagnose the presence or absence of an electrical failure of the diagnosis target site.

  For this reason, it is possible to detect abnormal noise without being affected by ambient noise while monitoring circuit operation, and it is possible to automatically diagnose and identify the cause of abnormal noise. it can. Furthermore, since the electrical characteristics are detected at the same time, the electrical failure of the circuit can be diagnosed in detail by frequency analysis.

  In addition, since the signal change detection unit is fixedly arranged, there is no need for 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.

  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.

  Therefore, it is possible to construct a failure diagnosis system that can be incorporated into a system at low cost and can monitor circuit operation and abnormal noise with high accuracy without adding a complicated failure diagnosis circuit in failure diagnosis of an electronic circuit board. .

(A), (B) is a figure explaining the basic composition for realizing this embodiment. (A) is a block diagram showing a configuration example of a failure diagnosis unit, and (B) is a block diagram of the shaping circuit 42. It is a functional block diagram which shows the basic composition of a switching power supply circuit. (A) is an example of a component layout of the switching power supply circuit shown in FIG. (A) is a figure which shows the frequency characteristic of the abnormal sound detected in this Embodiment, (B) is a figure which shows the frequency characteristic by the measurement of a sound. It is an example of the correction curve which shows the value correct | amended for every frequency in the correction | amendment part of an allophone index calculation part. It is a figure which shows the example of the pattern of the frequency characteristic of the abnormal noise of the switching power supply circuit made into object by this Embodiment. (A) is a method for diagnosing abnormal noise failure according to the present embodiment, a table showing an example of the calculated abnormal noise index and statistics, (B) is a reference for identifying the failure location from the calculated value It is a figure which shows a table. It is a conceptual diagram explaining the method of performing a failure diagnosis by analyzing the frequency of the induced electromotive force signal of the coil. It is a schematic circuit diagram of the switching power supply circuit made into object by this Embodiment. It is a figure which shows the frequency spectrum of the coil provided in the noise filter of the switching power supply circuit shown in FIG. It is a figure which shows the frequency spectrum of the coil provided in the control circuit of the switching power supply circuit shown in FIG. It is a figure which shows the other structural example of the coil which makes a detection probe. It is the figure which showed an example of the hardware constitutions in the case of constructing | assembling a failure diagnosis system using an electronic computer.

Explanation of symbols

1 Fault diagnosis system 4 Support board 10 Circuit board (electronic circuit)
32 coil (signal detection means)
33 Capacitor 70 Spiral Coil 90 Fault Diagnosis Unit 44 Frequency Conversion Unit (Conversion Unit)
45 Allophone index calculation part (calculation means)
47 Abnormal sound failure determination unit (determination means)
46 Statistical processing section (detection means)
50 Comparison determination unit (determination means)

Claims (13)

Signal detection means for detecting a signal flowing in the electronic circuit;
Conversion means for converting the detected signal into a frequency component;
Calculating means for calculating an abnormal sound index, which is a physical quantity representing the magnitude of the abnormal sound generated due to the change in the signal, from the converted frequency component;
Determination means for determining whether or not a failure has occurred in the electronic circuit based on the calculated abnormal sound index;
With
The calculation means corrects the value of the frequency component with a correction value determined in advance according to the frequency for correcting the value of the frequency component to a value corresponding to the sensitivity of human hearing depending on the frequency, and the corrected frequency component The failure diagnosing apparatus is characterized in that the abnormal noise index is calculated by integrating the value of within a predetermined frequency range in which abnormal noise is generated. Signal detection means for detecting a signal flowing in the electronic circuit;
Conversion means for converting the detected signal into a frequency component;
Calculating means for calculating an abnormal sound index, which is a physical quantity representing the magnitude of the abnormal sound generated due to the change in the signal, from the converted frequency component;
Detection means for detecting a peak frequency and its intensity of the converted frequency component, and dispersion and standard deviation in a frequency range to be calculated ;
Determination means for determining a failure location of the electronic circuit based on the calculated abnormal sound index, the peak frequency of the detected frequency component and its intensity, and variance and standard deviation ;
With
The calculation means corrects the value of the frequency component with a correction value determined in advance according to the frequency for correcting the value of the frequency component to a value corresponding to the sensitivity of human hearing depending on the frequency, and the corrected frequency component The failure diagnosing apparatus is characterized in that the abnormal noise index is calculated by integrating the value of within a predetermined frequency range in which abnormal noise is generated.   The failure diagnosis apparatus according to claim 1, wherein the determination unit further determines an electrical failure based on the converted frequency component.   The fault diagnosis apparatus according to claim 1, wherein the signal detection unit detects the signal without contacting the electronic circuit.   The fault diagnosis apparatus according to any one of claims 1 to 4, wherein the signal detection means includes a passive element.   6. The fault diagnosis apparatus according to claim 5, wherein the passive element is a capacitive reactance element that forms electrostatic coupling or an inductive reactance element that forms electromagnetic coupling.   The fault diagnosis apparatus according to claim 6, wherein the reactance element is formed on a circuit board by a wiring pattern.   8. The fault diagnosis apparatus according to claim 6, wherein the reactance element is a coil composed of windings arranged so as to surround a functional block of the electronic circuit.   The reactance element is opposed to the diagnosis target part in the electronic circuit, and the magnetic path length is substantially the same as or less than the width of the diagnosis target part, and is perpendicular and fixed to the direction of the signal flowing through the diagnosis target part. The fault diagnosis apparatus according to claim 6, wherein the fault diagnosis apparatus is a spiral coil disposed in the coil. The spiral coil is
A plurality of conductors formed by cutting off a part of two opposing conductor layers formed by a printed wiring pattern on a predetermined circuit board;
While supporting the conductor layer, a support layer through hole is formed for connecting between each of the plurality of conductors vertically,
With
The fault diagnosis apparatus according to claim 9, wherein the magnetic path length of the spiral coil is set to be substantially the same as or less than a predetermined wiring pattern corresponding to the diagnosis target part. Integrating means for integrating the detected signal;
A digital converter that converts the integrated signal into a digital value using different sampling clocks in a high-frequency region and a low-frequency region; and
With
The converting means converts the digital value into a frequency component;
The fault diagnosis apparatus according to claim 1, wherein the fault diagnosis apparatus is a fault diagnosis apparatus. Detecting a signal flowing in the electronic circuit;
Converting the detected signal into a frequency component;
Calculating an abnormal sound index, which is a physical quantity representing the magnitude of the abnormal sound generated due to the change in the signal, from the converted frequency component;
Determining whether a failure has occurred in the electronic circuit based on the calculated abnormal sound index;
With
In the calculating step, the frequency component value is corrected with a correction value determined in advance according to a frequency for correcting the value of the frequency component to a value corresponding to the sensitivity of human hearing depending on the frequency, and the corrected frequency A failure diagnosis method, wherein the abnormal sound index is calculated by integrating component values within a predetermined frequency range in which abnormal sound is generated. Detecting a signal flowing in the electronic circuit;
Converting the detected signal into a frequency component;
Calculating an abnormal sound index, which is a physical quantity representing the magnitude of the abnormal sound generated due to the change in the signal, from the converted frequency component;
Detecting the peak frequency of the converted frequency component and its intensity, and the variance and standard deviation in the frequency range to be calculated ;
Determining a fault location of the electronic circuit based on the calculated abnormal index, the peak frequency of the detected frequency component and its intensity, and variance and standard deviation ;
With
In the calculating step, the value of the frequency component is corrected with a correction value determined in advance according to a frequency for correcting to a value corresponding to the sensitivity of human hearing depending on the frequency, and then the corrected A failure diagnosis method, wherein the abnormal sound index is calculated by integrating the value of the frequency component within a predetermined frequency range in which abnormal sound is generated.

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