JP6915780B2 - Conduction noise visualization device and conduction noise visualization method - Google Patents

Description

The present invention relates to a conduction noise visualization device and a conduction noise visualization method for measuring (visualizing) conduction interference waves (conduction noise) generated by electrical / electronic equipment.

In the internal circuits of electrical and electronic equipment, tests (magnetic field probe method) are conducted to measure the magnetic field generated from semiconductors such as ICs and LSIs for the purpose of identifying the noise source of conduction noise and visualizing the transmission path. (See, for example, Non-Patent Document 1.).

In this test, the magnetic field strength at the measurement point and the frequency characteristics of the magnetic field strength are measured in the vicinity of the measurement target using a magnetic field probe, and from the results, the measurement point and the magnetic field strength are mapped on a plane. The noise source etc. are specified.

In addition, an electrostatic discharge (ESD) gun and a magnetic field probe are used for the purpose of visualizing the effect of transient electromagnetic fields such as static electricity on the circuit and visualizing the transmission path of conduction noise on the time axis. Therefore, a method of applying static electricity with an ESD gun and measuring the magnetic field strength at the measurement point and its time (phase) characteristics at that timing has also been proposed (see, for example, Non-Patent Document 2).

International Standard IEC 61967-6, “Measurement of Conducted Emissions, Magnetic Probe Method” Shiratori, et al., “EMC Visualization Solution-Visualization of Noise and Static Electricity-,” Electromagnetic Environmental Engineering Information EMC. No. 341, pp.103-113, 2016

Wide bandgap power semiconductor devices using SiC (silicon carbide), GaN (gallium nitride), etc. are incorporated as power supply circuits for electrical and electronic equipment. Conduction noise from these power semiconductor devices is generated at regular intervals due to the speed of the switching operation due to the characteristic that the switching operation is constantly performed.

When visualizing the transmission path of conduction noise on the time axis, in the conventional method, the transmission path of conduction noise generated by the applied static electricity is set to a plane (circuit plane) corresponding to the circuit to be measured. The intensity of static electricity measured at each measurement point is shown above by shades of color, and this can be visualized by comparing them in chronological order as multiple circuit planes generated for each of a plurality of measurement times. However, it has not been possible to visualize the transmission path of conduction noise generated by the switching operation of the power semiconductor device.

The present invention has been made in view of such a problem, and is a conduction noise visualization device and a conduction noise that make it possible to visualize the transmission path of the conduction noise generated by the switching operation of the semiconductor device on the time axis. The purpose is to provide a visualization method.

The conduction noise visualization device according to the present invention is detected by the trigger detecting means for detecting a trigger accompanying the switching operation of the circuit to be measured and the trigger detecting means at each measurement point arbitrarily set in the circuit to be measured. The maximum of the magnetic field strength measuring means for measuring the magnetic field strength at each measurement time arbitrarily set from the time when the trigger is detected and the magnetic field strength for each measurement time measured at each measurement point by the magnetic field strength measuring means. A data storage means that stores magnetic field strength data within an arbitrary difference range from the magnetic field strength of the above in association with the corresponding measurement point and measurement time, and the measurement time at each measurement point stored by the data storage means. Of the respective magnetic field strengths, the measurement time extraction means for extracting the measurement time at which the maximum magnetic field strength was measured and the measurement time at which the maximum magnetic field strength was measured, extracted by the measurement time extraction means, correspond. Based on the maximum magnetic field strength measurement time storage means stored in association with the measurement point, the measurement time in which the maximum magnetic field strength stored by the maximum magnetic field strength measurement time storage means was measured, and the corresponding measurement point, respectively. It is provided with a display control means for synthesizing an image showing a measurement point at which the maximum magnetic field strength was measured at each measurement time in chronological order of the measurement time with the image data of the circuit to be measured and displaying the image on the display unit.

According to the present invention, it is possible to visualize the transmission path on the time axis of the conduction noise generated by the switching operation of the semiconductor device.

The block diagram which shows the structure of the function of the conduction noise visualization apparatus 10 which concerns on 1st Embodiment of this invention. The block diagram which shows the structure of the conduction noise visualization apparatus 10. The figure which shows the relationship between the image data G of the power supply circuit 30 photographed by the camera 22 of the conduction noise visualization apparatus 10 and each measurement point P on the image data G. The block diagram which shows the structure of the function of the power supply circuit 30. The flowchart which shows the conduction noise visualization process of the conduction noise visualization apparatus 10. _{According to the conduction noise visualization process of the conduction noise visualization device 10, each measurement time t 0} , t ₁ , ..., T at each measurement point P (0,0) (0,1) ... (m, n) of the circuit under test. _The figure which shows the image which mapped the data of the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _{L acquired for each L to the image data G of the circuit under test.} The figure which shows the visualization image of _{the conduction noise transmission path NL} generated by the conduction noise visualization process of the conduction noise visualization apparatus 10. The block diagram which shows the structure of the function of the conduction noise visualization apparatus 10A which concerns on 2nd Embodiment of this invention. According to the conduction noise visualization process of the conduction noise visualization device 10A of the second embodiment, each measurement time t ₀ , t at each measurement point P (0,0) (0,1) ... (m, n) of the circuit under test. _{The data} of the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _L at the specified frequency bandwidth (0.1 * f _A ) acquired for each 1, ..., T _{L is} used as the image data G of the circuit to be measured. The figure which shows the image mapped to. The figure which shows the visualization image of the conduction noise transmission path _{NL in the designated frequency bandwidth (0.1 * f A} ) generated by the conduction noise visualization process of the conduction noise visualization apparatus 10A of the 2nd Embodiment. According to the conduction noise visualization process of the conduction noise visualization device 10A of the second embodiment, each measurement time t ₀ , t at each measurement point P (0,0) (0,1) ... (m, n) of the circuit under test. _{The data} of the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _L at the specified frequency bandwidth (0.1 * f _B ) acquired for each 1, ..., T _{L is} used as the image data G of the circuit to be measured. The figure which shows the image mapped to. The figure which shows the visualization image of the conduction noise transmission path _{NL in the designated frequency bandwidth (0.1 * f B} ) generated by the conduction noise visualization process of the conduction noise visualization apparatus 10A of the 2nd Embodiment.

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

(First Embodiment)
FIG. 1 is a block diagram showing a configuration of functions of the conduction noise visualization device 10 according to the first embodiment of the present invention.

The conduction noise visualization device 10 of the first embodiment is composed of an image capturing unit 11, a trigger unit 12, a magnetic field measuring unit 13, a data input / output unit 14, a storage unit 15, a control unit 16, and a display unit 17, and is a power semiconductor. It has a function of visualizing the transmission path of conduction noise for the power supply circuit 30 equipped with the device.

The image capturing unit 11 photographs the power supply circuit 30.

The trigger unit 12 detects a trigger associated with the switching operation of the power supply circuit 30.

The magnetic field measuring unit 13 measures the magnetic field strength of each measurement point (measurement point) set in the power supply circuit 30.

The data input / output unit 14 inputs data such as a measurement resolution for setting each measurement point in the power supply circuit 30, and each measurement time for setting a plurality of measurement timings from the detection time of the trigger. It also outputs data according to the measurement results.

The storage unit 15 includes image data of the power supply circuit 30 taken by the image capturing unit 11, data such as each measurement point and each measurement time according to the measurement resolution input by the data input / output unit 14, and the magnetic field. The data of the magnetic field strength for each measurement time at each measurement point measured by the measurement unit 13 is stored.

The control unit 16 has a photographing function by the image capturing unit 11, a function of storing captured image data in the storage unit 15, and data of magnetic field strength measured by the magnetic field measuring unit 13 at each of the measuring points. In the function of acquiring the peak value for each measurement time and storing it in the storage unit 15, the image data stored in the storage unit 15 and the peak value of the magnetic field strength for each measurement time at each of the measurement points. Based on the above data, the display unit 17 controls the function of displaying the transmission path of the conduction noise in the power supply circuit 30 and the like.

FIG. 2 is a block diagram showing the configuration of the conduction noise visualization device 10.

The conduction noise visualization device 10 includes a control PC (personal computer) 21, and realizes a function of visualizing the conduction noise transmission path by executing a conduction noise visualization processing program on the control PC 21. ..

A camera 22 and an oscilloscope 23 are connected to the control PC 21, and a voltage probe 24 and a magnetic field probe 25 are connected to the oscilloscope 23. Further, a probe moving machine (scanner) 26 for moving the magnetic field probe 25 to each measurement point on the power supply circuit 30 and scanning the control PC 21 is connected to the control PC 21. The control PC 21 includes a storage unit 27 such as a hard disk and a flash memory, and a display unit 28 such as a liquid crystal color display.

The image capturing unit 11 shown in FIG. 1 is realized by the camera 22, the trigger unit 12 and the magnetic field measuring unit 13 are realized by the oscilloscope 23, the voltage probe 24, and the magnetic field probe 25, and the data input / output unit 14 and the storage unit are stored. 15, the control unit 16, and the display unit 17 are realized by the control PC 21 and the probe moving device 26.

FIG. 3 is a diagram showing the relationship between the image data G of the power supply circuit 30 taken by the camera 22 of the conduction noise visualization device 10 and each measurement point P on the image data G.

The fineness of each measurement point P (0,0) (0,1) ... (m, n) with respect to the power supply circuit 30 depends on an arbitrary measurement resolution input according to the user operation in the control PC 21. Is set.

FIG. 4 is a block diagram showing a functional configuration of the power supply circuit 30.

The power supply circuit 30 is installed between the power supply 40 and the load 50, and is used for driving a power conversion circuit 31 that converts electric power using a power semiconductor device, a transformer, or the like, and a power semiconductor device in the power conversion circuit 31. It is composed of a drive circuit 32 that supplies a voltage, and a control circuit 33 that observes the input / output voltage and current and controls the frequency and ON / OFF timing of the voltage supplied by the drive circuit 32 based on the result. NS.

Here, since the switching operation of the power semiconductor device in the power conversion circuit 31 is controlled by the voltage supplied from the drive circuit 32, the conduction noise and the timing at which the magnetic field associated with the conduction noise is generated are also described above. It depends on the voltage supplied from the drive circuit 32. Therefore, by installing the voltage probe 24 for trigger detection at the output end of the drive circuit 32, a trigger for starting measurement is obtained at the timing when conduction noise is generated due to the switching operation of the power semiconductor device. be able to.

In the conduction noise visualization device 10 configured in this way, the CPU of the control PC 21 controls the operation of each part in the device according to the instruction described in the program of the conduction noise visualization process, and the software and the hardware cooperate with each other. By working and operating, various functions as described in the following operation explanation are realized.

Next, the operation of the conduction noise visualization device 10 having the above configuration will be described.

FIG. 5 is a flowchart showing the conduction noise visualization process of the conduction noise visualization device 10.

First, the user operates the control PC 21, and the measurement resolution for setting each measurement point P (0,0) (0,1) ... (m, n) in the power supply circuit 30, and the trigger by the voltage probe 24. Input _{each measurement time t 0} , t ₁ , ..., T _L for setting a plurality of measurement timings from the detection time of. The input measurement resolution and the data of each measurement time t ₀ , t ₁ , ..., T _L are stored in the storage unit 27.

When the user operates the control PC 21 and instructs the start of the conduction noise visualization process, the power supply circuit 30 as the circuit to be measured, which is arranged in advance at a predetermined position, is photographed by the camera 22, and the photographed image data G is It is stored in the storage unit 27 (step S1).

As shown in FIG. 3, the control PC 21 divides the image data G stored in the storage unit 27 according to the measurement resolution data, and divides each measurement point into the two-dimensional coordinates P which are the position information thereof. It is determined as (0,0) (0,1) ... (m, n) and stored in the storage unit 27 (step S2).

Then, the control PC 21 has the origin position information P (0,0) out of the position information P (0,0) (0,1) ... (m, n) of each measurement point stored in the storage unit 27. ) Is transferred to the probe moving device 26, and the magnetic field probe 25 is moved to the first measurement point P (0,0) of the power supply circuit 30 (step S3).

A preset constant voltage (voltage for switching the power semiconductor device in the power conversion circuit 31) is measured by the voltage probe 24 installed at the output end of the drive circuit 32 in the power supply circuit 30 (see FIG. 4). As a result, when the trigger is detected by the control PC 21 via the oscilloscope 23 (step S4 (Yes)), the measurement times t ₀ , t ₁ , stored in the storage unit 27 from the time when the trigger is detected, respectively. ..., Data of the magnetic field strength measured through the oscilloscope 23 by the magnetic field probe 25 is acquired for each _{t L (step S5).}

The control PC 21 has each magnetic field strength (peak value) Ht _{0 acquired for each measurement time t 0} , t ₁ , ..., T _L at the position of the measurement point P (0, 0) of the power supply circuit 30. , Ht ₁ , ..., Ht _L data is associated with the position information P (0, 0) of the measurement point and the data of each measurement time t ₀ , t ₁ , ..., T _{L in} the storage unit 27. It is memorized (step S6). At this time, among the data of each magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _{L acquired for each measurement time t 0} , t ₁ , ..., T _L , further arbitrary from the peak value. Only the data within the range of the difference (for example, [-5 dB]) is stored to reduce the amount of data.

Then, the control PC 21 determines whether or not the current movement position (measurement point) of the magnetic field probe 25 with respect to the power supply circuit 30 has reached the final measurement point stored in the storage unit 27 (step). S7).

Here, since it is determined that the current measurement point P (0,0) is not the final measurement point (step S7 (No)), the measurement point next to the current measurement point P (0,0) is determined. The position information P (0,1) is transferred to the probe moving device 26, and the magnetic field probe 25 is moved to the next measurement point P (0,1) of the power supply circuit 30 (step S8).

Then, at the measurement point P (0, 1) after the movement of the magnetic field probe 25, each measurement time t ₀ , t _{1 from the time of trigger detection according to the voltage measured by the voltage probe 25 is similarly described above.} , ..., Data of the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _{L measured by the magnetic field probe 25 is acquired for each t L} , and the position information P (0, 1) of the measurement point is acquired. ) And the data of each measurement time t ₀ , t ₁ , ..., T _L and stored in the storage unit 27 (steps S4 to S6).

After that, the control PC 21 repeatedly executes the processes of steps S4 to S8 in the same manner, so that all the measurement points P (0,0) (0,1) ... (m, n) of the power supply circuit 30 are executed. Data of magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _L for each measurement time t ₀ , t ₁ , ..., T _L in the above are acquired and stored in the storage unit 27.

Then, when it is determined that the current moving position (measurement point) of the magnetic field probe 25 with respect to the power supply circuit 30 has reached the final measurement point stored in the storage unit 27 (step S7 (Yes)), Acquisition of magnetic field strength on the time axis for all measurement points P (0,0) (0,1) ... (m, n) of the power supply circuit 30 executed according to steps S4 to S8 and processing of its storage. Is completed, and the process proceeds to step S9.

_{FIG. 6 shows each measurement time t 0} , t ₁ at each measurement point P (0,0) (0,1) ... (m, n) of the circuit under test according to the conduction noise visualization process of the conduction noise visualization device 10. It is a figure which shows the image which mapped the data of the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _L acquired for every t _{L to the image data G of the circuit under test.} Here, the strength of the magnetic field strength H mapped to the image data G is expressed by the shade of color.

That is, the control PC 21 has each measurement time at each measurement point P (0,0) (0,1) ... (m, n) of the power supply circuit (measured circuit) 30 stored in the storage unit 27. As shown in FIG. 6, the image data corresponding to the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _{L for each t 0} , t ₁ , ..., T _{L is the image data G of the power supply circuit 30.} By mapping (drawing and synthesizing) to and displaying on the display unit 28, the user can use the power conversion circuit 31 in each unit P (0,0) (0,1) ... (m, n) of the power supply circuit 30. The time (phase) characteristics of the magnetic field strength of the conduction noise generated by the switching operation of the power semiconductor device can be visually confirmed.

_{Next, the control PC 21 has each measurement time t 0} , t ₁ , ..., T for each measurement point P (0,0) (0,1) ... (m, n) stored in the storage unit 27. magnetic field intensity _{Ht 0,} Ht 1 in _L, ..., measurement points for comparing the Ht _L, of which extracts a maximum measurement time field strength Hmax is obtained _{t n} max, corresponds to the measurement time _{t n} max that the extracted Is stored in association with the position information P (m, n) of (step S9).

Then, the control PC 21 has a measurement time t in which the maximum magnetic field strength Hmax for each measurement point P (0,0) (0,1) ... (m, n) stored in the storage unit 27 in step S9 is obtained. based on the _n max data, for example, as shown in FIG. 7 (a) (B) ... (C), the time order of the measurement time t _n max, measurement points P corresponding to the measurement time t _n max The image data corresponding to (m, n) is sequentially mapped (drawn and synthesized) to the image data G of the power supply circuit 30, and as shown in FIG. 7D, the display unit 28 is used as _{the transmission noise transmission path NL.} Is displayed (step S10).

FIG. 7 is a diagram showing a visualization image of _{the conduction noise transmission path NL} generated according to the conduction noise visualization process of the conduction noise visualization device 10.

As a result, the user can visually confirm _{the transmission path NL} of the conduction noise generated by the switching operation of the power semiconductor device in the power conversion circuit 31 in the power supply circuit 30.

Therefore, according to the conduction noise visualization device 10 having the above configuration, the switching operation of the power semiconductor device is detected as a trigger for the power supply circuit 30 as the measurement circuit, and each measurement point according to the measurement resolution input in advance. At P (0,0) (0,1) ... (m, n), the magnetic field strength Ht ₀ , Ht ₁ , ..., Ht for _{each predetermined measurement time t 0} , t ₁ , ..., T _{L. L} is measured, and at each measurement point P (0,0) (0,1) ... (m, n), _{the data of the measurement times t 0} , t ₁ , ..., T _L and the measured magnetic field strength are obtained, respectively. The data of Ht ₀ , Ht ₁ , ..., Ht _L are stored in association with each other. Then, the measuring points P (0,0) (0,1) ... (m, n) the maximum magnetic field strength Hmax extracts the measurement time t n _... associated within each extracted each measurement time t _n The image data corresponding to the measurement point P (m, n) to which the maximum magnetic field strength Hmax is associated is mapped (drawn and synthesized) to the image data G captured by the power supply circuit 30 in the order of time of ... Is displayed on the display unit 28 as the transmission path _{NL of.}

This makes it possible to visualize the transmission path on the time axis of the conduction noise generated by the switching operation of the power semiconductor device.

(Second Embodiment)
FIG. 8 is a block diagram showing a functional configuration of the conduction noise visualization device 10A according to the second embodiment of the present invention.

The conduction noise visualization device 10A of the second embodiment is described from the image capturing unit 11, the trigger unit 12, the magnetic field measuring unit 13, the data input / output unit 14, the storage unit 15, the control unit 16, the display unit 17, and the frequency filter unit 18. It has a function of visualizing a transmission path of conduction noise in which a frequency band is specified for a power supply circuit 30 which is configured and is equipped with a power semiconductor device.

That is, the conduction noise visualization device 10A of the second embodiment has a magnetic field strength of the conduction noise measured by the magnetic field measuring unit 13 as compared with the conduction noise visualization device 10 of the first embodiment shown in FIG. The difference is that the frequency filter unit 18 acquires the magnetic field strength in a frequency band specified in advance.

Wherein the frequency filter unit 18, the control PC21 conduction noise visualization apparatus 10 shown in FIG. 2, the frequency band to be limited, which is input in response to a user operation center frequency (e.g., f _A) and any bandwidth Based on the data of (for example, 0.1 * f _A ), it is composed of a digital filter that is acquired by passing only the component of the corresponding frequency band out of the magnetic field strength of the conduction noise measured from the magnetic field probe 25 via the oscilloscope 23. do.

Then, in the conduction noise visualization device 10A of the second embodiment having the above configuration, the magnetic field acquired for _{each measurement time t 0} , t ₁ , ..., T _{L in step S5 of the conduction noise visualization process shown in FIG.} The intensity data is acquired by performing a filter process that allows only the components of the designated frequency band to pass through the digital filter.

That is, a preset constant voltage (voltage for switching the power semiconductor device in the power conversion circuit 31) is generated by the voltage probe 24 installed at the output end of the drive circuit 32 in the power supply circuit 30 (see FIG. 4). When the trigger is detected by the control PC 21 via the oscilloscope 23 (step S4 (Yes)), the measurement times t ₀ , t stored in the storage unit 27 from the time when the trigger is detected are measured. _For each 1, ..., T _L , the magnetic field strength data measured by the magnetic field probe 25 via the oscilloscope 23 is acquired as a peak value limited to a designated frequency band (step S5).

The control PC 21 is limited to the designated frequency band for _{each measurement time t 0} , t ₁ , ..., T _L at the position of the measurement point P (m, n) of the power supply circuit 30. Magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _L data, position information P (m, n) of the measurement point and measurement time t ₀ , t ₁ , ..., t _L data Is stored in the storage unit 27 in association with (step S6).

Since other processes are performed in the same manner as the conduction noise visualization process in the conduction noise visualization device 10 of the first embodiment, detailed description thereof will be omitted.

FIG. 9 shows each measurement time at each measurement point P (0,0) (0,1) ... (m, n) of the circuit under test according to the conduction noise visualization process of the conduction noise visualization device 10A of the second embodiment. _{t 0, t 1, ...,} t field strength (peak _value) in the _L acquired specified frequency bandwidth for each _{(0.1 * f a) Ht 0} , Ht 1, ..., data of Ht _L, measured circuit It is a figure which shows the image mapped to the image data G of.

FIG. 10 is a diagram showing a visualization image of the conduction noise transmission path _{NL in the specified frequency bandwidth (0.1 * f A} ) generated according to the conduction noise visualization process of the conduction noise visualization device 10A of the second embodiment. be.

FIG. 11 shows each measurement time at each measurement point P (0,0) (0,1) ... (m, n) of the circuit under test according to the conduction noise visualization process of the conduction noise visualization device 10A of the second embodiment. The data of the magnetic field strength (peak value) Ht ₀ , Ht ₁ , ..., Ht _L at the specified frequency bandwidth (0.1 * f _{B ) acquired for each t 0} , t ₁ , ..., T _{L is} measured by the circuit to be measured. It is a figure which shows the image mapped to the image data G of.

FIG. 12 is a diagram showing a visualization image of the conduction noise transmission path _{NL in the specified frequency bandwidth (0.1 * f B} ) generated according to the conduction noise visualization process of the conduction noise visualization device 10A of the second embodiment. be.

Therefore, according to the conduction noise visualization device 10A of the second embodiment of the above configuration, among the conduction noise generated by the switching operation of the power semiconductor device, the conduction noise in the frequency band arbitrarily specified by the user has a time axis. It becomes possible to visualize the transmission path in the above.

In addition, each processing method by the conduction noise visualization device 10 (10A) described in each of the above-described embodiments, that is, each method such as the conduction noise visualization processing shown in FIGS. 5 to 7 and 9 to 12 is all. External programs such as memory cards (ROM cards, RAM cards, etc.), magnetic disks (floppy (registered trademark) disks, hard disks, etc.), optical disks (CD-ROM, DVD, etc.), semiconductor memories, etc. can be executed by computers. It can be stored and distributed on the medium of the recording device. Then, the computer (control PC21 (CPU)) of the electronic device (conduction noise visualization device 10 (10A)) reads the program recorded on the medium of the external recording device into the storage device, and the read program operates the operation. By being controlled, the function of the conduction noise visualization described in each of the above-described embodiments can be realized, and the same processing by the above-described method can be executed.

Further, the data of the program for realizing each of the above methods can be transmitted on the network in the form of the program code, and the data of the program is taken into the electronic device from the computer device connected to the network and stored in the storage device. It is also possible to realize the above-mentioned transmission noise visualization function by storing it in a computer.

The present invention is not limited to each of the above-described embodiments, and can be variously modified at the implementation stage without departing from the gist thereof. Further, each of the above-described embodiments includes inventions at various stages, and various inventions can be extracted by an appropriate combination of a plurality of disclosed constituent requirements. For example, even if some constituent requirements are deleted from all the constituent requirements shown in each embodiment or some constituent requirements are combined in different forms, the problems described in the section of the problem to be solved by the invention Can be solved and the effects described in the section on the effects of the invention can be obtained, the configuration in which this constituent requirement is deleted or combined can be extracted as the invention.

10 ... Conduction noise visualization device (first embodiment),
10A ... Conduction noise visualization device (second embodiment),
11 ... Imaging unit, 12 ... Trigger unit, 13 ... Magnetic field measurement unit, 14 ... Data input / output unit,
15 ... storage unit, 16 ... control unit, 17 ... display unit, 18 ... frequency filter unit,
21 ... Control PC, 22 ... Camera, 23 ... Oscilloscope, 24 ... Voltage probe,
25 ... Magnetic field probe, 26 ... Probe moving device, 27 ... Storage unit of control PC,
28 ... Control PC display, 30 ... Power supply circuit, G ... Image data of power supply circuit,
P (0,0) to P (m, n) ... measurement point, t _{0 to t L} ... measurement time,
Ht _{0 to Ht L} ... Magnetic field strength, NL ... Conduction noise transmission path.

Claims (6)

A trigger detection means that detects a trigger as the switching operation of the circuit under test is performed, and
A magnetic field strength measuring means that measures the magnetic field strength at each measurement point arbitrarily set in the circuit to be measured at each measurement time arbitrarily set from the detection time of the trigger detected by the trigger detecting means.
Of the magnetic field strengths for each measurement time measured at each measurement point by the magnetic field strength measuring means, the magnetic field strength data within a range of an arbitrary difference from the maximum magnetic field strength is used as the corresponding measurement point and measurement time. Data storage means to store in association with
A measurement time extraction means for extracting the measurement time in which the maximum magnetic field strength was measured among the magnetic field strengths for each measurement time at each measurement point stored by the data storage means.
A maximum magnetic field strength measurement time storage means that stores the measurement time at which the maximum magnetic field strength was measured, which is extracted by the measurement time extraction means, in association with the corresponding measurement point.
Maximum magnetic field strength measurement time The maximum magnetic field strength is measured at each measurement time in the order of time of each measurement time based on the measurement time at which the maximum magnetic field strength was measured and the corresponding measurement point stored by the storage means. A display control means for synthesizing an image showing a measurement point with the image data of the circuit to be measured and displaying it on a display unit.
Conducted noise visualization device equipped with. The magnetic field strength measuring means has a frequency arbitrarily set for each measurement time arbitrarily set from the detection time of the trigger detected by the trigger detecting means at each measurement point arbitrarily set in the circuit to be measured. Measure the magnetic field strength in the band,
The conduction noise visualization device according to claim 1. The circuit under test includes a power conversion circuit that converts electric power using a power semiconductor device, and a power supply circuit that includes a drive circuit that supplies a driving voltage to the power semiconductor device.
The trigger detecting means has a voltage probe installed at the output end of the drive circuit, and detects a trigger as the switching operation of the power semiconductor device is performed based on the voltage measured by the voltage probe.
The conduction noise visualization device according to claim 1 or 2. An imaging means for photographing the circuit to be measured and
A measurement point setting means for setting a measurement point of the measurement circuit according to an arbitrary measurement resolution with respect to the image data of the measurement circuit photographed by the imaging means, and a measurement point setting means.
The conduction noise visualization device according to any one of claims 1 to 3, further comprising. The magnetic field strength measuring means includes a magnetic field probe for measuring the magnetic field strength and a probe moving means for moving the magnetic field probe on the circuit to be measured, and the magnetic field probe is moved to the circuit to be measured by the probe moving means. It is moved to each measurement point arbitrarily set, and the magnetic field strength is measured at each measurement point at each measurement time arbitrarily set from the detection time of the trigger detected by the trigger detecting means.
The conduction noise visualization device according to any one of claims 1 to 4. It is a conduction noise visualization method for visualizing the transmission path of conduction noise in the circuit under test by the control unit of an electronic device equipped with a display unit.
A trigger is detected as the switching operation of the circuit under test is performed.
At each measurement point arbitrarily set in the circuit to be measured, the magnetic field strength is measured at each measurement time arbitrarily set from the time when the trigger is detected.
Of the magnetic field strengths for each measurement time measured at each measurement point, the magnetic field strength data within a range of an arbitrary difference from the maximum magnetic field strength is stored in association with the corresponding measurement point and measurement time.
Of the magnetic field strengths for each measurement time at each of the stored measurement points, the measurement time at which the maximum magnetic field strength was measured was extracted.
The measured measurement time at which the extracted maximum magnetic field strength was measured is stored in association with the corresponding measurement point.
Based on the memorized measurement time at which the maximum magnetic field strength was measured and the corresponding measurement point, an image showing the measurement point at which the maximum magnetic field strength was measured at each measurement time is shown in chronological order of each measurement time. Combined with the image data of the circuit to be measured and displayed on the display unit,
Conducted noise visualization method.

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