JP6868196B2 - Fuse deterioration diagnosis method and deterioration diagnosis device - Google Patents

Description

The present invention relates to a deterioration diagnosis method and a deterioration diagnosis device for diagnosing a deterioration state of a fuse based on an increase in the electric resistance value of the fuse.

When Joule heat is repeatedly generated in the fuse, oxidation of the fuse and metal fatigue of the solder portion occur, and the electric resistance value increases. When the deterioration of the fuse progresses and the life of the fuse is reached, the fuse eventually breaks.

The following are known as conventional techniques for diagnosing deterioration and life of a fuse.
For example, in Patent Document 1, the fuse loss is obtained by using the current flowing through the fuse and the resistance value, the fuse temperature is estimated by using the fuse loss and the thermal resistance of the fuse, and the time-series change of the temperature estimation value is obtained. Describes a life estimation device that counts the number of occurrences of thermal ripple from the fuse and estimates that the fuse replacement time (life) has come when the count value reaches the set number of times.

Further, in Patent Document 2, for a fuse having a blown portion in which a low melting point metal is laminated on a high melting point metal base material, the temperature of the blown portion when a unit time elapses is estimated from the current flowing through the fuse, and the temperature is estimated. Deterioration diagnosis that calculates the total metallization progress over the entire usage time using the data showing the correlation between the value and the alloying progress over a unit time, and diagnoses the deterioration of the fuse based on this total metallization progress. The device is described.

Japanese Unexamined Patent Publication No. 2007-43860 (paragraphs [0010] to [0034], FIGS. 1, 2, etc.) Japanese Unexamined Patent Publication No. 2016-143597 (paragraphs [0024] to [0051], FIG. 1, etc.)

All of the above-mentioned conventional techniques focus on the temperature history of the fuse to diagnose the life and deterioration. However, these prior arts estimate the increase in resistance value, that is, the deterioration of the fuse, based on the temperature of the fuse, and do not detect the increase in the resistance value of the fuse, so that the deterioration diagnosis accuracy is insufficient. , It was not perfect as a countermeasure against the manufacturing variation of fuses.

Therefore, the problem to be solved by the present invention is to provide a fuse deterioration diagnosis method and a deterioration diagnosis device capable of diagnosing fuse deterioration with high accuracy by utilizing a so-called stochastic resonance phenomenon, which is one of the phenomena for improving detection sensitivity. To provide.

In order to solve the above problem, in the method for diagnosing deterioration of a fuse according to claim 1, noise is superimposed on the voltage of the capacitor when a diagnostic pulse voltage is applied to a series circuit of the fuse and the capacitor to be diagnosed. 1 Diagnostic signal is generated, the first diagnostic signal is compared with a threshold value to obtain a pulsed second diagnostic signal, and the integration result of the second diagnostic signal is compared with a reference voltage to generate a reset signal. It is characterized in that deterioration of the fuse is diagnosed by statistically processing the pulse width of the diagnostic pulse voltage reset by the reset signal and detecting a change in the resistance value of the fuse.

The fuse deterioration diagnosis method according to claim 2 is the fuse deterioration diagnosis method according to claim 1, wherein the noise is white noise generated by the noise generating means or is M-sequence. And.

The fuse deterioration diagnosis method according to claim 3 is the process for obtaining the median value of the pulse width of the diagnosis pulse voltage in the fuse deterioration diagnosis method according to claim 1 or 2. It is characterized in that the change in the resistance value of the fuse is detected based on the change in the value.

The fuse deterioration diagnosis method according to claim 4 is the fuse deterioration diagnosis method according to any one of claims 1 to 3, wherein the amplitude of the diagnosis pulse voltage is substantially equal to the threshold value.

The fuse deterioration diagnostic apparatus according to claim 5 includes a diagnostic pulse generating means for generating a diagnostic pulse voltage to be applied to the series circuit of the fuse and the capacitor to be diagnosed.
A first diagnostic signal generating means that generates a first diagnostic signal by superimposing noise on the voltage of the capacitor when the diagnostic pulse voltage is applied to the series circuit.
A second diagnostic signal generating means for generating a pulsed second diagnostic signal by comparing the first diagnostic signal with a threshold value, and
A third diagnostic signal generating means that integrates the second diagnostic signal to generate a third diagnostic signal,
A reset signal generation means for generating a reset signal by comparing the third diagnostic signal with a reference voltage,
A pulse width measuring means for measuring the pulse width of the diagnostic pulse voltage reset by the reset signal, and a pulse width measuring means.
A statistical processing means for statistically processing the pulse width measured by the pulse width measuring means, detecting a change in the resistance value of the fuse based on the result, and diagnosing deterioration of the fuse.
It is characterized by being equipped with.

The fuse deterioration diagnosis device according to claim 6 further includes noise generation means for generating the noise in the fuse deterioration diagnosis device according to claim 5, and the noise is white noise, or M. It is characterized by being a sequence.

The fuse deterioration diagnostic apparatus according to claim 7 is the fuse deterioration diagnostic apparatus according to claim 5, wherein the statistical processing means obtains the median value of the pulse width measured by the pulse width measuring means, and the present invention is described. It is characterized in that a change in the resistance value of the fuse is detected based on a change in the median value.

The fuse deterioration diagnosis device according to claim 8 is the fuse deterioration diagnosis device according to any one of claims 5 to 7, wherein the second diagnostic signal generation means is configured by a Schmitt trigger circuit, and the threshold value is set. It is characterized in that the threshold value on the high potential side of the Schmitt trigger circuit is set.

The fuse deterioration diagnosis device according to claim 9 is the fuse deterioration diagnosis device according to any one of claims 5 to 8, wherein the diagnostic pulse generating means includes an oscillator that generates a trigger pulse at a predetermined cycle. The RS flip-flop in which the trigger pulse is input to the set terminal and the reset signal is input to the reset terminal, and the trigger pulse and the output pulse of the RS flip-flop are input to output the diagnostic pulse voltage. It is characterized by having an OR gate.

According to the present invention, since it is possible to detect an increase in the resistance value of the fuse based on the pulse width of the diagnostic pulse voltage, the increase in the resistance value is estimated from the temperature history of the fuse. It is possible to diagnose fuse deterioration and manufacturing variation with high accuracy.

It is a block diagram which shows the embodiment of this invention. It is a conceptual waveform diagram of each part which shows the operation of FIG. It is a waveform figure of each part which shows the simulation result in embodiment of this invention. It is a histogram which shows the output pulse width of the OR gate based on the simulation result of FIG. It is a waveform diagram which showed the output pulse width of the OR gate based on the simulation result of FIG. 3 according to the fuse resistance value. It is a waveform figure of each part which shows the simulation result in embodiment of this invention. 6 is a histogram showing the output pulse width of the OR gate based on the simulation result of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a deterioration diagnosis device according to an embodiment of the present invention.
In FIG. 1, one end of the fuse F, which is the target of deterioration diagnosis, is connected to the pulse width measuring means 31 in the digital signal processor (DSP) 30 described later, and the other end of the fuse F is grounded via the capacitor 11. There is. The noise output from the noise source 12 by the adder 13 is superimposed on the voltage of the capacitor 11, and the output of the adder 13 is applied to the Schmitt trigger circuit 14.

Here, the capacitor 11, the noise generation source 12, and the adder 13 constitute the first diagnostic signal generating means according to the claim, and the output of the adder 13 corresponds to the first diagnostic signal.
Further, the Schmitt trigger circuit 14 constitutes the second diagnostic signal generating means in the claim, and the output of the Schmitt trigger circuit 14 corresponds to the second diagnostic signal.

An integrating circuit 15 made of a low-pass filter or the like is connected to the output side of the Schmitt trigger circuit 14, and the output of the integrating circuit 15 is added to the positive input terminal of the comparator 17. Further, a reference voltage 16 is input to the negative input terminal of the comparator 17.
The output of the comparator 17 is added to the reset terminal R of the RS flip-flop (RS-FF) 19, and a trigger pulse of a predetermined frequency having a small duty ratio is input from the oscillator 18 to the set terminal S of the RS-FF19. ..

The trigger pulse output from the oscillator 18 and the output of the RS-FF19 are input to the OR gate 20, and the output terminal of the OR gate 20 is connected to the fuse F and the pulse width measuring means 31 in the DSP 30. There is.

Here, the integrating circuit 15 constitutes the third diagnostic signal generating means in the claim, and the output of the integrating circuit 15 corresponds to the third diagnostic signal. The comparator 17 constitutes the reset signal generating means in the claim, and the output of the comparator 17 corresponds to the reset signal.
Further, the oscillator 18, RS-FF19 and the OR gate 20 constitute the diagnostic pulse generating means according to the claim, and the output pulse of the OR gate 20 corresponds to the diagnostic pulse voltage.

The pulse width measuring means 31 in the DSP 30 measures the pulse width of the pulse output from the OR gate 20, and the statistical processing means 32 calculates the median value of the measured pulse width. Here, the statistical processing means 32 may obtain a statistical index (for example, variance) other than the median value of the pulse width.

Next, the operation of this embodiment will be described with reference to the conceptual waveform diagram of FIG.
First, the duty ratio of the trigger pulse by the oscillator 18 is set as small as about 0.1 and operated (FIG. 2 (f)). When this trigger pulse reaches the "High" level, the output of RS-FF19 is latched to the "High" level, the output pulse of the OR gate 20 also reaches the "High" level, and this output pulse is applied to the fuse F as a diagnostic pulse voltage. (Fig. 2 (e)).
As a result, the voltage of the capacitor 11 connected to the output side of the fuse F gradually increases with a time constant determined by the resistance value of the fuse F and the capacity of the capacitor 11.

Since the noise from the noise source 12 is superimposed on the voltage of the capacitor 11, the voltage of the waveform in which the noise is superimposed on the charging waveform of the capacitor 11 is input to the Schmitt trigger circuit 14. (Fig. 2 (d)). Here, the high potential side threshold value of the Schmitt trigger circuit 14 is set to substantially the same level as the amplitude of the output voltage (diagnostic pulse voltage) of the OR gate 20.

Since noise is superimposed on the input voltage of the Schmitt trigger circuit 14, as the level of this input voltage approaches the high potential side threshold of the Schmitt trigger circuit 14, the output voltage of the Schmitt trigger circuit 14 is caused by the so-called stochastic resonance phenomenon. It stochastically transitions to the "High" level side (Fig. 2 (c)).
As is well known, the stochastic resonance phenomenon is a phenomenon in which a signal is strengthened and observable under a certain probability by adding noise to the signal. As a conventional technique utilizing the stochastic resonance phenomenon, for example, a signal reproduction device according to International Publication No. 2011/065500 is known.

When the output of the Schmitt trigger circuit 14 is integrated by the integrator circuit 15, the output voltage stochastically gradually increases (FIG. 2B). Then, when the output voltage of the integrating circuit 15 exceeds the reference voltage 16, a “High” level reset signal is output from the comparator 17 (FIG. 2A), RS-FF19 is reset, and the output of the OR gate 20 is output. Transitions to the "Low" level (Fig. 2 (e)).
The above operation is repeated according to the cycle of the trigger pulse output from the oscillator 18.

The output pulse width of the OR gate 20 varies according to noise, and the median value of the output pulse width changes according to the resistance value of the fuse F. Therefore, the output pulse width of the OR gate 20 is measured by the pulse width measuring means 31 in the DSP 30, and the statistical processing means 32 calculates, for example, the median value of the pulse width and observes the change in the fuse F. Deterioration of the fuse F due to a change in the resistance value of the fuse F and an increase in the resistance value can be diagnosed with high accuracy.

Next, the contents and results of the simulation for confirming the effect of this embodiment will be described.
First, the various parameters used in the simulation are as follows. Although white noise was used in the simulation, the effect of the embodiment is also obtained with M-sequence noise.
-Oscillation frequency of oscillator 18: 1 [kHz / duty ratio 0.1]
-Time constant for deterioration diagnosis: 300 [μs]
-Initial resistance value of fuse F: 10 [mΩ]
-Capacitor 11 capacity: 30 [mF]
-Noise (white noise): Maximum amplitude 30 [mV]
-High potential side threshold value of Schmitt trigger circuit 14: 500 [mV] (hysteresis width 23 [mV])
-Time constant of the integrating circuit 15: 2.2 [ms] or 47 [ns] (set so that the reference voltage 16 is reached within 1 [ms], which is the oscillation cycle of the oscillator 18).
-Reference voltage 16: 500 [mV]

Further, as a method for determining the resistance value of the fuse F, when it is detected that the median value of the period during which the pulse input to the pulse width measuring means 31 of the DSP 30 is at the “High” level has increased by 10 [μs], it is detected. It is determined that the resistance value of the fuse F has increased by 1 [%].

The simulation results when the time constant of the integrator circuit 15 is set in two ways (2.2 [ms], 47 [ns]) under the above conditions will be described below.

FIG. 3 is a waveform diagram of each part showing the simulation result when the time constant of the integrating circuit 15 is set to 2.2 [ms].
Further, FIG. 4 is a histogram showing the pulse width when the output pulse of the OR gate 20 is sampled 3000 times for each of a new fuse and a fuse whose resistance value has increased by 1 [%] due to deterioration. According to FIG. 4, the change width of the median pulse width with respect to the change of 1 [%] of the fuse resistance value is 10 [μs].
Further, FIG. 5 is a histogram showing the pulse width when the fuse resistance value is changed from 10.0 [mΩ] to 11.8 [mΩ] in steps of ΔR = 0.2 [mΩ].

On the other hand, FIG. 6 is a waveform diagram of each part showing the simulation result when the time constant of the integrating circuit 15 is set to 47 [ns], and FIG. 2 described above is a diagram conceptually showing FIG. Equivalent to.
Further, FIG. 7 is a histogram obtained under the same conditions as in FIG. 4 by setting the time constant of the integrator circuit 15 to 47 [ns]. According to FIG. 7, the change width of the median pulse width with respect to the change of 1 [%] of the fuse resistance value is 4 [μs].

As can be seen from FIGS. 4 and 7, there is a significant correlation between the median output pulse width of the OR gate 20 and the fuse resistance value regardless of the time constant of the integrating circuit 15.
In particular, in the case of FIG. 4 having a large time constant, the change width of the median output pulse width corresponding to 1 [%] of the fuse resistance value is more than twice that of FIG. 7, and is shown in FIG. As such, if the median value of the output pulse width of the OR gate 20 is obtained by statistical processing, it is possible to increase the fuse resistance value, that is, to accurately diagnose the deterioration and the life of the fuse F.
Further, at the time of manufacturing the fuse F, it can be used for quality control by individually checking the resistance value and inspecting the variation thereof.

The present invention can be applied to deterioration diagnosis, life diagnosis, variation inspection of resistance value at the time of manufacturing, etc. of a current fuse or a thermal fuse.

F: Fuse 11: Capacitor
12: Noise source 13: Adder 14: Schmitt trigger circuit (second diagnostic signal generation means)
15: Integrator circuit (third diagnostic signal generation means)
16: Reference voltage 17: Comparator (reset signal generation means)
18: Oscillator 19: RS flip-flop (RS-FF)
20: OR gate 30: Digital signal processor (DSP)
31: Pulse width measuring means 32: Statistical processing means

Claims (9)

A first diagnostic signal is generated by superimposing noise on the voltage of the capacitor when a diagnostic pulse voltage is applied to the series circuit of the fuse and the capacitor to be diagnosed, and the first diagnostic signal is compared with the threshold value to pulse. A second diagnostic signal is obtained, the integration result of the second diagnostic signal is compared with the reference voltage to generate a reset signal, and the pulse width of the diagnostic pulse voltage reset by the reset signal is statistically processed. A method for diagnosing deterioration of a fuse, which comprises diagnosing deterioration of the fuse by detecting a change in the resistance value of the fuse. In the method for diagnosing deterioration of a fuse according to claim 1,
A method for diagnosing deterioration of a fuse, wherein the noise is white noise generated by a noise generating means or is M-sequence. In the method for diagnosing deterioration of a fuse according to claim 1 or 2.
A method for diagnosing deterioration of a fuse, wherein the statistical processing is a process for obtaining a median value of a pulse width of the diagnostic pulse voltage, and detecting a change in the resistance value of the fuse based on a change in the median value. In the method for diagnosing deterioration of a fuse according to any one of claims 1 to 3.
A method for diagnosing deterioration of a fuse, wherein the amplitude of the diagnostic pulse voltage is substantially equal to the threshold value. A diagnostic pulse generating means for generating a diagnostic pulse voltage to be applied to a series circuit of a fuse and a capacitor to be diagnosed, and a diagnostic pulse generating means.
A first diagnostic signal generating means that generates a first diagnostic signal by superimposing noise on the voltage of the capacitor when the diagnostic pulse voltage is applied to the series circuit.
A second diagnostic signal generating means for generating a pulsed second diagnostic signal by comparing the first diagnostic signal with a threshold value, and
A third diagnostic signal generating means that integrates the second diagnostic signal to generate a third diagnostic signal,
A reset signal generation means for generating a reset signal by comparing the third diagnostic signal with a reference voltage,
A pulse width measuring means for measuring the pulse width of the diagnostic pulse voltage reset by the reset signal, and a pulse width measuring means.
A statistical processing means for statistically processing the pulse width measured by the pulse width measuring means, detecting a change in the resistance value of the fuse based on the result, and diagnosing deterioration of the fuse.
A fuse deterioration diagnostic device characterized by being equipped with. In the fuse deterioration diagnostic apparatus according to claim 5,
Further provided with noise generating means for generating the noise,
A fuse deterioration diagnostic apparatus, wherein the noise is white noise or is M-sequence. In the fuse deterioration diagnostic apparatus according to claim 5 or 6.
The statistical processing means is a fuse deterioration diagnostic apparatus characterized in that the median value of the pulse width measured by the pulse width measuring means is obtained and the change in the resistance value of the fuse is detected based on the change in the median value. .. In the fuse deterioration diagnostic apparatus according to any one of claims 5 to 7.
A fuse deterioration diagnostic apparatus, wherein the second diagnostic signal generation means is composed of a Schmitt trigger circuit, and the threshold value is set to a high potential side threshold value of the Schmitt trigger circuit. In the fuse deterioration diagnostic apparatus according to any one of claims 5 to 8.
The diagnostic pulse generating means
An oscillator that generates a trigger pulse at a predetermined cycle,
An RS flip-flop in which the trigger pulse is input to the set terminal and the reset signal is input to the reset terminal.
An OR gate to which the trigger pulse and the output pulse of the RS flip-flop are input and output the diagnostic pulse voltage,
A fuse deterioration diagnostic device characterized by being equipped with.

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