JP2001144243A - Preventive safety device for semiconductor integrated circuits - Google Patents

Abstract

(57) [Summary] [PROBLEMS] A semiconductor integrated circuit is used at a temperature exceeding a guaranteed environment temperature which cannot be predicted by a semiconductor maker. There was a problem that there was. SOLUTION: A temperature detecting device for periodically measuring an ambient temperature, an arithmetic device for storing +1 when the detected temperature is within a specified range and +2 when the detected temperature is out of a specified range in a nonvolatile memory; An output device for issuing an alarm when a predetermined set value is exceeded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a preventive safety device for a semiconductor integrated circuit constituting, for example, a microcomputer.

[0002]

2. Description of the Related Art Generally, a microcomputer is constituted by a semiconductor integrated circuit, and its life is determined by the environmental temperature at the place of use. Therefore, semiconductor manufacturers carry out reliability tests in advance according to the environmental temperature to be guaranteed, and guarantee the service life to the manufacturer to which the semiconductor device is to be delivered.

[0003] However, in some cases, the manufacturer of the delivery destination is used at an environmental temperature that deviates from the guaranteed temperature. In an extreme case, the life of the semiconductor itself is significantly shortened, and unexpected product failure may occur.

FIG. 7 is a schematic diagram showing the life of a semiconductor which guarantees the reliability of a device when used at a temperature guaranteed by a semiconductor maker. Is guaranteed. Therefore, a semiconductor manufacturer confirms that the specifications are satisfied by a reliability test, and a destination manufacturer configures a system so as to satisfy the guaranteed specifications and performs a product reliability test as necessary.

[0005]

Since the conventional semiconductor integrated circuit is configured as described above, it may be used at a temperature guaranteed by the semiconductor maker. As shown in FIG.
If the semiconductor device is used beyond the guaranteed environmental temperature of 85 ° C, which cannot be predicted by the semiconductor manufacturer (in the example shown, the temperature exceeds the guaranteed environmental temperature of 85 ° C twice), the life of the semiconductor becomes 7 years shorter than the guaranteed period, and unexpected product failure There is a problem that there is a risk of generating the problem. Conventionally, as this kind of preventive maintenance device, there are, for example, JP-A-11-175112, JP-A-2-17462, and JP-A-6-61414.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a preventive safety device for a semiconductor integrated circuit capable of detecting the life of a semiconductor integrated device that changes depending on a use environment temperature and appropriately notifying the same. The purpose is to obtain.

[0007]

According to the present invention, there is provided a preventive safety device for a semiconductor integrated circuit, comprising: a temperature detecting device for periodically measuring an ambient temperature; and a weighted count value when the detected temperature is out of a specified range. And an arithmetic unit for storing in a non-volatile memory, wherein the output unit issues an alarm when the storage count value exceeds a predetermined set value.

The weight of the preventive safety device for a semiconductor integrated circuit according to the present invention is +1 if the detected temperature is within a specified range.
If it is out of the standard range, +2 is added.

In the preventive safety device for a semiconductor integrated circuit according to the present invention, when the detected temperature is out of a specified range, the count value is weighted according to a temperature difference from the specified range.

In the preventive safety device for a semiconductor integrated circuit according to the present invention, when the detected temperature is below a specified range, the count value is subtracted according to a temperature difference from the specified range.

[0011] A preventive safety device for a semiconductor integrated circuit according to the present invention comprises: a temperature detecting device for periodically measuring an ambient temperature;
A power supply voltage detection device that detects the power supply voltage, and if the detected temperature is out of the specified range, weights the count value,
Calculating means for weighting the count value and storing the weighted count value in the nonvolatile memory when the detection voltage is out of the standard range;
The output means issues an alarm when the product of the temperature count value and the voltage count value exceeds a predetermined set value.

The weight of the preventive safety device for a semiconductor integrated circuit according to the present invention is +1 if the detected temperature is within a specified range.
When the detected voltage is outside the specified range, the value is increased by +2.

The weighting of the preventive safety device for a semiconductor integrated circuit according to the present invention increases the count value as the temperature difference from the standard range increases, and increases the count value according to the voltage difference from the standard range. Is what you do.

In the preventive safety device for a semiconductor integrated circuit according to the present invention, when the detected temperature is below the standard range, the count value is subtracted according to the temperature difference from the standard range, and the detected voltage is within the standard range. In such a case, the count value is subtracted according to the voltage difference from the standard range.

In the preventive safety device for a semiconductor integrated circuit according to the present invention, when the count value exceeds a set value, the time at that time is stored in a nonvolatile memory.

In the preventive safety device for a semiconductor integrated circuit according to the present invention, a semiconductor is provided with a temperature sensor to detect the temperature of the semiconductor itself.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below. Embodiment 1 FIG. FIG. 1 is a block diagram showing a microcomputer system having a preventive safety device for a semiconductor integrated circuit according to a first embodiment of the present invention, wherein 1 is a CPU, and 2 is a first storage storing a program for controlling the operation of the CPU 1. apparatus,
3 is a second storage device for storing the calculation result in the CPU 1, 4 is a time measuring device for measuring an interrupt time for the CPU 1, 5 is a temperature detecting device for detecting a use environment temperature,
Reference numeral 6 denotes an output device for notifying an operation result of the CPU 1 to the outside;
Is a bus connecting the devices 1 to 6 to each other.

Next, the operation will be described. FIG. 2 is a flowchart illustrating the operation. Although not specifically shown, the microcomputer system usually executes various programs to realize the operation of the system. The time measuring device 4 measures time and interrupts the CPU 1 periodically. When receiving the interrupt, the CPU 1 executes the temperature determination program stored in the first storage device 2 like the other programs.

First, the temperature is detected by the temperature detecting device 5 (step ST1), and it is determined whether or not the detected environmental temperature is outside the standard range stored in the second storage device 3 in advance (step ST2). If the detected environmental temperature is within the standard range (NO), a normal count, for example, +1 is counted (step ST3). If the detected environmental temperature is outside the standard range (YES), an extra count, for example, +2 is counted (step ST4). ).

In the counting method, the previous count value stored in the second storage device 3 is read and added thereto,
After the addition, the added value is stored in the second storage device 3 again. In this way, it is determined whether or not the added value has reached or exceeded a predetermined reference value (step ST5). If the reference value has not been reached (NO), the temperature determination program ends. If the count value has reached the reference value (YES,
That is, when the life is near, the alarm is output to the outside by the output device 6 (step ST6).

As described above, according to the first embodiment, even when the semiconductor device is used outside the usage environment specified by the semiconductor manufacturer, the life of the semiconductor is predicted and an alarm is issued, whereby the semiconductor is standardized. Even when the product is used outside, it is possible to predict the life and to ensure safety for the user who uses the product.

Embodiment 2 FIG. In the first embodiment, if the environmental temperature is within the standard range, the normal count, for example, +
1 is counted, and if it is out of the standard range, an extra count, for example, +2, is counted. However, in the second embodiment, when the detected temperature is out of the standard range, it is determined according to the temperature difference from the standard range. This is because the count value is weighted, and the life of the semiconductor generally becomes shorter as the environmental temperature becomes higher. The weighting when the standard temperature is 85 ° C. is, for example, as follows. Count +2 when the detected temperature is 85 ° C to 105 ° C Count +4 when the detected temperature is 105 ° C to 125 ° C Count +8 when the detected temperature is 125 ° C or higher. , 8, different weights are applied to the count value.

As described above, according to the second embodiment, since the count value is weighted in accordance with the temperature difference from the standard value, the accuracy of predicting the life of the semiconductor can be further improved.

Embodiment 3 FIG. In the first and second embodiments, if the environmental temperature is out of the standard range, the extra counting is performed. However, in the third embodiment, when the environmental temperature is within the standard range, that is, when the ambient temperature is used at a low temperature, the extra counting is performed. Since the life is extended, weighting is performed so as to reduce the count value. This weighting counts, for example, −1 when the detected temperature is 25 ° C. to 50 ° C.

Embodiment 4 FIG. 3 is a block diagram showing a microcomputer system provided with a preventive safety device for a semiconductor integrated circuit according to a fourth embodiment of the present invention. Reference numeral 8 denotes a power supply voltage detecting device for detecting a power supply voltage. I have. The other configuration is the same as that of the first embodiment shown in FIG.
Therefore, the same portions are denoted by the same reference numerals, and redundant description will be omitted.

Next, the operation will be described. FIG. 4 is a flowchart illustrating the operation. Although not specifically shown, the microcomputer system usually executes various programs to realize the operation of the system. The time measuring device 4 measures time and interrupts the CPU 1 periodically. When receiving the interrupt, the CPU 1 executes the temperature / voltage determination program stored in the first storage device 2 like the other programs.

First, the temperature is detected by the temperature detecting device 5 (step ST11), and the detected environmental temperature is determined in advance by the second temperature.
It is determined whether the data is out of the standard range stored in the storage device 3 (step ST12). If the detected environmental temperature is within the standard range (NO), the normal count, for example, +1
Are counted (step ST13), and out of the standard range (YE
If S), an extra count, for example, +2 is counted (step ST14). According to this counting method, the previous count value stored in the second storage device 3 is read out, added to this value, and after the addition, the added value is stored in the second storage device 3 again.

Next, voltage detection is performed by the power supply voltage detector 8, and it is determined whether the detected voltage is out of the standard range stored in the second storage device 3 in advance (step ST1).
5). If the detected voltage is within the standard range (NO),
A normal count, for example, +1 is counted (step ST
16) If it is out of the standard range (YES), an extra count, for example, +2 is counted (step ST1).
7). In this counting method, similarly to the above case, the previous count value stored in the second storage device 3 is read and added thereto, and after the addition, the added value is stored in the second storage device 3 again. .

The temperature counter value and the voltage counter value thus obtained are integrated, and it is determined whether or not the integrated value has reached a predetermined reference value (step ST18). ) Terminates the temperature / voltage determination program. If the count value has reached the reference value (YES, that is, the life is near), the output device 6 outputs an alarm to the outside (step ST19).

Embodiment 5 In the fourth embodiment, if the detection voltage is within the standard range, the normal count, for example, +1
Is counted, and if it is out of the standard range, an extra count, for example, +2, is counted. However, in the fifth embodiment, when the detected voltage is out of the standard range, counting is performed according to the voltage difference from the standard range. The value is weighted, because the higher the voltage, the shorter the life of the semiconductor. The weighting in the case of the standard voltage of 4.5 V to 5.5 V is, for example, as follows. Counts +2 when the detection voltage is 5.5 V to 5.7 V Counts +4 when the detection voltage is 5.7 V to 6.0 V Counts +8 when the detection voltage is 6.0 V or more, according to the detection voltage Thus, different weights are assigned to the count values as in 2, 4, and 8.

As described above, according to the fifth embodiment, the count value is weighted according to the voltage difference from the standard range, so that the accuracy of predicting the life of the semiconductor can be further improved.

Embodiment 6 FIG. In the above fourth and fifth embodiments, if the applied voltage is out of the standard range, the extra counting is performed. However, in the sixth embodiment, the applied voltage is lower than the standard range, that is, used at a low voltage. When this is done, the life is extended accordingly, so weighting is performed so as to reduce the count value. This weighting is performed, for example, on the basis of the detection voltage 4.
When the voltage is 5 V or less, -1 is counted.

Embodiment 7 FIG. 5 is a block diagram showing a microcomputer system provided with a preventive safety device for a semiconductor integrated circuit according to a seventh embodiment of the present invention. In Embodiments 1 to 6 above, when it is predicted that the semiconductor has reached the end of its life, an alarm is issued to the outside. However, in Embodiment 7, an alarm is not generated and the semiconductor reaches its end of life. The time at which the arrival is predicted is stored in the second storage device 3.

The structure is shown in FIG. 5, and is the same as that of the first embodiment except that the output device 6 is removed from the first embodiment shown in FIG.

Next, the operation will be described. FIG. 6 is a flowchart for explaining the operation. The time measuring device 4 measures time and interrupts the CPU 1 periodically. CP
When U1 receives the interrupt, it executes the temperature determination program stored in the second storage device 3, like the other programs.

First, the temperature is detected by the temperature detecting device 5 (step ST21), and the detected environmental temperature is set in advance to the second temperature.
It is determined whether the data is out of the standard range stored in the storage device 3 (step ST22). If the detected environmental temperature is within the standard range (NO), the normal count, for example, +1
Are counted (step ST23), and out of the standard range (YE
If S), an extra count, for example, +2 is counted (step ST24). In the counting method, the previous count value stored in the second storage device 3 is read out and added thereto, and after the addition, the added value is stored in the second storage device 3 again. In this way, it is determined whether or not the added value reaches a predetermined reference value (step ST
25) If the reference value has not been reached (NO), the temperature determination program ends. If the count value has reached the reference value (YES, that is, the life is near), this determination time is stored in the second storage device 3 (step ST2).
6).

As described above, according to the seventh embodiment, by storing the time at which it is determined that the semiconductor has reached the end of its life, the semiconductor manufacturer can use the stored data at a later date, This is effective for analyzing failure occurrence.

Embodiment 8 FIG. Embodiments 1 to 7 above
In the eighth embodiment, a semiconductor is provided with a temperature sensor to detect the temperature of the semiconductor itself. In this eighth embodiment, the temperature of the semiconductor is detected more accurately. be able to. As a result, the prediction that the semiconductor has reached the end of its life is made more accurately.

[0039]

As described above, according to the present invention, when the detected temperature is out of the standard range, the count value is weighted and stored in the nonvolatile memory, and the stored count value exceeds the predetermined set value. When the semiconductor integrated circuit is used in a severe environment outside of the standard, the life can be predicted with high accuracy because the alarm is issued at the time.

According to the present invention, the weighting is configured to be +1 if the detected temperature is within the specified range, and +2 if the detected temperature is out of the specified range. This has the effect of improving the prediction accuracy of

According to the present invention, the weight value is increased as the temperature difference from the standard range increases, so that weighting can be easily performed.

According to the present invention, when the detected temperature is within the specified range, the count value is subtracted according to the temperature difference from the specified range. There is an effect that the accuracy of predicting the life when used can be improved.

According to the present invention, when the detected temperature is out of the specified range, the count value is weighted. When the detected voltage is out of the specified range, the count value is weighted and stored in the nonvolatile memory. The product is obtained by multiplying the temperature count value and the voltage count value in advance, and an alarm is issued when the value exceeds a predetermined set value, so that the life expectancy when the semiconductor integrated circuit is used in a severe environment outside the standard can be predicted. There is an effect that it can be performed with high accuracy.

According to the present invention, when the detected voltage is out of the standard range, the count value is weighted according to the voltage difference from the standard range. Therefore, when the semiconductor integrated circuit is used in a severe environment outside the standard. There is an effect that the accuracy of predicting the life can be improved.

According to the present invention, since the weighting is configured to be +1 when the detected voltage is within the standard range and +2 when the detected voltage is out of the standard range, the weighting can be easily performed.

According to the present invention, when the detected voltage is within the standard range, the count value is subtracted according to the temperature difference from the standard range. There is an effect that the accuracy of predicting the life when used can be improved.

According to the present invention, when the count value exceeds the set value, the time at that time is stored in the non-volatile memory, so that it is effective in failure analysis when a failure occurs. .

According to the present invention, since the temperature sensor is provided on the semiconductor to detect the temperature of the semiconductor itself, the accuracy of the life prediction when the semiconductor integrated circuit is used in a severe environment outside the standard is further improved. There is an effect that can be.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a microcomputer system provided with a preventive safety device for a semiconductor integrated circuit according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation.

FIG. 3 is a block diagram showing a microcomputer system including a preventive safety device for a semiconductor integrated circuit according to a fourth embodiment of the present invention.

FIG. 4 is a flowchart illustrating an operation.

FIG. 5 is a block diagram showing a microcomputer system provided with a preventive safety device for a semiconductor integrated circuit according to a seventh embodiment of the present invention.

FIG. 6 is a flowchart illustrating an operation.

FIG. 7 is a schematic diagram showing the lifetime of a semiconductor that guarantees device reliability when used at a temperature guaranteed by a semiconductor manufacturer.

FIG. 8 is a schematic diagram showing the life of a semiconductor when used beyond a guaranteed environmental temperature which cannot be predicted by a semiconductor manufacturer.

[Explanation of symbols]

1 CPU, 2 first storage device, 3 second storage device, 4 hour measurement device, 5 temperature detection device, 6 output device, 7 bus, 8 power supply voltage detection device, 9 power supply voltage detection device.

Claims (10)

[Claims] A temperature detecting device for periodically measuring an ambient temperature; an arithmetic device for weighting a count value when the detected temperature is out of a specified range and storing the weighted value in a nonvolatile memory; A safety device for a semiconductor integrated circuit, comprising: an output device for issuing an alarm when a set value is exceeded. 2. The preventive safety device for a semiconductor integrated circuit according to claim 1, wherein the weighting is +1 if the detected temperature is within a specified range, and +2 if the detected temperature is out of a specified range. 3. The preventive safety device for a semiconductor integrated circuit according to claim 2, wherein the weighting is performed by increasing the count value as the temperature difference from the standard range increases. 4. The preventive safety device for a semiconductor integrated circuit according to claim 1, wherein when the detected temperature is lower than a specified range, the count value is subtracted according to a temperature difference from the specified range. 5. A temperature detecting device for periodically measuring an ambient temperature, a power supply voltage detecting device for detecting a power supply voltage, and when the detected temperature is out of a specified range, the count value is weighted and the detected voltage is set in the specified range. Otherwise, an arithmetic unit that weights the count value and stores the weighted value in the nonvolatile memory;
An output device that issues an alarm when a product of the temperature count value and the voltage count value exceeds a predetermined set value. 6. The method according to claim 1, wherein the weighting is +1 when the detected temperature is within the specified range, +2 when the detected temperature is outside the specified range, and +2 when the detected voltage is within the specified range, and +2 when the detected voltage is out of the specified range. Item 6. The preventive safety device for a semiconductor integrated circuit according to Item 5. 7. The weighting method, wherein the count value is increased as the temperature difference from the standard range increases, and the count value is increased as the voltage difference from the standard range increases. Item 6. The preventive safety device for a semiconductor integrated circuit according to Item 5. 8. When the detected temperature is below the specified range, the count value is subtracted according to the temperature difference from the specified range, and when the detected voltage is within the specified range, the count value is subtracted from the specified range. 6. The preventive safety device for a semiconductor integrated circuit according to claim 5, wherein the count value is decremented accordingly. 9. The preventive safety device for a semiconductor integrated circuit according to claim 1, wherein when the count value exceeds a set value, the time at that time is stored in a nonvolatile memory. 10. The preventive safety device for a semiconductor integrated circuit according to claim 1, wherein a temperature sensor is provided on the semiconductor to detect the temperature of the semiconductor itself.