JP6080691B2 - Temperature measuring device, temperature measuring method, and semiconductor module - Google Patents

Description

  The present invention relates to a temperature measurement device and a temperature measurement method using the temperature measurement device, and, for example, relates to a temperature measurement device that measures the temperature of a semiconductor module.

  In a semiconductor module equipped with a power semiconductor chip, it is necessary to measure and manage the temperature of the power semiconductor chip in order to protect the power semiconductor chip. In order to measure the temperature of the power semiconductor chip, a temperature measuring device is arranged in the power semiconductor module.

  A conventional temperature measuring device includes a constant current circuit and a diode as a temperature measuring element, and the diode is driven by the constant current circuit. Based on the voltage generated at both ends of the diode, the temperature is obtained by referring to the voltage-temperature characteristic of the diode.

  For example, in Patent Document 1, a current flowing through a diode is duplicated by a current duplicating circuit and is caused to flow through a reference resistor, and a voltage generated at both ends of the diode is compared with a voltage due to the reference resistor to obtain the temperature of the diode. .

JP 58-127134 A

  The conventional temperature measuring device measures the temperature on the assumption that the current generated by the constant current circuit is a constant value regardless of the temperature. However, in practice, when the temperature of the constant current circuit itself changes, the current value output from the constant current circuit also changes. Therefore, there has been a problem that a deviation occurs between the temperature measured by the temperature measuring device and the actual temperature.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a temperature measuring device that can accurately measure a temperature even when a current flowing through a temperature measuring element changes.

  A temperature measuring device according to the present invention includes a temperature measuring element driving unit that outputs a driving current and a temperature measuring element driven by the driving current, and detects a temperature difference between the temperature measuring element driving unit and the temperature measuring element. A temperature difference measuring device that detects a temperature difference is further provided, or the temperature measuring element driving unit includes a reference resistance and a temperature measuring resistance through which a current that is a duplicate of the current flowing through the reference resistance flows.

  According to the temperature measurement device of the present invention, when a temperature difference measuring device that detects a temperature difference between the temperature measuring element driving unit and the temperature measuring element as a detected temperature difference is provided, the drive current is the temperature of the temperature measuring element driving unit. The output voltage of the temperature measuring element is set so as to decrease as the temperature rises, and the output current of the temperature measuring element is set to decrease as the temperature of the temperature measuring element increases. If the output voltage of the temperature measuring element is set so as to increase as the temperature rises, and if the output voltage of the temperature measuring element is set so as to increase as the temperature of the temperature measuring element increases, the output voltage can be calculated by performing a predetermined calculation. From the detected temperature difference, it is possible to obtain the accurate temperature of the temperature measuring element.

  Further, according to the temperature measuring device according to the present invention, when the temperature measuring element driving unit includes the reference resistance and the temperature measuring resistance through which the current flowing through the reference resistance is duplicated, the driving current is the reference resistance. If the resistance value of the resistance temperature detector is more temperature-dependent than the resistance value of the reference resistor, the temperature can be accurately controlled even when the drive current varies with temperature. It is possible to measure.

1 is a diagram illustrating a configuration of a temperature measurement device in Embodiment 1. FIG. FIG. 3 is a diagram illustrating temperature dependence of a current flowing through a reference resistor in the first embodiment. FIG. 3 is a diagram showing temperature dependence of an output voltage VF in the first embodiment. FIG. 10 is a diagram showing a mutual matrix used in the temperature measurement method in the second embodiment. FIG. 6 is a diagram showing a configuration of a temperature measuring device in a third embodiment. It is a figure which shows the temperature dependence of the resistance value of the temperature measuring resistance in Embodiment 3. It is a figure which shows the temperature dependence of the both-ends voltage of the temperature measuring resistance in Embodiment 3.

<Embodiment 1>
<Configuration>
In FIG. 1, the structure of the temperature measuring apparatus 100 in this Embodiment is shown. The temperature measuring device 100 includes a temperature measuring element driving unit 8, a temperature measuring unit 9, and a temperature difference measuring device 16. The temperature measuring device 100 is used, for example, to measure the temperature of the power semiconductor chip inside the power module. The temperature measuring element driving unit 8 is disposed on the control board of the power module. Moreover, the temperature measuring part 9 is arrange | positioned on the power board | substrate with which a power semiconductor chip is arrange | positioned. The control board is installed in the upper part of the power module, and generally has a lower temperature than the power board in the lower part of the power module. For example, when the temperature of the power board is around 150 ° C., the control board is around 100 ° C.

  The temperature measuring element drive unit 8 includes a current replication circuit 8A and a current control circuit 8B. The current duplication circuit 8A is, for example, a current mirror circuit, and outputs a current I6 from the current supply source 5 and a drive current IF obtained by duplicating the current I6.

  The current control circuit 8B is a circuit that gives temperature dependency to the current I6. The current control circuit 8B includes a reference resistor R7 having temperature dependency and voltage dividing resistors R2 and R3 connected in series to the constant voltage source 1. The voltage dividing resistors R2 and R3 divide the voltage of the constant voltage source 1 to generate a reference voltage. The current control circuit 8B further includes a voltage comparator 4 and a transistor. The voltage comparator 4 amplifies the difference between the voltage generated by the reference resistor R7 and the reference voltage and inputs it to the gate of the transistor. The drain of the transistor is connected to the output of the current I6 of the current replication circuit 8A, and the source is connected to the reference resistor R7.

  The temperature measuring unit 9 includes a temperature measuring diode 10 as a temperature measuring element, and voltage dividing resistors R12 and R13 connected in series. A driving current IF output from the current duplicating circuit 8A flows through the temperature measuring diode 10. Resistors R12 and R13 divide the constant voltage source 11 to generate a reference voltage. The temperature measuring unit 9 further includes a voltage comparator 14. The voltage comparator 14 amplifies the difference between the voltage by the temperature measuring diode 10 and the reference voltage and outputs the output voltage VF.

  The temperature difference measuring device 16 is a thermocouple and detects a temperature difference between the temperature measuring element driving unit 8 and the temperature measuring unit 9. More specifically, as shown in FIG. 1, the temperature difference between the reference resistor R7 and the temperature measuring diode 10, that is, the temperature difference between the control board and the power board is detected.

<Operation>
The voltage obtained by dividing the voltage of the constant voltage source 1 by the voltage dividing resistors R2 and R3 is used as a reference voltage, and the current I6 from the current supply source 5 is converted to the voltage comparator 4 so that the voltage generated in the reference resistor 7 matches the reference voltage. Control by. As a result, the current I6 becomes a constant current depending on the resistance value of the reference resistor 7.

  The current I6 is duplicated by the current duplication circuit 8A, and the duplicated drive current IF flows to the temperature measuring diode 10 which is a temperature measuring element. The voltage generated in the temperature measuring diode 10 by the drive current IF is compared with the voltage obtained by dividing the voltage of the constant voltage source 11 by the voltage dividing resistors R12 and R13 by the voltage comparator 14, and the output voltage VF is determined by the comparison result. Occur.

  The temperature difference measuring device 16 detects the difference between the temperature of the reference resistor 7 and the temperature of the temperature measuring diode 10. This temperature difference is defined as the detected temperature difference.

  In the present embodiment, the resistance value of the reference resistor R7 has a temperature dependency that increases as the temperature rises. That is, the current I6 decreases as the temperature of the reference resistor R7 increases. Therefore, the temperature dependence of the current I6 flowing through the reference resistor R7 is expressed as shown in FIG. Note that since the drive current IF is a duplicate of the current I6, the temperature dependence of the drive current IF is also expressed as shown in FIG.

  Further, the resistance value of the temperature measuring diode 10 has a temperature dependency that decreases as the temperature rises. That is, the voltage generated at both ends of the temperature measuring diode 10 decreases as the temperature of the temperature measuring diode 10 increases. When the voltage generated at both ends of the temperature measuring diode 10 is reduced, the output voltage VF is also reduced.

  That is, in the present embodiment, as shown in FIG. 3, the output voltage VF under a constant drive current IF decreases as the temperature rises. Further, when the drive current IF decreases, the output voltage VF also decreases. In the present embodiment, both the drive current IF and the output voltage VF are set so as to decrease as the temperature rises.

<Temperature measurement method>
A temperature measurement method using the temperature measurement device 100 will be described. FIG. 2 shows the temperature dependence of the drive current IF generated by the temperature measuring element drive unit 8. FIG. 3 shows the temperature dependence of the output voltage VF under a constant drive current IF. The output voltage of the temperature measuring device 100 is VF, and the temperature difference detected by the temperature difference measuring device 16 is a detected temperature difference.

  First, the temperature of the reference resistor 7 is assumed to be an arbitrary temperature. This is the first temperature. Next, referring to FIG. 2, a current I6 flowing through the reference resistor R7 at the first temperature is obtained. Since the drive current IF is a duplicate of the current I6, the drive current IF is obtained.

  Next, referring to FIG. 3, the temperature of the temperature measuring diode 10 at the obtained output voltage VF is obtained from the temperature dependency of the output voltage VF under the obtained drive current IF. This is the second temperature. Then, the temperature difference is calculated by subtracting the first temperature from the second temperature. This temperature difference is defined as an assumed temperature difference.

  When the assumed temperature difference is larger than the detected temperature difference, the second temperature is recalculated assuming that the first temperature is larger, and the assumed temperature difference is calculated again. On the other hand, if the assumed temperature difference is smaller than the detected temperature difference, the second temperature is recalculated assuming that the first temperature is smaller, and the assumed temperature difference is calculated again. By repeating this process, the value of the assumed temperature difference gradually approaches the detected temperature difference. The first temperature and the second temperature when the assumed temperature difference coincides with the detected temperature difference are accurate temperatures of the temperature measuring element driver 8 and the temperature measuring diode 10, respectively.

  Hereinafter, the reason why accurate temperatures of the temperature measuring element driving unit 8 and the temperature measuring diode 10 are required by the above-described procedure will be described. In the configuration of temperature measuring apparatus 100 in the present embodiment, if the assumed value (first temperature) of reference resistor R7 is changed higher, the resistance value of reference resistor 7 is assumed to be larger, and as a result, The assumed values of the current I6 and the drive current IF are small (FIG. 2).

  On the other hand, as shown in FIG. 3, since the output of the temperature measuring diode 10 under the constant drive current IF is made smaller as the temperature rises, the temperature measurement necessary for producing a predetermined output voltage is performed. The temperature of the diode 10 decreases as the drive current IF decreases. Therefore, when the first temperature of the reference resistor R7 is increased, the second temperature of the temperature measuring diode 10 is further decreased. Therefore, when the temperature of the reference resistor R7 is lower than the temperature of the temperature measuring diode 10, the assumed temperature difference is necessarily reduced. On the contrary, if the first temperature of the reference resistor R7 is assumed to be low, the second temperature of the temperature measuring diode 10 becomes high, so that the assumed temperature difference always increases.

  As described above, when the assumed temperature difference does not match the detected temperature difference, and when the assumed temperature difference is larger than the detected temperature difference, the first temperature of the reference resistor R7 is assumed to be higher. On the other hand, when the assumed temperature difference is smaller than the detected temperature difference, the first temperature of the reference resistor R7 is assumed to be lower. By repeating this process, the assumed temperature difference can be made to coincide with the detected temperature difference. That is, the temperature of the temperature measuring element driving unit 8 and the temperature of the temperature measuring diode 10 can be accurately obtained.

  In the following, a description will be given with a numerical example. As shown in FIG. 3, when the drive current IF decreases, the output voltage VF decreases even at the same temperature. In other words, the conventional technique that assumes that the drive current IF is constant regardless of the temperature is misunderstood as an increase in temperature. For example, according to FIG. 3, when the temperature of the temperature measuring diode 10 is 150 ° C. and the drive current IF is 100 μA, the output voltage VF is 1.6V. If the drive current IF is reduced to 95 μA due to fluctuations in the control substrate temperature, the output voltage VF is reduced to 1.5V even if the temperature of the power substrate is actually kept at 150 ° C. In the conventional technique that assumes that the drive current IF does not change at 100 μA, it is mistaken for the temperature rising to about 155 ° C., and an incorrect temperature is obtained.

  For example, assuming that the first temperature of the reference resistor R7 is 100 ° C., the temperature (second temperature) of the temperature measuring diode 10 is obtained. Referring to FIG. 2, when the temperature of the reference resistor R7 (control board temperature) is 100 ° C., the current I6 (that is, the drive current IF) is 100 μA. At this time, assuming that the output voltage VF is 1.6 V, referring to FIG. 3, the temperature of the temperature measuring diode 10, that is, the temperature of the power substrate is 150.degree. Here, if the detected temperature difference detected by the temperature difference measuring device 16 is 50 ° C., the assumed temperature difference and the detected temperature difference coincide with each other, and therefore the first temperature and the second temperature are correct.

  Next, consider a case where the assumed temperature difference is 50 ° C. and the detected temperature difference is 40 ° C. In this case, it is necessary to reduce the assumed temperature difference. That is, it is necessary to re-assum the first temperature (that is, re-assum the driving current IF to be smaller). For example, assuming that the drive current IF is 95 μA, the first temperature (ie, the temperature of the control board) is 105 ° C. according to FIG. Further, from FIG. 3, the second temperature (that is, the temperature of the power substrate) of the temperature measuring diode 10 at which the output voltage VF of 1.6 V is obtained when the drive current IF is 95 μA is 145 ° C. Therefore, the assumed temperature difference is 40 ° C., which coincides with the detected temperature difference. If the assumed temperature difference does not match the detected temperature difference after one change in the assumed value, the assumed temperature difference will always be detected if repeated calculations are performed according to whether the assumed temperature difference needs to be reduced or expanded. Can match the difference.

  Next, consider a case where the assumed temperature difference is 50 ° C. and the detected temperature difference is 60 ° C. In this case, it is necessary to increase the assumed temperature difference. That is, it is necessary to re-assum the first temperature (that is, re-assum the driving current IF to be larger). For example, assuming that the drive current IF is 105 μA again, the first temperature (ie, the temperature of the control board) is 95 ° C. according to FIG. Further, as shown in FIG. 3, the second temperature (that is, the temperature of the power substrate) of the temperature measuring diode 10 at which the output voltage VF of 1.6 V is obtained when the drive current IF is 105 μA is 155 ° C. Therefore, the assumed temperature difference is 60 ° C., which matches the detected temperature difference.

  In temperature measuring apparatus 100 in the present embodiment, since drive current IF and output voltage VF are designed to decrease as the temperature rises, the assumed temperature difference and the detected temperature difference are always matched to measure temperature. Accurate temperatures of the element driving unit 8 (reference resistor R7) and the temperature measuring unit 9 (temperature measuring diode 10) can be obtained.

  Since temperature measuring apparatus 100 in the present embodiment is designed so that output voltage VF decreases as temperature rises, drive current IF is assumed to be smaller under the condition that constant output voltage VF is obtained. In other words, the calculated temperature (second temperature) of the temperature measuring diode 10 becomes lower. For example, when an output voltage VF of 1.6 V is obtained, assuming that the drive current IF is 100 μA, the temperature (second temperature) of the temperature measuring diode 10 is determined to be 150 ° C. according to FIG. Assuming that the drive current IF is as low as 95 μA, the temperature of the temperature measuring diode 10 (second temperature) decreases to 145 ° C. according to FIG.

  Further, since temperature measuring apparatus 100 in the present embodiment is designed so that drive current IF decreases as temperature rises, re-assuming drive current IF is reduced to the first temperature of reference resistor R7 ( That is, it is synonymous with re-assuming that the temperature of the control board is high.

  As described above, when the temperature measuring device 100 is arranged in the semiconductor module, the temperature of the reference resistor R7 is lower than the temperature of the temperature measuring diode 10, so that if the drive current IF is re-assumed, the reference resistor R7 Since the first temperature (that is, the temperature of the control board) increases and the second temperature of the temperature measuring diode 10 (that is, the temperature of the power board) decreases, the temperature difference between them (that is, the assumed temperature difference) is necessarily reduced. The reverse is also true, and assuming that the drive current IF is large again, the first temperature of the reference resistor R7 decreases and the second temperature of the temperature measuring diode 10 increases, so the assumed temperature difference necessarily increases.

  As described above, the assumed temperature difference can always be enlarged or reduced by re-assuming the drive current IF (or the first temperature), and the assumed temperature difference can be matched with the detected temperature difference.

  Further, when the drive current IF and the output voltage VF are designed to increase as the temperature rises, if the drive current IF is reassured largely, the first temperature of the reference resistor R7 (that is, the temperature of the control board) As the temperature rises and the second temperature of the temperature measuring diode (ie, the temperature of the power substrate) drops, the temperature difference between them (ie, the assumed temperature difference) is necessarily reduced. The reverse is also true, and if the drive current IF is assumed to be small again, the first temperature of the reference resistor R7 decreases and the second temperature of the temperature measuring diode 10 increases. It is possible.

  Note that the direction of temperature dependency of the drive current IF and the direction of temperature dependency of the output voltage VF are different, for example, the drive current IF increases and the output voltage VF decreases as the temperature rises. In this case, even if the drive current IF (or the first temperature) is re-assumed, the assumed temperature difference does not change and may not match the detected temperature difference. In this case, the correct temperature cannot be obtained.

<Effect>
The temperature measuring apparatus 100 in the present embodiment includes a temperature measuring element driving unit 8 that outputs a driving current IF and a temperature measuring element (that is, a temperature measuring diode 10) driven by the driving current IF. A temperature difference measuring device 16 for detecting a temperature difference between the drive unit 8 and the temperature measuring element as a detected temperature difference is further provided.

  Therefore, the drive current IF is set so as to decrease as the temperature of the temperature measuring element drive unit 8 increases, and the output voltage of the temperature measuring element is set so as to decrease as the temperature of the temperature measuring element increases. Alternatively, the drive current IF is set so as to increase as the temperature of the temperature measuring element drive unit 8 increases, and the output voltage of the temperature measuring element increases as the temperature of the temperature measuring element increases. If it is set to, it is possible to obtain the accurate temperature of the temperature measuring element from the output voltage VF and the detected temperature difference by performing a predetermined calculation.

  The temperature measuring apparatus 100 according to the present embodiment includes a temperature measuring element driving unit 8 that outputs a driving current IF, a temperature measuring element driven by the driving current IF (that is, a temperature measuring diode 10), and a temperature measuring element driving. A temperature difference measuring device 16 that detects a temperature difference between the temperature measuring element 8 and the temperature measuring element as a detected temperature difference, and the drive current IF is set to decrease as the temperature of the temperature measuring element driving unit 8 increases. In addition, the output voltage of the temperature measuring element is set so as to decrease as the temperature of the temperature measuring element increases, or the drive current IF increases as the temperature of the temperature measuring element driving unit 8 increases. And the output voltage of the temperature measuring element is set to increase as the temperature of the temperature measuring element increases.

  Accordingly, the drive current IF and the output voltage (that is, the output voltage VF of the temperature measuring device 100) decrease as the temperature measuring element drive unit 8 and the temperature measuring diode 10 increase in temperature, respectively, and the output of the temperature measuring element. Since the voltage is set to decrease as the drive current IF decreases, it is possible to obtain the accurate temperature of the temperature measuring element from the output voltage VF and the detected temperature difference by performing a predetermined calculation. is there.

  Further, the temperature measurement method using the temperature measuring device 100 in the present embodiment includes the step (a) in which the temperature of the temperature measuring element driving unit 8 is assumed as the first temperature, and the driving current of the temperature measuring element driving unit 8 − Step (b) for determining the drive current IF for the first temperature from the temperature characteristics, and the output voltage of the temperature measuring element (that is, the temperature measuring diode 10) under the drive current for the first temperature determined in step (b) − Step (c) for obtaining the temperature relative to the output voltage of the temperature measuring element as the second temperature from the temperature characteristics, Step (d) for obtaining an assumed temperature difference obtained by subtracting the first temperature from the second temperature, and detection of the assumed temperature difference (E) re-assuming the first temperature according to the magnitude relationship with the temperature difference, and repeating steps (a) to (e) until the assumed temperature difference matches the detected temperature difference It is characterized by.

  Therefore, the first temperature (that is, the temperature of the temperature measuring element drive unit 8) is assumed again according to the magnitude relationship between the assumed temperature difference and the detected temperature difference until the assumed temperature difference and the detected temperature difference coincide with each other. By making the assumed temperature difference and the detected temperature difference coincide with each other, it is possible to obtain an accurate temperature of the temperature measuring element driving unit 8 and a temperature of the temperature measuring element (that is, the temperature measuring diode 10).

  In addition, the semiconductor module according to the present embodiment includes the temperature measurement device 100 and a semiconductor chip.

  Therefore, even when there is a temperature difference in the semiconductor module, the temperature can be measured using the temperature measuring device 100 without being affected by the change in the drive current IF due to the temperature difference. It is possible to measure with high accuracy.

<Embodiment 2>
Since the temperature measuring device in the present embodiment is the same as temperature measuring device 100 (FIG. 1) in the first embodiment, description thereof is omitted. In the first embodiment, an accurate temperature is obtained by repeatedly comparing the assumed temperature difference and the detected temperature difference.

  On the other hand, in the present embodiment, the temperature of the temperature measuring diode 10 obtained for every combination of the first temperature, the second temperature, and the detected temperature is calculated in advance, and for example, a mutual matrix shown in FIG. 4 is prepared in advance. The second temperature is determined by the output voltage VF and the first temperature. FIG. 4 shows an accurate temperature of the temperature measuring diode 10 obtained when the first temperature (assumed temperature sensor driving unit temperature) is fixed at 100 ° C. and the second temperature and the detected temperature difference are changed. is there.

  A case where the detected temperature difference is 40 ° C. and the output voltage VF is 1.6 V will be described. First, the first temperature is set to 100 ° C., for example. Next, with reference to FIG. 2, the driving current IF when the temperature measuring element driving unit 8 is 100 ° C. is obtained. In this case, 100 μA is obtained. Next, referring to FIG. 3, the temperature of the temperature measuring diode 10 with respect to the output voltage VF = 1.6V when the drive current IF is 100 μA is obtained. In this case, it is determined to be 150 ° C.

  Therefore, in FIG. 4, it can be seen that the accurate temperature of the temperature measuring diode 10 is 145 ° C. by referring to the column where the temperature of the temperature measuring diode 10 is 150 ° C. and the detected temperature difference is 40 ° C.

  The fineness of the mutual matrix can be adjusted as necessary. For example, in FIG. 4, when the value of the second temperature and the detected temperature difference is in the middle of the row or column of the mutual matrix, the detected temperature may be obtained by interpolating the mutual matrix.

<Effect>
In the temperature measurement method using the temperature measurement device according to the present embodiment, the temperature measurement device further includes a mutual matrix, and the mutual matrix includes any combination of the first temperature, the second temperature, and the detected temperature difference. The temperature of the temperature measuring element obtained by repeating steps (a) to (e) in the first embodiment until the assumed temperature difference and the detected temperature difference coincide with each other is described. A step (f) of determining the temperature of the temperature measuring element with reference to the mutual matrix based on the temperature and the detected temperature difference is further provided.

  Therefore, by preparing the values after the convergence of the repeated calculation as a mutual matrix in advance, the temperature of the temperature measuring element (that is, the temperature measuring diode 10) is immediately obtained without performing the repeated calculation for each measurement. It is possible. Therefore, a circuit for performing repetitive calculations is not required, and a lower cost temperature measuring device can be realized.

<Embodiment 3>
<Configuration>
FIG. 5 shows a configuration of temperature measuring apparatus 200 in the present embodiment. The temperature measuring device 200 includes a temperature measuring element driving unit 18 and a temperature measuring diode 24 as a temperature measuring element. The temperature measuring device 200 is used to measure the temperature of the power semiconductor chip inside the power module, for example, similarly to the temperature measuring device 100 in the first embodiment.

  The temperature measuring element driving unit 18 includes a current duplicating circuit 18A, a reference resistor R22, and a temperature measuring resistor R20. The current replication circuit 18A is, for example, a current mirror circuit, and allows the current I21 from the current supply source 17 to flow through the reference resistor R22. In addition, the current duplicating circuit 18A passes the current I19 and the drive current IF that are duplicated from the current I21 to the temperature measuring resistor R20 and the temperature measuring diode 24, respectively.

<Operation>
The temperature dependency of the resistance value of the temperature measuring resistor R20 is larger than the temperature dependency of the resistance value of the reference resistor R22. The temperature dependence of the resistance value of the temperature measuring resistor R20 is expressed by, for example, FIG. The resistance temperature detector R20 is a thermistor, for example, and has a very large temperature dependency. That is, the temperature dependency curve of the temperature measuring resistor R20 is greatly inclined. From FIG. 6, it can be seen that the resistance value changes by 3% only when the temperature of the resistance temperature resistor R20 changes by 1 ° C. That the resistance value changes by 3 percent means that if the current I19 is constant, the voltage generated across the temperature measuring resistor R20 changes by 3 percent (FIG. 7).

  For example, assuming that the temperature is constant and the current I19 flowing through the temperature measuring resistor R20 changes by 1%, the voltage across the temperature measuring resistor R20 changes by 1%. This is a voltage change equivalent to a temperature change of approximately 0.3 ° C. On the other hand, assuming that the temperature has changed by, for example, 5 ° C., the voltage across the temperature measuring resistor R20 changes by approximately 15 percent (3 percent × 5). That is, it can be seen that the voltage across the temperature measuring resistor R20 is affected both by the temperature change and the current I19 change, but mainly by the temperature change.

  Therefore, it is considered that the influence of the change of the current I19 on the temperature dependence of the voltage across the temperature measuring resistor R20 is small. From the above, as shown in FIG. 7, it is assumed that the current I19 is constant at a standard value (for example, 100 μA), ignoring the change of the current I19, and the both ends of the resistance temperature detector R20 are only one curve. Even if the temperature dependence of voltage is expressed, the error is small.

  Further, the dependence of the current I21 flowing through the reference resistor R22 (ie, the driving current IF) on the temperature of the control board (ie, the temperature of the temperature measuring resistor R20 and the reference resistor R22) is ideally zero, but is very high. small. For example, it is assumed that when the temperature changes by 1 ° C., 0.1% current changes. That is, the temperature dependency of the resistance value of the reference resistor R22 is set smaller than the temperature dependency of the resistance value of the temperature measuring resistor R20. It is assumed that the current-temperature dependency of the reference resistor R22 is known in advance.

  Further, the relationship between the temperature of the temperature measuring diode 24 (that is, the power substrate) and the output voltage VF is represented by FIG. 3 as in the first embodiment.

<Temperature measurement method>
First, the voltage across the temperature measuring resistor R20 is measured. Next, with reference to FIG. 7, the temperature of the temperature measuring resistor R20 (that is, the temperature of the control board) corresponding to the voltage obtained by the measurement is obtained.

  Next, referring to FIG. 2, a current I21 flowing through the reference resistor R22 corresponding to the temperature of the control board is obtained. Since the drive current IF is a duplicate of the current I21, the drive current IF is obtained. Since the temperature dependency of the resistance value of the reference resistor R22 is smaller than the temperature dependency of the resistance value of the temperature measuring resistor R20, the drive current IF can be obtained almost accurately.

  Next, with reference to FIG. 3, the temperature of the temperature measuring diode 24 at the output voltage VF obtained by measurement is obtained from the temperature dependence of the output voltage VF under the drive current IF obtained from FIG. According to the above procedure, even when the drive current IF changes due to a temperature change, the temperature of the temperature measuring diode 10 (that is, the temperature of the power substrate) can be measured with high accuracy.

  In the present embodiment, the resistance value (voltage at both ends) of the temperature measuring resistor R20 has a large temperature dependency. According to the example of FIG. 7, the voltage at both ends changes by 3% when the temperature of 1 ° C. changes. Further, when the 1% current I19 changes, the 1% voltage at both ends naturally changes. That is, even when the current I19 changes by about ± 1%, it is possible to measure the temperature of the control board while suppressing the temperature error to about 0.3 ° C. Further, since the resistance value (current value) of the reference resistor R22 changes by 0.1 percent when the temperature changes by 1 ° C., the temperature error of 0.3 ° C. is converted into a current error of 0.03 percent. It is possible to obtain the drive current IF while suppressing the above error from 1% to 0.03% to about 1/30. Therefore, the temperature measurement accuracy can be improved about 30 times by adopting a configuration including the temperature measurement resistor R20 having a relatively large temperature dependency with respect to the reference resistor R22.

  As shown in FIG. 6, the resistance value of the temperature measuring resistor R20 decreases as the temperature rises, but may have a characteristic of increasing as the temperature rises.

<Effect>
The temperature measuring apparatus 200 in the present embodiment includes a temperature measuring element driving unit 18 that outputs a driving current IF and a temperature measuring element (that is, a temperature measuring diode 24) driven by the driving current IF. The drive unit 18 includes a reference resistor R22 and a temperature measuring resistor R20 through which a current I19 obtained by copying a current I21 flowing through the reference resistor R22 flows.

  Accordingly, the drive current IF is a current obtained by duplicating the current I21 flowing through the reference resistor R22. If the resistance value of the temperature measuring resistor R20 is more temperature-dependent than the resistance value of the reference resistor R22, the drive current IF is Even when the temperature varies depending on the temperature, it is possible to accurately measure the temperature.

  The temperature measuring apparatus 200 in the present embodiment includes a temperature measuring element driving unit 18 that outputs a driving current IF and a temperature measuring element (that is, a temperature measuring diode 24) driven by the driving current IF. The temperature element driving unit 18 includes a reference resistor R22 and a temperature measuring resistor R20 through which a current I19 that is a copy of the current I21 that flows through the reference resistor R22. The drive current IF is a copy of the current I21 that flows through the reference resistor R22. The resistance value of the temperature measuring resistor R20 is characterized in that the temperature dependency is larger than the resistance value of the reference resistor R22.

  Therefore, by providing the reference resistor R22 having a small temperature dependency and the temperature measuring resistor R20 having a large temperature dependency, the temperature is accurately measured even when the drive current IF changes depending on the temperature. It is possible.

  Further, the temperature measurement method in the present embodiment is a temperature measurement method using the temperature measurement device 200, and includes the step (a) of measuring the voltage at both ends of the temperature measurement resistor R20, and the voltage of the temperature measurement resistor R20− The step (b) for obtaining the temperature of the temperature measuring element drive unit 18 at the voltage measured in step (a) from the temperature characteristic, and the reference resistance at the temperature obtained in step (b) from the current-temperature characteristic of the reference resistor R22. Step (c) for obtaining the current flowing through R22, and using the current obtained in step (c) as the drive current IF, the output voltage VF-temperature characteristics of the temperature measuring element (ie, the temperature measurement diode 24) under the drive current IF. And obtaining a temperature with respect to the output voltage VF of the temperature measuring element.

  Therefore, first, by measuring the temperature of the control board with the temperature measuring resistor R20 having a temperature dependency larger than that of the reference resistor R22, it is possible to suppress the influence of the current change and obtain an accurate temperature. Then, by measuring the drive current based on the current-temperature characteristic of the reference resistor R22 having a temperature dependency smaller than that of the temperature measuring resistor R20, it is possible to suppress an error due to a temperature change and obtain a highly accurate drive current IF. It is. Therefore, by obtaining a highly accurate drive current IF, the temperature of the temperature measuring element (that is, the temperature of the power board) can be measured with high accuracy by the temperature measuring element (that is, the temperature measuring diode 24).

  In addition, the semiconductor module in this embodiment includes a temperature measurement device 200 and a semiconductor chip.

  Therefore, even when there is a temperature difference in the semiconductor module, the temperature can be measured using the temperature measuring device 200 without being affected by the change in the drive current IF due to the temperature difference. It is possible to measure with high accuracy.

  It should be noted that the present invention can be freely combined with each other within the scope of the invention, and each embodiment can be appropriately modified or omitted.

  1,11 constant voltage source, 4,14 voltage comparator, 5,17 current supply source, 8 temperature measuring element driving unit, 8A, 18A current duplicating circuit, 8B current control circuit, 9 temperature measuring unit, 10, 24 temperature measuring Diode, 16 Temperature difference measuring device, R2, R3, R12, R13 Voltage dividing resistor, R7, R22 Reference resistance, R20 Temperature measuring resistor, 100, 200 Temperature measuring device, VF output voltage, I6, I19, I21 Current, IF drive Current.

Claims (7)

A temperature measuring element driving unit for outputting a driving current;
A temperature measuring element driven by the drive current;
With
A temperature difference measuring device that detects a temperature difference between the temperature measuring element driving unit and the temperature measuring element as a detected temperature difference, or the temperature measuring element driving unit includes a reference resistor and a current flowing through the reference resistor; And a resistance temperature detector through which replicated current flows,
Temperature measuring device. A temperature difference measuring device for detecting a temperature difference between the temperature measuring element driving unit and the temperature measuring element as a detected temperature difference;
The driving current is set so as to decrease as the temperature measuring element driving unit increases in temperature, and the output voltage of the temperature measuring element is set so as to decrease as the temperature measuring element increases. Or
The drive current is set to increase as the temperature measuring element driving unit increases in temperature, and the output voltage of the temperature measuring element is set to increase as the temperature measuring element increases. It is characterized by
The temperature measuring device according to claim 1. A temperature measuring method using the temperature measuring device according to claim 2,
(A) assuming the temperature of the temperature measuring element drive unit as a first temperature;
(B) obtaining a driving current for the first temperature from a driving current-temperature characteristic of the temperature measuring element driving unit;
(C) A step of obtaining a temperature corresponding to the output voltage of the temperature measuring element as a second temperature from an output voltage-temperature characteristic of the temperature measuring element under the driving current for the first temperature obtained in the step (b). When,
(D) obtaining an assumed temperature difference obtained by subtracting the first temperature from the second temperature;
(E) re-asserting the first temperature according to a magnitude relationship between the assumed temperature difference and the detected temperature difference;
With
The steps (a) to (e) are repeated until the assumed temperature difference and the detected temperature difference coincide with each other,
Temperature measurement method. The temperature measuring device further comprises a mutual matrix,
In the mutual matrix, for each combination of the first temperature, the second temperature, and the detected temperature difference, the steps (a) to (e) are the same as the assumed temperature difference and the detected temperature difference. The temperature of the temperature measuring element obtained repeatedly until is described,
(F) The method further includes the step of obtaining the temperature of the temperature measuring element with reference to the mutual matrix based on the first temperature, the second temperature, and the detected temperature difference.
The temperature measuring method according to claim 3. The drive current is a current obtained by replicating the current flowing through the reference resistor,
The resistance value of the temperature measuring resistor has a temperature dependency larger than the resistance value of the reference resistor,
The temperature measuring device according to claim 1. A temperature measurement method using the temperature measurement device according to claim 5,
(A) measuring a voltage across the resistance temperature detector;
(B) obtaining the temperature of the temperature measuring element driving unit at the voltage measured in the step (a) from the voltage-temperature characteristics of the temperature measuring resistor;
(C) obtaining a current flowing through the reference resistor at the temperature obtained in the step (b) from the current-temperature characteristic of the reference resistor;
(D) obtaining the temperature relative to the output voltage of the temperature measuring element from the output voltage-temperature characteristics of the temperature measuring element under the driving current, using the current obtained in step (c) as the driving current; ,
Comprising
Temperature measurement method. A temperature measuring device according to any one of claims 1, 2, and 5;
A semiconductor chip;
Comprising
Semiconductor module.

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