JP7024614B2 - Electronic device - Google Patents

Description

The present disclosure relates to an electronic device in which a circuit element is mounted on a wiring board.

Conventionally, as an example of an electronic device in which a circuit element is mounted on a wiring board, there is an electronic device disclosed in Patent Document 1.

The electronic device includes a substrate, a circuit element including a switching element, a microcomputer, a resistor, a capacitor and a thermistor, a heat sink and the like. The thermistor is a second surface opposite to the first surface on which the heat radiation gel is applied to the substrate, and is provided near the switching element having a relatively high heat generation temperature among the plurality of switching elements. The microcomputer detects the temperature of the switching element, which has a relatively high heat generation temperature, by the output of the thermistor.

Japanese Unexamined Patent Publication No. 2017-147259

However, in the above electronic device, the temperature is detected by the output of a thermistor provided near a switching element having a relatively high heat generation temperature. Therefore, only the local temperature can be detected. Therefore, the electronic device has a problem that the temperature of the switching element cannot be accurately detected.

The present disclosure has been made in view of the above problems, and an object of the present disclosure is to provide an electronic device capable of accurately detecting the calorific value of a circuit element.

To achieve the above objectives, this disclosure is:
Wiring board (31) and
With at least one circuit element (32, 33) mounted on the wiring board and electrically connected to the wiring board,
It is mounted in contact with the entire area of the opposite surface to the opposite surface of the circuit element facing the wiring board, and in contact with the entire area of the opposite surface, an electric signal corresponding to the heat flux generated from the circuit element is transmitted. The heat flux sensor (41, 42) to output and
A calculation unit (81) for calculating the heat dissipation amount of the circuit element by multiplying the heat flux, which is the output result of the heat flux sensor, by the area of the region where the circuit element and the heat flux sensor face each other. It is characterized by being.

As described above, in the present disclosure, the heat flux sensor is mounted in a state of being in contact with the entire area of the opposite surface of the circuit element. Therefore, the present disclosure has good responsiveness to a temperature change of the circuit element, and can obtain a heat flux from the opposite surface of the circuit element. Then, in the present disclosure, since the heat dissipation amount of the circuit element is calculated based on the heat flux thus obtained, the heat generation amount of the circuit element can be accurately detected.

The scope of claims and the reference numerals in parentheses described in this section indicate the correspondence with the specific means described in the embodiment described later as one embodiment, and the technical scope of the present disclosure. Is not limited to.

It is a perspective view which shows the schematic structure of the electronic control apparatus in 1st Embodiment. It is sectional drawing which follows the II-II line of FIG. It is a top view which shows the 1st heat flux sensor mounted on the 1st semiconductor element in 1st Embodiment. It is a block which shows the schematic structure of the electronic control device in 1st Embodiment. It is a top view which shows the heat flux sensor mounted on the multi-core element in the modification. It is sectional drawing which shows the schematic structure of the electronic control apparatus in 2nd Embodiment. It is a block diagram which shows the schematic structure of the electronic control apparatus in 2nd Embodiment. It is a flowchart which shows the processing operation of the electronic control apparatus in 2nd Embodiment. It is a drawing which shows the schematic structure of the electronic apparatus in 3rd Embodiment. It is a graph at the time of estimating the calorific value by the electronic device in 3rd Embodiment.

Hereinafter, a plurality of embodiments for carrying out the present disclosure will be described with reference to the drawings. In each form, the same reference numerals may be given to the parts corresponding to the matters described in the preceding forms, and duplicate explanations may be omitted. In each form, when only a part of the configuration is described, the other parts of the configuration can be applied with reference to the other forms described above.

In the following, the three directions orthogonal to each other are referred to as the X direction, the Y direction, and the Z direction. Further, the plane defined by the X direction and the Y direction is referred to as an XY plane.

(First Embodiment)
The electronic device of the first embodiment will be described with reference to FIGS. 1 to 4. In this embodiment, an example in which the electronic device is applied to the electronic control device 100 is adopted. Further, the electronic control device 100 can be applied to, for example, an in-vehicle control device that is mounted on a vehicle together with an in-vehicle device and controls the in-vehicle device.

As shown in FIGS. 1 and 2, the electronic control device 100 includes a housing including a cover 10 and a base 20, a circuit board 30 housed in the housing, and a first heat flux sensor 41 housed in the housing. It is equipped with a second heat flux sensor 42 and the like. The heat flux sensor can be paraphrased as a heat flow sensor.

The cover 10 includes a cover base 11, a cover protrusion 12, a heat dissipation fin 13, a connector accommodating portion 14, and the like. The cover 10 is formed mainly of a metal such as aluminum. The cover 10 can be manufactured by a manufacturing method such as die casting. The cover 10 is configured to be able to form an accommodation space for accommodating the circuit board 30 by being assembled with the base 20. The outside of the housing can be referred to as an external space with respect to the accommodation space.

As shown in FIGS. 1 and 2, the cover 10 includes a cover base 11, a cover protrusion 12 projecting toward the accommodation space with respect to the cover base 11, and a heat radiation fin 13 projecting to the side opposite to the accommodation space. There is. Further, the cover 10 is provided with a connector portion 14 in which the connector 70 is arranged.

The cover protrusion 12 protrudes from the periphery and is provided at a portion facing the first heat flux sensor 41. The cover protrusion 12 is a portion for indirectly contacting the first semiconductor element 32 and the cover base 11. The cover protrusion 12 has a surface facing the first heat flux sensor 41 equal to the surface of the first heat flux sensor 41 or wider than the surface of the first heat flux sensor 41. The facing surface of the cover protrusion 12 and the surface of the first heat flux sensor 41 are flat surfaces along the XY plane. However, the cover protrusion 12 can be adopted even if the surface facing the first heat flux sensor 41 is narrower than the surface of the first heat flux sensor 41.

The heat radiating fin 13 is a portion for radiating the heat transferred to the cover 10 to the external space. The present disclosure can be adopted even if the cover 10 is not formed with the heat radiation fins 13.

The base 20 includes a base base 21 and a base protrusion 22 protruding toward the accommodation space with respect to the base base 21. The base 20 is formed mainly of a metal such as aluminum. The base 20 can be manufactured by a manufacturing method such as die casting.

The base protrusion 22 is a portion for indirectly contacting the second semiconductor element 33 and the base base 21. The base protrusion 22 has a surface facing the second heat flux sensor 42 equal to the surface of the second heat flux sensor 4 or wider than the surface of the second heat flux sensor 42. The facing surface of the base protrusion 22 and the surface of the second heat flux sensor 42 are flat surfaces along the XY plane. However, the base protrusion 22 can be adopted even if the surface facing the second heat flux sensor 42 is narrower than the surface of the second heat flux sensor 4.

The circuit board 30 includes a wiring board 31, a first semiconductor element 32, a second semiconductor element 33, a thermistor 34, a connector 70, a microcomputer 80, and the like.

In the wiring board 31, conductive wiring is formed on an insulating base material such as resin or ceramic. The wiring board 31 includes a first board surface S1 and a second board surface S2 which is an opposite surface of the first board surface S1. As the wiring board 31, for example, a board in which the first board surface S1 and the second board surface S2 are rectangular can be adopted. The first substrate surface S1 and the second substrate surface S2 are flat surfaces along the XY plane. The wiring board 31 may be provided with wiring, a solder resist, or the like on the first board surface S1 or the second board surface S2. However, they are sufficiently thin with respect to the insulating substrate. Therefore, the first substrate surface S1 and the second substrate surface S2 can be regarded as flat surfaces.

A plurality of circuit components are mounted on the wiring board 31. In the present embodiment, the wiring board 31 in which the first semiconductor element 32, thermistor 34, and the connector 70 are mounted on the first board surface S1 and the second semiconductor element 33 is mounted on the second board surface S2 is adopted. Further, in the present embodiment, the wiring board 31 in which the microcomputer 80 is mounted on at least one of the first board surface S1 and the second board surface S2 is adopted.

However, the present disclosure is not limited to this, as long as at least one circuit element is mounted on the wiring board 31, the second semiconductor element 33 and the thermistor 34 may not be mounted. Further, the wiring board 31 may be mounted with elements other than the first semiconductor element 32, the second semiconductor element 33, the thermistor 34, and the microcomputer 80.

The first semiconductor element 32 and the second semiconductor element 33 correspond to circuit elements. The first semiconductor element 32 and the second semiconductor element 33 may execute the same process or may execute different processes. In the following, when it is not necessary to distinguish between the first semiconductor element 32 and the second semiconductor element 33, the first semiconductor element 32 will be described as a representative. Therefore, when only the first semiconductor element 32 is described, the description can be adopted for the second semiconductor element 33 as well.

The first semiconductor element 32 includes, for example, a MOSFET or an IGBT configured by a semiconductor. The first semiconductor element 32 is an element that generates heat when operated. Therefore, the first semiconductor element 32 can be said to be a heat generating element. The first semiconductor element 32 is provided with an electrode on a surface facing the wiring board 31, for example, and the electrode and the wiring of the wiring board 31 are electrically connected via a conductive member such as solder. In this way, the first semiconductor element 32 is electrically connected to the wiring board 31.

In the first semiconductor element 32, the first heat flux sensor 41 is mounted on the first facing surface S3, which is the opposite surface of the facing surface to the wiring board 31. In other words, in the first semiconductor element 32, the first heat flux sensor 41 is in contact with the first facing surface S3. The first facing surface S3 is a flat surface along the XY plane. Similarly, the first facing surface S3 is a flat surface whose surface facing the first facing surface S3 is along the XY plane.

Similarly, in the second semiconductor element 33, the second heat flux sensor 42 is mounted on the second facing surface S4. The second facing surface S4 is a surface corresponding to the first facing surface S3, and is a surface opposite to the surface facing the wiring board 31 in the second semiconductor element 33. In the following, when it is not necessary to distinguish between the first heat flux sensor 41 and the second heat flux sensor 42, the first heat flux sensor 41 will be described as a representative. Therefore, when only the first heat flux sensor 41 is described, the description can also be adopted for the second heat flux sensor 42. As described above, it can be said that the electronic control device 100 includes two heat flux sensors 41 and 42 individually mounted on the plurality of semiconductor elements 32 and 33, respectively.

As shown in FIG. 2, the first heat flux sensor 41 is mounted in contact with the first facing surface S3 in contact with the entire area of the first facing surface S3. That is, as shown in FIG. 3, the first heat flux sensor 41 is mounted in contact with the entire area of the first facing surface S3 in the first semiconductor element 32. When the first heat flux sensor 41 is mounted on the first facing surface S3 via the first heat radiating member 61, it is preferable because the thermal resistance between the first heat flux sensor 41 and the first facing surface S3 can be reduced. The state of contact includes not only the state of direct contact but also the state of indirect contact via a heat radiating member for reducing thermal resistance.

The first heat flux sensor 41 is electrically connected to the wiring of the wiring board 31 by a conductive member such as solder via the first wiring 51. Further, the first heat flux sensor 41 is electrically connected to the microcomputer 80 via the wiring board 31. The first heat flux sensor 41 outputs a voltage corresponding to the heat flux generated by the heat generated by the first semiconductor element 32. Therefore, the output result of the first heat flux sensor 41 corresponds to the heat flux generated from the first semiconductor element 32. The second heat flux sensor 42 is electrically connected to the wiring of the wiring board 31 via the second wiring 52.

As shown in FIG. 2, the first heat dissipation member 61 is mounted on the opposite surface of the first heat flux sensor 41 from the surface facing the first semiconductor element 32. The first heat dissipation member 61 is provided between the first heat flux sensor 41 and the cover protrusion 12. The first heat dissipation member 61 is in contact with both the first heat flux sensor 41 and the cover protrusion 12. As the first heat radiating member 61, a member having good thermal conductivity such as a heat radiating gel can be adopted.

Therefore, it can be said that the first semiconductor element 32 is indirectly in contact with the cover 10 via the first heat flux sensor 41 and the first heat dissipation member 61. Further, it can be said that the cover 10 and the first heat flux sensor 41 are arranged so as to face each other with the first heat dissipation member 61 sandwiched between them.

Similarly, the second heat dissipation member 62 is provided between the second heat flux sensor 42 and the base protrusion 22. In the following, when it is not necessary to distinguish between the first heat radiating member 61 and the second heat radiating member 62, the first heat radiating member 61 will be described as a representative. Therefore, when only the first heat radiating member 61 is described, the description can be adopted for the second heat radiating member 62 as well.

In this way, the first semiconductor element 32 is connected to the cover 10 via the first heat flux sensor 41 and the first heat dissipation member 61. Therefore, when the first semiconductor element 32 generates heat, a heat flow is formed in the direction from the first semiconductor element 32 toward the cover 10. Similarly, when the second semiconductor element 33 generates heat, a heat flow is formed in the direction from the second semiconductor element 33 toward the base 20.

The thermistor 34 is electrically connected to the wiring of the wiring board 31 via a conductive member such as solder. The thermistor 34 outputs an electric signal corresponding to the heat generated from the first semiconductor element 32. For example, the thermistor 34 outputs an electric signal to a microcomputer 80 or the like. The connector 70 electrically connects the electronic control device 100 and an external device provided outside the electronic control device 100.

Here, the configuration and processing operation of the microcomputer 80 will be described with reference to FIG. The microcomputer 80 includes a processing unit such as a CPU and a storage unit 84 such as a ROM or RAM. Further, the microcomputer 80 includes a first AD converter 85 and a second AD converter 86. Further, the microcomputer 80 includes a calculation unit 81, a comparison unit 82, and an output calculation unit 83 as processing units. The processing unit can be rephrased as a function executed by the microcomputer 80. The storage unit 84 includes an area A1 [m ² ] of a surface (region) where the first semiconductor element 32 and the first heat flux sensor 41 face each other, a second semiconductor element 33, and a second heat flux sensor 42. The area A2 [m ² ] of the surface facing the surface is stored. The area A1 can also be said to be the area of the region where the heat flux from the first semiconductor element 32 passes through the first heat flux sensor 41. Similarly, the area A2 can be said to be the area of the region where the heat flux from the second semiconductor element 33 passes through the second heat flux sensor 42. The first semiconductor element 32 and the second semiconductor element 33 are not electrically connected to the first heat flux sensor 41 and the second heat flux 42. Due to the temperature difference between the S3 surface and the first heat radiating member 61 shown in FIG. 2, an electromotive voltage is generated by the Zeebeck effect.

The first AD converter 85 is electrically connected to the first heat flux sensor 41 and the calculation unit 81. The first AD converter 85 receives an electric signal (voltage) output from the first heat flux sensor 41, AD converts the electric signal, and outputs the electric signal to the calculation unit 81. Similarly, the second AD converter 86 is electrically connected to the second heat flux sensor 42 and the calculation unit 81, and the electric signal output from the first heat flux sensor 41 is AD-converted to the calculation unit 81. Output. Therefore, the signal H1 [V] indicating the heat flux caused by the first semiconductor element 32 and the signal H2 [V] indicating the heat flux caused by the second semiconductor element 33 are input to the calculation unit 81.

The calculation unit 81 corresponds to the calculation unit. The calculation unit 81 individually calculates the heat dissipation amount of the first semiconductor element 32 and the heat dissipation amount of the second semiconductor element 33. The calculation unit 81 uses the signals H1 and H2 output from the AD converters 85 and 86, the areas A1 and A2 stored in the storage unit 84, and the coefficient [mV / Wm- ² ] to determine the amount of heat radiation. calculate. The calculation unit 81 divides the signal H1 [V] output from the first AD converter 85 by a coefficient, and multiplies the value obtained by the division by the area A1 [m ² ] to obtain the first semiconductor element 32. The heat dissipation amount W1 (= H1 × A1) [W] is calculated. Similarly, the calculation unit 81 divides the signal H2 [V] output from the second AD converter 86 by a coefficient, and multiplies the value obtained by the division by the area A2 [m ² ] to obtain the second semiconductor. The heat dissipation amount W2 (= H2 × A2) [W] of the element 33 is calculated.

As described above, in the electronic control device 100, the first heat flux sensor 41 is mounted in a state of being in contact with the entire area of the first facing surface S3 in the first semiconductor element 32. Therefore, the electronic control device 100 has good responsiveness to the temperature change of the first semiconductor element 32, and can obtain the heat flux from the first facing surface S3 of the first semiconductor element 32. Then, the electronic control device 100 calculates the heat dissipation amount of the first semiconductor element 32 based on the heat flux thus obtained. The electronic control device 100 can exert the same effect on the second semiconductor element 33.

In the electronic control device 100, the heat generated from the first semiconductor element 32 is more likely to be transferred to the cover 10 than to the wiring board 31. That is, the electronic control device 100 easily concentrates the heat path generated from the first semiconductor element 32 on the first heat flux sensor 41, and suppresses the heat generated from the first semiconductor element 32 from escaping to the wiring board 31 or the like. can. Therefore, the electronic control device 100 calculates the heat dissipation amount W1 corresponding to the original heat dissipation amount of the first semiconductor element 32. The same applies to the electronic control device 100 on the second semiconductor element 32 side. The original heat dissipation amount corresponds to the heat dissipation amount measured for the entire surface of the first semiconductor element 32.

Further, in the present embodiment, the load of the element is balanced by balancing the heat dissipation amount of the first semiconductor element 32 and the heat dissipation amount of the second semiconductor element 33 based on the heat dissipation amount obtained as described above. The microcomputer 80 is adopted so that it can be turned on, loosened, or stopped. Therefore, the electronic control device 100 includes a comparison unit 82 and an output calculation unit 83.

The comparison unit 82 corresponds to the comparison unit. The comparison unit 82 is electrically connected to the calculation unit 81, and compares the heat dissipation amounts of the semiconductor elements 32 and 33 calculated by the calculation unit 81. Further, the comparison unit 82 is electrically connected to the output calculation unit 83, and outputs the comparison result to the output calculation unit 83.

The output calculation unit 83 corresponds to a power control unit. The output calculation unit 83 controls the operation of the first semiconductor element 32 and the second semiconductor element 33. Further, when the heat dissipation amounts of the semiconductor elements 32 and 33 are different in the comparison in the comparison unit 82, the output calculation unit 83 controls the power of the first semiconductor element 32 and the second semiconductor element 33 according to the comparison result. This balances the heat dissipation amount of the first semiconductor element 32 and the heat dissipation amount of the second semiconductor element 33. For example, when the second semiconductor element 33 has a larger amount of heat radiation than the first semiconductor element 32, the output calculation unit 83 reduces the processing load of the second semiconductor element 33 and the processing load of the first semiconductor element 32. To control the power.

Since the electronic control device 100 individually calculates the heat dissipation amount of the first semiconductor element 32 and the heat dissipation amount of the second semiconductor element 33, it is easy to identify the place where the heat dissipation amount is large. Further, the electronic control device 100 balances the heat dissipation amount of the first semiconductor element 32 and the heat dissipation amount of the second semiconductor element 33 according to the comparison result of the heat dissipation amounts of the semiconductor elements 32 and 33, so that the first semiconductor is used. It is possible to suppress an increase in the amount of heat radiation from only one of the element 32 and the second semiconductor element 33. It can also be said that the electronic control device 100 can suppress the concentration of heat load on only one of the first semiconductor element 32 and the second semiconductor element 33. It can also be said that the electronic control device 100 can limit the electric power of the individual semiconductor elements 32 and 33.

However, the present disclosure is not limited to this, and may be any microcomputer 80 that calculates the heat dissipation amount of at least one circuit element such as the first semiconductor element 32.

Further, the electronic control device 100 may be configured such that the heat dissipation amount of the first semiconductor element 32 and the heat dissipation amount of the second semiconductor element 33 calculated by the calculation unit 81 are input to the output calculation unit 83. In this case, the output calculation unit 83 controls the electric power of the first semiconductor element 32 based on the heat dissipation amount calculated by the first heat flux sensor 41. Similarly, the output calculation unit 83 controls the electric power of the second semiconductor element 33 based on the heat dissipation amount calculated by the second heat flux sensor 42.

The output calculation unit 83 compares, for example, the heat radiation amount calculated by the first heat flux sensor 41 with a predetermined value. Then, when the output calculation unit 83 determines that the heat dissipation amount of the first heat flux sensor 41 exceeds a predetermined value, the output calculation unit 83 considers that the heat dissipation amount of the first semiconductor element 32 may exceed the rating. In this case, the output calculation unit 83 operates the first semiconductor element 32 to control the electric power so that the heat dissipation amount of the first semiconductor element 32 is less than a predetermined value. As a result, the electronic control device 100 can suppress the first semiconductor element 32 from exceeding the rating, and can suppress the occurrence of an abnormality in the first semiconductor element 32 or the continuation of the abnormality. The electronic control device 100 can perform the same control on the second semiconductor element 33, and can exert the same effect.

Further, the microcomputer 80 may detect an abnormality in the heat dissipation path of the semiconductor element based on the heat dissipation amount calculated by the calculation unit 81 (abnormality detection unit). In this case, the microcomputer 80 detects an abnormality in the heat dissipation path of the first semiconductor element 32 based on the heat dissipation amount of the first semiconductor element 32 calculated by the calculation unit 81. Similarly, the microcomputer 80 detects an abnormality in the heat dissipation path of the second semiconductor element 33 based on the heat dissipation amount of the second semiconductor element 33 calculated by the calculation unit 81.

For example, the microcomputer 80 can also monitor the temperature of the first semiconductor element 32 with the thermistor 34 mounted on the wiring board 31. However, in this case, the first semiconductor element 32 may reduce heat dissipation to the wiring board 31 due to solder cracks or the like. Therefore, the microcomputer 80 erroneously recognizes that the temperature read by the thermistor 34 has decreased and the temperature of the first semiconductor element 32 has decreased.

On the other hand, since the microcomputer 80 can obtain the heat radiation amount based on the voltage from the first heat flux sensor 41 mounted on the first semiconductor element 32, the state of the heat radiation path of the first semiconductor element 32 can be checked. It can be monitored and anomalies can be detected. Further, it can be said that the microcomputer 80 can detect an abnormality in a portion where the thermistor 34 is not arranged. The electronic control device 100 can also detect an abnormality in the second semiconductor element 33 in the same manner. For example, when the amount of heat radiation decreases in a part of the heat flux sensor, there is a possibility that the first heat radiation member 61 is partially peeled off. In addition, when the amount of heat dissipated increases in a certain area, the amount of heat dissipated to the substrate 31 may decrease, and cracks or the like may occur in the solder balls.

In this embodiment, an example in which the heat flux sensors 41 and 42 are mounted on the two semiconductor elements 32 and 33, respectively, is adopted. However, the present disclosure is not limited to this, and even in a configuration in which one heat flux sensor mounted on one semiconductor element is mounted, the effect that the temperature of the semiconductor element can be accurately detected can be obtained. can. That is, the present disclosure can be effective even if it does not have a plurality of heat flux sensors.

(Modification example)
In the above embodiment, an example in which one heat flux sensor is provided for one circuit element is adopted. However, the present disclosure is not limited to this.

In this modification, as shown in FIG. 5, a multi-core element 32a provided with four cores (processing units) of a first core c1, a second core c2, a third core c3, and a fourth core c4 as circuit elements. Is adopted. Since the processing load of the multi-core element 32a is different for each core, the amount of heat radiation may be different for each core.

The heat flux sensor of this modification includes a sensor for the first core 411, a sensor for the second core 412, a sensor for the third core 413, and a sensor for the fourth core 414 corresponding to each of the cores c1 to c4. I'm out. Further, the heat flux sensor may be integrally formed with a first core sensor 411, a second core sensor 412, a third core sensor 413, and a fourth core sensor 414. It can be said that the electronic control device 100 has a plurality of heat flux sensors 411 to 414 mounted on the first facing surface S3 of the multi-core element 32a.

More specifically, in the heat flux sensor, the first core sensor 411 faces the first core c1, the second core sensor 412 faces the second core c2, and the third core sensor 413 faces the third core c3. The fourth core sensor 414 is mounted on the multi-core element 32a so as to face the fourth core c4. In the first core sensor 411, the wiring 511 for the first sensor and the wiring of the wiring board 31 are electrically connected via a conductive member such as solder, and are mainly formed by the heat flux generated from the first core c1. Outputs the corresponding electrical signal. In the second core sensor 412, the wiring 512 for the second sensor and the wiring of the wiring board 31 are electrically connected via a conductive member such as solder, and are mainly formed by the heat flux generated from the second core c2. Outputs the corresponding electrical signal. In the third core sensor 413, the wiring 513 for the third sensor and the wiring of the wiring board 31 are electrically connected via a conductive member such as solder, and are mainly formed by the heat flux generated from the third core c3. Outputs the corresponding electrical signal. In the sensor 414 for the fourth core, the wiring 514 for the fourth sensor and the wiring of the wiring board 31 are electrically connected via a conductive member such as solder, and mainly to the heat flux generated from the fourth core c4. Outputs the corresponding electrical signal.

In this case, the microcomputer 80 can measure the heat dissipation amount of each of the cores c1 to c4 of the multi-core element 32a. Therefore, the microcomputer 80 can apply the above embodiment to control the power of each core c1 to c4 of the multi-core element 32a according to the heat dissipation amount of each core c1 to c4. Therefore, the microcomputer 80 can suppress the increase in the amount of heat radiation locally only in the core having the multi-core element 32a. Further, the microcomputer 80 can also exert the same effect as that of the above embodiment.

In this modification, a multi-core element 32a provided with four cores is adopted. However, the number of cores is not limited to this. Further, it is preferable to adopt a heat flux sensor provided with a core sensor corresponding to the number of cores of the circuit element to be attached.

The preferred embodiments of the present disclosure have been described above. However, the present disclosure is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present disclosure. Hereinafter, the second embodiment and the third embodiment will be described as other embodiments of the present disclosure. The above-mentioned embodiment, the second embodiment, and the third embodiment can be carried out individually, but can also be carried out in combination as appropriate. The present disclosure is not limited to the combinations shown in the embodiments, but can be carried out by various combinations.

(Second Embodiment)
The electronic control device 100 of the second embodiment will be described with reference to FIGS. 6, 7, and 8. In this embodiment, for convenience, the same reference numerals as those in the above embodiment are adopted as the reference numerals of the electronic control device. Further, in the present embodiment, the same reference numerals as those in the above embodiment are adopted with respect to the same components as those in the above embodiment. Therefore, the components having the same reference numerals can be applied with reference to the above embodiment. This embodiment mainly differs from the above-described embodiment in the number of heat flux sensors provided for each of the semiconductor elements 32 and 33, the configuration of the microcomputer 80, and the processing operation.

As shown in FIG. 6, the electronic control device 100 includes a third heat flux sensor 43 and a fourth heat flux sensor 44. The third heat flux sensor 43 and the fourth heat flux sensor 44 correspond to the back surface side heat flux sensor. Note that FIG. 6 is a cross-sectional view corresponding to the cross-sectional view of FIG.

The third heat flux sensor 43 is mounted on the back surface of the mounting region of the first semiconductor element 32 in the wiring board 31. That is, the third heat flux sensor 43 is mounted on the second substrate surface S2 of the wiring board 31 in a region that overlaps with the mounting region of the first semiconductor element 32. The third heat flux sensor 43 is electrically connected to the wiring of the wiring board 31 by a conductive member such as solder via the third wiring 53. Further, the third heat flux sensor 43 is electrically connected to the microcomputer 80 via the wiring board 31.

The fourth heat flux sensor 44 is mounted on the back surface of the mounting region of the second semiconductor element 33 in the wiring board 31. That is, the fourth heat flux sensor 44 is mounted on the second substrate surface S2 of the wiring board 31 in a region that overlaps with the mounting region of the second semiconductor element 33. The fourth heat flux sensor 44 is electrically connected to the wiring of the wiring board 31 by a conductive member such as solder via the fourth wiring 54. Further, the fourth heat flux sensor 44 is electrically connected to the microcomputer 80 via the wiring board 31.

As shown in FIG. 7, the microcomputer 80 is provided with an AD converter according to the number of heat flux sensors. That is, the microcomputer 80 includes a third AD converter 87 electrically connected to the third heat flux sensor 43, and a fourth AD converter 88 electrically connected to the fourth heat flux sensor 44.

The third AD converter 87 inputs an electric signal (voltage) output from the third heat flux sensor 43, AD converts the electric signal, and outputs the electric signal to the calculation unit 81. Similarly, the 4th AD converter 88 is electrically connected to the 4th heat flux sensor 44 and the calculation unit 81, and the electric signal output from the 4th heat flux sensor 44 is AD-converted to the calculation unit 81. Output.

Therefore, the calculation unit 81 has a signal H1 [V] indicating the heat flux toward the cover 10 side by the first semiconductor element 32 and a signal H2 [V] indicating the heat flux toward the base 20 side by the second semiconductor element 33. Is entered. Further, the calculation unit 81 has a signal H3 [V] indicating the heat flux to the wiring substrate 31 side by the first semiconductor element 32 and a signal H4 [V] indicating the heat flux to the wiring substrate 31 side by the second semiconductor element 33. V] is input.

Further, in the storage unit 84, in addition to the areas A1 and A2 and the coefficient, the area A3 [m ² ] of the surface (region) where the wiring board 31 and the third heat flux sensor 43 face each other, and the wiring board 31 and the third. 4 The area A4 [m ² ] of the surface facing the heat flux sensor 44 is stored. The area A3 and the area A1 can be regarded as equivalent. Area A4 and area A2 can be regarded as equivalent. Further, the storage unit 84 also stores the calculation results calculated by the calculation unit 81.

Then, the calculation unit 81 calculates the heat dissipation amount W3 (= H3 × A3) [W] based on the electric signal output from the third heat flux sensor 43 in the same manner as described above. Further, the calculation unit 81 calculates the heat dissipation amount E4 (= H4 × A4) [W] based on the electric signal output from the fourth heat flux sensor 44. The heat radiation amount W3 and W4 correspond to the heat radiation amount based on the heat flux to the back surface side.

In the following, the heat dissipation amounts W1 and W2 calculated based on the electric signals output from the heat flux sensors 41 and 42 mounted on the semiconductor elements 32 and 33 are also referred to as upper heat dissipation amounts. On the other hand, the heat dissipation amounts W3 and W4 calculated based on the electric signals output from the heat flux sensors 43 and 44 mounted on the wiring board 31 are also referred to as lower heat dissipation amounts.

The first heat flux sensor 41 can be said to be a sensor for measuring the heat flux radiated from the first facing surface S3 of the first semiconductor element 32 to the cover 10 via the first heat radiating member 61. On the other hand, the third heat flux sensor 43 can be said to be a sensor for measuring the heat flux radiated to the air from the surface of the first semiconductor element 32 facing the wiring board 31 via the wiring board 31.

Similarly, the second heat flux sensor 42 can be said to be a sensor for measuring the heat flux radiated from the second facing surface S4 of the second semiconductor element 33 to the base 20 via the second heat radiating member 62. On the other hand, the fourth heat flux sensor 44 can be said to be a sensor for measuring the heat flux radiated to the air from the surface of the second semiconductor element 33 facing the wiring board 31 via the wiring board 31.

Here, the processing operation of the microcomputer 80 will be described with reference to FIG. The microcomputer 80 executes, for example, the process shown in the flowchart of FIG. 8 at a predetermined time.

In step S10, the electronic control device is activated. The output calculation unit 83 operates the electronic control device 100. The output calculation unit 83 operates the first semiconductor element 32, the second semiconductor element 33, and the like.

In step S11, heat flux measurement data is input. The calculation unit 81 inputs the conversion result in which the electric signals output from each of the heat flux sensors 41 to 44 are AD-converted by the AD converters 85 to 88. In this way, the conversion result can be said to be heat flux measurement data. The calculation unit 81 stores the conversion results of the AD converters 85 to 88 in the storage unit 84 each time. However, the conversion results of the AD converters 85 to 88 may be stored in the storage unit 84 without going through the calculation unit 81. Therefore, the storage unit 84 stores the signals H1 to H4 indicating the heat flux at predetermined time intervals.

In step S12, the amount of heat radiation is calculated. The calculation unit 81 calculates the heat dissipation amount by multiplying the conversion results of the AD converters 85 and 86 by the area in the same manner as in the calculation of the calorific value of the above embodiment. In this way, the calculation unit 81 calculates the heat dissipation amount W1 from the first semiconductor element 32 to the cover 10 and the heat dissipation amount W2 from the second semiconductor element 33 to the base 20.

In step S13, it is determined whether or not the heat flux measurement data has changed. The calculation unit 81 compares the heat flux measurement data acquired this time with the heat flux measurement data acquired last time, and determines whether or not the data has changed. The calculation unit 81 compares the heat flux measurement data acquired this time with the heat flux measurement data acquired last time for each of H1 and H2, and determines whether or not they have changed. For example, the calculation unit 81 compares the signal H1 which is the heat flux measurement data acquired this time with the signal H1 stored in the storage unit 84 which is the heat flux measurement data acquired last time, and determines whether or not the signal has changed. Is determined. The same applies to H2. Then, if it is determined that the calculation unit 81 has not changed, the process returns to step S11, and if it is determined that the change has not occurred, the process proceeds to step S14.

In step S14, the amount of heat radiation is calculated. The calculation unit 81 calculates the heat dissipation amounts W1 and W2 using the changed signals H1 and H2.

In step S15, the total calorific value is calculated. The total heat generation amount is, for example, the total value of the heat radiation amount radiated from the first semiconductor element 32 and the residual heat generation amount remaining in the first semiconductor element 32 without being radiated.

The calculation unit 81 calculates the total calorific value of each of the first semiconductor element 32 and the second semiconductor element 33. The total heat generation amount of the first semiconductor element 32 and the second semiconductor element 33 can be calculated in the same manner except that the heat dissipation amount used for the calculation is different. Therefore, in the following, a method of calculating the total calorific value of the first semiconductor device 32 will be described as a representative. The method for calculating the effective calorific value, which will be described later, will also be described by adopting the first semiconductor device 32 as a representative example for the same reason.

The calculation unit 81 uses the heat dissipation amounts W1 and W3 calculated based on the signals H1 and H3 acquired this time, and the heat dissipation amounts W1 and W3 calculated based on the signals H1 and H3 acquired last time, to form the first semiconductor element 32. Calculate the total calorific value. In the following, in order to distinguish between the current value and the previous value of the heat dissipation amount, the previous heat dissipation amount is W11 and W31, and the current heat dissipation amount is W12 and W32. Therefore, the previous upper heat dissipation amount is W11, the previous lower heat dissipation amount is W31, the current upper heat dissipation amount is W12, and the previous lower heat dissipation amount is W32.

The calculation unit 81 has an upper heat dissipation amount on the vertical axis and a lower heat dissipation amount on the horizontal axis, and shows a straight line connecting the points indicated by the previous heat dissipation amounts W11 and W31 and the points indicated by the current heat dissipation amounts W12 and W32. The intercept of the linear function is calculated as the total calorific value. In this graph of heat dissipation amount, the vertical axis of FIG. 10 is the upper heat dissipation amount, and the horizontal axis is the lower heat dissipation amount. As described above, the calculation unit 81 generates the heat radiation amount at a plurality of time points based on the output result of the first heat flux sensor 41 and the heat radiation amount at a plurality of time points based on the output result of the third heat flux sensor 43. The intercept of the linear function to be calculated is calculated as the total calorific value of the first semiconductor element 32.

In this way, the calculation unit 81 calculates not only the heat dissipation amount of the first semiconductor element 32 but also the total heat generation amount by using the heat flux sensor 41 and the heat flux sensor 43 mounted on the first semiconductor element 32. can do.

In step S16, the effective calorific value is calculated. The effective calorific value corresponds to the residual calorific value of the circuit element. The calculation unit 81 subtracts the heat radiation amount based on the output result of the first heat flux sensor 41 and the heat radiation amount based on the output result of the third heat flux sensor 43 from the total heat flux sensor, so that the first semiconductor element 32 Calculate the effective calorific value of.

A part of the heat generated in the first semiconductor element 32 is dissipated to the cover 10 or the like, and the rest remains in the first semiconductor element 32. As described above, since the effective heat generation amount is the amount of heat remaining in the first semiconductor element 32 without being dissipated, it may cause a defect in the first semiconductor element 32. That is, if the total calorific value of the first semiconductor element 32 exceeds a predetermined value (rated calorific value), there is a high possibility that a defect will occur. Therefore, since the electronic control device 100 calculates the effective calorific value by the calculation unit 81, it is possible to monitor whether or not the effective calorific value of the first semiconductor element 32 exceeds a predetermined value.

Further, the output calculation unit 83 controls the first semiconductor element 32 so that the effective calorific value of the first semiconductor element 32 falls below the predetermined value when the effective calorific value of the first semiconductor element 32 is likely to exceed the predetermined value. You may. That is, the output calculation unit 83 monitors whether or not the effective calorific value of the first semiconductor element 32 exceeds a predetermined value, and the first semiconductor so that the effective calorific value of the first semiconductor element 32 does not exceed the predetermined value. The power of the element 32 may be controlled. As a result, the electronic control device 100 can suppress the first semiconductor element 32 from exceeding the rating, and can suppress the occurrence of an abnormality in the first semiconductor element 32 or the continuation of the abnormality. The output calculation unit 83 can also control the second semiconductor element 33 in the same manner.

In step S17, the effective calorific value is compared (comparison unit). The comparison unit 82 compares the effective calorific value of the first semiconductor element 32 and the effective calorific value of the second semiconductor element 33 calculated in step S16.

In step S18, the calorific value is controlled (power control unit). The output calculation unit 83 controls the electric power of the first semiconductor element 32 and the second semiconductor element 33 based on the comparison result in step S17. When the effective calorific value of the first semiconductor element 32 and the second semiconductor element 33 are different in the comparison in step S17, the output calculation unit 83 reduces the processing load of the semiconductor element having the larger effective calorific value and the effective calorific value. The processing load of the semiconductor element with the smaller number is increased to control the power. In this way, the output calculation unit 83 balances the effective calorific value of the first semiconductor element 32 and the effective calorific value of the second semiconductor element 33 according to the comparison result of the effective calorific value of the semiconductor elements 32 and 33. Therefore, it is possible to suppress an increase in the effective calorific value of only one of the first semiconductor element 32 and the second semiconductor element 33. It can also be said that the electronic control device 100 can suppress the concentration of heat load on only one of the first semiconductor element 32 and the second semiconductor element 33.

When the value of the third heat flux sensor 43 is 0 [V], it can be considered that most of the heat generated by the first semiconductor element 32 passes through the first heat flux sensor 41. Therefore, the calculation unit 81 can obtain the calorific value of the first semiconductor element 32 by dividing the signal H1 [V] by a coefficient and multiplying the value obtained by the division by the area A1 [m ² ]. .. Further, even when the value of the third heat flux sensor 43 is 0 [V], the calculation unit 81 changes the temperature environment around the electronic control device 100 as described above, and the heat flux sensors 41 and 43 When the value of is changed, the calorific value can be estimated by linear approximation.

In this embodiment, as an example, an example of calculating the total heat generation amount by using the upper heat dissipation amount and the lower heat dissipation amount is adopted. However, the present disclosure is not limited to this, and the total heat generation amount can be calculated by using the upper heat flux and the lower heat flux instead of the upper heat radiation amount and the lower heat radiation amount. That is, it can be said that the present disclosure calculates the total calorific value by using the value that correlates with the upper heat dissipation amount and the value that correlates with the lower heat dissipation amount.

(Third Embodiment)
The electronic device of the third embodiment will be described with reference to FIGS. 9 and 10. In this embodiment, an example in which the electronic device of the present disclosure is applied to a measuring device is adopted. In this embodiment, the same reference numerals as those in the above embodiment are adopted for the same components as those in the above embodiment. Therefore, the components having the same reference numerals can be applied with reference to the above embodiment.

The measuring device can be mounted on another device in addition to the electronic control device 100 described above. Moreover, it is not limited to those mounted on a vehicle. This is a device for measuring the effective calorific value of the first semiconductor element 32 and the like mounted on the electronic control device 100. In this embodiment, the MOSFET 32b is adopted as a circuit element. The MOSFET 32b is a measurement target of the effective calorific value.

The MOSFET 32b is mounted on the wiring board 31. The wiring board 31 is electrically connected to the measuring unit 300. The MOSFET 32b operates by being supplied with electric power from the measuring unit 300 via the wiring board 31.

The measuring device includes a first heat flux sensor 41, a third heat flux sensor 43, a chiller 200, a measuring unit 300, and the like.

The first heat flux sensor 41 and the third heat flux sensor 43 are mounted on the MOSFET 32b and the wiring board 31 as in the second embodiment. The first heat flux sensor 41 and the third heat flux sensor 43 are electrically connected to the measuring unit 300, and output an electric signal to the measuring unit 300.

In this embodiment, as an example, the first heat flux sensor 41 is mounted on the MOSFET 32b via the element-side heat-dissipating member 91, and is mounted on the wiring board 32 via the substrate-side heat-dissipating member 92. The element-side heat-dissipating member 91 and the substrate-side heat-dissipating member 92 are made of the same material as the first heat-dissipating member 61, and are provided for the same reason. However, the element-side heat-dissipating member 91 and the substrate-side heat-dissipating member 92 may not be provided.

The chiller 200 is mounted on the first heat flux sensor 41. That is, the chiller 200 is mounted on the side opposite to the MOSFET 32b in the first heat flux sensor 41. The chiller 200 circulates water to cool an object (PLC32b). The chiller 200 is configured to be able to adjust the cooling force (temperature control) in response to a command from the measuring unit 300. The chiller 200 is provided to collect the heat flux from the MOSFET 32b in one direction on the first heat flux sensor 41 side. In this disclosure, a heat medium type chiller may be adopted instead of the chiller 200.

The measuring unit 300 includes a processing unit 310 such as a CPU, a storage unit 320 such as a ROM or RAM, and a power supply unit 330. The measuring unit 300 may be provided with an AD converter in the same manner as the microcomputer 80.

The processing unit 310 operates the MOSFET 32b and acquires electric signals from the heat flux sensors 41 and 43 to calculate the heat dissipation amount, the total heat generation amount, and the effective heat generation amount. Further, the processing unit 310 instructs the power supply unit 330 to supply power and instructs the chiller 200 to adjust the cooling power in order to calculate the effective calorific value.

The storage unit 320 stores the area corresponding to the areas A1 and A3 of the above embodiment, the calculation result of the processing unit 310, and the like. The power supply unit 330 supplies power to the wiring board 31 and the MOSFET 32b in response to an instruction from the processing unit 310.

The processing unit 310 calculates the heat dissipation amount, the total heat generation amount, and the effective heat generation amount in the same manner as the calculation unit 81. In this embodiment, as shown in FIG. 10, instead of the upper heat dissipation amount and the lower heat dissipation amount, an example of calculating the total heat generation amount and the effective heat generation amount by using the upper heat flux and the lower heat flux is adopted. There is.

Further, the measuring unit 300 may be heated not only from the MOSFET 32b but also from the surrounding environment and other elements due to the supercooling of the chiller 200. Therefore, the processing unit 310 controls the temperature of the chiller 200 so that the heat flux based on the third heat flux sensor 43 becomes 0 [W / m ² ].

As a result of actually calculating the effective calorific value as described above with the MOSFET 32b having the calorific value X [W] as the measurement target, the same value could be calculated. The calorific value X [W] is a value calculated from the measured data of the current × voltage of the MOSFET 32b. In this way, the measuring device can calculate the effective calorific value as in the above embodiment. Further, the measuring device controls the temperature of the chiller 200 so that the heat flux based on the third heat flux sensor 43 becomes 0 [W / m ² ], and calculates the effective calorific value. An accurate effective calorific value can be calculated without providing a heat flux sensor.

10 ... cover, 11 ... cover base, 12 ... cover protrusion, 13 ... heat dissipation fin, 14 ... connector part, 20 ... base, 21 ... base base, 22 ... base protrusion, 30 ... circuit board, 31 ... wiring board, 32 ... 1st semiconductor element, 33 ... 2nd semiconductor element, 34 ... Thermista, 41 ... 1st heat flux sensor, 42 ... 2nd heat flux sensor, 43 ... 3rd heat flux sensor, 44 ... 4th heat flux sensor, 51 ... 1st wiring, 52 ... 2nd wiring, 53 ... 3rd wiring, 54 ... 4th wiring, 61 ... 1st heat dissipation member, 62 ... 2nd heat dissipation member, 70 ... connector, 80 ... microcomputer, 81 ... calculation unit, 82 ... Comparison unit, 83 ... Output calculation unit, 84 ... Storage unit, 85 ... 1st AD converter, 86 ... 2nd AD converter, 87 ... 3rd AD converter, 88 ... 4th AD converter, 91 ... Element side heat dissipation member, 92 ... Board side heat dissipation member, 100 ... Electronic control device, 200 ... Chiller, 300 ... Measurement unit, 310 ... Processing unit, 320 ... Storage unit, 330 ... Power supply unit, S1 ... First board surface, S2 ... Second board surface , S3 ... 1st facing surface, S4 ... 2nd facing surface

Claims (9)

Wiring board (31) and
At least one circuit element (32, 33) mounted on the wiring board and electrically connected to the wiring board.
A heat flux sensor (a heat flux sensor that is mounted in contact with the entire area of the opposite surface of the circuit element facing the wiring board and outputs an electric signal according to the heat flux generated from the circuit element. 41, 42) and
A calculation unit (81) that calculates the amount of heat released from the circuit element by multiplying the heat flux, which is the output result of the heat flux sensor, by the area of the region where the circuit element and the heat flux sensor face each other. And equipped with electronic devices. The electronic device according to claim 1, further comprising a power control unit (83) that controls the electric power of the circuit element based on the heat dissipation amount of the circuit element calculated by the calculation unit. Two of the circuit elements mounted on the wiring board and performing at least the same processing,
The two heat flux sensors individually mounted on each of the plurality of circuit elements,
It is provided with a comparison unit (82) for comparing the heat dissipation amount of each circuit element calculated by the calculation unit.
When the heat dissipation amount of each circuit element is different in the comparison by the comparison unit, the power control unit reduces the processing load of the circuit element having the larger heat dissipation amount and reduces the processing load of the circuit element having the smaller heat radiation amount. The electronic device according to claim 2, wherein the processing load of the above is increased to control the electric power. The wiring board includes backside heat flux sensors (43, 44) mounted on the back surface of the mounting area of the circuit element.
The calculation unit multiplies the heat flux to the back surface side, which is the output result of the back surface side heat flux sensor, by the area of the region where the wiring board and the back surface side heat flux sensor face each other. The amount of heat released based on the heat flux to the back surface side was calculated, and the amount of heat released at a plurality of time points calculated based on the output result of the heat flux sensor was calculated based on the output result of the back surface side heat flux sensor. The electronic device according to claim 1, wherein a section of a linear function generated based on the heat dissipation amount at a plurality of time points is calculated as the total heat generation amount of the circuit element. The calculation unit subtracts the heat radiation amount calculated based on the output result of the heat flux sensor and the heat radiation amount calculated based on the output result of the back surface side heat flux sensor from the total heat generation amount. The electronic device according to claim 4, wherein the residual heat generation amount of the circuit element is calculated. Two of the circuit elements mounted on the wiring board and performing at least the same processing,
The two heat flux sensors individually mounted on each of the plurality of circuit elements,
A comparison unit (82) for comparing the residual calorific value of each circuit element calculated by the calculation unit, and a comparison unit (82).
When the residual calorific value of each circuit element is different in the comparison by the comparison unit, the processing load of the circuit element having the larger residual calorific value is reduced, and the processing load of the circuit element having the smaller residual calorific value is reduced. The electronic device according to claim 5, further comprising a power control unit (83) for increasing and controlling electric power. The electronic device according to any one of claims 1 to 6, further comprising a heat radiating member mounted on a surface opposite to the circuit element in the heat flux sensor. The electronic device according to any one of claims 1 to 7, further comprising an abnormality detection unit (80) for detecting an abnormality in the heat dissipation path of the circuit element based on the heat radiation amount calculated by the calculation unit. .. The electronic device according to any one of claims 1 to 7, wherein a plurality of the heat flux sensors are mounted on the opposite surface of the circuit element facing the wiring board.

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