Semiconductor device

Abstract

To provide a semiconductor device that can prevent deterioration of a function of protecting a switching element to be protected even when the temperature of the switching element differs from the temperature of a control circuit that controls the switching element.SOLUTION: A semiconductor device 1A includes: semiconductor element 12 having a switching element 121, a temperature detection unit 122, and a current detection unit 121a; and a control circuit 11A that controls the semiconductor element 12. The control circuit 11A includes: a signal generation unit 111 configured to generate a temperature variable signal Stv varying according to a detection temperature detected by the temperature detection unit 122, using a temperature detection signal St having information on the detection temperature; and an overcurrent detection unit 112A configured to detect that a current flowing into the switching element 121 is an overcurrent using a current detection signal Ss having information on the detection current detected by the current detection unit 121a and the temperature variable signal Stv output from the signal generation unit 111.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device including a switching element. [Background technology]

[0002] Patent Document 1 discloses the following technology: "For the purpose of providing a semiconductor device and its overcurrent protection function with improved accuracy of the switching element protection function, the device comprises a chip temperature detection diode of the switching element, a control circuit temperature detection diode arranged in a control circuit that controls the switching element, and an overcurrent reference voltage correction circuit that compares the detected potentials of both diodes, corrects the overcurrent reference voltage generated by the overcurrent reference voltage circuit, and outputs the corrected overcurrent reference voltage." [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-150820 Summary of the Invention [Problem to be solved by the invention]

[0004] A semiconductor device having a protection function for protecting a switching element from overcurrent has a problem in that the protection function for the switching element is reduced when the temperatures of the switching element to be protected and the control circuit that controls the switching element are different.

[0005] An object of the present invention is to provide a semiconductor device that can prevent a deterioration in the protection function of a switching element even when the temperature of the switching element to be protected differs from the temperature of a control circuit that controls the switching element. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a semiconductor device according to one aspect of the present invention comprises a switching element, a semiconductor element having a temperature detection unit that detects the temperature of the switching element and a current detection unit that detects the current of the switching element, and a control circuit that controls the semiconductor element, wherein the control circuit comprises a signal generation unit that generates a temperature variable signal that changes in accordance with the detected temperature using a temperature detection signal having information of the detected temperature detected by the temperature detection unit, and an overcurrent detection unit that detects that the current flowing through the switching element is an overcurrent using a current detection signal having information of the detected current detected by the current detection unit and the temperature variable signal output from the signal generation unit. [Effects of the Invention]

[0007] According to one aspect of the present invention, even when the temperature of a switching element to be protected differs from the temperature of a control circuit that controls the switching element, it is possible to prevent a deterioration in the protection function of the switching element. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a block diagram showing an example of a schematic configuration of a semiconductor device according to a first embodiment of the present invention. [Figure 2] 1 is a diagram for explaining the semiconductor device according to the first embodiment of the present invention, and is a graph showing an example of the temperature characteristics of a temperature detection unit that detects the temperature of a switching element. [Figure 3] 1 is a diagram schematically showing a cross section of a semiconductor device according to a first embodiment of the present invention. [Figure 4] 1 is a diagram for explaining the semiconductor device according to the first embodiment of the present invention, and is a graph showing an example of the temperature characteristics of a temperature variable signal relative to the temperature of a switching element. [Figure 5] 1 is a diagram illustrating the semiconductor device according to the first embodiment of the present invention, and is a graph showing an example of the voltage level of a temperature variable signal that is set when the temperature of a switching element is at room temperature. [Figure 6]1 is a diagram illustrating the semiconductor device according to the first embodiment of the present invention, and is a graph showing an example of the voltage level of a temperature variable signal that is set when the temperature of a switching element is a predetermined temperature that is higher than room temperature. [Figure 7] 10 is a graph showing an example of an overcurrent detection reference voltage that is set when the temperatures of a switching element and a control circuit are different in a conventional technique as a comparative example. [Figure 8] FIG. 10 is a block diagram showing an example of a schematic configuration of a semiconductor device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The embodiments of the present invention are merely examples of devices and methods for embodying the technical idea of ​​the present invention, and the technical idea of ​​the present invention does not specify the materials, shapes, structures, arrangements, etc. of the components to be described below. The technical idea of ​​the present invention can be modified in various ways within the technical scope defined by the claims.

[0010] [First embodiment] 1-1.Configuration of semiconductor device: The schematic configuration of a semiconductor device according to a first embodiment of the present invention will be described with reference to Figures 1 to 6. The semiconductor device according to this embodiment can be applied to, for example, an intelligent power module (IPM) in which a switching element, a freewheeling diode, and an integrated circuit for driving and protecting the switching element are integrated into a single package, or other semiconductor modules. Figure 1 is a block diagram showing an example of the schematic configuration of a semiconductor device 1A according to this embodiment.

[0011] 1, a semiconductor device 1A according to this embodiment includes a semiconductor element 12 and a control circuit 11A that controls the semiconductor element 12. The semiconductor element 12 includes a switching element 121, a temperature detection unit 122 that detects the temperature of the switching element 121, and a current detection unit 121a that detects the current of the switching element 121. The switching element 121 is formed of, for example, an insulated gate bipolar transistor.

[0012] In this embodiment, the switching element is, for example, a voltage-controlled element, such as the switching element 121. A collector C of the switching element 121 is connected to a predetermined circuit (not shown) formed in the semiconductor element 12. An emitter E of the switching element 121 is connected to a reference potential terminal T2 provided in the control circuit 11A. A gate G of the switching element 121 is connected to a gate signal output terminal T1 provided in the control circuit 11A. The reference potential terminal T2 is connected to a reference potential section maintained at a reference potential (e.g., ground potential) of the control circuit 11A. Therefore, the emitter E of the switching element 121 is connected to the reference potential section via the reference potential terminal T2 and is maintained at the same potential as the reference potential of the control circuit 11A.

[0013] The output of current detection unit 121a built into switching element 121 is connected to overcurrent detection terminal T3 provided in control circuit 11A. A current of, for example, about 1 / 10,000 of collector current Ic of switching element 121 is diverted to current detection unit 121a. Current detection unit 121a outputs detection current Is diverted from collector current Ic via overcurrent detection terminal T3 to control circuit 11A.

[0014] The anode of the temperature detection unit 122 is connected to a temperature detection terminal T4 provided in the control circuit 11A. The cathode of the temperature detection unit 122 is connected to a reference potential unit that is maintained at the reference potential of the semiconductor element 12. The temperature detection unit 122 is, for example, a diode that has temperature dependency. Therefore, the temperature detection unit 122 has temperature characteristics in which the resistivity is lower at high temperatures than at low temperatures. Therefore, the resistivity of the temperature detection unit 122 changes depending on the temperature of the switching element 121, and the forward voltage also changes.

[0015] 2 is a diagram schematically illustrating an example of the temperature characteristics of the forward voltage of temperature detection unit 122 relative to the temperature of switching element 121. The horizontal axis of the graph shown in Fig. 2 represents the temperature of switching element 121. The vertical axis of the graph shown in Fig. 2 represents the forward voltage VF of temperature detection unit 122.

[0016] 2, the temperature detection unit 122 has a temperature characteristic in which the forward voltage VF decreases as the temperature of the switching element 121 increases. The temperature detection unit 122 uses the forward voltage VF, which changes depending on the temperature of the switching element 121, as a detected temperature, and outputs a temperature detection signal St based on the detected temperature to the control circuit 11A. The relationship between the forward voltage VF of the temperature detection unit 122 and the temperature detection signal St will be described later.

[0017] Fig. 3 is a diagram schematically illustrating a cross section of semiconductor device 1A. To facilitate understanding, Fig. 3 does not illustrate bonding wires or lead frames connecting control circuit 11A and semiconductor element 12, and conductive patterns electrically connected to control circuit 11A and semiconductor element 12. Furthermore, the shapes, sizes, and arrangements of control circuit 11A and semiconductor element 12 shown in Fig. 3 differ from the actual shapes, sizes, and arrangements.

[0018] As shown in FIG. 3, the semiconductor device 1A includes an insulating substrate 31, a resin case 32, a semiconductor chip substrate 33, a circuit board 34, an integrated circuit substrate 35, and a base portion 36. The temperature detection unit 122 (not shown in FIG. 3) may be provided in any of the following: the semiconductor chip substrate 33 on which the semiconductor element 12 is formed; the insulating substrate 31 on which the semiconductor element 12 is mounted; the circuit board 34 on which the control circuit 11A is mounted; the interior 321 of the resin case 32 in which the semiconductor element 12 and the control circuit 11A are housed; or the exterior 322 of the resin case 32 in contact with the resin case 32. The semiconductor element 12 is mounted on the insulating substrate 31, for example, by mounting the semiconductor chip substrate 33 on the insulating substrate 31. The control circuit 11A is formed on the integrated circuit substrate 35, and the integrated circuit substrate 35 is mounted on the circuit board 34, for example, by mounting the integrated circuit substrate 35 on the circuit board 34. The insulating substrate 31, the circuit board 34, and the resin case 32 are disposed on the base portion 36. The space formed by the resin case 32 and the base portion 36 is the interior 321 of the resin case 32. The temperature detection portion 122 is preferably disposed close to the switching element 121 in order to detect the temperature of the switching element 121 with high accuracy.

[0019] Returning to FIG. 1, the control circuit 11A includes a signal generating section 111, an overcurrent detecting section 112A, an overheat detecting section 113, and a gate driving circuit 114.

[0020] The signal generating unit 111 includes a first reference signal generating unit 111a and a temperature variable signal generating unit 111b. The signal generating unit 111 uses a temperature detection signal St having information on the detected temperature detected by the temperature detecting unit 122 to generate a temperature variable signal Stv that changes in accordance with the detected temperature.

[0021] The first reference signal generating unit 111a generates a first reference signal Sr1 having a voltage that is not temperature dependent. The first reference signal generating unit 111a is configured, for example, with a BGR (Bandgap Reference) circuit. This allows the first reference signal generating unit 111a to generate a first reference signal Sr1 having an absolute reference voltage that is independent of the power supply voltage input to the control circuit 11A, the temperature of the control circuit 11A, and the process of the control circuit 11A.

[0022] The temperature variable signal generator 111b generates a temperature variable signal Stv based on the difference between the first reference signal Sr1 output from the first reference signal generator 111a and the temperature detection signal St. The temperature variable signal generator 111b has a differential circuit 111b-1 that generates a differential signal Sdf between the first reference signal Sr1 and the temperature detection signal St, and a level change circuit 111b-2 that changes the signal level of the differential signal Sdf output from the differential circuit 111b-1.

[0023] The differential circuit 111b-1 has an operational amplifier. The inverting input terminal (-) and non-inverting input terminal (+) of the operational amplifier serve as the two input terminals of the differential circuit 111b-1, and the output terminal of the operational amplifier serves as the output terminal of the differential circuit 111b-1. The inverting input terminal (-) of the differential circuit 111b-1 is connected to the temperature detection terminal T4. The non-inverting input terminal (+) of the differential circuit 111b-1 is connected to the output terminal of the first reference signal generator 111a. The output terminal of the differential circuit 111b-1 is connected to the input terminal of the level shift circuit 111b-2. This allows the differential circuit 111b-1 to output a differential signal Sdf, obtained by subtracting the temperature detection signal St from the first reference signal Sr1, to the level shift circuit 111b-2.

[0024] The level shifting circuit 111b-2 is configured with, for example, an adder circuit. The level shifting circuit 111b-2 adds a signal with a constant signal level (i.e., voltage level) without temperature dependency to the differential signal Sdf input from the differential circuit 111b-1 to shift the signal level of the differential signal Sdf. The constant signal is generated by, for example, a BGR circuit (not shown). The temperature variable signal generating unit 111b outputs the differential signal Sdf, whose signal level has been level-shifted in the level shifting circuit 111b-2, as the temperature variable signal Stv. The first reference signal Sr1 and the constant signal added in the level shifting circuit 111b-2 are both signals without temperature dependency. Therefore, the differential signal Sdf and the temperature variable signal Stv obtained by converting the signal level of the differential signal Sdf are signals containing only information about the temperature of the switching element 121.

[0025] Fig. 4 is a diagram schematically showing an example of the temperature characteristic of the voltage level Vtv of the temperature variable signal Stv with respect to the temperature of the switching element 121. The horizontal axis of the graph shown in Fig. 4 represents the temperature of the switching element 121. The vertical axis of the graph shown in Fig. 4 represents the voltage level Vtv of the temperature variable signal Stv.

[0026] 4, the temperature variable signal Stv has a characteristic that the voltage level Vtv of the temperature variable signal Stv increases in accordance with a decrease in the forward voltage VF of the temperature detection unit 122 (see FIG. 2) due to an increase in the temperature of the switching element 121. The absolute value of the rate of increase of the voltage level Vtv of the temperature variable signal Stv with respect to the temperature change of the switching element 121 is approximately equal to the absolute value of the rate of decrease of the forward voltage VF of the temperature detection unit 122 with respect to the temperature change of the switching element 121.

[0027] 1, the overcurrent detection unit 112A includes a current detection signal generation circuit 112c, a comparator 112d, and a filter circuit 112e. The overcurrent detection unit 112A detects whether the current flowing through the switching element 121 is an overcurrent by using a current detection signal Ss having information on the detection current Is detected by the current detection unit 121a and a temperature variable signal Stv output from the signal generation unit 111.

[0028] The current detection signal generating circuit 112c generates a voltage current detection signal Ss based on the detection current Is. The current detection signal generating circuit 112c has a resistive element R. The resistive element R is provided between the overcurrent detection terminal T3 and the reference potential part of the control circuit 11A. The current detection signal generating circuit 112c generates the current detection signal Ss having, as a signal level, the voltage generated across both terminals of the resistive element R when the detection current Is flows through the resistive element R.

[0029] The comparator 112d compares the temperature variable signal Stv with the current detection signal Ss. The non-inverting input terminal (+) of the comparator 112d is connected to the output terminal of the signal generator 111, i.e., the output terminal of the temperature variable signal generator 111b. The inverting input terminal (-) of the comparator 112d is connected to the overcurrent detection terminal T3 and one terminal of the resistor element R. The other terminal of the resistor element R is connected to the reference potential part of the control circuit 11A. Therefore, the temperature variable signal Stv, which serves as a reference signal for determining whether the current flowing through the switching element 121 is an overcurrent, is input to the non-inverting input terminal (+) of the comparator 112d. On the other hand, the current detection signal Ss, which has information about the detection current Is (i.e., the current value) proportional to the collector current Ic flowing through the switching element 121, is input to the inverting input terminal (-) of the comparator 112d.

[0030] The comparator 112d outputs a comparison signal Sc having a high signal level when the signal level of the current detection signal Ss is lower than the signal level of the temperature variable signal Stv. On the other hand, the comparator 112d outputs a comparison signal Sc having a low signal level when the signal level of the current detection signal Ss is higher than the signal level of the temperature variable signal Stv. In this embodiment, the signal levels of the temperature variable signal Stv, the current detection signal Ss, and the comparison signal Sc are, for example, voltage levels.

[0031] In this way, the overcurrent detection unit 112A detects that the current flowing through the switching element 121 is an overcurrent when the comparator 112d outputs a comparison signal Sc (in this embodiment, the comparison signal Sc has a low signal level) indicating that the current detection signal Ss has a higher signal level than the temperature variable signal Stv.

[0032] The input impedance of the inverting input terminal (-) of the comparator 112d is very high compared to the resistance value of the resistor element R. Therefore, the detection current Is flows to the resistor element R with almost no flow to the comparator 112d side. Therefore, the voltage generated in the resistor element R has a voltage level corresponding to the current value of the detection current Is. Therefore, the signal level of the current detection signal Ss changes depending on the amount of the collector current Ic flowing through the switching element 121. As described above, the temperature variable signal Stv has a signal level that changes depending on the temperature of the switching element 121, not depending on the temperature of the control circuit 11A. Therefore, by comparing the current detection signal Ss with the temperature variable signal Stv, the comparator 112d can determine whether the current flowing through the switching element 121 is an overcurrent, taking into account the temperature of the switching element 121.

[0033] Here, the relationship between the temperature of the switching element 121, the temperature variable signal Stv, and the current detection signal Ss will be described with reference to Fig. 5 and Fig. 6. Fig. 5 is a graph showing an example of the characteristics of the signal level of the current detection signal with respect to the collector current Ic when the temperature of the switching element 121 is at room temperature (for example, the temperature at the start of operation of the switching element 121). Fig. 6 is a graph showing an example of the characteristics of the signal level of the current detection signal with respect to the collector current Ic when the temperature of the switching element 121 is at a predetermined temperature higher than room temperature.

[0034] The horizontal axis of each graph shown in Figures 5 and 6 represents the collector current Ic flowing through the switching element 121, and the vertical axis of each graph shown in Figures 5 and 6 represents the signal level of the current detection signal in terms of voltage level. Note that the horizontal axis of each graph shown in Figures 5 and 6 represents numerical values ​​normalized by the same maximum value. Similarly, the vertical axis of each graph shown in Figures 5 and 6 represents numerical values ​​normalized by the same maximum value. Hereinafter, a current detection signal whose signal level is represented by a voltage level may be referred to as a "current detection voltage."

[0035] As shown in Figures 5 and 6, the current detection voltage Vs increases as the collector current Ic flowing through the switching element 121 increases. Because the switching element 121 has element variations due to various factors such as manufacturing variations, variations occur in the collector current Ic even when the same gate voltage is applied to the gate G. This causes variations in the detection current Is output from the current detection unit 121a provided in the switching element 121, and therefore variations also occur in the current detection voltage Vs. Figures 5 and 6 show design characteristics when variations occur in the current detection voltage Vs.

[0036] The standard characteristic VCH-t of the current detection voltage Vs indicates the characteristic when the collector current Ic of the design value flows through the switching element 121. The minimum characteristic VCH-n of the current detection voltage Vs indicates the characteristic when the minimum collector current Ic within the design range flows through the switching element 121. The maximum characteristic VCH-x of the current detection voltage Vs indicates the characteristic when the maximum collector current Ic within the design range flows through the switching element 121.

[0037] As shown by the standard characteristic VCH-t, minimum characteristic VCH-n, and maximum characteristic VCH-x of the current detection voltage Vs, the variation in the current detection voltage Vs due to the element variation of the switching element 121 increases as the collector current Ic flowing through the switching element 121 increases. Furthermore, as can be seen from a comparison of the standard characteristic VCH-t, minimum characteristic VCH-n, and maximum characteristic VCH-x of the current detection voltage Vs shown in Figures 5 and 6, when the collector current Ic flowing through the switching element 121 is the same, the current detection voltage Vs becomes higher overall when the temperature of the switching element 121 is higher.

[0038] The temperature variable signal Stv, which is used as an overcurrent threshold to determine whether the current flowing through the switching element 121 is an overcurrent, varies within a predetermined range relative to the design value due to variations in the switching element 121 and the electronic components constituting the signal generating unit 111. For this reason, the temperature variable signal Stv varies within a range between a design minimum value Stv-n and a design maximum value Stv-x. The standard value Stv-t indicates a value that corresponds to the design value and is the center value between the minimum value Stv-n and the maximum value Stv-x. As shown in FIGS. 5 and 6, the range of variation of the temperature variable signal Stv becomes wider, for example, when the temperature of the switching element 121 is higher.

[0039] The standard value Stv-t of the temperature variable signal Stv is set so as to intersect with the standard characteristic VCH-t of the current detection voltage Vs at the collector current Ic having a current value that coincides with the standard current value Iocg-t of the overcurrent protection current, which serves as a criterion for determining whether the current flowing through the switching element 121 is an overcurrent. If the current value of the collector current Ic flowing through the switching element 121 is equal to or less than the standard current value Iocg-t, it is determined that the current flowing through the switching element 121 is not an overcurrent. On the other hand, if the current value of the collector current Ic flowing through the switching element 121 is greater than the standard current value Iocg-t, it is determined that the current flowing through the switching element 121 is an overcurrent.

[0040] As described above, the signal generating unit 111 can change the signal level (i.e., voltage level) of the temperature variable signal Stv in accordance with the temperature of the switching element 121. For this reason, as shown in Fig. 6, when the temperature of the switching element 121 becomes higher than room temperature, the standard value Stv-t of the temperature variable signal Stv becomes larger. As a result, even if the temperature of the switching element 121 becomes a predetermined temperature higher than room temperature and the standard characteristic VCH-t of the current detection voltage Vs shifts to a higher voltage level, the standard value Stv-t of the temperature variable signal Stv intersects with the standard characteristic VCH-t of the current detection voltage Vs at the standard current value Iocg-t of the switching element 121 at the predetermined temperature.

[0041] The temperature variable signal Stv changes so that the signal level corresponding to the standard value Stv-t increases as the temperature of the switching element 121 increases, and decreases as the temperature of the switching element 121 decreases. Therefore, as shown in Figures 5 and 6, the semiconductor device 1A can set the current value of the collector current Ic at which the standard value Stv-t of the temperature variable signal Stv intersects with the standard characteristic VCH-t of the current detection voltage Vs to the standard current value Iocg-t of the overcurrent protection current regardless of the temperature of the switching element 121.

[0042] This allows the semiconductor device 1A to achieve high accuracy in detecting overcurrent of the switching element 121 as the temperature of the switching element 121 changes. Incidentally, the temperature variable signal Stv and the current detection voltage Vs each vary within a predetermined design range. Therefore, the current value of the collector current Ic at the intersection between the temperature characteristics of the temperature variable signal Stv and the current detection voltage Vs may also vary. Therefore, in the design of the semiconductor device 1A, an allowable range is set for the variation in the current value of the collector current Ic at the intersection between the temperature characteristics of the temperature variable signal Stv and the current detection voltage Vs. In the semiconductor device 1A, for example, the allowable range is set to the range from the minimum current value Iocg-n to the maximum current value (not shown) of the overcurrent protection current. Even if the collector current Ic at the intersection varies within the range from the minimum current value Iocg-n to the maximum current value, the accuracy of detecting overcurrent of the switching element 121 in the semiconductor device 1A does not deteriorate.

[0043] An input terminal of a filter circuit 112e is connected to the output terminal of the comparator 112d. The filter circuit 112e outputs an overcurrent protection signal Soc when the signal level of the comparison signal Sc output from the comparator 112d remains low even after a predetermined time (e.g., 4 μsec) has elapsed since the signal level changed from high to low. The filter circuit 112e is a delay circuit that delays the comparison signal Sc input from the comparator 112d by the predetermined time. By providing the filter circuit 112e on the output side, the overcurrent detection unit 112A can prevent the overcurrent protection signal Soc from being output due to a malfunction of the comparator 112d caused by noise or the like.

[0044] 1, the overheat detection unit 113 includes a constant current source 113a, a comparator 113b, and a reference signal generation unit 113c. The overheat detection unit 113 detects the temperature of the switching element 121, and outputs an overheat protection signal Soh if the detected temperature exceeds the rated temperature.

[0045] The constant current source 113a is provided between an output terminal from which a power supply voltage serving as the power supply for the control circuit 11A is output, and the temperature detection terminal T4, the inverting input terminal (-) of the comparator 113b, and the inverting input terminal (-) of the differential circuit 111b-1 provided in the signal generating unit 111. The constant current source 113a outputs a constant current of a predetermined current value toward the temperature detection terminal T4, the comparator 113b, and the differential circuit 111b-1. The input impedance of each inverting input terminal (-) of the operational amplifiers constituting the comparator 113b and the differential circuit 111b-1 is very high compared to the resistance of the forward resistance of the temperature detecting unit 122. Therefore, the constant current output from the constant current source 113a flows to the temperature detecting unit 122, with almost no current flowing toward the comparator 113b or the differential circuit 111b-1.

[0046] The temperature detection unit 122 has a characteristic that its resistivity changes depending on the temperature. Therefore, when the temperature of the switching element 121 increases and the temperature of the temperature detection unit 122 increases, the forward resistance decreases. Therefore, the forward voltage VF of the temperature detection unit 122 decreases as the temperature of the switching element 121 increases, and increases as the temperature of the switching element 121 decreases. As a result, the forward voltage VF of the temperature detection unit 122, i.e., the voltage at the temperature detection terminal T4, changes depending on the temperature of the switching element 121. Therefore, the overheat detection unit 113 inputs the voltage at the temperature detection terminal T4, which changes in the forward voltage VF of the temperature detection unit 122, to the inverting input terminal (-) of the comparator 113b as the signal level of the temperature detection signal St. As a result, the temperature detection signal St becomes a signal whose signal level contains information about the detected temperature detected by the temperature detection unit 122.

[0047] As described above, the temperature detection terminal T4 is connected to the inverting input terminal (-) of the differential circuit 111b-1 provided in the temperature variable signal generation unit 111b of the signal generation unit 111. Therefore, a temperature detection signal St having, as a signal level, information on the detected temperature detected by the temperature detection unit 122 (i.e., temperature information on the switching element 121) is input to the inverting input terminal (-) of the differential circuit 111b-1.

[0048] A reference signal generating unit 113c is connected to the non-inverting input terminal (+) of the comparator 113b. The reference signal generating unit 113c is configured, for example, by a DC power supply. The positive terminal of the reference signal generating unit 113c is connected to the non-inverting input terminal (+) of the comparator 113b, and the negative terminal of the reference signal generating unit 113c is connected to the reference potential unit of the control circuit 11A.

[0049] A reference signal Sr generated by a reference signal generating unit 113c is input to a non-inverting input terminal (+) of the comparator 113b. The reference signal Sr has a constant signal level (i.e., a constant voltage level). On the other hand, a temperature detection signal St having a signal level (i.e., a voltage level) that reflects the temperature of the switching element 121 is input to an inverting input terminal (-) of the comparator 113b.

[0050] When the signal level of the temperature detection signal St is lower than the signal level of the reference signal Sr, the comparator 113b outputs a comparison signal with a high signal level as the overheat protection signal Soh. On the other hand, when the signal level of the temperature detection signal St is higher than the signal level of the reference signal Sr, the comparator 113b outputs a comparison signal with a low signal level as the overheat protection signal Soh. In this embodiment, the signal levels of the reference signal Sr, the temperature detection signal St, and the overheat protection signal Soh are, for example, voltage levels.

[0051] The overheat detection unit 113 detects that the switching element 121 is in an overheated state when the signal level of the temperature detection signal St is higher than the reference signal Sr, and outputs a comparison signal with a low signal level as the overheat protection signal Soh to the comparator 113b. In this way, the overheat detection unit 113 notifies that the switching element 121 is in an overheated state by changing the signal level of the overheat protection signal Soh.

[0052] The gate drive circuit 114 generates a gate signal for controlling the switching element 121 based on a pulsed input signal (not shown) input from outside the control circuit 11A. The output terminal of the gate drive circuit 114 is connected to a gate signal output terminal T1. When turning on the switching element 121, the gate drive circuit 114 outputs a gate signal from the gate signal output terminal T1 to the gate G of the switching element 121. Therefore, the gate signal is input from the gate drive circuit 114 to the gate G of the switching element 121 (i.e., a gate current is supplied), and a gate capacitance (not shown) is charged. As a result, the gate voltage of the gate G of the switching element 121 becomes high level, and the switching element 121 is turned on.

[0053] When turning off the switching element 121, the gate drive circuit 114 does not output a gate signal from the gate signal output terminal T1 to the gate G of the switching element 121, but instead shorts, for example, between the gate G and the reference potential part of the control circuit 11A. As a result, the charge stored in the gate capacitance of the switching element 121 is discharged, and the gate voltage of the gate G becomes low level, turning off the switching element 121.

[0054] In this way, the control circuit 11A drives the switching element 121 by the gate drive circuit 114, and protects the switching element 121 by the overcurrent detection unit 112A and the overheat detection unit 113. The control circuit 11A is formed, for example, by being integrated on an integrated circuit board 35 (see FIG. 3), and functions as an integrated circuit for driving and protecting the switching element 121.

[0055] 1-2. Operation of semiconductor device: An example of the overcurrent detection operation of the semiconductor device 1A according to this embodiment will be described with reference to FIGS. 1, 5 and 6 again.

[0056] When the gate drive circuit 114 turns on the switching element 121 (see FIG. 1), a collector current Ic flows through the switching element 121. When the collector current Ic flows through the switching element 121, a detection current Is is input from the current detection unit 121a to the current detection signal generation circuit 112c (see FIG. 1) via the overcurrent detection terminal T3. The current detection signal generation circuit 112c generates a current detection signal Ss using the detection current Is input from the current detection unit 121a, and outputs the signal to the inverting input terminal (-) of the comparator 112d.

[0057] When the temperature of the switching element 121 is, for example, room temperature, a temperature variable signal Stv having a signal level corresponding to room temperature is input from the signal generating unit 111 (see FIG. 1) to the non-inverting input terminal (+) of the comparator 112d, and a current detection signal Ss is input from the current detection signal generating circuit 112c to the inverting input terminal (-) of the comparator 112d. The temperature variable signal Stv input to the non-inverting input terminal (+) of the comparator 112d varies, for example, within a range from a minimum value Stv-n to a maximum value Stv-x shown in FIG. 5. The signal level (i.e., voltage level) of the current detection signal Ss input to the inverting input terminal (-) of the comparator 112d varies, for example, within a range from a minimum characteristic VCH-n to a maximum characteristic (not shown) of the current detection voltage Vs shown in FIG. 5.

[0058] Comparator 112d compares the signal level of the input temperature variable signal Stv with the signal level of the current detection signal Ss. If comparator 112d determines that the signal level of the current detection signal Ss is equal to or lower than the signal level of the temperature variable signal Stv, it outputs a comparison signal Sc having a high signal level indicating that no overcurrent is occurring to filter circuit 112e (see FIG. 1). As a result, overcurrent detection unit 112A does not output overcurrent protection signal Soc (see FIG. 1).

[0059] On the other hand, when the comparator 112d determines that the signal level of the current detection signal Ss is higher than the signal level of the temperature variable signal Stv, it outputs a comparison signal Sc having a low signal level indicating the occurrence of an overcurrent to the filter circuit 112e. When the comparator 112d outputs the comparison signal Sc having a low signal level continuously for a predetermined time (for example, 4 μsec), the overcurrent detection unit 112A outputs an overcurrent protection signal Soc.

[0060] Suppose that the temperature of the switching element 121 rises due to continuous operation. In this case, the signal level of the current detection signal Ss output from the current detection signal generating circuit 112c becomes higher than that at room temperature. The signal level of the temperature variable signal Stv output from the signal generating unit 111 increases in accordance with the temperature rise of the switching element 121, regardless of the temperature of the control circuit 11A.

[0061] When the temperature of the switching element 121 rises and the current detection voltage Vs has the temperature characteristic shown in FIG. 6, for example, the temperature variable signal Stv shown in FIG. 6 is input from the signal generating unit 111 to the non-inverting input terminal (+) of the comparator 112d, and the current detection signal Ss having the voltage level of the current detection voltage Vs shown in FIG. 6 as its signal level is input from the current detection signal generating circuit 112c to the inverting input terminal (-) of the comparator 112d. The temperature variable signal Stv input to the non-inverting input terminal (+) of the comparator 112d varies within a range from a minimum value Stv-n to a maximum value Stv-x shown in FIG. 6. The signal level (i.e., voltage level) of the current detection signal Ss input to the inverting input terminal (-) of the comparator 112d varies within a range from a minimum characteristic VCH-n to a maximum characteristic (not shown) of the current detection voltage Vs shown in FIG. 6.

[0062] The comparator 112d compares the signal level of the input temperature variable signal Stv with the signal level of the current detection signal Ss. If the comparator 112d determines that the signal level of the current detection signal Ss is equal to or lower than the signal level of the temperature variable signal Stv, it outputs a comparison signal Sc having a high level indicating that no overcurrent is occurring to the filter circuit 112e. As a result, the overcurrent detection unit 112A does not output the overcurrent protection signal Soc.

[0063] On the other hand, when the comparator 112d determines that the signal level of the current detection signal Ss is higher than the signal level of the temperature variable signal Stv, it outputs a comparison signal Sc having a low signal level indicating the occurrence of an overcurrent to the filter circuit 112e. When the comparator 112d outputs the comparison signal Sc having a low signal level continuously for a predetermined time (for example, 4 μsec), the overcurrent detection unit 112A outputs an overcurrent protection signal Soc.

[0064] In this way, the semiconductor device 1A can set the signal level of the temperature variable signal Stv depending on the temperature of the switching element 121, regardless of the temperature of the control circuit 11A, even if the temperature of the control circuit 11A is the same as or different from the temperature of the switching element 121. This allows the semiconductor device 1A to improve the accuracy of detecting an overcurrent in the switching element 121, even if the temperatures of the control circuit 11A and the switching element 121 are different from each other.

[0065] 1-3.Effects of semiconductor devices: The effects of the semiconductor device 1A according to the present embodiment will be described using Fig. 7 with reference to Fig. 1, Fig. 5, and Fig. 6. First, before describing the effects of the semiconductor device 1A, the problems with IPM in conventional semiconductor devices will be described.

[0066] In a conventional IPM, similar to the semiconductor device 1A, the current flowing through a switching element is detected based on the detection current flowing through a current detector provided in the switching element. The current detection voltage based on the detection current has temperature dependency, increasing as the temperature of the switching element increases (see FIGS. 5 and 6). In a conventional IPM, the reference signal (corresponding to the temperature-variable signal Stv in this embodiment) input to the overcurrent detection comparator is given temperature characteristics, taking into account the temperature characteristics of the switching element. That is, in a conventional IPM, multiple reference signals with different signal levels corresponding to the temperature of the switching element are prepared. Furthermore, a conventional IPM includes a detection circuit for detecting the temperature of the control circuit controlling the switching element. This allows the overcurrent detection threshold (corresponding to the overcurrent threshold in this embodiment) to remain as designed, even if the temperature of the switching element changes and the characteristics of the current detection voltage relative to the collector current change. However, in a conventional IPM, the reference signal for overcurrent detection has temperature characteristics, assuming that the temperatures of the switching element and the control circuit controlling the switching element are the same or within a predetermined range. That is, in a conventional IPM, the signal level of the reference signal is set according to the temperature of the control circuit.

[0067] For this reason, even if the switching element generates heat due to its operation and its temperature rises above room temperature, the temperature of the control circuit may remain at, for example, room temperature. In this case, as shown in FIG. 7, even if the current detection voltage Vs for the collector current Ic is generally higher than at room temperature (see FIG. 5), the standard value Sref-t of the reference signal Sref is set to the value used at room temperature. Therefore, at the standard current value Icrev-t of the collector current Ic flowing through the switching element, the current detection voltage Vs is higher than the standard value Sref-t of the reference signal Sref. The standard current value Icrev-t of the collector current Ic is smaller than the standard current value Iocgn-t of the overcurrent protection current. As a result, conventional IPMs erroneously detect the current flowing through the switching element as an overcurrent, even though the collector current Ic equivalent to the overcurrent protection current (i.e., an overcurrent) is not flowing through the switching element.

[0068] In conventional IPMs, the reference signal Sref and the current detection voltage Vs each vary within a predetermined design range. Therefore, the value of the collector current Ic at the point where the reference signal Sref and the temperature characteristics of the current detection voltage Vs intersect may also vary. That is, the current value at the point where the reference signal Sref and the current detection voltage Vs intersect may vary within a range from the minimum current value Icrev-n to the maximum current value Icrev-x. However, the range from the minimum current value Icrev-n to the maximum current value Icrev-x is in a region where the collector current Ic is smaller than the range from the minimum current value Icong-n to the maximum current value (not shown) of the overcurrent protection current. Therefore, conventional IPMs may erroneously detect the current flowing through the switching element as an overcurrent even when the value of the collector current Ic at the point where the reference signal Sref and the temperature characteristics of the current detection voltage Vs intersect varies.

[0069] As described above, conventional IPMs can detect overcurrent in switching elements by taking into account the temperatures of the control circuit and the switching elements, but when the temperature of the control circuit and the IBGT differ, the accuracy of overcurrent detection can be reduced, which causes a problem in conventional IPMs in that the protection function of the switching elements is reduced.

[0070] In contrast, in the semiconductor device 1A of this embodiment, the temperature variable signal Stv depends on the temperature of the switching element 121 but does not depend on the temperature of the control circuit 11A. Therefore, in the semiconductor device 1A, the temperature variable signal Stv changes according to changes in the temperature of the switching element 121 but does not change even if the temperature of the control circuit 11A changes. This allows the semiconductor device 1A to compare the temperature variable signal Stv corresponding to the temperature of the switching element 121 with the current detection voltage Vs based on the detection current Is, even if the temperatures of the control circuit 11A and the switching element 121 differ. This improves the accuracy of detecting overcurrent in the switching element 121 and prevents a deterioration in the protection function of the switching element 121. Furthermore, the semiconductor device 1A does not need to detect the temperature of the control circuit 11A, eliminating the need for a circuit for detecting the temperature of the control circuit 11A. This allows the semiconductor device 1A to achieve a simplified, compact, and inexpensive circuit configuration for the control circuit 11A.

[0071] As described above, the semiconductor device 1A according to this embodiment includes a semiconductor element 12 having a switching element 121, a temperature detection unit 122 that detects the temperature of the switching element 121, and a current detection unit 121a that detects the current of the switching element 121, and a control circuit 11A that controls the semiconductor element 12. The control circuit 11A includes a signal generation unit 111 that generates a temperature variable signal Stv that changes in accordance with the detected temperature using a temperature detection signal St that has information about the detected temperature detected by the temperature detection unit 122, and an overcurrent detection unit 112A that detects that the current flowing through the switching element 121 is an overcurrent using a current detection signal Ss that has information about the detected current Is detected by the current detection unit 121a and the temperature variable signal Stv output from the signal generation unit 111.

[0072] According to the semiconductor device 1A having such a configuration, even if the temperature of the switching element 121 to be protected and the temperature of the control circuit 11A that controls the switching element 121 are different, it is possible to prevent the protection function of the switching element 121 from being deteriorated.

[0073] Second Embodiment A semiconductor device according to a second embodiment of the present invention will be described with reference to Fig. 8. The semiconductor device according to this embodiment is characterized in that it compares a second reference signal generated by a second reference signal generating circuit controlled by a temperature variable signal with a current detection signal to detect whether the current flowing through the switching element is an overcurrent.

[0074] 2-1. Overview of semiconductor device: The schematic configuration of the semiconductor device 1B according to this embodiment will be described with reference to Fig. 8. Fig. 8 is a block diagram showing an example of the schematic configuration of the semiconductor device 1B according to this embodiment. Concerning the components of the semiconductor device 1B, components that have the same actions and functions as those of the semiconductor device 1A according to the first embodiment described above will be denoted by the same reference numerals, and their description will be omitted unless necessary.

[0075] 2, a semiconductor device 1B according to this embodiment includes a switching element 121, a semiconductor element 12 having a temperature detection unit 122 that detects the temperature of the switching element 121, and a current detection unit 121a that detects the current through the switching element 121, and a control circuit 11B that controls the semiconductor element 12. The control circuit 11B includes a signal generation unit 111 that generates a temperature variable signal Stv that changes in accordance with the detected temperature using a temperature detection signal St that contains information about the detected temperature detected by the temperature detection unit 122. The control circuit 11B also includes an overcurrent detection unit 112B that detects whether the current flowing through the switching element 121 is an overcurrent using a current detection signal Ss that contains information about a detected current Is detected by the current detection unit 121a and the temperature variable signal Stv output from the signal generation unit 111.

[0076] The overcurrent detection unit 112B includes a current detection signal generation circuit 112c, a comparator 112d, a filter circuit 112e, and a second reference signal generation circuit 112f. The second reference signal generation circuit 112f generates a second reference signal Sr2 whose signal level changes according to the signal level of the temperature variable signal Stv. The comparator 112d compares the second reference signal Sr2 output from the second reference signal generation circuit 112f with the current detection signal Ss.

[0077] The second reference signal generating circuit 112f includes, for example, a variable constant current source configured with an operational amplifier (not shown) and a transistor (not shown), and a conversion circuit that converts the current output from the variable constant current source into a voltage. The variable constant current source outputs a constant current with a larger current amount as the signal level of the temperature variable signal Stv increases, and the conversion circuit outputs a constant voltage with a higher voltage level (i.e., a signal with a higher signal level) as the current output from the variable constant current source increases. The second reference signal generating circuit 112f outputs the signal output from the conversion circuit as a second reference signal Sr2 to the non-inverting input terminal (+) of the comparator 112d.

[0078] The signal level of the second reference signal Sr2 output from the second reference signal generation circuit 112f increases or decreases in accordance with the increase or decrease in the signal level of the temperature variable signal Stv. Therefore, the second reference signal generation circuit 112f is configured to appropriately adjust the signal level of the second reference signal Sr2 in consideration of the temperature characteristics of the switching element 121. For example, the signal level of the second reference signal Sr2 is adjusted to be approximately the same as the signal level of the reference signal Sr in the first embodiment with respect to the temperature of the switching element 121. This allows the comparator 112d in this embodiment to operate in the same manner as the comparator 112d in the first embodiment. As a result, the overcurrent detection unit 112B can operate in the same manner as the overcurrent detection unit 112A in the first embodiment.

[0079] Therefore, when the comparator 112d outputs a comparison signal Sc indicating that the current detection signal Ss has a higher signal level than the second reference signal Sr2, the overcurrent detection unit 112B detects that the current flowing through the switching element 121 is an overcurrent.

[0080] 2-2. Operation of semiconductor device: In the semiconductor device 1B according to the present embodiment, the configuration of the overcurrent detection unit 112B is different from the configuration of the overcurrent detection unit 112A in the above-described first embodiment, but the overcurrent detection operation is the same as that of the semiconductor device 1A according to the above-described first embodiment. Therefore, a description of the operation of the semiconductor device 1B will be omitted.

[0081] 2-3.Effects of semiconductor devices: The semiconductor device 1B according to the present embodiment includes a signal generating unit 111 having the same configuration as the signal generating unit 111 according to the first embodiment. Therefore, similar to the semiconductor device 1A according to the first embodiment, the semiconductor device 1B can compare a voltage corresponding to a preset overcurrent protection current with a current detection voltage Vs based on a detection current Is even if the temperature of the control circuit 11B differs from the temperature of the switching element 121. As a result, the semiconductor device 1B can improve the accuracy of detecting an overcurrent of the switching element 121.

[0082] As described above, the semiconductor device 1B according to this embodiment includes a semiconductor element 12 having a switching element 121, a temperature detection unit 122 that detects the temperature of the switching element 121, and a current detection unit 121a that detects the current of the switching element 121, and a control circuit 11B that controls the semiconductor element 12. The control circuit 11B includes a signal generation unit 111 that generates a temperature-variable signal Stv that changes in accordance with the detected temperature using a temperature detection signal St that has information about the detected temperature detected by the temperature detection unit 122, and an overcurrent detection unit 112B that detects that the current flowing through the switching element 121 is an overcurrent using a current detection signal Ss that has information about the detected current Is detected by the current detection unit 121a and the temperature-variable signal Stv output from the signal generation unit 111.

[0083] According to the semiconductor device 1B having such a configuration, even if the temperature of the switching element 121 to be protected and the temperature of the control circuit 11B that controls the switching element 121 are different, it is possible to prevent the protection function of the switching element 121 from being deteriorated.

[0084] The present invention is not limited to the above-described embodiment, and various modifications are possible. In the semiconductor device 1A according to the first embodiment and the semiconductor device 1B according to the second embodiment, the switching elements are, for example, insulated gate bipolar transistors, but the present invention is not limited to this. For example, the switching elements may be insulated gate bipolar transistors or metal oxide semiconductor field effect transistors.

[0085] In the semiconductor device 1A according to the first embodiment and the semiconductor device 1B according to the second embodiment, the overheat detection unit 113 is configured to output the comparison signal output from the comparator 113b as the overheat protection signal Soh, but the present invention is not limited to this. For example, the overheat detection unit 113 may have a filter circuit on the output side of the comparator 113b as a delay circuit that functions in the same manner as the filter circuit 112e. This allows the semiconductor device to suppress erroneous detection in the overheat detection unit.

[0086] In the semiconductor device 1B according to the second embodiment, the temperature-variable signal generation unit 111b of the signal generation unit 111 includes the level shifting circuit 111b-2, but the present invention is not limited to this. For example, the temperature-variable signal generation unit 111b may not include the level shifting circuit 111b-2 and may instead output the differential signal Sdf output from the differential circuit 111b-1 as the temperature-variable signal Stv to the second reference signal generation circuit 112f provided in the overcurrent detection unit 112B. In this case, the signal level of the temperature-variable signal Stv input to the second reference signal generation circuit 112f differs from the signal level of the temperature-variable signal Stv in the second embodiment. However, the second reference signal generation circuit 112f can generate a second reference signal Sr2 having a signal level corresponding to the signal level of the temperature-variable signal Stv by appropriately adjusting or modifying its components.

[0087] Although the semiconductor device 1A according to the first embodiment and the semiconductor device 1B according to the second embodiment have a configuration in which the temperature detection signal St is input to the differential circuit 111b-1 provided in the signal generating unit 111, the present invention is not limited to this. For example, the signal generating unit 111 may have a configuration in which the temperature detection signal St is directly input to the level shifting circuit 111b-2 without including the differential circuit 111b-1. In this case, the signal generating unit 111 may output the temperature detection signal St, whose level has been changed by the level shifting circuit 111b-2 to a signal level applicable to the comparator 112d provided in the overcurrent detection unit 112A, as the temperature variable signal Stv to the comparator 112d provided in the overcurrent detection unit 112A. Also, for example, the signal generating unit 111 may output the temperature detection signal St, whose level has been changed to a signal level capable of controlling the second reference signal generating circuit 112f, as the temperature variable signal Stv to the second reference signal generating circuit 112f provided in the overcurrent detection unit 112A.

[0088] Alternatively, for example, the temperature detection signal St may be input as the temperature variable signal Stv to the comparator 112d provided in the overcurrent detection unit 112A without providing the signal generation unit 111. Furthermore, for example, the temperature detection signal St may be used as the temperature variable signal Stv to control the second reference signal generation circuit 112f provided in the overcurrent detection unit 112A without providing the signal generation unit 111. In these cases, the resistance value of the resistor element R provided in the current detection signal generation circuit 112c of the overcurrent detection unit 112A needs to be appropriately adjusted so that the comparators 112d provided in the overcurrent detection units 112A and 112B can compare the temperature detection signal St or the second reference signal Sr2 with the current detection signal Ss.

[0089] When the semiconductor device has any of these configurations, the same effects as those of the semiconductor device 1A according to the first embodiment and the semiconductor device 1B according to the second embodiment can be obtained.

[0090] The technical scope of the present invention is not limited to the exemplary embodiments shown and described, but also includes all embodiments that achieve equivalent effects to the object of the present invention. Furthermore, the technical scope of the present invention is not limited to the combination of inventive features defined by the claims, but can be defined by any desired combination of specific features from among all the respective disclosed features. [Explanation of symbols]

[0091] 1A, 1B Semiconductor device 11A, 11B control circuit 12 Semiconductor elements 31 Insulating substrate 32 Resin case 33 Semiconductor chip substrate 34 Circuit Board 35 Integrated Circuit Board 36 Base 111 Signal generation unit 111a First reference signal generation section 111b Temperature variable signal generator 111b-1 Differential circuit 111b-2 Level change circuit 112A, 112B Overcurrent detection section 112c Current detection signal generation circuit 112d,113b Comparator 112e filter circuit 112f Second reference signal generation circuit 113 Overheat detection unit 113a constant current source 113c Reference signal generation section 114 Gate drive circuit 121 Switching element 121a Current detection section 122 Temperature detection unit 321 Internal 322 External Ic Collector current Iocg-n minimum current value Iocg-t standard current value Is detection current Sc comparison signal Sdf difference signal Soc overcurrent protection signal Soh overheating protection signal Sr,Sref reference signal Sr1 First reference signal Sr2 Second reference signal Ss Current detection signal St Temperature detection signal Stv variable temperature signal Stv-n minimum value Stv-t standard value Stv-x maximum value VCH-n minimum characteristics VCH-t standard characteristics VCH-x maximum characteristics Vs Current detection voltage

Claims

1. a semiconductor device having a switching element, a temperature detection unit that detects the temperature of the switching element, and a current detection unit that detects the current of the switching element; a control circuit for controlling the semiconductor element; Equipped with The control circuit a signal generating unit that generates a temperature variable signal that changes in response to the detected temperature using a temperature detection signal having information about the detected temperature detected by the temperature detecting unit; an overcurrent detection unit that detects whether the current flowing through the switching element is an overcurrent using a current detection signal having information on the detected current detected by the current detection unit and the temperature variable signal output from the signal generation unit; have Semiconductor device.

2. The signal generation unit a first reference signal generating unit that generates a first reference signal having a voltage that does not have temperature dependency; a temperature variable signal generation unit that generates the temperature variable signal based on a difference between the first reference signal output from the first reference signal generation unit and the temperature detection signal; have The semiconductor device according to claim 1 .

3. The temperature variable signal generating unit a differential circuit that generates a differential signal between the first reference signal and the temperature detection signal; a level change circuit that changes the signal level of the differential signal output from the differential circuit; have The semiconductor device according to claim 2 .

4. The overcurrent detection unit has a comparator that compares the temperature variable signal with the current detection signal. The semiconductor device according to claim 1 .

5. The overcurrent detection unit detects that an overcurrent is flowing through the switching element when the comparator outputs a signal indicating that the current detection signal has a higher signal level than the temperature variable signal. The semiconductor device according to claim 4 .

6. The overcurrent detection unit a second reference signal generating circuit that generates a second reference signal whose signal level changes in response to the signal level of the temperature variable signal; a comparator that compares the second reference signal output from the second reference signal generating circuit with the current detection signal; have The semiconductor device according to claim 1 .

7. The overcurrent detection unit detects that an overcurrent is flowing through the switching element when the comparator outputs a signal indicating that the current detection signal has a higher signal level than the second reference signal. The semiconductor device according to claim 6.

8. The temperature detection unit a semiconductor chip substrate on which the semiconductor element is formed; an insulating substrate on which the semiconductor element is mounted; a circuit board on which the control circuit is mounted; Inside a resin case in which the semiconductor element and the control circuit are housed, or The outside of the resin case in contact with the resin case It is set up in The semiconductor device according to claim 1 .

9. The switching element is an insulated gate bipolar transistor or a metal oxide semiconductor field effect transistor. The semiconductor device according to claim 1 .

10. The temperature detection unit is a diode having temperature dependency. The semiconductor device according to claim 1 .

Images