Measuring device for semiconductor characteristic curves, measuring method for semiconductor characteristic curves and program

Abstract

In a measuring device (101) for semiconductor characteristic curves, a first potential difference measuring device (102) measures a first potential difference (V CE ) between two connection terminals (4, 6) which are connected to a first and second main electrode of a power semiconductor element (2), respectively. A second potential difference measuring device (103) measures a second potential difference (V EE) between two connection terminals (6, 7) that are connected at different positions along a current path of a main current to or from the second main electrode. A storage device (104) stores a first relationship between the first potential difference, an element temperature, and the main current, and a second relationship between the second potential difference, the element temperature, and the main current. When a value of the element temperature and a value of the main current corresponding to a measurement of the first potential difference specified by the first relationship match a value of the element temperature and a value of the main current corresponding to a measurement of the second potential difference specified by the second relationship, a processing device (105) outputs the matching value of the element temperature and the matching value of the main current as estimates at a present time.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a semiconductor characteristic measuring apparatus, a semiconductor characteristic measuring method, and a program. STATE OF THE ART

[0002] For equipment including a semiconductor device, such as a power semiconductor module, the integrity of the equipment can be ensured by monitoring a state of the semiconductor device. For this purpose, it is necessary to know a current flowing through the semiconductor device and a temperature of the semiconductor device. If these can be accurately measured, a characteristic margin of the semiconductor device can be minimized, leading to a reduction in cost. It is desirable that a method for detecting the current and temperature should be as simple and inexpensive as possible. That is, it is desirable to measure the current and temperature without using a sensor specialized for current detection and a sensor specialized for temperature detection. The following are examples of the related conventional techniques.

[0003] International Publication No. 2020 / 261385 (PTL 1) discloses the technique of estimating a temperature by using the fact that a voltage between an emitter terminal and an emitter reference terminal changes depending on the temperature when a collector current flowing through a power semiconductor element is constant.

[0004] In the technique disclosed in Japanese Patent Application Laid-Open No. 2016-63674 (PTL 2), a current value is obtained by controlling a voltage of a sensor cell of a power semiconductor element using a controller. Furthermore, a change in the gate threshold voltage is measured by measuring a gate voltage of the power semiconductor element, and a temperature is estimated based on the measured change in the gate threshold voltage.

[0005] In the technique disclosed in Japanese Patent Application Laid-Open No. 2021-19435 (PTL 3), a flowing current is estimated based on the switching speed of a power semiconductor device. Furthermore, a turn-on voltage of the power semiconductor device is measured, and a temperature is estimated based on its temperature dependence. LIST OF CITIONSPATENT LITERATURE PTL 1: International Publication No. 2020 / 261385 PTL 2: Japanese Patent Application Laid-Open No. 2016-63674 PTL 3: Japanese Patent Application Laid-Open No. 2021-19435 SUMMARY OF THE INVENTION TECHNICAL PROBLEM

[0006] In the conventional techniques described above, either a current sensor or a temperature sensor is required to measure the current and temperature, or a sensor cell is required in a power semiconductor element, or a complicated and expensive device such as a voltage controller, a gate voltage measuring device, or a switching speed measuring device is required.

[0007] The present disclosure has been made in view of the above-described problem, and an object thereof is to provide the technique that enables simultaneous estimation of a value of a current flowing through a semiconductor device and a temperature by simple means, which does not use a current sensor and a temperature sensor, and which does not require complicated control. SOLUTION TO THE PROBLEM

[0008] In one embodiment, a semiconductor characteristic measuring device for estimating a temperature of a semiconductor device and a main current flowing through the semiconductor device is provided. The semiconductor device includes: a power semiconductor element; and a plurality of connection terminals. The power semiconductor element has a first main electrode, a second main electrode, and a control electrode for controlling the main current flowing between the first main electrode and the second main electrode. Each of the plurality of connection terminals is connected to any one of the first main electrode, the second main electrode, and the control electrode. The semiconductor characteristic measuring device includes: first potential difference measuring means; second potential difference measuring means; storage means; and processing means.The first potential difference measuring device measures a first potential difference based on a potential difference between two connection terminals connected to the first main electrode and the second main electrode, respectively, of the plurality of connection terminals. The second potential difference measuring device measures a second potential difference between a first connection terminal and a second connection terminal of the plurality of connection terminals, wherein the first connection terminal is connected to a current path of the main current to or from the second main electrode, wherein the second connection terminal is connected to the second main electrode or is connected to the current path at a position closer to the second main electrode than the first connection terminal.The storage device stores data indicating a first relationship and data indicating a second relationship, wherein the first relationship is a relationship between the first potential difference, a temperature of the power semiconductor element, and the main current, and the second relationship is a relationship between the second potential difference, the temperature of the power semiconductor element, and the main current. The processing device obtains a measured value of the first potential difference from the first potential difference measuring device and obtains a measured value of the second potential difference from the second potential difference measuring device.The processing device specifies, based on the data indicating the first relationship, a value of the temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the first potential difference, and specifies, based on the data indicating the second relationship, a value of the temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the second potential difference.When the temperature value of the power semiconductor element and the main current value specified based on the measured value of the first potential difference agree with the temperature value of the power semiconductor element and the main current value specified based on the measured value of the second potential difference, the processing device outputs the agreed temperature value and the agreed main current value as estimates at a current time. ADVANTAGEOUS EFFECTS OF THE INVENTION

[0009] According to the above-described embodiment, the semiconductor characteristic measuring apparatus can simultaneously estimate the value of the current flowing through the semiconductor device and the temperature with a simple configuration including the first potential difference measuring means, the second potential difference measuring means, the storage means, and the processing means. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1A is a configuration diagram of a semiconductor characteristic measuring apparatus according to a first embodiment. Fig. 1B is a representation showing a modification of the Fig. 1A shows the measuring device for semiconductor characteristics. Fig. 1C is a representation showing another variation of the Fig. 1A shows the measuring device for semiconductor characteristics. Fig. 2 is a diagram illustrating a functional principle of the Fig. 1A shown measuring device for semiconductor characteristics. Fig. 3A is a flowchart illustrating a process flow performed by a processing device of the type described in Fig. 1A shown measuring device for semiconductor characteristics. Fig. Figure 3B is a flowchart illustrating the process flow performed by the processing device of the Fig. 1A shown measuring device for semiconductor characteristics. Fig. 4 is a configuration diagram of a semiconductor characteristic measuring apparatus according to a second embodiment. Fig. 5 is a diagram illustrating a working principle of the Fig. 4 shown measuring device for semiconductor characteristics. Fig. 6A is a flowchart illustrating a process flow performed by a processing device of the type described in Fig. 4 shown measuring device for semiconductor characteristics. Fig. Figure 6B is a flowchart illustrating the process flow performed by the processing device of the Fig. 4 shown measuring device for semiconductor characteristics. Fig. 7 is a diagram illustrating an operational principle of a semiconductor characteristic measuring apparatus according to a third embodiment. Fig. 8A is a flowchart illustrating the operation of a processing means of the semiconductor characteristic measuring apparatus according to the third embodiment. Fig. 8B is a flowchart illustrating the operation of the processing means of the semiconductor characteristic measuring apparatus according to the third embodiment. Fig. 9 is a configuration diagram of a semiconductor characteristic measuring apparatus according to a fourth embodiment. Fig. 10 is a diagram for illustrating an operation example of a Fig. 9 shown processing device. Fig. 11A is a flowchart illustrating a process flow performed by the processing device of the Fig. 9 shown measuring device for semiconductor characteristics. Fig. 11B is a flowchart illustrating the process flow performed by the processing device of the Fig. 9 shown measuring device for semiconductor characteristics. DESCRIPTION OF EMBODIMENTS

[0010] Embodiments will be described in more detail below with reference to the drawings. Identical or corresponding sections are designated by the same reference numerals, and their description will not be repeated. First Embodiment[Configuration of a Semiconductor Characteristics Measuring Device]

[0011] Fig. 1A is a configuration diagram of a semiconductor characteristic measuring apparatus 101 according to a first embodiment. Referring to Fig. 1A, the semiconductor characteristic curve measuring device 101 includes a first potential difference measuring device 102, a second potential difference measuring device 103, a storage device 104, and a processing device 105.

[0012] Fig. 1A further illustrates a semiconductor device 1 to be measured by the semiconductor characteristic measuring device 101. The semiconductor device 1 includes a power semiconductor element 2, a collector main terminal 4, a gate terminal 5, an emitter reference terminal 6, and an emitter main terminal 7. The semiconductor device 1, a gate driver 8, the semiconductor characteristic measuring device 101, and the like may constitute a power module 150.

[0013] In the Fig. In the example shown in Figure 1A, an insulated gate bipolar transistor (IGBT) is used as the power semiconductor element 2 incorporated in the semiconductor device 1. In this case, the main collector terminal 4 is connected to a collector electrode C of the IGBT, the gate terminal 5 is connected to a gate electrode G of the IGBT, and the main emitter terminal 7 is connected to an emitter electrode E of the IGBT. A main current of the power semiconductor element 2 flows through the main collector terminal 4 and the main emitter terminal 7. The emitter reference terminal 6 is connected to the emitter electrode E and is connected to the gate driver 8 described below. A parasitic resistance component 3 is present in a wire between the main emitter terminal 7 and the emitter electrode E of the IGBT.

[0014] The gate driver 8 is connected between the gate terminal 5 and the emitter reference terminal 6 of the semiconductor device 1. The gate driver 8 supplies a drive voltage between the gate electrode and the emitter electrode of the IGBT.

[0015] In the present disclosure, more generally, the collector electrode may be referred to as a first main electrode, the emitter electrode may be referred to as a second main electrode, and the gate electrode may be referred to as a control electrode. The gate electrode is provided to control the main current flowing between the first main electrode and the second main electrode. Furthermore, the collector main terminal 4, the gate terminal 5, the emitter reference terminal 6, and the emitter main terminal 7 provided in the semiconductor device 1 may be referred to as connection terminals 4 to 7, respectively. Each of the connection terminals 4 to 7 is connected to any one of the first main electrode, the second main electrode, and the control electrode.

[0016] The first potential difference measuring device 102 of the measuring device 101 for semiconductor characteristics is connected to the collector main terminal 4 and the emitter reference terminal 6 of the semiconductor component 1. The first potential difference measuring device 102 measures a first potential difference between the collector main terminal 4 and the emitter reference terminal 6. Since the IGBT in the Fig. 1A is used as power semiconductor element 2, the first potential difference is V CE (ie a collector-emitter voltage).

[0017] The second potential difference measuring device 103 is connected to the emitter reference terminal 6 and the emitter main terminal 7 of the semiconductor component 1. The second potential difference measuring device 103 measures a second potential difference between the emitter reference terminal 6 and the emitter main terminal 7. Since the IGBT in the Fig. 1A is used as power semiconductor element 2, the second potential difference is V EE marked.

[0018] The memory device 104 stores data indicating a first relationship between the pre-measured or calculated first potential difference, the main current, and a junction temperature, and data indicating a second relationship between the pre-measured or calculated second potential difference, the main current, and the junction temperature. Hereinafter, the main current of the semiconductor device 1 is also simply referred to as the current.

[0019] The processing device 105 simultaneously estimates the main current and the junction temperature of the semiconductor device 1 based on the first potential difference measured by the first potential difference measuring device 102, the second potential difference measured by the second potential difference measuring device 103, and correlation data of the first relationship and correlation data of the second relationship obtained from the storage device 104. The processing device 105 outputs the estimated main current as current information 106 and outputs the estimated temperature as temperature information 107. Hereinafter, the main current of the semiconductor device 1 is denoted as I C characterized because the main current of the semiconductor device 1 is a collector current of the IGBT, and the temperature of the semiconductor device 1 is T J characterized because the temperature of the semiconductor component 1 is a junction temperature of the IGBT.

[0020] A hardware configuration of the semiconductor characteristic measuring device 101 is not particularly limited. For example, each of the first potential difference measuring device 102 and the second potential difference measuring device 103 may be implemented by an analog-to-digital converter. A non-volatile semiconductor memory such as a flash memory may be used as the storage device 104, or a hard disk may be used as the storage device 104. The processing device 105 may be configured based on a microcomputer including a central processing unit (CPU) and a memory, may be configured using a field-programmable gate array (FPGA), or may be configured by a dedicated circuit. Alternatively, the processing device 105 may be configured by two or more combinations of these components.

[0021] A modification of the connection between the first potential difference measuring device 102 and the semiconductor component 1 is described below with reference to the Fig. 1B and Fig. 1C described.

[0022] Fig. 1B is a representation showing a modification of the Fig. 1A shows the semiconductor characteristic curve measuring device 101. As shown in Fig. 1B, the first potential difference measuring device 102 may be connected between the collector main terminal 4 and the emitter main terminal 7 of the semiconductor device 1 and may be configured to measure a potential difference between the collector main terminal 4 and the emitter main terminal 7. Since a voltage drop caused by the parasitic resistance component 3 is approximately one order of magnitude smaller than the collector-emitter voltage V CEof the power semiconductor element 2, the measured potential difference between the collector main terminal 4 and the emitter main terminal 7 can be used as the first potential difference V CE which does not lead to a large error. Alternatively, a value obtained by subtracting the second potential difference V EE between the emitter reference terminal 6 and the emitter main terminal 7 from the potential difference between the collector main terminal 4 and the emitter main terminal 7 is obtained as the first potential difference V CE be defined.

[0023] As another variation, if a collector reference terminal (in the Fig. 1A and Fig. 1B not present), which is connected to the collector electrode C of the power semiconductor element 2, is provided separately from the collector main terminal 4 through which the main current flows, the first potential difference measuring device 102 measures a potential difference between the collector reference terminal and the emitter reference terminal 6 as the first potential difference V CEHowever, since a current path from the collector electrode C to the collector main terminal 4 is a copper plate attached to a rear surface (collector) of a semiconductor chip, a parasitic resistance component thereof is extremely small and hardly contributes to an error. In contrast, since the emitter electrode E and the emitter main terminal 7 on a front surface of the semiconductor chip are connected by an aluminum wire, a non-negligible resistance component is present. Therefore, the emitter reference terminal 6 is provided for connecting the gate driver 8. To reduce an error, it is desirable that the first potential difference measuring device 102 should also be connected to the emitter reference terminal 6.

[0024] Fig. 1C is a representation showing yet another variation of the Fig. 1A shows the measuring device 101 for semiconductor characteristics. Fig. In the semiconductor device 1 shown in FIG. 1C, an emitter detection terminal 9 for connecting the second potential difference measuring device 103 is provided separately from the emitter main terminal 7, and a collector detection terminal 10 for connecting to the first potential difference measuring device 102 is provided separately from the collector main terminal 4. In this case, it is possible to prevent the main current from flowing through the connection terminals to which each of the first potential difference measuring device 102 and the second potential difference measuring device 103 is connected.

[0025] Therefore, in consideration of each of the modifications described above, the first potential difference measuring device 102 more generally measures a first potential difference based on a potential difference between two connection terminals (between the collector main terminal 4 or the collector detection terminal 10 and the emitter reference terminal 6 or the emitter main terminal 7) connected to the first main electrode and the second main electrode, respectively (one is the collector electrode C and the other is the emitter electrode E), of the plurality of connection terminals provided in the semiconductor device 1.The second potential difference measuring device 103 measures a second potential difference between a first connection terminal (the emitter main terminal 7 or the emitter detection terminal 9) and a second connection terminal (the emitter reference terminal 6) of the plurality of connection terminals, the first connection terminal being connected to a current path of the main current to or from the second main electrode (the emitter electrode E), the second connection terminal being connected to the second main electrode or the current path at a position closer to the second main electrode (the emitter electrode E) than the first connection terminal. [Operating principle of the measuring device for semiconductor characteristics]

[0026] Now, an operation principle of the semiconductor characteristic measuring apparatus 101 configured as described above will be described. Fig. 2 is a diagram illustrating a functional principle of the Fig. 1A shown measuring device 101 for semiconductor characteristics.

[0027] In Fig. 2, the first relationship and the second relationship stored in the storage device 104 of the semiconductor characteristic measuring device 101 are shown in diagram form. The first relationship is a relationship between the first potential difference V CE , the current I C and the temperature T J . The second relationship is a relationship between the second potential difference V EE , the current I C and the temperature T J .

[0028] In particular, Fig. 2 the relationship between the first potential difference V CE and the current I C as the first relationship by three thick lines according to the three types of temperatures T Jtracked, with the horizontal axis representing the first potential difference V CE and the vertical axis represents the current I C The three types of temperatures T J are 25 °C, 75 °C and 125 °C. The relationship between the first potential difference V CE and the current I C , when the temperature T J 25 °C is indicated by a thick dash-dot line, the relationship between the first potential difference V CE and the current I C , when the temperature T J 75 °C is indicated by a thick dash-dot-dot line and the relationship between the first potential difference V CE and the current I C , when the temperature T J 125 °C is indicated by a thick solid line.

[0029] Likewise, in Fig. 2 the relationship between the second potential difference V EE and the current I Cas the second relationship by three thin lines according to the three kinds of temperatures T J tracked, with the horizontal axis representing the second potential difference V EE and the vertical axis represents the current I C The three types of temperatures T J are 25 °C, 75 °C and 125 °C. The relationship between the second potential difference V EE and the current I C , when the temperature T J 25 °C is indicated by a thin dash-dot line, the relationship between the second potential difference V EE and the current I C , when the temperature T J 75 °C is indicated by a thin dash-dot-dot line and the relationship between the second potential difference V EE and the current I C , when the temperature T J125 °C is indicated by a thin solid line. In contrast to the case of the first potential difference V CE However, there is a gain G = 10, ie a value obtained by multiplying the actual value of the second potential difference V EE with 10, in the case of the second potential difference V EE The reason for this is that the value of the second potential difference V EE is easier to see in the diagram because the value of the second potential difference V EE generally about an order of magnitude smaller than the first potential difference V CE is.

[0030] As from Fig. As can be seen in Figure 2, the relationship between the current I C and the first potential difference V CE nonlinearity and is expressed by the curved line in the current-voltage diagram. In contrast, the relationship between the current I Cand the second potential difference V EE Linearity and is expressed by the straight line passing through the origin in the current-voltage diagram. This difference is due to a difference between a mechanism for generating the first potential difference V CE and a mechanism for generating the second potential difference V EE due to.

[0031] The first potential difference V CE corresponds to the voltage between the main electrodes of the power semiconductor component, which in this case is the voltage between the collector and emitter of the IGBT. The collector-emitter voltage V CE of the IGBT is related to the collector current I C nonlinear. In particular, the collector-emitter voltage V CE , if the collector current I C is small compared to the collector current I C a large value. In contrast, when the collector current IC is large, the collector-emitter voltage V CE a not very large value as a ratio to the collector current I C Consequently, a large current can be passed through the IGBT with a relatively low turn-on voltage and relatively low power loss. Since the IGBT itself has such a nonlinear characteristic, the relationship between the current I C and the first potential difference V CE nonlinear.

[0032] In contrast, the second potential difference V EE mainly reflects the voltage generated between both ends of the parasitic resistance component 3 on the emitter side of the semiconductor device 1. The parasitic resistance component 3 on the emitter side of the semiconductor device 1 is largely composed of a resistance component of the bonding wires made of aluminum. Therefore, the relationship between the main current I Cand the second potential difference V EE linear.

[0033] Regarding the temperature dependence of the first potential difference V CE At a certain threshold current or more, the resistance value between the collector and the emitter increases with increasing temperature. This means that the first potential difference V CE becomes larger with increasing temperature compared to the main current I C Conversely, the resistance value between the collector and the emitter at the threshold current described above or less becomes lower with increasing temperature. That is, V CE becomes higher with increasing temperature compared to the main current I C lower.

[0034] On the other hand, with regard to the temperature dependence of the second potential difference V EEa resistance value between the emitter main terminal 7 and the emitter reference terminal 6 increases with increasing temperature. That is, the second potential difference V EE becomes larger with increasing temperature compared to the main current I C This feature reflects the temperature dependence of the electrical resistance of the aluminum material.

[0035] As described above, the first relationship and the second relationship have different characteristics with respect to linearity and temperature dependence. Using these characteristics, the semiconductor characteristic measuring apparatus 101 according to the present embodiment simultaneously measures the current flowing through the semiconductor device and the temperature. An overview of the operation of the processing device 105 of the semiconductor characteristic measuring apparatus 101 will be described below with reference to Fig. 2 described.

[0036] As an example, assume that the measured first potential difference V CE 1.28 V, and it is assumed that a value obtained by multiplying the measured second potential difference V EE with 10 (G = 10) is 1.17 V. These values ​​are in Fig. 2 on the horizontal axis.

[0037] A straight line (through a dash-dot line in Fig. 2) is parallel to the vertical axis from the point of V CE = 1.28V on the horizontal axis in Fig. 2 is drawn, and points of intersection are drawn between this straight line and the group of thick curved lines indicating the first relationship (ie an I C -V CE characteristic curve). As a result, a current value I C , the V CE = 1.28V. Since the temperature T J However, it is unknown, there are many candidates for the current value I C . In Fig. 2, the intersection points with the group of thick curved lines in the case of 25 °C, 75 °C and 125 °C are indicated by the triangle mark, the circle mark and the square mark, respectively.

[0038] Likewise, a straight line (defined by a solid line in Fig. 2) parallel to the vertical axis from the point of V EE × 10 = 1.17 V on the horizontal axis in Fig. 2 and points of intersection are drawn between this line and the group of thin lines which indicate the second relationship (ie an I C -V EE characteristic curve). Consequently, the current I C be specified, the V EE × 10 = 1.17 V. Since the temperature T J However, it is unknown, there are many candidates for the current value I C . In Fig. 2, the points of intersection with the group of thin straight lines in the case of 25 °C, 75 °C and 125 °C are indicated by the triangle mark, the circle mark and the square mark, respectively.

[0039] In the above, many candidate values ​​for the current I C and the temperature T J from the measured value of the first potential difference V CE and the measured value of the second potential difference V EE Here, a restriction condition exists that the values ​​of the current I C and the temperature T J , which results from the first potential difference V CE be obtained, with the values ​​of the current I C and the temperature T J , which results from the second potential difference V EE The reason for this is obvious, since the collector current I C and the junction temperature T J the same semiconductor device 1.

[0040] Here, assuming that, for example, T J = 25 °C, the current I C , which results from the first potential difference V CE is obtained (corresponding to the triangle marking on the thick dash-dot line), and the current I C , which results from the second potential difference V EE (corresponding to the triangle marking on the thin dashed-dotted line). That is, the potential difference V CE obtained triangular mark is located at a position higher than that of the second potential difference V EE This contradicts the constraint that the current I C of the same semiconductor device. Therefore, it is concluded that the assumption for the temperature T J is incorrect.

[0041] Next, assuming that T J = 125 °C, the current IC , which results from the first potential difference V CE is obtained (corresponding to the square mark on the thick solid line), and the current I C , which results from the second potential difference V EE (corresponding to the square mark on the thin solid line). That is, the potential difference V CE obtained square mark is located at a position lower than that of the second potential difference V EE This contradicts the constraint that the current I C of the same semiconductor device. Therefore, it is concluded that the assumption of T J = 125 °C is incorrect.

[0042] Next, assuming that, for example, T J = 75 °C, the current I C , which results from the first potential difference V CEis obtained (corresponding to the circle mark on the thick dash-dot-dot line), and the current I C , which results from the second potential difference V EE (corresponding to the circle marking on the thin dashed-dot-dotted line). That is, the potential difference V CE obtained circle marking and the second potential difference V EE obtained circle marking are at the same height. This fulfills the constraint condition that the I C of the same semiconductor device. Therefore, the temperature T J and the current I C values ​​to be achieved in this case. T J = 75 °C and I C = 560 A are determined using Fig. 2 determined. [Specific process contents of the processing device of the semiconductor characteristic curve measuring device]

[0043] The process contents of the processing device 105, the overview of which is described above, will now be described with reference to the Fig. 3A and Fig. 3B is described in detail. Fig. 3A and Fig. 3B are flowcharts each illustrating a process executed by the processing device 105 of the Fig. 1A illustrates the process flow carried out by the measuring device 101 for semiconductor characteristics.

[0044] In the first steps S101 and S102, the processing device 105 obtains a measured value of the first potential difference V CE from the first potential difference measuring device 102 and obtains a measured value of the second potential difference V EE from the second potential difference measuring device 103. Either step S101 or step S102 can be performed first or steps S101 and S102 can be performed simultaneously.

[0045] In the next steps S103 and S104, the processing device 105 T J (0), which is an initial value of the temperature T J to 25 °C and sets, for example, a step size ΔT J the temperature T J to 0.1 °C. Either step S103 or step S104 can be performed first, or steps S103 and S104 can be performed simultaneously. Alternatively, steps S103 and S104 can be performed before steps S101 and S102.

[0046] In the next step S105, the processing device 105 sets T J (0) into the temperature T J This processing means that the output value T J (0) as a candidate value for the temperature T J is set.

[0047] In the next step S106, the processing device 105 specifies a value of a current I C (V CE , TJ ) corresponding to the measured value of the first potential difference V CE and the candidate value for the temperature T J based on the I C -V CE -Characteristic based on the measured value of the first potential difference V CE This processing means that the value of the current I C at the specified first potential difference V CE is read from the curved line which represents the I C -V CE -Characteristic curve at the specified temperature T J indicates.

[0048] In the next step S107, the processing device 105 specifies a value of a current I C (V EE , T J ) corresponding to the second potential difference V EE and the candidate value for the temperature T J based on the I C -V EE -Characteristic based on the measured value of the second potential difference V EEThis processing means that the current I C at the specified second potential difference V EE is read from the straight line which the I C -V EE -Characteristic curve at the specified temperature T J Either step S106 or step S107 may be performed first, or steps S106 and S107 may be performed simultaneously.

[0049] In the next step S108, the processing device 105 calculates a difference I C (V CE , T J ) - I C (V EE , T J ) between the two current values ​​specified in steps S106 and S107 and sets the calculation result in ΔI C (0). ΔI C (0) refers in the case of repeated calculation of a difference between two current values ​​I C during the change of the candidate value for the temperature T Jto a difference between the current values ​​that are related to a previously set candidate value for the temperature T J is calculated.

[0050] In the next step S109, the processing device 105 determines whether the difference ΔI C (0) between two current values ​​I calculated in step S108 C is equal to 0. If ΔI C (0) = 0 is satisfied (YES in step S109), the value of the current I C , which results from the first potential difference V CE is obtained, with the value of the current I C , which results from the second potential difference V EE is obtained. Therefore, in the next step S121, the processing device 105 outputs the current I C (V CE , T J ) as an estimate of the current and returns the current candidate value for the temperature T J as an estimate of the temperature and then terminates the process.

[0051] In contrast, the processing device 105, when ΔI C (0) = 0 is not satisfied (NO in step S109), the process proceeds to step S110. In step S110, the processing device 105 sets a temperature T J + ΔT J , which can be achieved by changing the temperature T J by the step size ΔT J obtained as a new candidate value for the temperature T J In the case of Fig. 3A and Fig. 3B the step size ΔT J the temperature T J in step S104 is set to 0.1 °C and thus the temperature T J updated to a value that is 0.1 °C higher than the temperature T at a current time J is.

[0052] In the next step S111, the processing device 105 specifies a value of the current I C (V CE , T J ) based on the I C -V CE-Characteristic curve at the updated temperature T J based on the measured value of the first potential difference V CE This processing means that the current I C at the specified first potential difference V CE is read from the curved line which represents the I C -V CE -Characteristic curve at the updated temperature T J indicates.

[0053] In the next step S112, the processing device 105 specifies a value of the current I C (V EE , T J ) based on the I C -V EE -Characteristic curve at the updated temperature T J based on the measured value of the second potential difference V EE This processing means that the current I C at the specified second potential difference V EE is read from the straight line which the I C -V EE -Characteristic curve at the updated temperature TJ Either step S111 or step S112 can be performed first, or steps S111 and S112 can be performed simultaneously.

[0054] In the next step S113, the processing device 105 calculates a difference I C (V CE , T J ) - I C (V EE , T J ) between the two current values ​​specified in steps S111 and S112 and sets the calculation result in ΔI C (1). ΔI C (1) refers in the case of repeated calculation of a difference between two current values ​​I C during the change of the candidate value for the temperature T J to a difference between the current values ​​that are related to a currently set candidate value for the temperature T J is calculated.

[0055] In the next step S114, the processing device 105 determines whether the difference ΔIC (1) between two current values ​​I calculated in step S113 C is equal to 0. If ΔI C (1) = 0 is satisfied (YES in step S114), the value of the current I C , which results from the first potential difference V CE is obtained, with the value of the current I C , which results from the second potential difference V EE is obtained. Therefore, in the next step S121, the processing device 105 outputs the current I C (V CE , T J ) as the current value and outputs the current T J than the temperature and then ends the process.

[0056] In contrast, the processing device 105, when ΔI C (1) = 0 is not satisfied (NO in step S114), the process proceeds to step S115. In step S115, the processing device 105 obtains (ΔI C (0) / abs(ΔI C (0))) × (ΔI C (1) / abs(ΔI C(1))) using the difference ΔI C (0) between current values ​​I C , which is related to the previously set candidate value for the temperature T J is calculated, and the difference ΔI C (1) between current values ​​I C , which is related to the currently set candidate value for the temperature T J is calculated and sets this into a first determination value S. If a sign of the difference ΔI C (0) between current values ​​I C , which is related to the previously set candidate value for the temperature T J is calculated, and a sign of the difference ΔI C (1) between current values ​​I C , which is related to the currently set candidate value for the temperature T J calculated are reversed, S = -1 is satisfied. If the signs are not reversed, S = 1 is satisfied.

[0057] A calculation formula for the first determination value S is described in more detail. abs(x) is a function for obtaining an absolute value of x. ΔI C (0) / abs(ΔI C (0)) means that a value of ΔI C (0) is divided by an absolute value of it. Therefore, ΔI C (0) / abs(ΔI C (0)) is equal to 1 if the difference ΔI C (0) between the previous current values ​​is positive, and equal to -1 if the difference ΔI C (0) between the previous current values ​​is negative. Likewise, ΔI C (1) / abs(ΔI C (1)) is equal to 1 if the difference ΔI C (1) between the current values ​​is positive, and equal to -1 if the difference ΔI C (1) between the current values ​​is negative. A result obtained by multiplying them is substituted into S. Therefore, if the difference ΔI C (0) between the previous current values ​​and the difference ΔI C(1) between the current values ​​are both 1 or both -1, S = 1. If one of the difference ΔI C (0) between the previous current values ​​and the difference ΔI C (1) between the current values ​​is 1 and the other is -1, S = -1 is satisfied.

[0058] In summary, if the difference ΔI C between the current values ​​at the previously set value of temperature T J and the difference ΔI C between the current values ​​at the currently set value of the temperature T J are reversed with respect to whether they are positive or negative (ie the sign), S = -1. The reversal of the sign of the difference ΔI C between the current values ​​means that the potential difference V CE obtained current I C smaller than that from the second potential difference V EE obtained current I Cat the currently set value of temperature T J is, although the potential difference V CE obtained current I C greater than that from the second potential difference V EE at the previously set value of temperature T J obtained current I C is, or means that the potential difference V CE obtained I C greater than that from the second potential difference V EE at the currently set value of temperature T J obtained current I C is, although the potential difference V CE obtained I C smaller than that from the second potential difference V EE at the previously set value of temperature T J The fact that the size relationship of I C simply reverses by changing the temperature T J by the step size ΔT Jis changed, means that the temperature T J is updated via an optimal value (value to be obtained). This can also be confirmed by the fact that the sign of the difference ΔI C between the current values ​​when the temperature T J = 25 °C, and the sign of the difference ΔI C between the current values ​​when the temperature T J = 125 °C, in Fig. 2 is reversed. Here, if the step size ΔT J the temperature T J has a sufficiently low value, the currently set candidate value for the temperature T J as the optimal value of temperature T J be viewed.

[0059] Thus, in the next step S116, the processing device 105 determines whether the first determination value S calculated in step S115 is equal to -1. If S = -1 is satisfied (YES in step S116), the processing device 105 proceeds to step S121. In step S121, the processing device 105 outputs the current I C (V CE , T J ) as the current value and outputs the current T J than the temperature and then ends the process.

[0060] In contrast, if S = -1 is not satisfied (NO in step S116), S = 1 is satisfied. This means that the difference ΔI C between the current values ​​both at the previously set value of the temperature T J as well as at the currently set value of the temperature T J is positive (ΔI C (0) > 0 and ΔI C (1) > 0) or the difference ΔI Cbetween the current values ​​both at the previously set value of the temperature T J as well as at the currently set value of the temperature T J (ΔI C (0) < 0 and ΔI C (1) < 0) is negative. This means that the potential difference V CE obtained current I C remains greater than that resulting from the second potential difference V EE obtained current I C or the one resulting from the first potential difference V CE obtained current I C remains smaller than that resulting from the second potential difference V EE obtained current I C . Since the temperature T J does not change beyond the optimal value, the temperature T J further by ΔT J be changed.

[0061] Here it is necessary to determine whether a direction of change of the set value of the temperature T J is correct. A decrease in the difference ΔI Cbetween the current values ​​caused by the change from the previously set value of the temperature T J to the currently set value of temperature T J means that the temperature T J is changed in a correct direction. Conversely, an increase in the difference ΔI C between the current values ​​caused by the change from the previously set value of the temperature T J to the currently set value of temperature T J causes the set value of the temperature T J is changed in the wrong direction.

[0062] Thus, in the next step S117, the processing means 105 calculates a second determination value D for determining whether the direction of change of the temperature T J is correct. A product of ΔI C (0) / abs(ΔI C (0)) and (ΔI C (0) - ΔI C (1)) / abs(ΔI C (0) - ΔI C(1)) is inserted into the second determination value D.

[0063] First, ΔI C (0) / abs(ΔI C (0)) the sign of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J as described above. Next, ΔI C (0) - ΔI C (1) a difference between the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J In the following description, this difference is referred to as the remainder. Since (ΔI C (0) - ΔI C (1)) / abs(ΔI C (0) - ΔI C (1)) is obtained by dividing this remainder by an absolute value thereof, is (ΔI C (0) - ΔI C (1)) / abs(ΔI C (0) - ΔI C(1)) is equal to 1 if the sign of the remainder is positive and equal to -1 if the sign of the remainder is negative.

[0064] If the sign of the remainder is positive, ΔI C (0) > ΔI C (1) is fulfilled, which means that the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J smaller than the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J It should be noted that “smaller” here means smaller in value, not in absolute value. Therefore, if the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J both are positive, the absolute value of the difference ΔI C(1) between the current values ​​is smaller than the absolute value of the difference ΔI C (0) between the previous current values. Conversely, if the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J both are negative, the absolute value of the difference ΔI C (1) between the current values ​​greater than the absolute value of the difference ΔI C (0) between the previous current values.

[0065] In contrast, if the sign of the remainder is negative, ΔI C (0) < ΔI C (1) is fulfilled, which means that the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J greater than the difference ΔI C(0) between the current values ​​at the previously set value of temperature T J Therefore, if the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J both are positive, the absolute value of the difference ΔI C (1) between the current values ​​greater than the absolute value of the difference ΔI C (0) between the previous current values. Conversely, if the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J both are negative, the absolute value of the difference ΔI C (1) between the current values ​​is smaller than the absolute value of the difference ΔI C(0) between the previous current values.

[0066] In summary, since the product of the sign of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and the sign of the remainder (ΔI C (0) - ΔI C (1)) is inserted into the second determination value D, the following four cases occur.

[0067] (i) The case where the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J is positive and the currently calculated remainder is positive. In this case, the difference ΔI C between the current values ​​both at the previously set value of the temperature T J as well as at the currently set value of the temperature T J positive, and is the absolute value of the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T Jsmaller than the absolute value of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J . The value of the second determinant D in this case is D = 1 × 1 = 1.

[0068] (ii) The case where the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J is positive and the currently calculated remainder is negative. In this case, the difference ΔI C between the current values ​​both at the previously set value of the temperature T J as well as at the currently set value of the temperature T J positive, and is the absolute value of the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J greater than the absolute value of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J. The value of the second determinant D in this case is D = 1 × -1 = -1.

[0069] (iii) The case where the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J is negative and the currently calculated remainder is positive. In this case, the difference ΔI C between the current values ​​both at the previously set value of the temperature T J as well as at the currently set value of the temperature T J negative, and is the absolute value of the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J greater than the absolute value of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J . The value of the second determinant D in this case is D = -1 × 1 = -1.

[0070] (iv) The case where the difference ΔI C(0) between the current values ​​at the previously set value of temperature T J is negative and the currently calculated remainder is negative. In this case, the difference ΔI C between the current values ​​both at the previously set value of the temperature T J as well as at the currently set value of the temperature T J negative, and is the absolute value of the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J smaller than the absolute value of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J . The value of the second determinant D in this case is D = -1 × -1 = 1.

[0071] From the above it can be seen that D = 1 is satisfied when the absolute value of the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T Jsmaller than the absolute value of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J is, and otherwise D = -1 is satisfied. That is, D = 1 is satisfied if the temperature T J is updated in the correct direction, and D = -1 is satisfied when the temperature T J is updated in the wrong direction.

[0072] Thus, in the next step S118, the processing device 105 determines whether the second determination value D is equal to 1. If D = 1 is satisfied (YES in step S118), the processing device 105 proceeds to step S120 without changing the step size ΔT J of the temperature. In contrast, if D = -1 is satisfied (NO in step S118), the processing device 105 sets -ΔT J in ΔT J to change the sign of the step size ΔT J the temperature in the next step S119.

[0073] In the next step S120, the processing device 105 sets the value of the difference ΔI C (1) between the current values ​​at the currently set value of the temperature T J into the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J and updates the value of the difference ΔI C (0) between the current values ​​at the previously set value of temperature T J . Thereafter, the processing device 105 returns the process to step S110, changes the temperature T J to the temperature T J + ΔT J by controlling the temperature T J by the step size ΔT J changes, and performs the processing again in the subsequent steps. By performing such a repetitive calculation, an event eventually occurs such that the difference ΔI Cbetween the current values ​​becomes 0 (YES in step S114) or the sign of the difference ΔI C between the current values ​​at the previously set value of temperature T J and the sign of the difference ΔI C between the current values ​​at the currently set value of the temperature T J be reversed (YES in step S116). Consequently, the current I C and the temperature T J as the optimal estimates (step S121).

[0074] In the process described above, the output value T J (0) of the temperature T J , which is set in step S103, and the step size ΔT J The temperature change set in step S104 is given as an example and can be changed as needed. For example, it is useful to set the initial value of the temperature T Jto a temperature around an expected temperature to reduce the frequency of calculation. Furthermore, it is also useful to set the step size ΔT J of the temperature change to increase the calculation accuracy, or the step size ΔT J the temperature change if necessary to reduce the frequency of calculation.

[0075] Since each of the first relationship and the second relationship is stored in the storage device 104, detailed data can be stored as needed or representative data can be stored.

[0076] For example, by saving the detailed data, such as the detailed data obtained by changing the temperature T J with a step size of 0.1 °C and recording the temperature T J over a wide temperature range, in the storage device 104 a precise current IC at temperature T J and the measurement accuracy can be improved, although the data volume increases. By increasing the step size of the temperature T J and reducing the data volume, the cost of the storage device 104 can be reduced. In this case, the data can be stored at temperature T J that are not saved (corresponding to a track in Fig. 2), can be calculated by interpolation using traces on both sides of this trace, and the current I C using the interpolated track. Linear interpolation using only two tracks on both sides, spline interpolation using three or more tracks for more accurate interpolation, or the like can be selected as an interpolation method, as appropriate.

[0077] A data interval each from the first potential difference V CE and the second potential difference V EE can also be arbitrarily selected taking into account storage capacity and accuracy. If the traces are prepared at small voltage intervals, accurate traces can be obtained, although the data volume increases. If the traces are prepared at large voltage intervals and the data is obtained by interpolation, the data volume can be reduced and the storage capacity can be reduced. In this case, linear interpolation, spline interpolation, or the like can be freely selected as an interpolation method, taking into account calculation speed and calculation accuracy.

[0078] By performing a calculation according to the procedure described in the Fig. 3A and Fig. 3B, the estimation of the specified main current IC as the current information 106 and the estimation of the specified temperature T J output as the temperature information 107. By comparing this current information 106 and temperature information 107 with the defined values ​​separately held in the memory, a current operating state of the semiconductor device 1 can be detected. Consequently, an operating state of the semiconductor device 1 or a power conversion device, such as an inverter, incorporating this semiconductor device 1 can be detected, and a malfunction of a system caused by a malfunction of the semiconductor device 1 or the power conversion device can be prevented in advance.

[0079] Although this is Fig. 1A is not shown, a terminal unit that extracts current information 106 and temperature information 107, and a determination unit that determines the state of the semiconductor device 1 or the power conversion device based on the extracted current information 106 and temperature information 107 may be provided. The determination unit may feed the determination information back into the gate driver 8, thereby performing control according to the state of the semiconductor device 1 or the power conversion device. Hardware constituting the determination unit may be configured based on a microcomputer including a CPU and a memory, may be configured using an FPGA, or may be configured by a dedicated circuit. Alternatively, the determination unit may be configured by two or more combinations of these components. [Effects of the first embodiment]

[0080] As described above, in the semiconductor characteristic measuring apparatus 101 according to the first embodiment, the main current I C and the temperature T J simultaneously simply by measuring the two potential differences of the semiconductor device 1. A current sensor and a temperature sensor are unnecessary, the power semiconductor element 2 does not require a sensor cell, and a complicated and expensive device such as a voltage controller, a gate voltage measuring device, or a switching speed measuring device is also unnecessary. Thus, the current I C and the temperature T J of the semiconductor device 1 can be measured at a lower cost, resulting in such a remarkable effect that the integrity of the semiconductor device 1 can be ensured at a low cost.

[0081] Furthermore, if the temperature T J and the current I C of the semiconductor device 1 using the semiconductor characteristic measuring device 101, the integrity of a power conversion device, such as an inverter device, incorporating the semiconductor device 1 can be easily checked by determining whether a voltage of each section of this power conversion device agrees with a value determined from the above-described estimates of the temperature T J and current I C is calculated. Furthermore, since the integrity of the semiconductor device 1 can be easily verified, there is no need to manufacture the power conversion device with an unnecessarily large power margin, which can lead to a reduction in costs.

[0082] Furthermore, the semiconductor characteristic measuring device 101 only measures a voltage between terminals provided in an existing device including the semiconductor device 1. Therefore, the semiconductor characteristic measuring device 101 can not only be integrated into a new device but can also be retrofitted to an existing device, resulting in a wide range of applications. Second embodiment

[0083] In the first embodiment, the IGBT is used as the power semiconductor element 2 incorporated into the semiconductor device 1. In a second embodiment, the case where a metal oxide semiconductor field-effect transistor (MOSFET) is used as the power semiconductor element 2A incorporated into a semiconductor device 1A will be described.

[0084] Fig. 4 is a configuration diagram of a semiconductor characteristic measuring apparatus 101 according to the second embodiment. Fig. 4 illustrates the semiconductor device 1A to be measured by the semiconductor characteristic measuring device 101.

[0085] The semiconductor device 1A includes a MOSFET serving as the power semiconductor element 2A, a main drain terminal 4A, a gate terminal 5A, a source reference terminal 6A, and a main source terminal 7A. The main drain terminal 4A is connected to a drain electrode D of the MOSFET, the gate terminal 5A is connected to a gate electrode G of the MOSFET, and the main source terminal 7A is connected to a source electrode S of the MOSFET. A main current (i.e., a drain current I D) of the power semiconductor element 2A flows through the drain main terminal 4A and the source main terminal 7A. Although the source reference terminal 6A is connected to the source electrode S, the main current does not flow through the source reference terminal 6A. A parasitic resistance component 3A is present in a wire between the source main terminal 7A and the source electrode S. The gate driver 8 is connected between the gate terminal 5A and the source reference terminal 6A.

[0086] Since the Fig. 4 shown configuration of the measuring device 101 for semiconductor characteristics of the Fig. 1A, the same or corresponding sections are designated by the same reference numerals, and the detailed description is not repeated. However, since the MOSFET is used as the power semiconductor element instead of the IGBT, some of the notations are changed. Specifically, the collector of the IGBT is replaced by the drain of the MOSFET, and the emitter of the IGBT is replaced by the source of the MOSFET. Accordingly, the first potential difference V CE as V DS is the second potential difference V EE as V SS and is the main current I C as I D marked.

[0087] According to the above marking, the first potential difference measuring device 102 of the Fig. 4 shown measuring device 101 for semiconductor characteristics, the first potential difference V DSbetween the drain main terminal 4A and the source reference terminal 6A. The second potential difference measuring device 103 measures the second potential difference V SS between the source reference terminal 6A and the source main terminal 7A. The storage device 104 stores a first relationship between the previously measured or calculated first potential difference V DS , the main stream I D and junction temperature T J and a second relationship between the previously measured or calculated second potential difference V SS , the main stream I D and the junction temperature T J . The processing device 105 specifies the main stream I D and the temperature T J using the measured first potential difference V DS and the second potential difference V SSand the first relationship and the second relationship stored in the memory device 104, and outputs the main current I D and the temperature T J as the current information 106 and the temperature information 107.

[0088] As mentioned with reference to Fig. 1B, the first potential difference measuring device 102 can measure a potential difference between the drain main terminal 4A and the source main terminal 7A. In general, the first potential difference measuring device 102 measures the first potential difference V DS based on a potential difference between two connection terminals connected to a first main electrode and a second main electrode, respectively, of a plurality of connection terminals provided in the semiconductor device 1A.

[0089] Fig. 5 is a diagram illustrating a working principle of the Fig. 4 shown measuring device 101 for semiconductor characteristics. In Fig. 5, the first relationship and the second relationship stored in the storage device 104 of the semiconductor characteristic measuring device 101 are shown in diagram form. The first relationship is a relationship between the first potential difference V DS , the current I D and the temperature T J . The second relationship is a relationship between the second potential difference V SS , the current I D and the temperature T J .

[0090] As in Fig. 5, has a track that has an I D -V DS -characteristic, which is the first relationship in the case of the MOSFET, has a nonlinearity different from that of the trace indicating the I D -V CEcharacteristic curve in the case of the IGBT. This is because the operating principle of the MOSFET is different from that of the IGBT. Even in the case of the MOSFET, an I D -V SS -Characteristic reflects an electrical resistance of the bond wires made of aluminum and thus the trace thereof has a linearity similar to that of the IGBT.

[0091] As described above, the first relationship and the second relationship are two types of relationships that differ in their linearity. Therefore, even in the second embodiment, the main current I D and the temperature T Jof the semiconductor device 1 can be obtained simultaneously according to a functional principle and process contents that are substantially similar to those in the first embodiment. Specifically, the collector is replaced by the drain in the process contents in the first embodiment, and the emitter is replaced by the source in the process contents in the first embodiment. However, when an absolute value of the current I D is low, an extraordinary process is required. This extraordinary process is described in a third embodiment.

[0092] As an example in Fig. 5, it is assumed that a measured value of the first potential difference V DS 0.65 V, and it is assumed that a measured value of the second potential difference V SS (Gain G = 10) is 0.81 V. In this case, the junction temperature T Jthan 75 °C based on a temperature when a value of the current I D , which results from the first potential difference V DS is obtained, with a value of current I D , which results from the second potential difference V SS Furthermore, since the matching value of the current I D is 550 A, outputs 550 A as the current information 106 and outputs 75 °C as the temperature information 107.

[0093] The Fig. 6A and Fig. 6B are flowcharts each illustrating a process executed by the processing device 105 of the Fig. 4 illustrates the process flow carried out by the measuring device 101 for semiconductor characteristics.

[0094] Since the process flow in each of the Fig. 6A and Fig. 6B, the flow charts show the process flow in each of the Fig. 3A and Fig. 3B, the detailed description is not repeated. Steps S201 to S221 in the Fig. 6A and Fig. 6B correspond to steps S101 to S121 in the Fig. 3A or 3B. In the Fig. 6A and Fig. 6B are however V CE , V EE and I C in the Fig. 3A and Fig. 3B through V DS , V SS or I D replaced.

[0095] As described above, the main current I D and the temperature T JBasically similar to the semiconductor characteristic measuring device according to the first embodiment, the two potential differences of the semiconductor device 1A can be measured simultaneously in the semiconductor characteristic measuring device according to the second embodiment, which is also designed for the MOSFET. A current sensor and a temperature sensor are unnecessary, the power semiconductor element 2A does not require a sensor cell, and complicated and expensive equipment such as a voltage controller, a gate voltage measuring device, or a switching speed measuring device is also unnecessary. Thus, the current I D and the temperature T J of the semiconductor device 1A can be measured at a lower cost, resulting in such a remarkable effect that the integrity of the semiconductor device 1A can be ensured at a low cost. Third embodiment

[0096] If the power semiconductor element 2A incorporated in the semiconductor device 1A is the MOSFET, the I D -V DS -Characteristic shows a gentle nonlinearity similar to a straight line passing through the origin in a region where the absolute value of the current I D is relatively low, and thus the I D -V DS -Characteristic of the linearity of the I D -Vss characteristic. This makes it difficult to determine the temperature T J and an estimation error of the temperature T J and an estimation error of the current I D may become larger. This is explained below with reference to Fig. 7 described.

[0097] Fig. Fig. 7 is a diagram illustrating an operating principle of a semiconductor characteristic measuring apparatus according to a third embodiment. Similar to the Fig. 5, the first relationship and the second relationship in the case of the MOSFET in Fig. 7 is shown in the form of a diagram.

[0098] As an example in Fig. 7, it is assumed that a measured value of the first potential difference V DS 0.26 V, and it is assumed that a measured value of the second potential difference V SS (gain G = 10) is 0.42 V. In this case, the temperature T J than 75 °C and a value of the current I D using the same method as in the first and second embodiments can be estimated as 290 A. Even if the temperature T J deviates from 75 °C, which is an optimal temperature, however, a difference ΔI D between a current estimate based on the measured value of the first potential difference V DSand a current estimate based on the measured value of the second potential difference V SS low. Therefore, the temperature T J be estimated incorrectly. An incorrect determination of the temperature T J leads to an incorrect determination of the value of the current I D .

[0099] Thus, the semiconductor characteristic measuring apparatus according to the third embodiment performs temperature estimation only in a range where the measured value of the first potential difference V DS is equal to or greater than a certain threshold, which is a range in which the nonlinearity of the first potential difference V DS is high. When the first potential difference V DS is less than the threshold, the immediately preceding estimated temperature T J as an estimate of the temperature T JThis process is based on the fact that a change in temperature T J is gentler than a change in current I D . Consequently, even if the current I D flowing through the MOSFET is relatively small, the current I D and the temperature T J be estimated with a reduced error.

[0100] The first potential difference V DS , which serves as the threshold value described above, may be predetermined according to the accuracy of the processing device 105 used. For example, if the accuracy of the processing device 105 used is low, the first potential difference V DS , which serves as the threshold value, can be set to a relatively large value. If the accuracy of the processing device 105 is high, the first potential difference V DS, which serves as the threshold, should be set to a relatively low value.

[0101] For example, it is assumed that the measured value of the first potential difference V DS 0.26 V as in Fig. 7. The second potential difference V SS (G = 10), which shows the same current value when the temperature T J 75 °C is 0.42 V. The difference ΔI D between the current values ​​at 125 °C, which are 50 °C higher than the temperature T J shifted upwards from 75 °C, and the difference ΔI D between the current values ​​I D at 25 °C, which is 50 °C higher than the temperature T J from 75 °C downwards. Whether 0.26 V should be set as the threshold can be determined based on whether these differences ΔI D between the current values ​​are acceptable in relation to the accuracy of the processing device 105.

[0102] As described above, temperature estimation and current estimation are performed when the measured value of the first potential difference V DS is equal to or greater than the predetermined threshold, and the immediately preceding measured value is used as the estimated temperature T J used when the first potential difference V DS is smaller than the threshold. Therefore, an error can be suppressed.

[0103] Fig. 8A and Fig. 8B are flowcharts each illustrating the operation of the processing means of the semiconductor characteristic measuring apparatus according to the third embodiment. Fig. 8A and Fig. 8B, steps S2021, S2051, S2061 and S2062 are furthermore added to steps S201 to S221 in the flowcharts shown in the Fig. 6A and Fig. 6B. The added steps are described below and the description of the same steps as those in the Fig. 6A and Fig. 6B described steps S201 to S221 (ie the steps corresponding to the Fig. 3A and Fig. 3B) is not repeated.

[0104] Step S2021 is performed before step S203. In step S2021, the processing device 105 determines whether the output value T J (0) of the temperature T J is not set. If the output value T J (0) of the temperature T J is not set (YES in step S203), the processing device 105 sets the output value to, for example, 25 °C in the next step S203.

[0105] If, however, the initial value T J (0) of the temperature T Jhas already been set (NO in step S203), the processing device 105 proceeds to step S204 using the already set initial value. Here, a previously outputted estimate of the temperature T J as initial value T J (0) in step S2062 described below.

[0106] Step S2051 is performed simultaneously with, before, or after steps S2021, S204, and S205. In step S2051, the processing device 105 sets, for example, 0.3 V as the threshold value V DST the first potential difference V DS a.

[0107] Step S2061 is performed after step S206. In step S2061, the processing device 105 determines whether the first potential difference V obtained in step S201 DS less than the threshold V DST is.

[0108] If the first potential difference V DSless than the threshold V DST (YES in step S105), the processing device 105 proceeds to steps S2062 and S221. In this case, the processing device 105 outputs the temperature T as the final estimation results. J , which outputs the output value, and the current I D , which is based on the first potential difference V DS using this temperature, from (S221). Furthermore, the processing device 105 stores the output temperature T J (ie the previous value) as the next output value T J (0) (S2062). As described above, when the first potential difference V DS less than the threshold V DST is the previous value unchanged without estimating the temperature T J used and thus an estimation error can be suppressed.

[0109] In contrast, if the first potential difference V DS equal to or greater than the threshold V DST (NO in step S105), the processing device 105 proceeds to the next step S207. The procedure in step S207 and the subsequent steps is similar to that in the second embodiment shown in FIGS. Fig. 6A and Fig. 6B. As described above, when the first potential difference V DS equal to or greater than the threshold V DST is the process flow for estimating the temperature T J and current I D and can therefore provide more accurate estimates of the temperature T J and current I D be issued.

[0110] As described above, in the semiconductor characteristic measuring apparatus according to the third embodiment, even if the current I D when estimating the temperature TJ and current I D of the semiconductor device 1A containing the MOSFET is relatively small, an error can be suppressed. Fourth embodiment

[0111] In the power semiconductor element 2 used in the semiconductor device 1, a breakage or detachment of a portion of many bonding wires connected to a surface of the power semiconductor element 2 occurs when the power semiconductor element 2 is used for a long time. This may result in a sudden increase in the measured first potential difference V CE and the second potential difference V EE Since this occurs instantaneously, the measured values ​​of the first potential difference V CE and the second potential difference V EE discontinuous, as if the measured values ​​of the first potential difference V CE and the second potential difference V EEsuddenly jump. This increase in the measured values ​​is irreversible.

[0112] In a fourth embodiment, a semiconductor characteristic measuring apparatus capable of handling the above-described case is provided. Although the following technique is described based on the semiconductor characteristic measuring apparatus according to the first embodiment, the following technique is also applicable to the semiconductor characteristic measuring apparatus configured for the MOSFET as in the second and third embodiments.

[0113] Fig. 9 is a configuration diagram of the semiconductor characteristic measuring apparatus 101 according to the fourth embodiment. Fig. The measuring device 101 for semiconductor characteristics shown in Figure 9 differs from the one shown in Fig. 1A in that the processing device 105 has the function of updating the data stored in the storage device 104.

[0114] In particular, the processing device 105 monitors the first potential difference V CE , which is measured by the first potential difference measuring device 102, and the second potential difference V EE , which is measured by the second potential difference measuring device 103. When the first potential difference V CE and the second potential difference V EE suddenly increase, the processing device 105 corrects the first potential difference V by a magnification rate of the increase. CE in the data indicating the first relationship, and the second potential difference V EE in the data representing the second relationship stored in the storage device 104.

[0115] If the first potential difference V CE and the second potential difference V EE By continuously measuring the potential difference at high frequency by the first potential difference measuring device 102 and the second potential difference measuring device 103, the magnitude of each jump can be measured. Since this voltage jump occurs instantaneously, the temperature and current before and after the voltage jump are considered unchanged.

[0116] Fig. 10 is a diagram illustrating an operation example of the Fig. 9 illustrated processing device 105. In Fig. 10 is the I stored in the memory device 104 C -V CE -Characteristic is indicated by a dash-dot line and is the I C -V EE -characteristic is indicated by a solid line. In addition, the characteristics before the jump of the first potential difference V CE and the second potential difference VEE indicated by thin lines and the updated characteristics after the jump occurs are indicated by thick lines.

[0117] Since the first potential difference V CE and the second potential difference V EE due to the detachment or breakage of the bond wires, the increase of the first potential difference V CE and the increase of the second potential difference V EE always simultaneously. An increase in the rate of increase of the first potential difference V CE and a rate of increase of the second potential difference V EE may, however, be slightly different.

[0118] For example, it is assumed that the first potential difference V CE has jumped by 1.2 times and the second potential difference V EE has jumped by 1.5 times. In this case, as shown in Fig. 10, the processing device 105 determines the value of the first potential difference V CE at the same temperature and at the same current value in the data stored in the storage device 104 indicating the first relationship by a factor of 1.2. Likewise, the processing device 105 changes the value of the second potential difference V EE at the same temperature and the same current value in the data stored in the storage device 104 indicating the second relationship by a factor of 1.5.

[0119] The Fig. 11A and Fig. 11B are flowcharts each illustrating a process executed by the processing device 105 of the Fig. 9 shown measuring device 101 for semiconductor characteristics. Fig. 11A and Fig. 11B, steps S1021, S1026, S1091 and S1092 are furthermore added to steps S101 to S121 in the flowcharts shown in the Fig. 3A and Fig. 3B. The added steps are described below, and the description of the same steps as steps S101 to S121 in the Fig. 3A and Fig. 3B will not be repeated.

[0120] Steps S1021 to S1026 are performed after step S102. In steps S1021 and S1022, the processing device 105 sets, for example, a threshold magnification rate V CEX a rate of increase of the first potential difference V CE to 1.01 and sets a threshold magnification rate V EEX the second potential difference V EEto 1.02. Steps S1021 and S1022 may be performed simultaneously, or one of step S1021 or step S1022 may be performed first.

[0121] In the next step S1023, the processing device 105 determines whether a previous measured value V CE (0) of the first potential difference V CE has already been set. The previous measured value V CE (0) of the first potential difference V CE and a previous measured value V EE (0) of the second potential difference V EE are set in steps S1091 and S1092. If the previous measured value V CE (0) of the first potential difference V CE has not been set (NO in step S1023), the processing device 105 proceeds to step S103. In step S103 and the subsequent steps, the processing device 105 performs the process similar to that in the Fig. 3A and Fig. 3B shown by.

[0122] If, however, the previous measured value V CE (0) of the first potential difference V CE has already been set (YES in step S 1023), the processing device 105 determines in the next step S1024 whether a magnification rate of the currently measured first potential difference V CE with respect to the previous measured value V CE (0) the threshold magnification rate V CEX exceeds, ie, whether V CE > V CE (0) × V CEX is met. Furthermore, the processing device 105 determines whether an increase rate of the currently measured second potential difference V EE with respect to the previous measured value V EE (0) the threshold magnification rate V EEX exceeds, ie, whether V EE > V EE (0) × V EEX is fulfilled.

[0123] If at least one of the above conditions is met (YES in step S1024), the processing device 105 proceeds to steps S1025 and S1026. In step S1025, the processing device 105 changes the value of the first potential difference V CE at the same temperature and at the same current value in the data stored in the memory device 104 indicating the first relationship by a factor of V CE / V CE (0), which is the detected magnification rate. In step S1026, the processing device 105 changes the value of the second potential difference V EE at the same temperature and the same current value in the data stored in the memory device 104 indicating the second relationship by a factor of V EE / V EE(0), which is the detected magnification rate. Either step S1025 or step S1026 may be performed first, or steps S1025 and S1026 may be performed simultaneously. Thereafter, the processing device 105 proceeds to step S103.

[0124] If, however, both determinations are not met in step S1024 (NO in step S1024), the processing device 105 proceeds to step S103 without updating the data stored in the storage device 104. In step S103 and the subsequent steps, the processing device 105 performs the process similar to that in the Fig. 3A and Fig. 3B shown by.

[0125] As described above, in the semiconductor characteristic measuring apparatus according to the fourth embodiment, even if the I C -V CE -Characteristic and the I C-V EE -Characteristic of the semiconductor component suddenly changes due to the detachment or breakage of the bond wires connected to the power semiconductor, the data stored in the memory device 104 is updated to incorporate the change. Therefore, the measurement of the temperature T J and the main stream I C of the semiconductor device 1 can be continued without causing a defect due to detachment or breakage of the bond wires.

[0126] It is to be understood that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present application is defined by the scope of the claims rather than by the above description, and is intended to include any modifications that are within the meaning and scope equivalent to the scope of the claims. LIST OF REFERENCE SYMBOLS

[0127] 1, 1A semiconductor component; 2, 2A power semiconductor element; 3, 3A parasitic resistance component; 4 main collector terminal; 4A main drain terminal; 5, 5A gate terminal; 6 emitter reference terminal; 6A source reference terminal; 7 main emitter terminal; 7A main source terminal; 8 gate driver; 101 measuring device for semiconductor characteristics; 102 first potential difference measuring device; 103 second potential difference measuring device; 104 storage device; 105 processing device; 106 current information; 107 temperature information; 150 power module; I C Collector current (main current); I D Drain current (main current); T J temperature; V CE , V DS first potential difference; V CEX , V EEX Threshold augmentation rate; V DST Threshold of the first potential difference V DS , V EE , V SS second potential difference. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2020 / 261385

[0003] JP 2016-63674

[0004] JP 2021-19435

[0005]

Claims

[1] A semiconductor characteristic measuring device for estimating a temperature of a semiconductor device and a main current flowing through the semiconductor device, wherein the semiconductor device comprises: a power semiconductor element having a first main electrode, a second main electrode, and a control electrode for controlling the main current flowing between the first main electrode and the second main electrode; and a plurality of connection terminals, each of the plurality of connection terminals being connected to any one of the first main electrode, the second main electrode and the control electrode, wherein the semiconductor characteristic measuring device comprises: a first potential difference measuring device for measuring a first potential difference based on a potential difference between two connection terminals connected to the first main electrode and the second main electrode of the plurality of connection terminals, respectively; a second potential difference measuring device for measuring a second potential difference between a first connection terminal and a second connection terminal of the plurality of connection terminals, the first connection terminal being connected to a current path of the main current to or from the second main electrode, the second connection terminal being connected to the second main electrode or being connected to the current path at a position closer to the second main electrode than the first connection terminal; a storage device for storing data indicating a first relationship and data indicating a second relationship, wherein the first relationship is a relationship between the first potential difference, a temperature of the power semiconductor element, and the main current, wherein the second relationship is a relationship between the second potential difference, the temperature of the power semiconductor element, and the main current; and a processing device, wherein the processing facility a measured value of the first potential difference is obtained from the first potential difference measuring device, obtains a measured value of the second potential difference from the second potential difference measuring device, based on the data indicating the first relationship, a value of the temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the first potential difference are specified, based on the data indicating the second relationship, a value of the temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the second potential difference are specified, and, when the value of the temperature of the power semiconductor element and the value of the main current specified based on the measured value of the first potential difference agree with the value of the temperature of the power semiconductor element and the value of the main current specified based on the measured value of the second potential difference, outputs the agreed value of the temperature and the agreed value of the main current as estimates at a current time. [2] A semiconductor characteristic measuring device according to claim 1, wherein the processing means sets a candidate value for the temperature, using the data indicating the first relationship, specify a value of the main current corresponding to the measured value of the first potential difference and the candidate value of the temperature, using the data indicating the second relationship, specifying a value of the main current corresponding to the measured value of the second potential difference and the candidate value of the temperature, and, when the value of the main current specified based on the measured value of the first potential difference and the candidate value for the temperature agrees with the value of the main current specified based on the measured value of the second potential difference and the candidate value for the temperature, outputs the candidate value for the temperature and the agreed value of the main current as estimates at a current time. [3] A semiconductor characteristic measuring device according to claim 2, wherein the processing device successively sets candidate values ​​for the temperature by changing the temperature by one step from an initial value, and the processing facility for each of the successively set candidate values ​​for the temperature, a difference between the value of the main current specified from the data indicating the first relationship and the value of the main current specified from the data indicating the second relationship is calculated, and when a sign of a value of the difference calculated for a previously set candidate value for the temperature is different from a sign of a value of the difference calculated for a currently set candidate value for the temperature, outputs the currently set candidate value for the temperature and the value of the main current corresponding thereto as estimates at a current time. [4] A semiconductor characteristic measuring device according to claim 3, wherein the processing means calculates a remainder, where the remainder is a difference between the value of the difference calculated for the previously set candidate value for the temperature and the value of the difference calculated for the currently set candidate value for the temperature, and, if the sign of the value of the difference calculated for the previously set candidate value of the temperature differs from a sign of the calculated residual value, a sign of the step size is reversed. [5] A semiconductor characteristic measuring device according to any one of claims 1 to 4, wherein the power semiconductor element is a metal-oxide-semiconductor field-effect transistor (MOSFET) and the processing facility based on the data indicating the first relationship, specifying a value of the main current corresponding to a previously outputted estimate of the temperature of the power semiconductor element and the measured value of the first potential difference as a first current value, and if the first current value is equal to or less than a threshold value, outputs the previously outputted estimate of the temperature of the power semiconductor element and the first current value as estimates at a current time. [6] The semiconductor characteristic measuring device according to any one of claims 1 to 5, wherein, when the first potential difference currently measured by the first potential difference measuring means changes by a first threshold magnification rate or more with respect to the first potential difference previously measured by the first potential difference measuring means, or when the second potential difference currently measured by the second potential difference measuring means changes by a second threshold magnification rate or more with respect to the second potential difference previously measured by the second potential difference measuring means, the processing means corrects a value of the first potential difference in the data indicating the first relationship and a value of the second potential difference in the data indicating the second relationship by the detected magnification rates. [7] Semiconductor characteristic measurement method for estimating a temperature of a semiconductor device and a main current flowing through the semiconductor device, wherein the semiconductor device comprises: a power semiconductor element having a first main electrode, a second main electrode, and a control electrode for controlling the main current flowing between the first main electrode and the second main electrode; and a plurality of connection terminals, each of the plurality of connection terminals being connected to any one of the first main electrode, the second main electrode and the control electrode, wherein the measurement method for semiconductor characteristics comprises: Obtaining, by a processing device, a measured value of a first potential difference based on a potential difference between two connection terminals connected to the first main electrode and the second main electrode of the plurality of connection terminals, respectively; Obtaining, by the processing device, a measured value of a second potential difference between a first connection terminal and a second connection terminal of the plurality of connection terminals, wherein the first connection terminal is connected to a current path of the main current to or from the second main electrode, wherein the second connection terminal is connected to the second main electrode or is connected to the current path at a position closer to the second main electrode than the first connection terminal; Specifying, by the processing device, based on data stored in a storage device indicating a first relationship, a value of a temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the first potential difference, the first relationship being a relationship between the first potential difference, the temperature of the power semiconductor element and the main current; Specifying, by the processing device, based on data stored in the storage device indicating a second relationship, a value of the temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the second potential difference, the second relationship being a relationship between the second potential difference, the temperature of the power semiconductor element and the main current; and, when the value of the temperature of the power semiconductor element and the value of the main current specified based on the measured value of the first potential difference agree with the value of the temperature of the power semiconductor element and the value of the main current specified based on the measured value of the second potential difference, outputting, by the processing device, the agreed value of the temperature and the agreed value of the main current as estimates at a current time. [8] A semiconductor characteristic measuring method according to claim 7, further comprising setting, by the processing means, a candidate value for the temperature, wherein specifying a value of a temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the first potential difference, specifying, based on the data indicating the first relationship, a value of the main current corresponding to the measured value of the first potential difference and the candidate value for the temperature, specifying a value of the temperature of the power semiconductor element and a value of the main current corresponding to the measured value of the second potential difference, specifying, based on the data indicating the second relationship, a value of the main current corresponding to the measured value of the second potential difference and the candidate value for the temperature, and outputting the matched value of temperature and the matched value of main current as estimates at a current time when the value of main current specified based on the measured value of first potential difference and the candidate value for temperature matches the value of main current specified based on the measured value of second potential difference and the candidate value for temperature, outputting the candidate value for temperature and the matched value of main current as estimates at the current time. [9] A method for measuring semiconductor characteristics according to claim 8, wherein setting a candidate value for the temperature sequentially setting candidate values ​​for the temperature by changing the temperature by an increment from an initial value, the measurement method for semiconductor characteristics further includes: for each of the successively set candidate temperature values, calculating, by the processing device, a difference between the value of the main current specified on the basis of the measured value of the first potential difference and the candidate temperature value and the value of the main current specified on the basis of the measured value of the second potential difference and the candidate temperature value; and, if a sign of a value of the difference calculated for a previously set candidate value for the temperature differs from a sign of a value of the difference calculated for a currently set candidate value for the temperature, outputting, by the processing means, the currently set candidate value for the temperature and the value of the main current corresponding thereto as estimates at a current time. [10] A semiconductor characteristic measurement method according to claim 9, further comprising: Calculating, by the processing device, a remainder, the remainder being a difference between the value of the difference calculated for the previously set candidate value for the temperature and the value of the difference calculated for the currently set candidate value for the temperature, and, if the sign of the value of the difference calculated for the previously set candidate value of the temperature differs from a sign of the calculated residual value, inverting, by the processing device, a sign of the step size. [11] A method for measuring semiconductor characteristics according to any one of claims 7 to 10, wherein the power semiconductor element is a metal-oxide-semiconductor field-effect transistor (MOSFET) and the measurement method for semiconductor characteristics further includes: Specifying, by the processing device, from the data indicating the first relationship, a value of the main current corresponding to a previously outputted estimate of the temperature of the power semiconductor element and the measured value of the first potential difference as a first current value; and, if the first current value is equal to or less than a threshold value, outputting the previously outputted estimate of the temperature of the power semiconductor element and the first current value as estimates at a current time. [12] The semiconductor characteristic measuring method according to any one of claims 7 to 11, further comprising, when the first potential difference currently measured changes by a first threshold magnification rate or more with respect to the previously measured first potential difference, or when the currently measured second potential difference changes by a second threshold magnification rate or more with respect to the previously measured second potential difference, correcting, by the processing means, a value of the first potential difference in the data indicating the first relationship and a value of the second potential difference in the data indicating the second relationship by the detected magnification rates. [13] A program for causing a computer to carry out the semiconductor characteristic measurement method according to any one of claims 7 to 12.

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