Semiconductor characteristic measuring device, semiconductor characteristic measuring method, and program

Abstract

In this semiconductor characteristic measurement device (101), a first potential difference measurement device (102) measures a first potential difference (VCE) between two connection terminals (4, 6) connected respectively to a first and a second main electrode of a power semiconductor element (2). A second potential difference measurement device (103) measures a second potential difference (VEE) between two connection terminals (6, 7) connected at different locations in 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 an element temperature value and a main current value corresponding to a measured value of the first potential difference, as specified from the first relationship, match an element temperature value and a main current value corresponding to a measured value of the second potential difference, as specified from the second relationship, then a processing device (105) outputs the matching element temperature value and the matching main current value as the estimated values for the current point in time.

Description

[Technical field]

[0001] The present disclosure relates to a semiconductor characteristic measuring apparatus, a semiconductor characteristic measuring method, and a program. [Background technology]

[0002] In equipment using semiconductor devices such as power semiconductor modules, the soundness of the equipment can be ensured by monitoring the state of the semiconductor devices. To do this, it is necessary to know the current flowing through the semiconductor device and the temperature of the semiconductor device. If these can be measured accurately, the characteristic margin of the semiconductor device can be minimized, leading to cost reduction. It is desirable to have a method of knowing the current and temperature that is as simple and low-cost as possible. In other words, it is desirable to be able to measure the current and temperature without using sensors specialized for current detection and sensors specialized for temperature detection. Below are examples of related prior art.

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

[0004] In the technology disclosed in JP 2016-63674 A (Patent Document 2), a current value is obtained by controlling the voltage of a sense cell of a power semiconductor element with a control device. Furthermore, a change in a 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 technology disclosed in JP 2021-19435 A (Patent Document 3), the flow current is estimated from the switching speed of a power semiconductor device. Furthermore, the on-voltage of the power semiconductor device is measured and the temperature is estimated from its temperature dependency. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2020 / 261385 [Patent Document 2] JP 2016-63674 A [Patent Document 3] Patent Publication No. 2021-19435 Summary of the Invention [Problem to be solved by the invention]

[0007] In the above-mentioned conventional techniques, either a current sensor or a temperature sensor is required to measure the current and temperature, a sense cell is required in the power semiconductor element, or complex and costly devices such as a voltage control device, a gate voltage measurement device, or a switching speed measurement device are required.

[0008] The present disclosure has been made in consideration of the above problems, and its purpose is to provide a technology that can simultaneously estimate the current value and temperature flowing through a semiconductor device using a simple means that does not use a current sensor or a temperature sensor and does not require a complex control device. [Means for solving the problem]

[0009] In one embodiment, a semiconductor characteristic measuring apparatus 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 a 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 apparatus includes a first potential difference measuring apparatus, a second potential difference measuring apparatus, a storage device, and a processing device. The first potential difference measuring apparatus measures a first potential difference based on a potential difference between two connection terminals among the plurality of connection terminals that are connected to the first main electrode and the second main electrode, respectively. The second potential difference measuring apparatus measures a second potential difference between a first connection terminal among the plurality of connection terminals that is connected to a current path of a main current to or from the second main electrode, and a second connection terminal that 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 representing a first relationship between the first potential difference, the temperature of the power semiconductor element, and the main current, and data representing a second relationship between the second potential difference, the temperature of the power semiconductor element, and the main current. The processing device acquires a measurement value of the first potential difference from the first potential difference measuring device, and acquires a measurement value of the second potential difference from the second potential difference measuring device. The processing device identifies a temperature value and a main current value of the power semiconductor element corresponding to the measurement value of the first potential difference from the data representing the first relationship, and identifies a temperature value and a main current value of the power semiconductor element corresponding to the measurement value of the second potential difference from the data representing the second relationship. When the temperature value and the main current value of the power semiconductor element identified based on the measurement value of the first potential difference and the temperature value and the main current value of the power semiconductor element identified based on the measurement value of the second potential difference match each other, the processing device outputs the matched temperature value and the matched main current value as current estimates. Effect of the Invention

[0010] According to the above embodiment, the semiconductor characteristic measuring apparatus can simultaneously estimate the current value and temperature flowing through a semiconductor device with a simple configuration including a first potential difference measuring apparatus, a second potential difference measuring apparatus, a memory device, and a processing apparatus. [Brief description of the drawings]

[0011] [Figure 1A] 1 is a configuration diagram of a semiconductor characteristic measuring device according to a first embodiment. [Figure 1B] FIG. 1B is a diagram showing a modification of the semiconductor characteristic measuring apparatus of FIG. 1A. [Figure 1C] FIG. 1B is a diagram showing still another modified example of the semiconductor characteristic measuring apparatus of FIG. 1A. [Diagram 2] 1B is a diagram for explaining the operating principle of the semiconductor characteristic measuring apparatus of FIG. 1A. [Figure 3A] 1B is a flowchart showing a processing procedure performed by a processing device of the semiconductor characteristic measuring apparatus of FIG. 1A. [Figure 3B] 1B is a flowchart showing a processing procedure performed by a processing device of the semiconductor characteristic measuring apparatus of FIG. 1A. [Figure 4] FIG. 11 is a configuration diagram of a semiconductor characteristic measuring device according to a second embodiment. [Diagram 5] 5 is a diagram for explaining the operation principle of the semiconductor characteristic measuring apparatus of FIG. [Figure 6A] 5 is a flowchart showing a processing procedure performed by a processing device of the semiconductor characteristic measuring apparatus of FIG. [Figure 6B] 5 is a flowchart showing a processing procedure performed by a processing device of the semiconductor characteristic measuring apparatus of FIG. [Figure 7] 11 is a diagram for explaining the operation principle of a semiconductor characteristic measuring apparatus according to a third embodiment. FIG. [Figure 8A] 11 is a flowchart showing the operation of a processing device of the semiconductor characteristic measuring apparatus of the third embodiment. [Figure 8B] 11 is a flowchart showing the operation of a processing device of the semiconductor characteristic measuring apparatus of the third embodiment. [Figure 9] FIG. 11 is a configuration diagram of a semiconductor characteristic measuring device according to a fourth embodiment. [Figure 10] 10 is a diagram for explaining an example of the operation of the processing device in FIG. 9. [Figure 11A] 10 is a flowchart showing a processing procedure of a processing unit of the semiconductor characteristic measuring apparatus of FIG. [Figure 11B] 10 is a flowchart showing a processing procedure of a processing unit of the semiconductor characteristic measuring apparatus of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, each embodiment will be described in detail with reference to the drawings. Note that the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0013] Embodiment 1 [Configuration of semiconductor characteristic measurement equipment] 1A is a configuration diagram of a semiconductor characteristic measuring apparatus 101 according to embodiment 1. With reference to FIG 1A, semiconductor characteristic measuring apparatus 101 includes a first potential difference measuring apparatus 102, a second potential difference measuring apparatus 103, a storage device 104, and a processing device 105.

[0014] 1A further shows a semiconductor device 1 that is an object to be measured by the semiconductor characteristic measuring apparatus 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. Note that a power module 150 may be configured by the semiconductor device 1, a gate driver 8, the semiconductor characteristic measuring apparatus 101, and the like.

[0015] In the example of FIG. 1A, an IGBT (Insulated Gate Bipolar Transistor) is used as the power semiconductor element 2 built into the semiconductor device 1. In this case, the collector main 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 emitter main terminal 7 is connected to an emitter electrode E of the IGBT. A main current of the power semiconductor element 2 flows through the collector main terminal 4 and the emitter main terminal 7. The emitter reference terminal 6 is connected to the emitter electrode E, and is connected to a gate driver 8, which will be described later. A parasitic resistance component 3 exists in the wiring between the emitter main terminal 7 and the emitter electrode E of the IGBT.

[0016] A 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 and emitter electrodes of the IGBT.

[0017] In the present disclosure, more generally, the collector electrode may be referred to as the first main electrode, the emitter electrode as the second main electrode, and the gate electrode as the control electrode. The gate electrode is provided to control the main current flowing between the first main electrode and the second main electrode. Also, 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 the connection terminals 4 to 7. Each of the connection terminals 4 to 7 is connected to one of the first main electrode, the second main electrode, and the control electrode.

[0018] A first potential difference measuring device 102 of the semiconductor characteristic measuring apparatus 101 is connected to the collector main terminal 4 and the emitter reference terminal 6 of the semiconductor device 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. In the example of FIG. 1A, an IGBT is used as the power semiconductor element 2, so the first potential difference is expressed as V CE (i.e., collector-emitter voltage).

[0019] The second potential difference measuring device 103 is connected to the emitter reference terminal 6 and the emitter main terminal 7 of the semiconductor device 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. In the example of FIG. 1A, an IGBT is used as the power semiconductor element 2, so the second potential difference is V EE It is written as follows.

[0020] The storage device 104 stores data representing a first relationship between a first potential difference, a main current, and a junction temperature that has been measured or calculated in advance, and data representing a second relationship between a second potential difference, a main current, and a junction temperature that has been measured or calculated in advance. Hereinafter, the main current of the semiconductor device 1 will also be simply referred to as a current.

[0021] 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 the correlation data of the first relationship and the correlation data of the second relationship acquired 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 the collector current of the IGBT, and therefore is referred to as I C Since the temperature of the semiconductor device 1 is the junction temperature of the IGBT, T J It is written as follows.

[0022] The hardware configuration of the semiconductor characteristic measuring device 101 is not particularly limited. For example, the first potential difference measuring device 102 and the second potential difference measuring device 103 may be configured by an analog / 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. The processing device 105 may be configured based on a microcomputer including a CPU (Central Processing Unit) and a memory, may be configured by using an FPGA (Field Programmable Gate Array), or may be configured by a dedicated circuit. Alternatively, the processing device 105 may be configured by a combination of two or more of these.

[0023] Below, a modified example of the connection between the first potential difference measuring device 102 and the semiconductor device 1 will be further described with reference to FIGS. 1B and 1C.

[0024] 1B is a diagram showing a modified example of the semiconductor characteristic measuring apparatus 101 of FIG. 1A. As shown in FIG. 1B, a first potential difference measuring apparatus 102 may be connected between the collector main terminal 4 and the emitter main terminal 7 of the semiconductor device 1 and configured to measure the potential difference between the collector main terminal 4 and the emitter main terminal 7. The voltage drop due to the parasitic resistance component 3 is the collector-emitter voltage V CE Since the potential difference between the measured collector main terminal 4 and the emitter main terminal 7 is approximately one order of magnitude smaller than the first potential difference V CE Or, the second potential difference V between the emitter reference terminal 6 and the emitter main terminal 7 is calculated from the potential difference between the collector main terminal 4 and the emitter main terminal 7. EE The value obtained by subtracting CE It is also possible to use the following.

[0025] As another modified example, although not shown in FIGS. 1A and 1B, if a collector reference terminal 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 the potential difference between the collector reference terminal and the emitter reference terminal 6 as a first potential difference V CE However, since the current path from the collector electrode C to the collector main terminal 4 is a copper plate attached to the back surface (collector) of the semiconductor chip, the parasitic resistance component is extremely small and hardly causes an error. On the other hand, the emitter electrode E on the front surface of the semiconductor chip is connected to the emitter main terminal 7 by an aluminum wire, and therefore has a resistance component that cannot be ignored. For this reason, an emitter reference terminal 6 is provided for connecting the gate driver 8. It is preferable to connect the first potential difference measuring device 102 to the emitter reference terminal 6 as well in order to reduce errors.

[0026] Fig. 1C is a diagram showing yet another modified example of semiconductor characteristic measuring apparatus 101 of Fig. 1A. In semiconductor device 1 of Fig. 1C, emitter detection terminal 9 for connecting second potential difference measuring apparatus 103 is provided separately from emitter main terminal 7, and collector detection terminal 10 for connecting first potential difference measuring apparatus 102 is provided separately from collector main terminal 4. In this case, it is possible to prevent main current from flowing through the connection terminals to which first potential difference measuring apparatus 102 and second potential difference measuring apparatus 103 are connected.

[0027] Therefore, more generally, taking into consideration the above-mentioned modified examples, the first potential difference measuring device 102 measures a first potential difference based on a potential difference between two connection terminals (between the collector main terminal 4 or collector detection terminal 10 and the emitter reference terminal 6 or emitter main terminal 7) connected to a first main electrode and a second main electrode (one of which is the collector electrode C and the other is the emitter electrode E) among a plurality of connection terminals provided on the semiconductor device 1. The second potential difference measuring device 103 measures a second potential difference between a first connection terminal (emitter main terminal 7 or emitter detection terminal 9) connected to a current path of a main current to or from a second main electrode (emitter electrode E) among a plurality of connection terminals, and a second connection terminal (emitter reference terminal 6) connected to the second main electrode or connected to the current path at a position closer to the second main electrode (emitter electrode E) than the first connection terminal.

[0028] [Operation principle of semiconductor characteristic measuring device] Next, a description will be given of the operating principle of the semiconductor characteristic measuring apparatus 101 configured as above. Figure 2 is a diagram for explaining the operating principle of the semiconductor characteristic measuring apparatus 101 of Figure 1A.

[0029] 2, the first relationship and the second relationship stored in the storage device 104 of the semiconductor characteristic measuring device 101 are shown in the form of a graph. The first relationship is CE and current I C and temperature T J The second relationship is the second potential difference V EE and current I C and temperature T J This is the relationship between the two.

[0030] More specifically, in FIG. 2, the first relationship is expressed as three temperatures T J The first potential difference V according to CE and current I C The relationship between the first potential difference V CE is the horizontal axis and the current I C The vertical axis is traced by three thick lines. J are 25℃, 75℃, and 125℃. Temperature T JThe first potential difference V when CE and current I C The relationship between the temperature and the temperature T J The first potential difference V when CE and current I C The relationship between the temperature and the temperature T J The first potential difference V when CE and current I C The relationship is shown by a thick solid line.

[0031] Similarly, in Figure 2, the second relationship is J The second potential difference V EE and current I C The relationship between the second potential difference V EE is the horizontal axis and the current I C The vertical axis is traced by three thin lines. J are 25℃, 75℃, and 125℃. Temperature T J The second potential difference V when EE and current I C The relationship between the temperature T J The second potential difference V when EE and current I C The relationship between the temperature and the temperature T J The second potential difference V when EE and current I C The relationship between the first potential difference V CE Unlike the case of the second potential difference V EE In this case, the gain G is 10, i.e., the actual second potential difference V EE The reason for this is that the second potential difference V EE The value of the first potential difference V CE This is to make it easier to see on the graph, as it is about an order of magnitude smaller than the

[0032] As can be seen from Figure 2, the current I C and the first potential difference V CEThe relationship between the current and the voltage is nonlinear and is represented by a curve on a current-voltage graph. On the other hand, the current I C and the second potential difference V EE The relationship between the potential difference and the voltage is linear and is represented on a current-voltage graph as a straight line passing through the origin. This difference is the first potential difference V CE The mechanism by which the second potential difference V occurs EE This is because the mechanism by which

[0033] First potential difference V CE is the voltage between the main electrodes of a power semiconductor device, which corresponds to the voltage between the collector and emitter of an IGBT in this case. The collector-emitter voltage V CE is the collector current I C Specifically, the collector current I C When the collector-emitter voltage V CE is the collector current I C On the other hand, the collector current I C When is large, the collector-emitter voltage V CE is the collector current I C As a result, the IGBT can pass a large current with a relatively small on-state voltage and power loss. Because the IGBT itself has such a nonlinear characteristic, the current I C and the first potential difference V CE The relationship becomes nonlinear.

[0034] On the other hand, the second potential difference V EE reflects the voltage generated across the parasitic resistance 3 on the emitter side of the semiconductor device 1. The parasitic resistance 3 on the emitter side of the semiconductor device 1 is composed mainly of the resistance of the aluminum bonding wire. Therefore, the main current I C and the second potential difference V EE The relationship between is linear.

[0035] Regarding the temperature dependence, the first potential difference V CEIn the case of , above a certain threshold current, the higher the temperature, the higher the resistance between the collector and emitter. In other words, the higher the temperature, the higher the main current I C The first potential difference V CE On the other hand, below the threshold current, the higher the temperature, the lower the collector-emitter resistance. In other words, the higher the temperature, the higher the main current I C Compared to V CE This shows the characteristic that

[0036] On the other hand, the second potential difference V EE Regarding the temperature dependence of I, the higher the temperature, the higher the resistance between the emitter main terminal 7 and the emitter reference terminal 6. That is, the higher the temperature, the lower the main current I C The second potential difference V EE This characteristic reflects the temperature dependence of the electrical resistance of the aluminum material.

[0037] As described above, the first relationship and the second relationship have different characteristics in terms of linearity and temperature dependency. The semiconductor characteristic measuring apparatus 101 of the present embodiment utilizes these characteristics to simultaneously measure the current flowing through the semiconductor device and the temperature. Below, an overview of the operation of the processing device 105 of the semiconductor characteristic measuring apparatus 101 will be described with reference to FIG. 2.

[0038] As an example, the first measured potential difference V CE is 1.28 V, and the second measured potential difference V EE Suppose that 10 times (G=10) the value is 1.17 V. These values ​​are shown on the horizontal axis of Figure 2.

[0039] V on the horizontal axis of Figure 2 CE Draw a straight line (represented by a dashed line in Figure 2) parallel to the vertical axis from the point of I = 1.28 V, and compare this line with the thick curves that represent the first relationship (i.e., I C -V CE As a result, V CE = Current value I corresponding to 1.28V C However, the temperature T JSince is unknown, several current values ​​I C In Figure 2, the intersections with the thick curves for 25°C, 75°C, and 125°C are indicated by triangle, circle, and square markers, respectively.

[0040] Similarly, V on the horizontal axis of Fig. 2 EE Draw a straight line (represented by a solid line in Figure 2) parallel to the vertical axis from the point of ×10 = 1.17 V, and draw a line between this line and the group of thin lines that represent the second relationship (i.e., I C -V EE By finding the intersection with the characteristic EE Current I corresponding to ×10=1.17V C However, the temperature T J Since is unknown, several current values ​​I C In Figure 2, the intersections of the thin lines with the group of straight lines for 25°C, 75°C, and 125°C are indicated by triangles, circles, and squares, respectively.

[0041] In the above, the first potential difference V CE The measured value of the second potential difference V EE From the measured values ​​of C and temperature T J Here, the first potential difference V CE The current I obtained from C and temperature T J and the value of the second potential difference V EE The current I obtained from C and temperature T J The reason for this is that the collector current I C and junction temperature T J This is self-evident since we are measuring

[0042] Here, for example, T J = 25°C, the first potential difference V CE The current I obtained from C (corresponding to the triangle mark on the thick dashed line) and the second potential difference V EE The current I obtained from C(corresponding to the triangle mark on the thin dashed line). That is, the first potential difference V CE The triangle mark obtained from the second potential difference V EE This is higher than the triangle obtained from the current I C This contradicts the constraint that we are measuring the temperature T J It can be concluded that the assumption is incorrect.

[0043] Next, T J = 125°C, the first potential difference V CE The current I obtained from C (corresponding to the square mark on the thick solid line) and the second potential difference V EE The current I obtained from C (corresponding to the square mark on the thin solid line). That is, the first potential difference V CE The square mark obtained from the second potential difference V EE This is lower than the square obtained from the current I C This contradicts the constraint that we are measuring T J It can be concluded that the assumption of =125°C is incorrect.

[0044] Next, T J = 75°C, the first potential difference V CE The current I obtained from C (corresponding to the circle on the thick dashed line) and the second potential difference V EE The current I obtained from C (corresponding to the circle on the thin dashed double-dashed line). That is, the first potential difference V CE The circle and the second potential difference V obtained from EE This is the same height as the circle obtained from the I C Therefore, the temperature T J and current I C From Figure 2, T J = 75°C and I C = 560A.

[0045] [Specific processing contents in the processing device of the semiconductor characteristic measuring device] Next, the processing contents of the processing device 105 outlined above will be described in detail with reference to Figures 3A and 3B. Figures 3A and 3B are flow charts showing the processing procedure by the processing device 105 of the semiconductor characteristic measuring device 101 of Figure 1A.

[0046] In the first steps S101 and S102, the processing device 105 calculates a first potential difference V CE A measurement value of the second potential difference V is obtained from the first potential difference measuring device 102. EE The measured value of is obtained from the second potential difference measuring device 103. Note that steps S101 and S102 may be executed either first or simultaneously.

[0047] In the next steps S103 and S104, the processing device 105 detects the temperature T J The initial value of T J (0) is set to, for example, 25°C, and the temperature T J Step width ΔT J is set to 0.1° C. Note that steps S103 and S104 may be executed either first or simultaneously. Also, steps S103 and S104 may be executed before steps S101 and S102.

[0048] In the next step S105, the processing device 105 detects the temperature T J T J (0). This process is performed at temperature T J As a candidate value of the initial value T J This means that it is set to (0).

[0049] In the next step S106, the processing device 105 calculates a first potential difference V CE Based on the measured values ​​of I C -V CE From the characteristics, the first potential difference V CE Measurement value and temperature T J The current I corresponding to the candidate values ​​of C (V CE ,TJ This process determines the value of the specified temperature T J I in C -V CE From the characteristic curve, the first potential difference V CE Current I C This means reading the value of

[0050] In the next step S107, the processing device 105 determines the second potential difference V EE Based on the measured values ​​of I C -V EE From the characteristics, the second potential difference V EE and temperature T J The current I corresponding to the candidate values ​​of C (V EE ,T J This process determines the value of the specified temperature T J I in C -V EE From the characteristic line, the specified second potential difference V EE Current I C It should be noted that steps S106 and S107 may be executed either first or simultaneously.

[0051] In the next step S108, the processing device 105 calculates the difference between the two current values ​​determined in steps S106 and S107, I C (V CE ,T J )-I C (V EE ,T J ) and calculate the result as ΔI C Substitute for (0). ΔI C (0) is temperature T J While changing the candidate value of I C When the difference between the values ​​of the previously set temperature T J This means the difference in the current value calculated for the candidate value of

[0052] In the next step S109, the processing device 105 calculates the two current values ​​I CDifference ΔI C Determine whether (0) is equal to 0. ΔI C If (0)=0 (YES in step S109), the first potential difference V CE The current I calculated from C and the value of the second potential difference V EE The current I calculated from C Therefore, in the next step S121, the processing device 105 uses the current I C (V CE ,T J ) and outputs the current temperature T J The candidate value of is output and the process ends.

[0053] On the other hand, ΔI C If (0)=0 is not satisfied (NO in step S109), the processing device 105 advances the process to step S110. In step S110, the processing device 105 J Step width ΔT J The temperature T shifted by J +ΔT J At the new temperature T J In the case of FIG. 3A and FIG. 3B, the temperature T J Step width ΔT J is set to 0.1°C, so the temperature T J is the current temperature T J is updated to a value 0.1°C higher than the

[0054] In the next step S111, the processing device 105 calculates a first potential difference V CE Based on the measured value of J I in C -V CE From the characteristics, current I C (V CE ,T J This process determines the value of the updated temperature T J I in C -V CE From the characteristic curve, the first potential difference V CE Current IC This means to read out the

[0055] In the next step S112, the processing device 105 calculates a second potential difference V EE Based on the measured value of J I in C -V EE From the characteristics, current I C (V EE ,T J This process determines the value of the updated temperature T J I in C -V EE From the characteristic line, the specified second potential difference V EE Current I C It should be noted that steps S111 and S112 may be executed either first or simultaneously.

[0056] In the next step S113, the processing device 105 calculates the difference between the two current values ​​determined in steps S111 and S112, I C (V CE ,T J )-I C (V EE ,T J ) and calculate the result as ΔI C Substitute into (1). ΔI C (1) is the temperature T J While changing the candidate value of I C When the difference is calculated repeatedly, the temperature T J This means the difference in the current value calculated for the candidate value of

[0057] In the next step S114, the processing device 105 calculates the two current values ​​I C Difference ΔI C Determine whether (1) is equal to 0. ΔI C If (1)=0 (YES in step S114), the first potential difference V CE The current I calculated from C and the value of the second potential difference V EEThe current I calculated from C Therefore, in the next step S121, the processing device 105 sets the current I C (V CE ,T J ) as the temperature. J Then, the process ends.

[0058] On the other hand, ΔI C If (1)=0 is not satisfied (NO in step S114), the processing device 105 advances the process to step S115. In step S115, the processing device 105 J The current value I calculated for each candidate value C Difference ΔI C (0) and the temperature T J The current value I calculated for each candidate value C Difference ΔI C (1) and (ΔI C (0) / abs(ΔI C (0)))×(ΔI C (1) / abs(ΔI C (1)) is calculated and substituted into the first judgment value S. J The current value I calculated for each candidate value C Difference ΔI C (0) and the temperature T J The current value I calculated for each candidate value C Difference ΔI C If the sign of (1) is inverted, S = -1; if the sign is not inverted, S = 1.

[0059] To explain the calculation formula of the first judgment value S in a little more detail, abs(x) is a function that calculates the absolute value of x. ΔI C (0) / abs(ΔI C (0)) is ΔI C This means dividing the value of (0) by its absolute value, so the difference in the previous current value ΔI C If (0) is positive, it becomes 1, and if it is negative, it becomes -1. Similarly, ΔI C (1) / abs(ΔIC (1)) is the current difference ΔI C If (1) is positive, it becomes 1, if it is negative, it becomes -1. The product of these is substituted into S. Therefore, the difference in the previous current value ΔI C The difference between (0) and this current value ΔI C (1) When both and are 1 or -1, S = 1; when one is 1 and the other is -1, S = -1.

[0060] To summarize the above, the difference in current value ΔI C The positive and negative (i.e., sign) of the temperature T J If the current difference is inverted with respect to the set value, S=-1. C The sign of the previous temperature T J At the set value, the first potential difference V CE The current I calculated from C The second potential difference V EE The current I calculated from C Although the temperature T J The setting value was reversed, or the previous temperature T J At the set value, the first potential difference V CE I calculated from C The second potential difference V EE The current I calculated from C This time, the temperature T J This means that the setting value of temperature T J Step width ΔT J Just by shifting it I C The magnitude relationship between the temperature T J This means that the temperature T J = 25°C and temperature T J = 125℃ and the current difference ΔI C This can also be confirmed by the fact that the sign of is reversed. Here, the temperature T J Step width ΔT J If is a sufficiently small value, the temperature T J The candidate value of temperature T JIt can be considered to be the optimal value of

[0061] Therefore, in the next step S116, the processing device 105 judges whether or not the first judgment value S calculated in step S115 is equal to -1. If S=-1 (YES in step S116), the processing device 105 advances the process to step S121. In step S121, the processing device 105 calculates the current I C (V CE ,T J ) as the temperature. J Then, the process ends.

[0062] On the other hand, if S=-1 is not satisfied (NO in step S116), S=1. In this case, the current difference ΔI C is the previous temperature T J The set value and the current temperature T J In either case, the setting value is positive (ΔI C (0)>0 and ΔI C (1)>0), or the previous temperature T J The set value and the current temperature T J In all cases, the setting value is negative (ΔI C (0)<0 and ΔI C (1)<0). That is, the first potential difference V CE The current I calculated from C The second potential difference V EE The current I calculated from C or the first potential difference V CE The current I calculated from C The second potential difference V EE The current I calculated from C The temperature T J Since the temperature T J Further increase by ΔT J You just need to change it.

[0063] Here, the temperature T J It is necessary to determine whether the direction of change in the set value of is correct.J From the set value of the current temperature T J As a result of shifting the set value to the current value, ΔI C If is decreasing, the temperature T J It can be said that the temperature T J From the set value of the current temperature T J As a result of shifting the set value to the current value, ΔI C If is increasing, the temperature T J This means that the direction in which the setting value is changed is incorrect.

[0064] Therefore, in the next step S117, the processing device 105 J A second judgment value D is calculated to determine whether the direction of change of ΔI is correct. C (0) / abs(ΔI C (0)) and (ΔI C (0)-ΔI C (1)) / abs(ΔI C (0)-ΔI C (1)) is substituted.

[0065] First, ΔI C (0) / abs(ΔI C (0)) is the previous temperature T J The difference in current value at the set value ΔI C (0) sign. Next, ΔI C (0)-ΔI C (1) is the previous temperature T J The difference in current value at the set value ΔI C (0) and the current temperature T J The difference in current value at the set value ΔI C (1). Hereafter, this difference will be called the residual. (ΔI C (0)-ΔI C (1)) / abs(ΔI C (0)-ΔI C (1)) divides this residual by its absolute value, so when the sign of the residual is positive, it is 1, and when it is negative, it is -1.

[0066] When the residual sign is positive, ΔIC (0)>ΔI C (1), that is, the current temperature T J The difference in current value at the set value ΔI C (1) is the previous temperature T J The difference in current value at the set value ΔI C (0). Note that "small" here means small in value, not in absolute value. Therefore, the previous temperature T J The difference in current value at the set value ΔI C (0) and the current temperature T J The difference in current value at the set value ΔI C (1) When both are positive, the current difference ΔI C The absolute value of (1) is the difference in the previous current value ΔI C (0) is smaller than the absolute value of the previous temperature T J The difference in current value at the set value ΔI C (0) and the current temperature T J The difference in current value at the set value ΔI C (1) When both are negative, the current difference ΔI C The absolute value of (1) is the difference in the previous current value ΔI C Greater than the absolute value of (0).

[0067] On the other hand, when the residual sign is negative, ΔI C (0)<ΔI C (1), that is, the current temperature T J The difference in current value at the set value ΔI C (1) is the previous temperature T J The difference in current value at the set value ΔI C (0). Therefore, the previous temperature T J The difference in current value at the set value ΔI C (0) and the current temperature T J The difference in current value at the set value ΔI C (1) When both are positive, the current difference ΔI C The absolute value of (1) is the difference in the previous current value ΔI C (0) is greater than the absolute value of the previous temperature T J The difference in current value at the set value ΔI C(0) and the current temperature T J The difference in current value at the set value ΔI C (1) When both are negative, the current difference ΔI C The absolute value of (1) is the difference in the previous current value ΔI C Less than the absolute value of (0).

[0068] To summarize the above, the previous temperature T J The difference in current value at the set value ΔI C The sign of (0) and the residual (ΔI C (0)-ΔI C Since the product of the sign of (1)) and the sign of the second decision value D is substituted, the following four cases arise:

[0069] (i) Previous temperature T J The difference in current value at the set value ΔI C (0) is positive and the residual calculated this time is positive. In this case, both the previous and current temperature T J The current difference ΔI C is positive, and the temperature T J The difference in current value at the set value ΔI C The absolute value of (1) is the previous temperature T J The difference in current value at the set value ΔI C It is smaller than the absolute value of (0). In this case, the value of the second judgment value D is D=1×1=1.

[0070] (ii) Previous temperature T J The difference in current value at the set value ΔI C (0) is positive and the residual calculated this time is negative. In this case, both the previous and current temperature T J The current difference ΔI C is positive, and the temperature T J The difference in current value at the set value ΔI C The absolute value of (1) is the previous temperature T J The difference in current value at the set value ΔI C It is larger than the absolute value of (0). In this case, the value of the second judgment value D is D=1×−1=−1.

[0071] (iii) Previous temperature T J The difference in current value at the set value ΔI C (0) is negative and the residual calculated this time is positive. In this case, both the previous and current temperature T J The current difference ΔI C is negative, and the temperature T J The difference in current value at the set value ΔI C The absolute value of (1) is the previous temperature T J The difference in current value at the set value ΔI C It is larger than the absolute value of (0). In this case, the value of the second judgment value D is D = -1 x 1 = -1.

[0072] (iv) Previous temperature T J The difference in current value at the set value ΔI C (0) is negative and the residual calculated this time is negative. In this case, both the previous and current temperature T J The current difference ΔI C is negative, and the temperature T J The difference in current value at the set value ΔI C The absolute value of (1) is the previous temperature T J The difference in current value at the set value ΔI C It is smaller than the absolute value of (0). In this case, the value of the second judgment value D is D=-1×-1=1.

[0073] From the above, the current temperature T J The difference in current value at the set value ΔI C The absolute value of (1) is the previous temperature T J The difference in current value at the set value ΔI C If the absolute value of the temperature T is smaller than (0), D=1, otherwise D=-1. J If is updated in the correct direction, D=1, and the temperature T J If is updated in the wrong direction, D=-1.

[0074] Therefore, in the next step S118, the processing device 105 judges whether or not the second judgment value D is equal to 1. If D=1 (YES in step S118), the processing device 105 determines the temperature step width ΔT J On the other hand, if D=-1 (NO in step S118), the processor 105 changes the temperature step width ΔT J To invert the sign of -ΔT J ΔT J Assign to .

[0075] In the next step S120, the processing device 105 detects the current temperature T J The difference in current value at the set value ΔI C (1) is the previous temperature T J The difference in current value at the set value ΔI C (0) and the previous temperature T J The difference in current value at the set value ΔI C Then, the processing device 105 returns the process to step S110 and updates the value of the temperature T J Step width ΔT J Shift the temperature by T J +ΔT J Then, the process is repeated. By performing such an iterative calculation, the current difference ΔI C becomes 0 (YES in step S114), or the previous temperature T J The setting value of this temperature T J The difference in current value between the set value and C As a result, the current I C and temperature T J It is calculated (step S121).

[0076] In the above process flow, the temperature T set in step S103 J The initial value of T J (0), and the temperature change step width ΔT set in step S104 Jis an example and can be changed as necessary. For example, in order to reduce the number of calculations, J It is useful to set the initial value of near the expected temperature. Also, to improve the accuracy of the calculation, the step size of the temperature change ΔT J To reduce the number of calculations, the temperature change step width ΔT J It is also useful to increase the

[0077] Furthermore, the first relationship and the second relationship stored in the storage device 104 can be either detailed data or representative data, as necessary.

[0078] For example, detailed data, such as temperature T J If detailed data is recorded in 0.1°C increments over a wide temperature range, the data volume will increase, but the temperature T J Accurate current I C can be determined, improving measurement accuracy. J By making the step size of T larger and reducing the amount of data, the cost of the storage device 104 can be reduced. J The data for (corresponding to the trace in Figure 2) can be calculated by interpolation from the adjacent traces, and the interpolated trace is used to calculate the current I C The interpolation method can be selected appropriately, such as linear interpolation using only the two adjacent traces, or spline interpolation using three or more traces for more accurate interpolation.

[0079] First potential difference V CE and the second potential difference V EE The data interval can also be selected arbitrarily, taking into account the balance between memory capacity and accuracy. If traces are prepared with fine voltage intervals, the amount of data increases but the traces are accurate, while if traces are prepared with coarse voltage intervals and the data in between is calculated by interpolation, the amount of data can be reduced and memory capacity can be saved. In this case, the interpolation method can be freely selected from linear interpolation, spline interpolation, etc., taking into account the balance between calculation speed and accuracy.

[0080] By performing the calculation according to the procedure of Figures 3A and 3B as described above, the identified main current I C The estimated value of is output as the current information 106, and the specified temperature T J The estimated value of current is output as temperature information 107. The current information 106 and temperature information 107 are compared with specified values ​​stored in a separate memory, thereby making it possible to grasp the current operating state of the semiconductor device 1. As a result, the operating state of this semiconductor device 1 or a power conversion device such as an inverter using this semiconductor device 1 can be grasped, and system malfunctions due to malfunctions of the semiconductor device 1 or the power conversion device can be prevented in advance.

[0081] Although not shown in FIG. 1A, a terminal unit for extracting current information 106 and temperature information 107, and a judgment unit for judging the state of semiconductor device 1 or the power conversion apparatus based on the extracted current information 106 and temperature information 107 may be provided. The judgment unit can perform control according to the state of semiconductor device 1 or the power conversion apparatus by feeding back judgment information to gate driver 8. The hardware constituting the judgment unit may be configured based on a microcomputer including a CPU and memory, may be configured using an FPGA, or may be configured by a dedicated circuit. Alternatively, the judgment unit may be configured by a combination of two or more of these.

[0082] [Advantages of the first embodiment] As described above, according to the semiconductor characteristic measuring apparatus 101 of the first embodiment, the main current I can be easily measured by simply measuring the difference between the two potentials of the semiconductor device 1. C and temperature T J The current I of the semiconductor device 1 can be measured at the same time. A current sensor and a temperature sensor are not required, a sense cell is not required for the power semiconductor element 2, and complex and expensive devices such as a voltage control device, a gate voltage measurement device, or a switching speed measurement device are not required. This allows the current I C and temperature T JThis provides the remarkable effect of ensuring the soundness of the semiconductor device 1 at low cost.

[0083] Furthermore, the temperature T J and current I C If it is estimated that the voltage of each part of a power conversion device such as an inverter device using the semiconductor device 1 is J and current I C The soundness of the power conversion device can be easily confirmed by checking whether the measured value matches the value calculated from the estimated value of . In addition, since the soundness of the semiconductor device 1 can be easily confirmed, it is not necessary to manufacture a power conversion device with an unnecessarily large performance margin, which makes it possible to reduce costs.

[0084] Furthermore, semiconductor characteristic measuring apparatus 101 only measures the voltage between terminals of an existing apparatus that uses semiconductor device 1. Therefore, semiconductor characteristic measuring apparatus 101 can be incorporated not only into new apparatus, but also retrofitted to existing apparatus, and has the characteristic of being applicable in a wide range of applications.

[0085] Embodiment 2 In the first embodiment, an IGBT is used as the power semiconductor element 2 built into the semiconductor device 1. In the second embodiment, a case will be described in which a MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor) is used as the power semiconductor element 2A built into the semiconductor device 1A.

[0086] Fig. 4 is a configuration diagram of a semiconductor characteristic measuring apparatus 101 according to the embodiment 2. In Fig. 4, a semiconductor device 1A which is an object to be measured by the semiconductor characteristic measuring apparatus 101 is shown.

[0087] The semiconductor device 1A includes a MOSFET as a power semiconductor element 2A, a drain main terminal 4A, a gate terminal 5A, a source reference terminal 6A, and a source main terminal 7A. The drain main 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 source main terminal 7A is connected to a source electrode S of the MOSFET. A main current (i.e., a drain current I D ) flows. Although the source reference terminal 6A is connected to the source electrode S, no main current flows through the source reference terminal 6A. A parasitic resistance component 3A exists in the wiring 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.

[0088] The configuration of semiconductor characteristic measuring apparatus 101 in FIG. 4 is the same as that in FIG. 1A, so the same or corresponding parts are given the same reference characters and detailed description will not be repeated. However, since MOSFETs are used instead of IGBTs as power semiconductor elements, some names have been changed. Specifically, the collector of the IGBT is replaced with the drain of the MOSFET, and the emitter of the IGBT is replaced with the source of the MOSFET. Accordingly, the first potential difference V CE is V DS and the second potential difference V EE is V SS and the main current I C I D It is written as follows.

[0089] According to the above description, the first potential difference measuring device 102 of the semiconductor characteristic measuring device 101 of FIG. 4 measures the first potential difference V between the drain main terminal 4A and the source reference terminal 6A. DS The second potential difference measuring device 103 measures a second potential difference V between the source reference terminal 6A and the source main terminal 7A. SS The storage device 104 stores the first potential difference V DS and the main current I D and junction temperature T J and a previously measured or calculated second potential difference VSS and the main current I D and junction temperature T J The processing device 105 stores the second relationship between the measured first potential difference V DS and the second potential difference V SS and the first relationship and the second relationship stored in the memory device 104 are used to calculate the main current I D and temperature T J and outputting them as current information 106 and temperature information 107.

[0090] As described with reference to FIG. 1B, the first potential difference measuring device 102 may measure the potential difference between the drain main terminal 4A and the source main terminal 7A. In general, the first potential difference measuring device 102 measures a first potential difference V based on the potential difference between two connection terminals connected to the first main electrode and the second main electrode, respectively, among a plurality of connection terminals provided on the semiconductor device 1A. DS Measure.

[0091] 5 is a diagram for explaining the operation principle of the semiconductor characteristic measuring apparatus 101 of FIG. 4. In FIG. 5, the first relationship and the second relationship stored in the storage device 104 of the semiconductor characteristic measuring apparatus 101 are shown in graph form. The first relationship is DS and current I D and temperature T J The second relationship is the second potential difference V SS and current I D and temperature T J This is the relationship between the two.

[0092] As shown in Figure 5, the first relationship for the MOSFET is I D -V DS The characteristic trace is I C -V CE The reason for this is that the operating principle of MOSFETs is different from that of IGBTs. D -V SSThe characteristics reflect the electrical resistance of the aluminum bond wire, so the traces have the same linearity as IGBTs.

[0093] Since the first relationship and the second relationship are two types of relationships with different linearities, the main current I D and temperature T J The specific processing contents are the same as those in the processing contents of the first embodiment except that the collector is replaced with the drain and the emitter with the source. However, the current I D When the absolute value of is relatively small, exceptional processing is required. This exceptional processing will be described in the third embodiment.

[0094] As shown by way of example in FIG. 5, a first potential difference V DS The measured value of the second potential difference V SS Assume that the measured value (gain G=10) of the first potential difference V is 0.81 V. DS Current I calculated from D and the value of the second potential difference V SS Current I calculated from D The junction temperature T J is calculated as 75°C. Also, the matched current I D Since the value of is 550 A, the processing device 105 outputs 550 A as the current information 106 and 75° C. as the temperature information 107.

[0095] 6A and 6B are flow charts showing a processing procedure by the processing device 105 of the semiconductor characteristic measuring apparatus 101 of FIG.

[0096] The process steps in the flowcharts of Figures 6A and 6B are similar to those in the flowcharts of Figures 3A and 3B, and therefore detailed description will not be repeated. Steps S201 to S221 in Figures 6A and 6B correspond to steps S101 to S121 in Figures 3A and 3B, respectively. However, in Figures 6A and 6B, V in Figures 3A and 3B CE , V EE , I C V DS , V SS , I D can be read as follows:

[0097] As described above, the semiconductor characteristic measuring apparatus of the second embodiment, which is intended for a MOSFET, can also simply measure the main current I by simply measuring the two potential differences of the semiconductor device 1A, similarly to the semiconductor characteristic measuring apparatus of the first embodiment. D and temperature T J The current I of the semiconductor device 1A can be measured at the same time. A current sensor and a temperature sensor are not required, a sense cell is not required for the power semiconductor element 2A, and complex and expensive devices such as a voltage control device, a gate voltage measurement device, or a switching speed measurement device are not required. This allows the current I D and temperature T J This provides the remarkable effect of ensuring the soundness of the semiconductor device 1A at low cost.

[0098] Embodiment 3 When the power semiconductor element 2A built into the semiconductor device 1A is a MOSFET, the current I D In the range where the absolute value of is relatively small, I D -V DS The characteristic has a gentle nonlinearity close to a straight line passing through the origin, so I D -V SS This is similar to the linearity of the characteristic. J It becomes difficult to distinguish the temperature T J and current I D In the following, the estimation error may become large. This will be described with reference to FIG.

[0099] Fig. 7 is a diagram for explaining the operation principle of the semiconductor characteristic measuring apparatus according to the embodiment 3. In Fig. 7, the first relationship and the second relationship in the case of a MOSFET are shown in a graph, similarly to Fig. 5 .

[0100] As shown by way of example in FIG. 7, the first potential difference V DS The measured value of the second potential difference V SS Assume that the measured value (gain G=10) is 0.42 V. In this case, the temperature T J can be estimated to be 75°C, and the current I D However, even if the temperature deviates from the optimum temperature of 75°C, the first potential difference V DS The estimated current based on the measured value and the second potential difference V SS The difference between the estimated current and the measured current ΔI D Therefore, the temperature T J There is a risk of misestimating the temperature T J If the judgment is incorrect, the current I D The value of will also be judged incorrectly.

[0101] Therefore, the semiconductor characteristic measuring apparatus of the third embodiment uses the first potential difference V DS The first potential difference V DS The temperature is estimated only when the measured value of the first potential difference V is greater than or equal to a certain threshold. DS If is less than the threshold, the temperature T J The estimate of the temperature T J This process uses the current I D than the change in temperature T J This makes use of the fact that the change in current I D Even if is relatively small, the current I D and temperature T J It can be estimated that:

[0102] The first potential difference V DScan be determined in advance according to the accuracy of the processing device 105 to be used. For example, when the accuracy of the processing device 105 to be used is low, the first potential difference V DS can be set to a relatively large value, and the first potential difference V DS can be set to a relatively small value.

[0103] For example, as shown in Figure 7, the first potential difference V DS The measured value of temperature T is 0.26V. J The second potential difference V that shows the same current value when SS (G=10) is 0.42V. Temperature T J The difference in current value at 125℃ when the temperature is shifted upward by 50℃ is ΔI D and temperature T of 75°C J The current value I at 25°C, which is 50°C lower than the D Difference ΔI D Calculate the difference between these current values ​​ΔI D Whether or not 0.26 V should be set as the threshold value can be determined depending on whether this is acceptable compared to the accuracy of the processing unit 105.

[0104] Thus, the first potential difference V DS When the measured value is equal to or greater than a predetermined threshold, a temperature estimation and a current estimation are performed, and a first potential difference V DS Then the estimated temperature T J The error can be reduced by substituting the previous measured value.

[0105] Figures 8A and 8B are flowcharts showing the operation of the processing device of the semiconductor characteristic measuring apparatus of the embodiment 3. The flowcharts of Figures 8A and 8B are obtained by adding steps S2021, S2051, S2061, and S2062 to steps S201 to S221 in the flowcharts of Figures 6A and 6B. The added steps will be described below, and description of the same steps as steps S201 to S221 in Figures 6A and 6B (i.e., steps corresponding to steps S101 to S121 in Figures 3A and 3B) will not be repeated.

[0106] Step S2021 is executed before step S203. In step S2021, the processing device 105 detects the temperature T J The initial value of T J The processor 105 determines whether the temperature T J The initial value of T J If (0) is not set (Step S 2021 If the answer is YES in step S203, the initial value is set to, for example, 25°C.

[0107] On the other hand, the processing device 105 is J The initial value of T J If (0) is already set (step S 2021 If the answer is NO, the process advances to step S204 using the set initial value. J (0), the temperature T previously output in step S2062 described later J An estimate of has been set.

[0108] Step S2051 is executed simultaneously with or before or after steps S2021, S204, and S205. In step S2051, the processing device 105 calculates the first potential difference V DS Threshold V DST For example, 0.3V is set.

[0109] Step S2061 is executed after step S206. In step S2061, the processing device 105 calculates the first potential difference V DS is the threshold V DST Determine whether it is smaller than

[0110] The processing device 105 detects a first potential difference V DS is the threshold V DST If it is smaller than (step S 2061 In this case, the processor 105 determines whether the initial temperature T J and the first potential difference VDS The current I determined based on D The processing device 105 outputs the output temperature T J (i.e., the previous value) to the next initial value T J (0) is stored (S2062). In this way, the first potential difference V DS is the threshold V DST If it is smaller than the temperature T J By using the previous value without estimating it, the estimation error can be suppressed.

[0111] On the other hand, the processing device 105 detects a first potential difference V DS is the threshold V DST In the above case (step S 2061 In step S207, the process proceeds to step S207. The procedure after step S207 is the same as that in the second embodiment shown in FIG. 6A and FIG. 6B. In this way, the first potential difference V DS is the threshold V DST If the temperature T J and current I D A more accurate temperature T can be obtained by carrying out a processing procedure to estimate J and current I D It can output an estimate of

[0112] As described above, according to the semiconductor characteristic measuring apparatus of the third embodiment, the temperature T J and current I D When estimating the current I D Even if is relatively small, the error can be suppressed.

[0113] Embodiment 4 In the power semiconductor element 2 used in the semiconductor device 1, when the element is used for a long period of time, some of the bonding wires connected to the surface of the element 2 break or peel off. This causes the first potential difference V CE and the second potential difference V EE This can happen suddenly. Since this happens instantly, the first potential difference V CE and the second potential difference VEE The measured value of increases discontinuously, as if by a sudden jump. This increase in the measured value is irreversible.

[0114] In the fourth embodiment, a semiconductor characteristic measuring device capable of dealing with the above-mentioned cases is provided. Note that, although the following description will be based on the semiconductor characteristic measuring device of the first embodiment, the following technology can also be applied to the semiconductor characteristic measuring device for a MOSFET as in the second and third embodiments.

[0115] Fig. 9 is a configuration diagram of semiconductor characteristic measuring apparatus 101 according to embodiment 4. Semiconductor characteristic measuring apparatus 101 in Fig. 9 differs from semiconductor characteristic measuring apparatus 101 in Fig. 1A in that processing device 105 has a function of updating data stored in storage device 104.

[0116] Specifically, the processing device 105 detects the first potential difference V measured by the first potential difference measuring device 102. CE and the second potential difference V measured by the second potential difference measuring device 103 EE Then, the processing device 105 monitors the first potential difference V CE and the second potential difference V EE When suddenly increasing, the first potential difference V in the data representing the first relationship stored in the storage device 104 is increased by the increased magnification. CE and the second potential difference V in the data representing the second relationship EE Correct the following.

[0117] The first potential difference V is measured by the first potential difference measuring device 102 and the second potential difference measuring device 103. CE and the second potential difference V EE If we measure the voltage continuously at a high frequency, we can measure the magnitude of each jump. Because this voltage jump is instantaneous, we can assume that the temperature and current do not change before and after it.

[0118] FIG. 10 is a diagram for explaining an example of the operation of the processing device 105 in FIG. C -V CEThe characteristic is shown by the dashed line, and I C -V EE The characteristic is shown by a solid line. Also, the first potential difference V CE and the second potential difference V EE The characteristic before the jump occurs is shown by a thin line, and the updated characteristic after the jump occurs is shown by a thick line.

[0119] First potential difference V CE and the second potential difference V EE The jump in voltage is caused by the peeling or breaking of the bonding wire, so the first potential difference V CE and the second potential difference V EE However, the increase in the potential difference V CE and the second potential difference V EE There may be some differences between the two.

[0120] For example, the first potential difference V CE is 1.2 times the second potential difference V EE In this case, as shown in FIG. 10, the processing device 105 calculates the first potential difference V CE Similarly, the processing device 105 changes the value of the second potential difference V at the same temperature and the same current value for the data representing the second relationship stored in the storage device 104. EE Change the value to 1.5 times.

[0121] Figures 11A and 11B are flowcharts showing the processing procedure of processing device 105 of semiconductor characteristic measuring apparatus 101 of Figure 9. The flowchart of Figures 11A and 11B is obtained by adding steps S1021 to S1026, S1091, and S1092 to steps S101 to S121 in the flowchart of Figures 3A and 3B. The added steps will be described below, and description of the same steps as steps S101 to S121 in Figures 3A and 3B will not be repeated.

[0122] Steps S1021 to S1026 are executed after step S102. In steps S1021 and S1022, the processing device 105 calculates the first potential difference V CE Threshold magnification V CEX is set to, for example, 1.01, and the second potential difference V EE Threshold magnification V EEX is set to 1.02. Steps S1021 and S1022 may be executed simultaneously, or either may be executed first.

[0123] In the next step S1023, the processing device 105 determines the first potential difference V CE The previous measured value of V CE Determine whether or not the first potential difference V(0) has been set. CE The previous measured value of V CE (0) and the second potential difference V EE The previous measured value of V EE (0) is set in steps S1091 and S1092. CE The previous measured value of V CE If (0) has not been set (NO in step S1023), the processor 105 advances the process to step S103. After step S103, the processor 105 advances the same processes as those in Figs. 3A and 3B.

[0124] On the other hand, the first potential difference V CE The previous measured value of V CE If (0) has already been set (YES in step S1023), in the next step S1024, the processing device 105 CE The previous measured value of V CE The magnification for (0) is the threshold magnification V CEX , i.e., V CE >V CE (0) × V CEX Furthermore, the processor 105 determines whether the second potential difference V EE The previous measured value of V EE The magnification for (0) is the threshold magnification V EEX , i.e., V EE >VEE (0) × V EEX It is determined whether or not the following expression is true.

[0125] If at least one of the above is true (YES in step S1024), the processing device 105 advances the process to steps S1025 and S1026. In step S1025, the processing device 105 calculates the first potential difference V CE The value of is the observed magnification, V CE / V CE In step S1026, the processing device 105 changes the second potential difference V EE The value of is the observed magnification, V EE / V EE The processing unit 105 then changes the multiplication factor to (0). Either step S1025 or S1026 may be executed first, or they may be executed simultaneously. After that, the processing unit 105 advances the process to step S103.

[0126] On the other hand, if none of the determinations in step S1024 are true (NO in step S1024), the processor 105 advances the process to step S103 without updating the stored data in the memory device 104. After step S103, the processor 105 advances the same processes as those in FIGS. 3A and 3B.

[0127] As described above, according to the semiconductor characteristic measuring apparatus of the fourth embodiment, the I of the semiconductor device is not affected by the peeling or breaking of the bonding wire connected to the power semiconductor. C -V CE Characteristics and I C -V EE If the characteristics suddenly change, the data stored in the memory device 104 is updated to incorporate the change. Thus, the temperature T J and the main current I C Measurements can continue.

[0128] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of this application is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0129] 1,1A semiconductor device, 2,2A power semiconductor element, 3,3A parasitic resistance component, 4 collector main terminal, 4A drain main terminal, 5,5A gate terminal, 6 emitter reference terminal, 6A source reference terminal, 7 emitter main terminal, 7A source main terminal, 8 gate driver, 101 semiconductor characteristic measuring device, 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 magnification, V DST First potential difference V DS Threshold, V EE ,V SS Second potential difference.

Claims

1. 1. A semiconductor characteristic measuring apparatus for estimating a temperature of a semiconductor device and a main current flowing through the semiconductor device, comprising: The semiconductor device is 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; 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; The semiconductor characteristic measuring device includes: a first potential difference measuring device that measures a first potential difference based on a potential difference between two connection terminals among the plurality of connection terminals that are connected to the first main electrode and the second main electrode, respectively; a second potential difference measuring device that measures a second potential difference between a first connection terminal among the plurality of connection terminals that is connected to a current path of the main current to or from the second main electrode, and a second connection terminal that 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; a storage device that stores data representing a first relationship between the first potential difference, the temperature of the power semiconductor device, and the main current, and data representing a second relationship between the second potential difference, the temperature of the power semiconductor device, and the main current; a processing device; The processing device includes: obtaining a measurement of the first potential difference from the first potential difference measuring device; obtaining a measurement of the second potential difference from the second potential difference measuring device; identifying a temperature value of the power semiconductor element and a value of the main current corresponding to the measured value of the first potential difference from the data representing the first relationship; identifying a temperature value of the power semiconductor element and a value of the main current corresponding to the measured value of the second potential difference from data representing the second relationship; when a temperature value of the power semiconductor element and a value of the main current specified based on the measurement value of the first potential difference and a temperature value of the power semiconductor element and a value of the main current specified based on the measurement value of the second potential difference match each other, the semiconductor characteristic measuring device outputs the matched temperature value and the matched main current value as current estimated values.

2. The processing device includes: Set the temperature candidate value, identifying a value of the main current corresponding to the measured value of the first potential difference and the candidate value of the temperature from the data representing the first relationship; identifying a value of the main current corresponding to the measured value of the second potential difference and the candidate value of the temperature from data representing the second relationship; 2. The semiconductor characteristic measuring apparatus according to claim 1, wherein, when a value of the main current specified based on the measurement value of the first potential difference and the candidate value of the temperature and a value of the main current specified based on the measurement value of the second potential difference and the candidate value of the temperature match each other, the candidate value of the temperature and the matched value of the main current are output as current estimated values.

3. the processing device sequentially sets the candidate temperature values ​​by changing the candidate temperature values ​​by a step width from an initial value; The processing device includes: calculating a difference between the value of the main current identified from the data representing the first relationship and the value of the main current identified from the data representing the second relationship for each of the sequentially set candidate values ​​of the temperature; 3. The semiconductor characteristic measuring apparatus according to claim 2, wherein, when a sign of the difference value calculated for the previously set candidate temperature value is different from a sign of the difference value calculated for the currently set candidate temperature value, the currently set candidate temperature value and the corresponding main current value are output as current estimated values.

4. The processing device includes: Calculating a residual between the difference value calculated for the previously set candidate temperature value and the difference value calculated for the currently set candidate temperature value; 4. The semiconductor characteristic measuring device according to claim 3, wherein the sign of the step width is reversed when the sign of the difference value calculated for the previously set candidate temperature value is different from the sign of the calculated residual.

5. The power semiconductor element is a metal oxide semiconductor field effect transistor (MOSFET), The processing device includes: identifying, from the data representing the first relationship, a value of the main current corresponding to the previously outputted estimated value of the temperature of the power semiconductor device and the measured value of the first potential difference as a first current value; When the measured value of the first potential difference is equal to or less than a threshold value, the previously outputted estimated value of the temperature of the power semiconductor element and the first current value are output as current estimated values. A semiconductor characteristic measuring device according to any one of claims 1 to 4.

6. 6. The semiconductor characteristic measuring device according to claim 1, wherein, when the first potential difference currently measured has changed by a first threshold factor or more with respect to the first potential difference previously measured by the first potential difference measuring device, or when the second potential difference currently measured has changed by a second threshold factor or more with respect to the second potential difference previously measured by the second potential difference measuring device, the processing device corrects the value of the first potential difference in the data representing the first relationship and the value of the second potential difference in the data representing the second relationship by an observed factor.

7. 1. A semiconductor characteristic measuring method for estimating a temperature of a semiconductor device and a main current flowing through the semiconductor device, comprising: The semiconductor device is a power semiconductor element having a first main electrode, a second main electrode, and a control electrode for controlling a main current flowing between the first main electrode and the second main electrode; 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; The semiconductor characteristic measuring method includes: A processing device acquires a measurement value of a first potential difference based on a potential difference between two connection terminals among the plurality of connection terminals that are connected to the first main electrode and the second main electrode, respectively; the processing device acquiring a measurement of a second potential difference between a first connection terminal among the plurality of connection terminals connected to a current path of the main current to or from the second main electrode and a second connection terminal connected to the second main electrode or connected to the current path at a position closer to the second main electrode than the first connection terminal; a step of the processing device identifying a value of the temperature of the power semiconductor device and a value of the main current corresponding to a measured value of the first potential difference from data representing a first relationship between the first potential difference, the temperature of the power semiconductor device, and the main current stored in a storage device; a step of the processing device identifying a value of the temperature of the power semiconductor device and a value of the main current corresponding to a measured value of the second potential difference from data representing a second relationship between the second potential difference, the temperature of the power semiconductor device, and the main current stored in the storage device; and when a temperature value and a main current value of the power semiconductor element identified based on the measurement value of the first potential difference and a temperature value and a main current value of the power semiconductor element identified based on the measurement value of the second potential difference match each other, the processing device outputs the matched temperature value and the matched main current value as current estimated values.

8. The processing device further includes a step of setting a candidate value for temperature, the step of identifying 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 includes a step of identifying a value of the main current corresponding to the measured value of the first potential difference and a candidate value of the temperature from data representing the first relationship; the step of identifying 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 includes a step of identifying a value of the main current corresponding to the measured value of the second potential difference and a candidate value of the temperature from data representing the second relationship; 8. The semiconductor characteristic measuring method according to claim 7, wherein the step of outputting the matched temperature value and the matched main current value as current estimates includes the step of outputting the candidate value of temperature and the matched main current value as current estimates when the main current value specified based on the measurement value of the first potential difference and the candidate value of temperature and the main current value specified based on the measurement value of the second potential difference and the candidate value of temperature match each other.

9. the step of setting the candidate temperature value includes a step of sequentially setting the candidate temperature value by changing the candidate temperature value from an initial value by a step width; The semiconductor characteristic measuring method includes: a step of the processing device calculating, for each of the sequentially set candidate values ​​of the temperature, a difference between a value of the main current determined based on the measurement value of the first potential difference and the candidate value of the temperature and a value of the main current determined based on the measurement value of the second potential difference and the candidate value of the temperature; 9. The semiconductor characteristic measuring method according to claim 8, further comprising a step of: when a sign of the difference value calculated for the previously set candidate value of the temperature is different from a sign of the difference value calculated for the currently set candidate value of the temperature, outputting the currently set candidate value of the temperature and the corresponding value of the main current as current estimated values.

10. a step of the processing device calculating a residual which is a difference between the difference value calculated for the previously set candidate value of the temperature and the difference value calculated for the currently set candidate value of the temperature; 10. The semiconductor characteristic measuring method according to claim 9, further comprising a step in which the processing device inverts the sign of the step width when a sign of the difference value calculated for the previously set candidate temperature value is different from a sign of the calculated residual.

11. The power semiconductor element is a metal oxide semiconductor field effect transistor (MOSFET), the processing device specifying, from the data representing the first relationship, a value of the main current corresponding to the previously outputted estimated value of the temperature of the power semiconductor device and the measured value of the first potential difference as a first current value; When the measured value of the first potential difference is equal to or less than a threshold value, the method further comprises: outputting the previously outputted estimated value of the temperature of the power semiconductor element and the first current value as current estimated values.

12. The semiconductor characteristic measuring method according to any one of claims 7 to 11, further comprising a step in which, when the first potential difference measured currently changes from the first potential difference measured previously by a first threshold factor or more, or when the second potential difference measured currently changes from the second potential difference measured previously by a second threshold factor or more, the processing device corrects the value of the first potential difference in the data representing the first relationship and the value of the second potential difference in the data representing the second relationship by an observed factor.

13. A program for causing a computer to execute the semiconductor characteristic measuring method according to any one of claims 7 to 12.

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