Semiconductor Devices

Abstract

To provide a semiconductor device composed using a plurality of power semiconductor switching elements for accurately detecting and efficiently collecting the temperature of each of the power semiconductor switching elements.SOLUTION: The semiconductor device includes: a first power semiconductor chip provided in any one phase among three phases and including a first temperature detection diode; a second power semiconductor chip provided in any other phase among the three phases and including a second temperature detection diode; a first protection circuit that outputs a first warning signal when detecting a temperature abnormality based on a detection voltage of the first temperature detection diode; a second protection circuit that outputs a second warning signal when detecting a temperature abnormality based on a detection voltage of the second temperature detection diode; and an aggregating circuit that outputs at least a logical sum of the first warning signal and the second warning signal.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a semiconductor device comprising a plurality of power modules each consisting of a power semiconductor switching element such as an IGBT and a drive circuit for driving the element, and more particularly to a semiconductor device having a temperature detection function and an overheat protection function for the power semiconductor switching element. [Background technology]

[0002] Generally, devices that operate using power semiconductor switching elements such as IGBTs are equipped with an overheat protection function. This function detects the temperature of the power semiconductor switching elements and, if it exceeds a certain temperature, issues an alarm or stops the operation of the device or takes other protective action.

[0003] Conventionally, technologies have been proposed for detecting the temperatures of multiple power semiconductor switching elements in an integrated manner. For example, in a semiconductor module incorporating a three-phase bridge circuit described in Patent Document 1, the voltage output from a temperature detection diode provided on each semiconductor element (IGBT) is amplified by an analog isolation amplifier and used as temperature information. Then, from the temperature information of each semiconductor element, the temperature information of the location with the highest temperature is selected, and a protective operation is performed when the temperature information exceeds a threshold value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-134074 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because there is variation in the output voltage and temperature of the temperature detection diode, the method of comparing values ​​obtained by amplifying the output voltage of the temperature detection diode as described in Patent Document 1 does not necessarily allow for accurate selection of the IGBT with the highest temperature. In addition, there is a possibility that a discrepancy occurs between the actual temperature of the selected IGBT and the temperature estimated based on the output voltage value of the temperature detection diode.

[0006] The present invention has been made in response to the above-described conventional circumstances, and has an object to provide a semiconductor device configured using a plurality of power semiconductor switching elements, which is capable of accurately detecting the temperature of each power semiconductor switching element and efficiently collecting the temperature. [Means for solving the problem]

[0007] In order to achieve the above object, the semiconductor device of the present invention comprises: a first power semiconductor chip provided in one of the three phases and including a first temperature detection diode; a second power semiconductor chip provided in any other one of the three phases and including a second temperature detection diode; When a temperature abnormality is detected based on the detection voltage of the first temperature detection diode, a first protection operation unit that outputs a first protection operation signal; and a first output unit that outputs a first signal related to temperature based on a detection voltage of the first temperature detection diode, separately from the first protection operation unit. a first protection circuit; When a temperature abnormality is detected based on the detection voltage of the second temperature detection diode, a second protection operation unit that outputs a second protection operation signal; and a second output unit that outputs a second signal related to temperature based on a detection voltage of the second temperature detection diode separately from the second protection operation unit. a second protection circuit; At least the above First signal and the above Second signal an aggregation circuit that outputs the logical sum of It has.

[0008] The semiconductor device of the present invention further comprises: a power semiconductor switching element having a temperature detection diode; a drive circuit including an output circuit for turning on and off the power semiconductor switching element, the drive circuit outputting a warning signal to call attention when the value of the forward voltage of the temperature detection diode becomes equal to or less than a first reference voltage value, and outputting a protection operation signal to stop the on and off operation of the power semiconductor switching element when the value of the forward voltage becomes equal to or less than a second reference voltage value that is smaller than the first reference voltage value; a plurality of power modules each having A semiconductor device that outputs an external warning signal as a logical sum of the warning signals of each power module, Each of the power modules is characterized by having a switching means for permitting or prohibiting the output of the warning signal.

[0009] In the present invention, for each power semiconductor switching element, it is determined whether the forward voltage of the temperature detection diode mounted on that element exceeds a certain threshold voltage, and the determination result is output to the outside as a logical sum. Furthermore, each power module is equipped with a switching means for permitting or prohibiting the output of the warning signal. This allows efficient adjustment of the reference voltage for determining whether to output a warning signal or a protection operation signal.

[0010] Preferably, the first reference voltage value and / or the second reference voltage value is adjustable, whereby temperature detection is performed accurately for each power module first, and then the detection results are output as a logical sum, thereby enabling a warning signal based on accurate temperature detection to be efficiently output to the outside.

[0011] The driving circuit of the semiconductor device according to the present invention is a first comparator that compares the forward voltage with the first reference voltage and outputs the warning signal; a second comparator that compares the forward voltage with the second reference voltage and outputs the protection operation signal; The first comparator and the second comparator are characterized by being hysteresis comparators.

[0012] By using a hysteresis comparator as the comparator, stable operation can be achieved without repeatedly generating and resetting overheat protection using warning and protection operation signals.

[0013] If the semiconductor device is a single-phase inverter, it is preferable to aggregate the warning signals of the upper arm power module and the lower arm power module and output them to the outside. If the semiconductor device is a three-phase inverter, it is also preferable to aggregate the warning signals of each phase and output them to the outside. [Effects of the Invention]

[0014] As described above, according to the present invention, the temperature of each semiconductor switching element can be detected with high accuracy, and temperature information can be collected efficiently as a semiconductor device. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a configuration diagram of a semiconductor device according to a first embodiment of the present invention; [Figure 2] 2 is a timing chart for explaining the operation of FIG. 1; [Figure 3] 1 is another embodiment of the present invention. [Figure 4] FIG. 10 is a configuration diagram of a semiconductor device according to a second embodiment of the present invention. [Figure 5] FIG. 10 is a configuration diagram of a semiconductor device according to a third embodiment of the present invention. [Figure 6] FIG. 10 is a configuration diagram of a semiconductor device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0016] A first embodiment of a semiconductor device according to the present invention will be described below with reference to the drawings.

[0017] FIG. 1 is a configuration diagram of a semiconductor device 1 according to this embodiment. As shown in this diagram, the semiconductor device 1 is composed of a plurality of power modules 2 (2a to 2n). Each power module 2 (2a to 2n) is composed of a power semiconductor switching element 10 such as an IGBT and a drive circuit 20. The power semiconductor switching element 10 is not limited to an IGBT, and may be a MOSFET or the like, but the following description will be given taking an IGBT as an example. The IGBT 10 in this embodiment has a temperature detection diode 12 inside the chip.

[0018] The drive circuit 20 includes an output circuit 21 that applies a voltage to the gate terminal of the IGBT 10 based on an input drive signal 41 to turn the IGBT 10 on and off. The drive circuit 20 also includes a constant current source 24. This constant current flows through the temperature detection diode 12 of the IGBT 10, detecting the forward voltage (hereinafter referred to as the "detection voltage"). This detection voltage is input to the inverting input terminals of comparators 22 and 23. The non-inverting input terminal of the comparator 22 is connected to a reference voltage source 25 that outputs a voltage having a reference voltage value Vref1, and the non-inverting input terminal of the comparator 23 is connected to a reference voltage source 26 that outputs a voltage having a reference voltage value Vref2. The reference voltage value Vref2 is set to a value smaller than the reference voltage value Vref1. These comparators 22 and 23 preferably use hysteresis comparators.

[0019] The output of the comparator 22 of each drive circuit 20 of the plurality of power modules 2 (2a to 2n) is connected to the input terminal of the aggregation circuit 3, which is made up of an OR circuit. From the output terminal of the aggregation circuit 3, an external warning signal 44 is output as the calculation result of the OR condition of warning signals 43 for warning about the temperature of each IGBT 10.

[0020] A protection operation signal 42 is output from the output terminal of the comparator 23 of each drive circuit 20. This protection operation signal 42 is input to an external circuit such as a PWM circuit (not shown). When the external circuit receives the protection operation signal 42, it performs a predetermined protection operation, such as lowering the switching frequency or stopping operation. One example of a simple protection method is to input the protection operation signal 42 to the output circuit 21 of the drive circuit 20 that output the protection operation signal 42, and when the protection operation signal 42 is on (enabled state), forcibly turn off the output of the output circuit 21 regardless of the drive signal 41. In this way, an overheat protection function can be achieved with a simple configuration.

[0021] The forward voltage of the temperature detection diode 12 is temperature dependent, and as the temperature increases, the value of the forward voltage decreases. Therefore, when the detection voltage value falls below the reference voltage value Vref1, the output of the comparator 22 turns on (high level), and the warning signal 43 turns on (enabled). This notifies the outside that the chip temperature of the IGBT 10 is approaching an abnormal level.

[0022] The operation of the power module having the above configuration when an abnormal temperature occurs will be explained using Figure 2. In the graphs shown in Figures 2(a) to (d), the horizontal axis is the time axis. On the vertical axis, Figure 2(a) shows the temperature change and the operation timing of comparators 22 and 23, Figure 2(b) shows the waveform of the output timing of protection operation signal (alarm) 42, Figure 2(c) shows the waveform of warning signal 43, and Figure 2(d) shows the output pulse waveform from the OUT terminal of power module drive circuit 21.

[0023] In the semiconductor device 1 having the above configuration, when the temperatures of all IGBTs 10 are below a predetermined value and all power modules 2 (2a to 2n) are operating normally, the value of the forward voltage (detection voltage) of the temperature detection diode 12 is greater than the reference voltage value Vref1, and therefore no warning signal 43 is output from any of the power modules 2 (2a to 2n). As a result, the external warning signal 44 output from the aggregation circuit 3 is turned off (disabled).

[0024] The temperature of the IGBT 10 in a power module 2 gradually rises and exceeds the temperature warning level at time t1. That is, when the voltage detected by the temperature detection diode 12 falls below the reference voltage Vref1, the output of the comparator 22 turns on, and the output (warning output terminal) of the integration circuit 3 goes high. The temperature of the IGBT 10 then continues to rise. At time t2, the temperature exceeds the overheat protection level. That is, when the voltage detected by the temperature detection diode 12 falls below the reference voltage Vref2, the output of the comparator 23 turns on, and the protection operation signal 42 is enabled. An external circuit (not shown) detects that the protection operation signal 42 has been enabled and performs protection operation. In the example shown in FIG. 2(d), the gate current of the IGBT 10 is cut off during the protection operation period, stopping operation. This causes the temperature of the IGBT 10 to begin to decrease. Then, at time t3, when the detected voltage exceeds the reference voltage Vref2 by the amount of hysteresis, the output of the comparator 23 turns off, and the protection operation signal 42 is reset. As a result, the external circuit (not shown) starts operating again, and a voltage pulse is again supplied to the gate terminal of IGBT 10, restarting on / off switching. After that, when the temperature drops further and the detected voltage value becomes larger than the reference voltage value Vref1 by the amount of hysteresis at time t4, the output of comparator 22 turns off, and as a result, warning signal 43 is reset.

[0025] As described above, according to this embodiment, a protection operation signal for overheat protection is output for each power module 2 (2a to 2n), while warning signals for external attention are collected and output by a collection circuit. This ensures that a protection operation is performed for a power module that has become abnormally overheated, while collecting warning signals simplifies processing, enabling efficient collection of temperature information as a semiconductor device.

[0026] (Other Examples) In Fig. 1, the aggregation circuit 3 is provided at the end of the warning signal 43 output from each power module 2 (2a to 2n). This aggregation circuit 3 can be mounted on a board separate from the power modules 2 (2a to 2n) and attached to the semiconductor device 1. Alternatively, as shown in Fig. 3, the aggregation circuit 3 may be provided in one of the power modules 2 (2a to 2n).

[0027] (Application example) Next, an application example of the present invention will be described. The unit in which warning signals are aggregated is important, but in the case of a semiconductor device 1 incorporating a single-phase inverter circuit, the power module constituting the upper arm and the power module constituting the lower arm are paired, and the warning signals 43 of each power module are ORed by the aggregation circuit 3, and the result can be output as an external warning signal 44.

[0028] When the semiconductor device 1 has a built-in three-phase inverter circuit, the warning signals of the power modules constituting each phase can be subjected to a logical OR operation by an aggregation circuit, and the result can be output as a warning signal 43.

[0029] Next, a second embodiment of the present invention will be described. In this embodiment, the reference voltage value Vref1 can be variably set externally. FIG. 4 is a configuration diagram of a semiconductor device 1 according to this embodiment. The main difference in configuration from FIG. 1 is that the output terminal of a constant current source 31 is connected to one terminal of a variable resistor 32 and the non-inverting input terminal of a comparator 22, and the other terminal of the variable resistor 32 is connected to a reference potential (GND). In addition, the output of the constant current source 31 is connected to the positive terminal of a reference voltage source 33, and the negative terminal of the reference voltage source 33 is connected to the non-inverting output terminal of the comparator 23. The voltage across the reference voltage source 33 is a reference voltage value Vref3. Since the rest of the configuration is the same as in FIG. 1, the same elements are designated by the same reference symbols and their description will be omitted.

[0030] In the semiconductor device 1 having the above configuration, the forward voltage (detection voltage) of the temperature detection diode 12 built into the IGBT 10 is applied to the inverting input terminals of the comparators 22 and 23. Meanwhile, a constant current flows from the constant current source 31 to the variable resistor 32, and the voltage generated across the variable resistor is applied to the non-inverting input terminal of the comparator 22. This voltage value Vref1 serves as a reference voltage value for determining whether or not the comparator 22 should output a warning signal based on the detection voltage of the temperature detection diode 12. Meanwhile, a reference voltage value (Vref1-Vref3) is applied to the non-inverting input terminal of the comparator 23. This reference voltage value (Vref1-Vref3) serves as a reference voltage value for determining whether or not the power module 2 should output a protection operation signal 42.

[0031] In the semiconductor device 1 according to this embodiment, the reference voltage value Vref1 when the comparator 22 turns on the warning signal 43 can be adjusted. Generally, there is a variation in the forward voltage value when a constant current flows through the temperature detection diode 12 and the temperature of the IGBT. Also, the detected voltage may differ for each phase. Therefore, when testing the semiconductor device 1, the IGBT 10 is turned on to pass a collector current, and based on the detected voltage value when the IGBT 10 reaches a certain temperature, the variable resistor 32 is adjusted so that the detected voltage value at the temperature when the warning signal is output becomes the reference voltage value Vref1.

[0032] In the semiconductor device 1 in which the reference voltage value is adjusted in this manner, when the detected voltage value of the IGBT 10 of a certain power module 2 reaches the reference voltage value Vref1, a warning signal 43 for that power module is output. Then, when the detected voltage value further drops by Vref3 from the time the warning signal was output, a protection operation signal 42 is output.

[0033] In this embodiment, the reference voltage value Vref1 is configured to be adjustable for each power module 2, and therefore, in addition to the effect of the first embodiment, there is an effect that the variation error between the forward voltage value when a constant current is passed through the temperature detection diode 12 and the temperature of the IGBT is reduced, thereby enabling the temperature of the IGBT to be detected with high accuracy.

[0034] It goes without saying that in this embodiment, the integrated circuit 3 can also be mounted on one power module as shown in FIG.

[0035] Next, a third embodiment of the present invention will be described. A feature of this embodiment is that not only the reference voltage value Vref1, which is the criterion for outputting a warning signal, but also the reference voltage value Vref2, which is the criterion for outputting a protection action signal 42, is adjustable. Figure 5 is a configuration diagram of a semiconductor device 1 according to this embodiment. The main difference from Figure 4 is that a constant current source 34 and a variable resistor 35 are newly provided, the output of the constant current source 34 is connected to one end of the variable resistor 35 and the non-inverting input terminal of the comparator 23, and the other end of the variable resistor 35 is connected to the reference potential (GND). As the rest is the same as in Figure 4, the same elements are assigned the same reference numerals and their description will be omitted.

[0036] According to this embodiment, not only the reference voltage value Vref1, which is the basis for determining whether or not to output the warning signal 43, but also the reference voltage value Vref2, which is the basis for determining whether or not the power module 2 outputs the protection operation signal 42, can be adjusted independently.

[0037] According to this embodiment, in addition to the effects of the first and second embodiments, it is possible to detect the temperature with high accuracy even when outputting a protection action signal.

[0038] Next, a fourth embodiment of the present invention will be described. The feature of this embodiment is that, as shown in FIG. 6, a switching circuit 4 is provided between each power module and the aggregation circuit 3 to switch whether or not to pass a warning signal 43 output from the power module.

[0039] This switching circuit 4 includes a switch 4a for manually permitting / prohibiting passage of each warning signal 43, and a pull-down resistor 4b on the input side of the aggregation circuit (OR circuit) 3. As the rest is the same as in Figure 4, the same elements are given the same reference numerals and their explanations are omitted.

[0040] In the semiconductor device 1 according to this embodiment, when adjusting the reference voltage value Vref1 using the variable resistor 32, only the switch of the power module to be adjusted in the switching circuit 4 is turned on, and the other switches are turned off. This makes the adjustment easier because the external warning signal 44 output from the aggregation circuit 3 is only the warning signal of the power module to be adjusted. Also, since each variable resistor 32 can be adjusted while all IGBTs are collectively brought to a predetermined temperature, the adjustment can be made more efficient. After adjusting the variable resistor 32, all switches 4a of the switching circuit 4 are turned on, so that warning signals 43 of each power module are input to the aggregation circuit 3 during operation.

[0041] The switching circuit 4 may be provided in a configuration in which an aggregation circuit is provided in a drive circuit of a power module as in FIG. 3, or in a configuration in which the two reference voltage values ​​Vref1 and Vref2 in FIG. 5 are adjustable.

[0042] As described above, according to this embodiment, in addition to the effects of the first to third embodiments, it is possible to improve the efficiency when adjusting the reference voltage value. In a configuration in which a semiconductor device is realized by housing a substrate that constitutes an inverter inside a housing, the switches of the switching circuit and the knobs of the variable resistors (trimmers) for adjusting the reference voltage value may be provided at the end of the substrate so that they can be operated while the substrate is mounted, or they may be drawn out to the outside of the substrate so that the reference voltage values ​​of multiple power modules can be adjusted collectively.

[0043] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, the switching of the switch of the switching circuit 4 may be automatically switched by a command from a computer depending on the mode, such as the adjustment mode or the operation mode. [Explanation of symbols]

[0044] 1. Semiconductor device 2(2a-2n) Power Module 3 Aggregation Circuit 4 Switching circuit 4a switch 4b Pull-down resistor 10 Power semiconductor switching element 12 Temperature detection diode 20 Drive circuit 21 Output circuit 22,23 Comparator (hysteresis comparator) 24,31,34 constant current source 25, 26, 33 Reference voltage source 32,35 variable resistor 41 Drive signal 42 Protection operation signal 43 Warning Signal 44 External warning signal

Claims

1. a first power semiconductor chip provided in one of the three phases and including a first temperature detection diode; a second power semiconductor chip provided in any other one of the three phases and including a second temperature detection diode; a first protection circuit including: a first protection operation unit that outputs a first protection operation signal when a temperature abnormality is detected based on the detection voltage of the first temperature detection diode; and a first output unit that outputs a first signal related to temperature based on the detection voltage of the first temperature detection diode, separately from the first protection operation unit; a second protection circuit including a second protection operation unit that outputs a second protection operation signal when a temperature abnormality is detected based on the detection voltage of the second temperature detection diode, and a second output unit that outputs a second signal related to temperature based on the detection voltage of the second temperature detection diode separately from the second protection operation unit; an aggregation circuit that outputs a logical sum of at least the first signal and the second signal; A semiconductor device having:

2. At a temperature at which the first protection operation signal and the second protection operation signal are output, the first signal and the second signal are output. The semiconductor device according to claim 1 .

3. The threshold voltage at which the first protection operation signal and the second protection operation signal are output is smaller than the threshold voltage at which the first signal and the second signal are output.

3. The semiconductor device according to claim 1.

4. The first signal is a first warning signal, and the second signal is a second warning signal. The semiconductor device according to claim 1 .

5. The aggregation circuit outputs an external warning signal that alerts the outside. The semiconductor device according to claim 1 .

6. The semiconductor device is an inverter equipped with a power module, The external warning signal is a signal that calls attention to the outside of the inverter. The semiconductor device according to claim 5 .

7. The power module includes a drive circuit. The semiconductor device according to claim 6.

8. The external warning signal is output by the aggregation circuit aggregating the signals from the plurality of power modules into one.

8. The semiconductor device according to claim 6.

9. The first protection operation signal and the second protection operation signal are output for each of the power modules. The semiconductor device according to claim 6 .

10. The integrated circuit is provided on a substrate outside the power module. The semiconductor device according to claim 6 .

11. When the first protection operation signal or the second protection operation signal is output, the gate current of the first power semiconductor chip or the second power semiconductor chip is cut off. The semiconductor device according to claim 1 .

12. When the first protection operation signal or the second protection operation signal is output, a switching frequency of the semiconductor device is reduced. The semiconductor device according to claim 1 .

13. The output of the logical sum to the outside can be permitted or prohibited. The semiconductor device according to claim 1 .

14. A first power semiconductor chip provided in any one of three phases and including a first temperature detection diode; a second power semiconductor chip provided in any other one of the three phases and including a second temperature detection diode; a third power semiconductor chip provided in the remaining phase of the three phases and including a third temperature detection diode; a first protection circuit including: a first protection operation unit that outputs a first protection operation signal when a temperature abnormality is detected based on the detection voltage of the first temperature detection diode; and a first output unit that outputs a first signal related to temperature based on the detection voltage of the first temperature detection diode, separately from the first protection operation unit; a second protection circuit including a second protection operation unit that outputs a second protection operation signal when a temperature abnormality is detected based on the detection voltage of the second temperature detection diode, and a second output unit that outputs a second signal related to temperature based on the detection voltage of the second temperature detection diode separately from the second protection operation unit; a third protection circuit including a third protection operation unit that outputs a third protection operation signal when a temperature abnormality is detected based on the detection voltage of the third temperature detection diode, and a third output unit that outputs a third signal related to temperature based on the detection voltage of the third temperature detection diode separately from the third protection operation unit; an aggregation circuit that outputs a logical sum of the first signal, the second signal, and the third signal; A semiconductor device having:

15. The semiconductor device is a three-phase inverter, the first signal, the second signal, and the third signal are warning signals, The aggregation circuit aggregates warning signals of the phases constituting the three-phase inverter and outputs the aggregated signals to the outside. The semiconductor device according to claim 14.

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