Semiconductor device

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 including a plurality of power modules each including a power semiconductor switching element such as an IGBT and a drive circuit for driving the power semiconductor switching 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 use 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 executes protective actions such as issuing an alarm or stopping the operation of the device if the temperature exceeds a certain level.

[0003] Conventionally, a technology has been proposed for aggregating and detecting the temperatures of multiple power semiconductor switching elements. 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] JP 2000-134074 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, since 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 accurate selection of the IGBT with the highest temperature. In addition, there may be a discrepancy 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-mentioned conventional circumstances, and has an object to provide a semiconductor device that is configured using a plurality of power semiconductor switching elements and that is capable of accurately detecting and efficiently collecting the temperature of each power semiconductor switching element. [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 any 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 that outputs a first warning signal when a temperature abnormality is detected based on a detection voltage of the first temperature detection diode; a second protection circuit that outputs a second warning signal when a temperature abnormality is detected based on a detection voltage of the second temperature detection diode; an aggregation circuit that outputs a logical sum of at least the first warning signal and the second warning signal; 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 a forward voltage value of the temperature detection diode becomes equal to or lower 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 forward voltage value becomes equal to or lower than a second reference voltage value that is smaller than the first reference voltage value; A power module having the above structure is provided. 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 or not the forward voltage of the temperature detection diode mounted on the element exceeds a certain threshold voltage, and the determination result is output to the outside as a logical sum. Also, each of the power modules is provided with a switching means for permitting or prohibiting the output of the warning signal. This makes it possible to efficiently adjust the reference voltage for determining whether or not 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. With this, the temperature is detected accurately for each power module first, and the detection results are output as a logical sum, so that a warning signal based on accurate temperature detection can 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 in that they are 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] When 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 the aggregated signal to the outside. When the semiconductor device is a three-phase inverter, it is preferable to aggregate the warning signals of each phase and output the aggregated signal to the outside. Effect 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 efficiently collected as a semiconductor device. [Brief description of the drawings]

[0015] [Figure 1] 1 is a configuration diagram of a semiconductor device according to a first embodiment of the present invention. [Diagram 2] 2 is a timing chart for explaining the operation of FIG. 1; [Diagram 3] 2 is another embodiment of FIG. 1. [Figure 4] FIG. 11 is a configuration diagram of a semiconductor device according to a second embodiment of the present invention. [Diagram 5] FIG. 11 is a configuration diagram of a semiconductor device according to a third embodiment of the present invention. [Figure 6] FIG. 13 is a configuration diagram of a semiconductor device according to a fourth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 the present embodiment. As shown in this figure, 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 includes a temperature detection diode 12 within 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. A constant current is passed from the constant current source 24 to the temperature detection diode 12 of the IGBT 10 to detect the forward voltage (hereinafter referred to as the "detection voltage"). The detection voltage is input to the inverting input terminals of a comparator 22 and a comparator 23. The non-inverting input terminal of the comparator 22 is connected to a reference voltage source 25 that outputs a voltage of 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 of a reference voltage value Vref2. The reference voltage value Vref2 is set to a value smaller than the reference voltage value Vref1. It is preferable that the comparators 22 and 23 are hysteresis comparators.

[0019] The output of the comparator 22 of each drive circuit 20 of the multiple power modules 2 (2a to 2n) is connected to an input terminal of an aggregation circuit 3 consisting of an OR circuit. An external warning signal 44 is output from the output terminal of the aggregation circuit 3 as a calculation result of the OR condition of a warning signal 43 for calling attention to 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 executes a predetermined protection operation such as lowering the switching frequency or stopping the operation. An 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 has output the protection operation signal 42, and when the protection operation signal 42 is on (enabled state), the output of the output circuit 21 is forcibly turned off regardless of the drive signal 41. In this way, an overheat protection function can be realized 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 becomes equal to or lower than 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 Fig. 2. In the graphs shown in Fig. 2(a) to (d), the horizontal direction is the time axis. In the vertical direction, Fig. 2(a) shows the temperature change and the operation timing of comparators 22, 23, Fig. 2(b) shows the waveform of the output timing of protection operation signal (alarm) 42, Fig. 2(c) shows the waveform of warning signal 43, and Fig. 2(d) shows the output pulse waveform from the OUT terminal of drive circuit 21 of the power module.

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

[0024] Now, the temperature of the IGBT 10 of a certain power module 2 gradually rises, and at time t1, it exceeds the temperature warning level, i.e., when the detection voltage of the temperature detection diode 12 becomes equal to or lower than the reference voltage value Vref1, the output of the comparator 22 turns on and the output (warning output terminal) of the aggregation circuit 3 becomes high level. After that, the temperature of the IGBT 10 continues to rise, and at time t2, it exceeds the overheat protection level, i.e., when the detection voltage of the temperature detection diode 12 becomes equal to or lower than the reference voltage value Vref2, the output of the comparator 23 turns on and the protection operation signal 42 becomes enabled. An external circuit (not shown) detects that the protection operation signal 42 has become enabled and performs a protection operation. In the example of FIG. 2(d), the gate current of the IGBT 10 is cut off during the protection operation period to stop the operation. As a result, the temperature of the IGBT 10 starts to drop. Then, when the detection voltage value becomes larger than the reference voltage value Vref2 by the amount of hysteresis at time t3, 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 the IGBT 10, restarting on-off switching. After that, when the temperature further decreases and the detected voltage value becomes larger than the reference voltage value Vref1 by the amount of hysteresis at time t4, the output of the comparator 22 turns off, and as a result, the 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 abnormal due to overheating, while the processing for warning signals is simplified by collecting them, enabling efficient collection of temperature information as a semiconductor device.

[0026] (Other Examples) In Fig. 1, the aggregation circuit 3 is provided ahead of the warning signal 43 output from each power module 2 (2a to 2n). This aggregation circuit 3 can be mounted on a substrate 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 any 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 the warning signals are aggregated is important, but in the case of a semiconductor device 1 incorporating a single-phase inverter circuit, a power module constituting an upper arm and a power module constituting a 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 from the outside. 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 a 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 both ends of the reference voltage source 33 is a reference voltage value Vref3. Since the rest is the same as in Fig. 1, the same elements are given the same symbols and description will be omitted.

[0030] In the semiconductor device 1 having the above configuration, a forward voltage (detection voltage) of the temperature detection diode 12 built in 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 a voltage generated across the variable resistor is applied to the non-inverting input terminal of the comparator 22. This voltage value Vref1 becomes a reference voltage value for determining whether or not the comparator 22 outputs 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) becomes a reference voltage value for determining whether or not the power module 2 outputs 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. In general, there is variation between 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 becomes the reference voltage value Vref1, a warning signal 43 of that power module is output. Then, when the detected voltage value further decreases by Vref3 from the time of output of the warning signal, a protection operation signal 42 is output.

[0033] In the present embodiment, the reference voltage value Vref1 is configured to be adjustable for each power module 2. Therefore, in addition to the effect of the first embodiment, the present embodiment has the effect of reducing 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, thereby enabling the temperature of the IGBT to be detected with high accuracy.

[0034] It goes without saying that in this embodiment, the aggregation 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. The 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 operation signal 42, is adjustable. Fig. 5 is a configuration diagram of a semiconductor device 1 according to this embodiment. The main difference from Fig. 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 a reference potential (GND). The rest is the same as in Fig. 4, so the same elements are given the same symbols and their explanations are omitted.

[0036] According to this embodiment, not only the reference voltage value Vref1 serving as a reference for determining whether or not to output the warning signal 43, but also the reference voltage value Vref2 serving as a reference 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 for switching whether or not a warning signal 43 output from the power module is passed.

[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. Since the rest is the same as in Fig. 4, the same elements are given the same reference numerals and the description will be omitted.

[0040] In the semiconductor device 1 according to the present embodiment, when the reference voltage value Vref1 is adjusted by the variable resistor 32, in the switching circuit 4, only the switch of the power module to be adjusted is turned on, and the other switches are turned off. As a result, the external warning signal 44 output from the aggregation circuit 3 is only the warning signal of the power module to be adjusted, making the adjustment easier. Also, since each variable resistor 32 can be adjusted in a state where all the IGBTs are collectively brought to a predetermined temperature, the efficiency of the adjustment can be improved. After the adjustment of the variable resistor 32, all the switches 4a of the switching circuit 4 are turned on, so that the warning signals 43 of each power module are input to the aggregation circuit 3 in the operating state.

[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, 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 substrate constituting an inverter is housed in a housing to realize a semiconductor device, the switch of the switching circuit and the knob of the variable resistor (trimmer) 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 may be drawn out to the outside of the substrate so that the reference voltage values ​​of a plurality of 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 switching circuit 4 may be automatically performed 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 that outputs a first warning signal when a temperature abnormality is detected based on a detection voltage of the first temperature detection diode; a second protection circuit that outputs a second warning signal when a temperature abnormality is detected based on the detection voltage of the second temperature detection diode; an aggregation circuit that outputs a logical sum of at least the first warning signal and the second warning signal; A semiconductor device having:

2. The semiconductor device described in Claim 1, characterized in that it is configured to be able to allow or prohibit the output of the logical sum to the outside.

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