Semiconductor device and method for driving semiconductor device

Abstract

Provided is a semiconductor device that makes it possible to suppress loss while controlling a jump-up voltage at turn-off and turn-on under all conditions for an output electric current and a temperature within a use range.　The semiconductor device comprises an IGBT and a driving circuit that drives a gate of the IGBT. The driving circuit includes four MOSFETs and four resistors constituting a bridge circuit, a driver for driving each of the four MOSFETs, an electric current detection circuit for detecting an output electric current of the IGBT, a temperature detection circuit for detecting the temperature of the IGBT, and a determination circuit for controlling driving of the driver on the basis of detection values from the electric current detection circuit and the temperature detection circuit. When the output electric current detected by the electric current detection circuit is greater than a prescribed electric current threshold value, the determination circuit increases an OFF gate resistance of the IGBT. When the temperature detected by the temperature detection circuit is lower than a prescribed temperature threshold value, the determination circuit increases an ON gate resistance of the IGBT.

Description

Semiconductor device and method for driving the same

[0001] The present invention relates to a semiconductor device configuration and a driving method thereof, and in particular to a technique that is effective when applied to an IGBT.

[0002] IGBTs (Insulated Gate Bipolar Transistors), which are capable of high-power, high-speed switching, are widely used in a wide range of applications, from industrial to consumer, and even automotive applications, including motor control inverters for electric vehicles and trains, and inverter circuits for induction cookware, washing machines, and air conditioners.

[0003] Since a jump voltage occurs when an IGBT is turned off or on (during recovery of the arm diode), it is necessary to adjust the gate resistance during turn-off drive and turn-on drive so that the jump voltage does not exceed the device's withstand voltage under all conditions of output current and temperature within the operating range.

[0004] As background art in this technical field, for example, there is a technique such as that described in Patent Document 1. Patent Document 1 discloses "a gate drive circuit and a power conversion device capable of sufficiently suppressing noise and switching loss occurring in a semiconductor element."

[0005] International Publication No. 2022 / 244361

[0006] As described above, in an IGBT, in order to suppress the jump voltage when turning off or on, it is necessary to adjust the gate resistance when turning off or on. However, if the gate resistance is made excessively large, there is a concern that loss will increase.

[0007] In the above-mentioned Patent Document 1, as shown in FIG. 6 thereof, in order to reduce the jump voltage of the diode during small current recovery, the gate resistance (on side) is increased (7a) when the current and temperature reach a certain range of values, thereby suppressing the jump voltage during recovery, and a low gate resistance (7b) is used in other cases, thereby reducing losses.

[0008] However, in an IGBT, a jump voltage occurs not only when it is turned on (recovery) but also when it is turned off, but Patent Document 1 only considers the recovery period, which is an insufficient consideration.

[0009] To reduce the jump voltage at turn-off, it is necessary to increase the gate resistance at turn-off, but this has not been considered, and there is room for improvement.

[0010] Therefore, an object of the present invention is to provide a semiconductor device and a method for driving the semiconductor device that can suppress losses while controlling the jump voltage at turn-off and turn-on under all conditions of output current and temperature within the operating range.

[0011] In order to solve the above problems, the present invention provides an IGBT and a drive circuit that drives the gate of the IGBT, wherein the drive circuit has four MOSFETs and four resistors that form a bridge circuit, a driver that drives each of the four MOSFETs, a current detection circuit that detects the output current of the IGBT, a temperature detection circuit that detects the temperature of the IGBT, and a judgment circuit that controls the drive of the driver based on the detection values ​​of the current detection circuit and the temperature detection circuit, and wherein the judgment circuit increases the off-gate resistance of the IGBT when the output current detected by the current detection circuit is greater than a predetermined current threshold, and increases the on-gate resistance of the IGBT when the temperature detected by the temperature detection circuit is lower than the predetermined temperature threshold.

[0012] The present invention also includes the steps of (a) a current detection circuit detecting an output current of an IGBT, (b) a judgment circuit comparing the output current detected in step (a) with a predetermined current threshold value, (c) a temperature detection circuit detecting a temperature of the IGBT, and (d) a judgment circuit comparing the temperature detected in step (c) with a predetermined temperature threshold value, wherein the judgment circuit increases the OFF gate resistance of the IGBT when the output current detected by the current detection circuit is greater than the predetermined current threshold value, and increases the ON gate resistance of the IGBT when the temperature detected by the temperature detection circuit is lower than the predetermined temperature threshold value.

[0013] According to the present invention, it is possible to realize a semiconductor device and a method for driving the semiconductor device that are capable of suppressing losses while controlling jump voltages at turn-off and turn-on under all conditions of output current and temperature within the range of use.

[0014] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments.

[0015] FIG. 1 is a diagram schematically showing the output current and temperature dependency of a semiconductor device according to a first embodiment of the present invention; FIG. 2 is a diagram showing the relationship between the output current and temperature and the gate resistance of a semiconductor device according to a first embodiment of the present invention; FIG. 3 is a diagram showing the output current and temperature dependency of a jump voltage after adjusting the gate resistance; FIG. 4 is a diagram showing a schematic configuration of a semiconductor device according to a first embodiment of the present invention; FIG. 5 is a flowchart showing a method for driving a semiconductor device according to a first embodiment of the present invention; FIG. 6 is a flowchart showing a method for driving a semiconductor device according to a second embodiment of the present invention; and FIG. 7 is a flowchart showing a method for driving a semiconductor device according to a third embodiment of the present invention.

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same components are designated by the same reference numerals, and detailed description of overlapping parts will be omitted.

[0017] A semiconductor device and a method for driving the same according to a first embodiment of the present invention will be described with reference to FIGS.

[0018] First, the basic concept of the present invention will be explained with reference to FIGS.

[0019] Fig. 1 is a diagram showing the output current and temperature dependency of a semiconductor device according to the present invention, Fig. 2 is a diagram showing the relationship between the output current and temperature of a semiconductor device according to the present invention and the gate resistance, and Fig. 3 is a diagram showing the output current and temperature dependency of a jump voltage after adjusting the gate resistance.

[0020] FIG. 1 shows the output current (Ic) dependency and temperature (Tc) dependency of the jump voltage when the IGBT is turned off and when the paired arm diode is recovered (when the IGBT is turned on).

[0021] As shown in FIG. 1, the jump voltage at the time of turning off the IGBT increases as the output current increases, but the jump voltage has little dependency on temperature.

[0022] On the other hand, the jump voltage when the IGBT is turned on (during recovery) has little dependency on the output current, and the jump voltage decreases as the temperature increases.

[0023] As described above, by sensing the output current and temperature of the IGBT and setting a current threshold (Ic) and a temperature threshold (Tc) for switching the gate resistance for each current and temperature, and switching the gate resistance Rg(on) and Rg(off) as shown in FIG. 2, it is possible to use a smaller gate resistance while suppressing the jump voltage as shown in FIG. 3, thereby achieving low loss.

[0024] In other words, in the present invention, the gate resistance Rg(on) when on and the gate resistance Rg(off) when off are switched according to the output current and temperature conditions so as to control the jump voltage while reducing losses under all conditions of output current and temperature within the IGBT usage range.

[0025] A specific example of a circuit configuration and a driving method for realizing the above-described present invention will be described with reference to FIGS.

[0026] Fig. 4 is a diagram showing a schematic configuration of the semiconductor device 1 of this embodiment, and Fig. 5 is a flowchart showing a method for driving the semiconductor device 1 of Fig. 4.

[0027] 4, the semiconductor device 1 of this embodiment mainly comprises an IGBT 3 and a drive circuit 2 that drives the gate of the IGBT 3. The IGBT 3 and the drive circuit 2 may be mounted on the same semiconductor chip, or the IGBT 3 and the drive circuit 2 may be mounted on separate semiconductor chips.

[0028] The drive circuit 2 includes four MOSFETs 4 to 7 and four resistors 8 to 11 that form a bridge circuit, a driver 12 that drives each of the four MOSFETs 4 to 7, a current detection circuit 14 that detects the output current of the IGBT 3, a temperature detection circuit 15 that detects the temperature of the IGBT 3, and a determination circuit 13 that controls the drive of the driver 12 based on the detection values ​​of the current detection circuit 14 and the temperature detection circuit 15.

[0029] The IGBT 3 has a main IGBT 16, a sense IGBT 17 for detecting current connected in parallel with the main IGBT 16, a temperature sense diode 18 for detecting temperature, and a resistor 19 for detecting current.

[0030] The main IGBT 16 is connected between the terminals of the collector 20 and the emitter 21. One end of the sense IGBT 17 is connected to the terminal of the collector 20, and the other end is connected to the terminal of the sense emitter 22 via a current detection resistor 19. The temperature sense diode 18 is built into the IGBT 3 and is connected between the terminals of the anode 23 and the cathode 24.

[0031] In the semiconductor device 1 of this embodiment, when the output current detected by the current detection circuit 14 is larger than a predetermined current threshold, the judgment circuit 13 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance of the IGBT 3 (main IGBT 16) is increased when it is off, and when the temperature detected by the temperature detection circuit 15 is lower than a predetermined temperature threshold, the judgment circuit 13 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance of the IGBT 3 (main IGBT 16) is increased when it is on.

[0032] The above driving method is shown in the flowchart of FIG.

[0033] First, when the process starts (step S1), in step S2, the current detection circuit 14 detects the output current (I) of the IGBT 3 (main IGBT 16). In parallel with step S2, in step S3, the temperature detection circuit 15 detects the temperature (T) of the IGBT 3 (main IGBT 16).

[0034] Next, in step S4, the determination circuit 13 compares the output current (I) detected by the current detection circuit 14 with a preset current threshold value (Ic).

[0035] If the output current (I) is smaller than the predetermined current threshold (Ic) (No), the process proceeds to step S6, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(off) when off is small. On the other hand, if the output current (I) is equal to or greater than the predetermined current threshold (Ic) (Yes), the process proceeds to step S7, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(off) when off is large.

[0036] In parallel with step S4, in step S5, the determination circuit 13 compares the temperature (T) detected by the temperature detection circuit 15 with a preset temperature threshold value (Tc).

[0037] If the temperature (T) is equal to or higher than the predetermined temperature threshold (Tc) (Yes), the process proceeds to step S8, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(on) when on is small. On the other hand, if the temperature (T) is lower than the predetermined temperature threshold (Tc) (No), the process proceeds to step S9, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(on) when on is large.

[0038] After any one of steps S6 to S9 is completed, the process ends (step S10), and the process returns to step S1 to continue the process.

[0039] Second Embodiment A method for driving a semiconductor device according to a second embodiment of the present invention will be described with reference to FIG.

[0040] In the first embodiment (FIG. 5), an embodiment was described in which control of gate resistance Rg(off) by current detection and control of gate resistance Rg(on) by temperature detection were performed in parallel. In the present embodiment (FIG. 6), an embodiment will be described in which control of gate resistance Rg(off) by current detection is performed first, and then control of gate resistance Rg(on) by temperature detection is performed.

[0041] First, when the process starts (step S1), the current detection circuit 14 detects the output current (I) of the IGBT 3 (main IGBT 16) in step S2.

[0042] Next, in step S3, the determination circuit 13 compares the output current (I) detected by the current detection circuit 14 with a preset current threshold value (Ic).

[0043] If the output current (I) is smaller than the predetermined current threshold (Ic) (No), the process proceeds to step S4, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(off) when off is small. On the other hand, if the output current (I) is equal to or greater than the predetermined current threshold (Ic) (Yes), the process proceeds to step S5, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(off) when off is large.

[0044] Next, in step S6, the temperature detection circuit 15 detects the temperature (T) of the IGBT 3 (main IGBT 16).

[0045] Next, in step S7, the determination circuit 13 compares the temperature (T) detected by the temperature detection circuit 15 with a preset temperature threshold value (Tc).

[0046] If the temperature (T) is equal to or higher than the predetermined temperature threshold (Tc) (Yes), the process proceeds to step S8, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(on) when on is small. On the other hand, if the temperature (T) is lower than the predetermined temperature threshold (Tc) (No), the process proceeds to step S9, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(on) when on is large.

[0047] After either step S8 or step S9 is completed, the process ends (step S10), and the process returns to step S1 to continue the process.

[0048] Third Embodiment A method for driving a semiconductor device according to a third embodiment of the present invention will be described with reference to FIG.

[0049] In the first embodiment (FIG. 5), an embodiment was described in which control of gate resistance Rg(off) by current detection and control of gate resistance Rg(on) by temperature detection were performed in parallel. In the present embodiment (FIG. 7), an embodiment will be described in which control of gate resistance Rg(on) by temperature detection is performed first, and then control of gate resistance Rg(off) by current detection is performed.

[0050] First, when the process starts (step S1), the temperature detection circuit 15 detects the temperature (T) of the IGBT 3 (main IGBT 16) in step S2.

[0051] Next, in step S3, the determination circuit 13 compares the temperature (T) detected by the temperature detection circuit 15 with a preset temperature threshold value (Tc).

[0052] If the temperature (T) is equal to or higher than the predetermined temperature threshold (Tc) (Yes), the process proceeds to step S4, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(on) when on is small. On the other hand, if the temperature (T) is lower than the predetermined temperature threshold (Tc) (No), the process proceeds to step S5, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(on) when on is large.

[0053] Next, in step S6, the current detection circuit 14 detects the output current (I) of the IGBT 3 (main IGBT 16).

[0054] Next, in step S7, the determination circuit 13 compares the output current (I) detected by the current detection circuit 14 with a preset current threshold value (Ic).

[0055] If the output current (I) is smaller than the predetermined current threshold (Ic) (No), the process proceeds to step S8, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(off) when off is small. On the other hand, if the output current (I) is equal to or greater than the predetermined current threshold (Ic) (Yes), the process proceeds to step S9, where the driver 12 controls the on / off of the four MOSFETs 4 to 7 so that the gate resistance Rg(off) when off is large.

[0056] After either step S8 or step S9 is completed, the process ends (step S10), and the process returns to step S1 to continue the process.

[0057] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0058] 1... semiconductor device 2... drive circuit 3... IGBT 4, 5, 6, 7... MOSFET 8, 9, 10, 11, 19... resistor 12... driver 13... determination circuit 14... current detection circuit 15... temperature detection circuit 16... main IGBT 17... sense IGBT 18... temperature sense diode 20... collector 21... emitter 22... sense emitter 23... anode 24... cathode

Claims

1. A semiconductor device comprising: an IGBT; and a drive circuit that drives the gate of the IGBT, wherein the drive circuit has four MOSFETs and four resistors that form a bridge circuit; a driver that drives each of the four MOSFETs; a current detection circuit that detects the output current of the IGBT; a temperature detection circuit that detects the temperature of the IGBT; and a judgment circuit that controls the operation of the driver based on the detection values ​​of the current detection circuit and the temperature detection circuit, wherein the judgment circuit increases the OFF gate resistance of the IGBT when the output current detected by the current detection circuit is greater than a predetermined current threshold, and increases the ON gate resistance of the IGBT when the temperature detected by the temperature detection circuit is lower than the predetermined temperature threshold.

2. A semiconductor device according to claim 1, further comprising a sense IGBT for current detection connected in parallel with said IGBT, wherein said current detection circuit detects the output current of said IGBT by detecting the current of said sense IGBT.

3. A semiconductor device according to claim 1, wherein the IGBT is provided with a temperature sensing diode, and the temperature detection circuit detects the temperature of the IGBT via the temperature sensing diode.

4. A semiconductor device according to claim 1, wherein the IGBT and the drive circuit are mounted on a single semiconductor chip.

5. A semiconductor device according to claim 1, wherein the IGBT and the drive circuit are mounted on separate semiconductor chips.

6. A method for driving a semiconductor device comprising: (a) a step in which a current detection circuit detects an output current of an IGBT; (b) a step in which a judgment circuit compares the output current detected in step (a) with a predetermined current threshold; (c) a step in which a temperature detection circuit detects the temperature of the IGBT; and (d) a step in which a judgment circuit compares the temperature detected in step (c) with a predetermined temperature threshold, wherein the judgment circuit increases the OFF gate resistance of the IGBT if the output current detected by the current detection circuit is greater than the predetermined current threshold, and increases the ON gate resistance of the IGBT if the temperature detected by the temperature detection circuit is lower than the predetermined temperature threshold.

7. A method for driving a semiconductor device according to claim 6, characterized in that steps (a) to (b) and steps (c) to (d) are carried out in parallel.

8. A method for driving a semiconductor device according to claim 6, characterized in that after steps (a) to (b) are performed, steps (c) to (d) are performed.

9. A method for driving a semiconductor device according to claim 6, characterized in that steps (a) to (b) are executed after steps (c) to (d) are executed.

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