JP5447983B2 - Electronic equipment - Google Patents

Description

  The present invention relates to an electronic device including a switching element and a drive circuit.

  Conventionally, as an electronic device including a switching element and a drive circuit, for example, there is a power converter disclosed in Patent Document 1.

  This power converter includes an IGBT, three MOSFETs, and a control circuit. The source of the first MOSFET is connected to the drive circuit power supply, the drain is connected to the gate of the IGBT, and the gate is connected to the control circuit. The sources of the second and third MOSFETs are connected to the emitter of the IGBT, the drain is connected to the gate of the IGBT, and the gate is connected to the control circuit.

  The control circuit drives the IGBT by controlling the three MOSFETs based on a drive signal input from the outside. When the drive signal instructs to turn on the IGBT, the control circuit turns on the first MOSFET and turns off the second MOSFET. As a result, charges are charged from the drive circuit power supply to the gate of the IGBT. As a result, the gate voltage becomes higher than the on / off threshold voltage, and the IGBT is turned on.

  On the other hand, when the drive signal instructs to turn off the IGBT, the control circuit turns off the first MOSFET and turns on the second MOSFET. As a result, charges are discharged from the gate of the IGBT. As a result, the gate voltage becomes lower than the on / off threshold voltage, and the IGBT is turned off. Then, when the gate voltage becomes a predetermined value or less, the control circuit turns on the third MOSFET. As a result, the electric charge is further discharged from the gate of the IGBT, and the off state of the IGBT is maintained.

Japanese Patent No. 3430878

  By the way, in the power converter described above, when the second MOSFET is turned on when the first MOSFET is turned on due to an on failure or malfunction, the gate voltage of the IGBT is not lowered, and an abnormal state in which the IGBT cannot be turned off occurs. At this time, if the gate voltage of the IGBT is a voltage within a predetermined range near the ON / OFF threshold voltage, the collector-emitter voltage, that is, the ON voltage increases, and the heat generation of the IGBT increases. If such an abnormal state continues, there is a possibility that the IGBT generates heat and is thermally destroyed.

  The present invention has been made in view of such circumstances, and detects an abnormal state in which a switching element corresponding to an IGBT, which is caused by an on-failure or malfunction of an on-driving switching element corresponding to a first MOSFET, cannot be turned off. It is an object of the present invention to provide an electronic device that can be used.

  Therefore, as a result of intensive research and trial and error to solve this problem, the present inventors cannot turn off the switching element based on the current flowing through the on-drive switching element and the time during which the current flows. The present inventors have found that an abnormal state can be detected and have completed the present invention.

That is, the electronic device according to claim 1 is connected to the control terminal of the first switching element and the first switching element driven by controlling the voltage of the control terminal, and is turned on by turning on the first switching element. An on-drive switching element that charges the control terminal and an off-drive switching element that is connected to the control terminal of the first switching element and discharges the charge from the control terminal of the first switching element by being turned on. A control circuit for controlling the voltage of the control terminal of the first switching element to drive the first switching element by controlling the on-drive switching element and the off-drive switching element based on the drive signal the electronic device, on driving when the on-drive switching element and the off-drive switching element are both turned on A predetermined threshold is set to a value below the current value flowing through the switching element, the control circuit, when the current equal to or higher than a predetermined threshold value to turn on the drive switching element is flowing more than a predetermined time, the first switching element is abnormal It is characterized by determining that it is in a state.

According to this configuration, when the on-drive switching element is turned on when the on-drive switching element is turned on due to an on-failure or malfunction, the voltage at the control terminal of the IGBT does not decrease, and an abnormal state in which the IGBT cannot be turned off occurs. . At this time, a current flows from the on-drive switching element to the off-drive switching element. In the on-drive switching element, a current that does not flow in a normal state and that is equal to the current that flows when both the on-drive switching element and the off-drive switching element are turned on flows for a predetermined time or more. The predetermined threshold value is set to a value equal to or less than a current value that flows when both the on-drive switching element and the off-drive switching element are turned on. Therefore, it can be determined that the first switching element is in an abnormal state when a current greater than or equal to a predetermined threshold flows through the on-drive switching element for a predetermined time or more.

In the electronic device according to claim 2, the predetermined time is set to a time longer than a time required for charging the control terminal of the first switching element by the on-drive switching element. Features. According to this configuration, when the on-drive switching element is turned on, a current flows through the on-drive switching element for a time required to charge the control terminal of the first switching element, and thereafter, No current flows. However, when the on-drive switching element is turned on due to an on-failure or malfunction, when the off-drive switching element is turned on, the time required to charge the control terminal of the first switching element has elapsed. Current continues to flow. Therefore, by setting the predetermined time to a time longer than the time required for charging the control terminal of the first switching element, the current flows when charging the control terminal of the first switching element. It is possible to prevent erroneous judgment due to current.

The electronic device according to claim 3 has a drive power supply circuit that supplies a voltage for driving the first switching element, and the control circuit drives when the first switching element is determined to be in an abnormal state. The voltage supply from the power supply circuit is cut off and the first switching element is turned off. According to this configuration, when it is determined that the first switching element is in an abnormal state, the first switching element is turned off by cutting off the voltage for driving the first switching element. Therefore, it is possible to prevent thermal destruction of the first switching element.

In the electronic device according to claim 4, when the control circuit determines that the first switching element is in an abnormal state, the control terminal of the first switching element is disconnected from the on-drive switching element and the off-drive switching element. It is characterized by doing. According to this configuration, when it is determined that the first switching element is in an abnormal state, the first switching element is turned off by interrupting the supply of voltage to the control terminal for driving the first switching element. Therefore, it is possible to prevent thermal destruction of the first switching element.

The electronic device according to claim 5 is connected to the control terminal of the first switching element driven by controlling the voltage of the control terminal and the control terminal of the first switching element when turned on. An on-driving switching element that charges electric charge, an off-driving switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element, and an input drive An electronic apparatus comprising: a control circuit that drives the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the signal in is connected to the control terminal of the first switching element, a charge from the control terminal of the first switching element by turning on The control circuit has an off-holding switching element that discharges, and the control circuit controls the off-holding switching element when the voltage at the control terminal of the first switching element falls below an off-holding threshold value that is lower than the on-off threshold voltage. 1 switching element is kept in an off state, and when a current exceeding a predetermined threshold flows through the on drive switching element for a predetermined time or more, it is determined that the first switching element is in an abnormal state , and the first switching element is in an abnormal state When it is determined that the first switching element is off, the off-holding switching element is controlled to turn off the first switching element. According to this arrangement, when the first switching element is determined to be in an abnormal state, by Ru to discharge the charge from the control terminal of the first switching element to control the OFF-drive switching element, the first switching element Turn off. Therefore, it is possible to prevent thermal destruction of the first switching element.

The electronic device according to claim 6 is connected to the control terminal of the first switching element driven by controlling the voltage of the control terminal and the control terminal of the first switching element when turned on. An on-driving switching element that charges electric charge, an off-driving switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element, and an input drive An electronic apparatus comprising: a control circuit that drives the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the signal in is connected to the control terminal of the first switching element, a charge from the control terminal of the first switching element by turning on An off-holding switching element that discharges, and a voltage clamping circuit that clamps a voltage at a control terminal of the first switching element to an on-off threshold voltage lower than an on-off threshold voltage, and the control circuit performs the first switching When the voltage at the control terminal of the element becomes equal to or lower than the off-holding threshold, the off-holding switching element is controlled to hold the off state of the first switching element, and a current equal to or higher than the predetermined threshold flows in the on-drive switching element for a predetermined time or more. When it is determined that the first switching element is in an abnormal state, and when it is determined that the first switching element is in an abnormal state, the voltage clamp circuit is activated to keep the voltage at the control terminal of the first switching element off. It is characterized by clamping below a threshold value. According to this configuration, when it is determined that the first switching element is in an abnormal state, the voltage clamp circuit is activated to set the voltage at the control terminal of the first switching element to be equal to or lower than the off-hold threshold. Therefore, the charge can be discharged from the control terminal of the first switching element by the off-holding switching element, and the first switching element can be turned off. Therefore, it is possible to prevent thermal destruction of the first switching element.

The electronic device according to claim 7 is connected to the control terminal of the first switching element driven by controlling the voltage of the control terminal and the control terminal of the first switching element when turned on. An on-driving switching element that charges electric charge, an off-driving switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element, and an input drive An electronic apparatus comprising: a control circuit that drives the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the signal in is driven by controlling the voltage of the control terminal, a second switching element which are connected in series to the first switching element And driving the second switching element by controlling the voltage of the control terminal of the second switching element based on the input drive signal, and turning off the second switching element when an abnormal current flows through the second switching element. And the control circuit determines that the first switching element is in an abnormal state when a current greater than or equal to a predetermined threshold is flowing through the on-drive switching element for a predetermined time, and the first switching element When it is determined that is in an abnormal state, the first switching element is turned on. According to this configuration, when the first switching element is in an abnormal state, when the second switching element is turned on, both the first and second switching elements are turned on, and an abnormal current flows through the first and second switching elements. . When an abnormal current flows through the second switching element, the second drive circuit turns off the second switching element. Therefore, the abnormal current flowing through the first switching element can be interrupted. Therefore, it is possible to prevent thermal destruction of the first switching element.

In the electronic device according to claim 8, the predetermined threshold is set to a value equal to or less than a current value flowing through the on-drive switching element when both the on-drive switching element and the off-drive switching element are turned on. Features. According to this configuration, when the on-drive switching element is turned on when the on-drive switching element is turned on due to an on failure or malfunction, the on-drive switching element and the off-drive switching element are included in the on-drive switching element. A current equal to the current that flows when both are turned on flows. Therefore, when the on-drive switching element and the off-drive switching element are both turned on, the on-drive switching element is turned on by setting the predetermined threshold value to be equal to or less than the current value flowing through the on-drive switching element. It is possible to reliably determine that it has been turned on due to a malfunction.

In the electronic device according to claim 9, the predetermined time is set to a time longer than a time required for charging the control terminal of the first switching element by the on-drive switching element. Features. According to this configuration, when the on-drive switching element is turned on, a current flows through the on-drive switching element for a time required to charge the control terminal of the first switching element, and thereafter, No current flows. However, when the on-drive switching element is turned on due to an on-failure or malfunction, when the off-drive switching element is turned on, the time required to charge the control terminal of the first switching element has elapsed. Current continues to flow. Therefore, by setting the predetermined time to a time longer than the time required for charging the control terminal of the first switching element, the current flows when charging the control terminal of the first switching element. It is possible to prevent erroneous judgment due to current.

The electronic device according to claim 10 is characterized in that when the control circuit determines that the first switching element is in an abnormal state, the control circuit outputs an abnormal signal to the outside. According to this configuration, it is possible to notify the outside that the first switching element is in an abnormal state.
The first and second switching elements are introduced for convenience in order to distinguish the switching elements.

It is a circuit diagram of the motor control device in a 1st embodiment. It is a circuit diagram of the control apparatus in FIG. It is a timing chart of the drive signal in the normal state, the on-drive FET and the off-drive FET, the current flowing through each FET, and the gate voltage waveform of the IGBT. FIG. 5 is a timing chart of a drive signal, an on-drive FET, and an off-drive FET when the on-drive FET is turned on, and a current flowing through each FET and a gate voltage waveform of the IGBT. FIG. 6 is a timing chart of a drive signal, an on-drive FET, and an off-drive FET when the off-drive FET is turned on, and a current flowing through each FET and an IGBT gate voltage waveform. It is a circuit diagram of the control apparatus in 2nd Embodiment. It is a circuit diagram of the control apparatus in 3rd Embodiment.

  Next, an embodiment is given and this invention is demonstrated in detail. In the present embodiment, an example in which the electronic device according to the present invention is applied to a motor control device that is mounted on a vehicle and controls a motor for driving the vehicle is shown.

(First embodiment)
First, the configuration of the motor control device of the first embodiment will be described with reference to FIG. Here, FIG. 1 is a circuit diagram of the motor control device according to the first embodiment.

  The motor control device 1 (electronic device) shown in FIG. 1 converts a DC high voltage (for example, 288V) output from a high voltage battery B1 insulated from the vehicle body into a three-phase AC voltage and supplies it to the vehicle drive motor M1. This is a device for controlling the vehicle drive motor M1. The motor control device 1 includes a smoothing capacitor 10, an inverter device 11, and a control device 12.

  The smoothing capacitor 10 is an element for smoothing the DC high voltage of the high voltage battery B1. One end of the smoothing capacitor 10 is connected to the positive terminal of the high voltage battery B1. The other end is connected to the negative terminal of the high voltage battery B1. Furthermore, the negative terminal of the high voltage battery B1 is connected to the ground for the high voltage battery insulated from the vehicle body.

  The inverter device 11 is a device that converts the DC voltage smoothed by the smoothing capacitor 10 into a three-phase AC voltage and supplies it to the vehicle drive motor M1. The inverter device 11 includes IGBTs 110a to 110f and current sense resistors 111a to 111f.

  The IGBTs 110a to 110f are switching elements that are driven by controlling the voltage of the gate (control terminal) and convert the DC voltage smoothed by the smoothing capacitor 10 by turning on and off to a three-phase AC voltage. . The IGBTs 110a to 110f include a current sense terminal through which a current that is proportional to the collector current and smaller than the collector current flows. The IGBTs 110a (second switching elements) and 110d (first switching elements), the IGBTs 110b and 110e, and the IGBTs 110c and 110f are respectively connected in series. Specifically, the emitters of the IGBTs 110a to 110c are connected to the collectors of the IGBTs 110d to 110f, respectively. Three sets of IGBTs 110a and 110d, IGBTs 110b and 110e, and IGBTs 110c and 110f connected in series are connected in parallel. The collectors of the IGBTs 110 a to 110 c are connected to one end of the smoothing capacitor 10, and the emitters of the IGBTs 110 d to 110 f are connected to the other end of the smoothing capacitor 10. The gates and emitters of the IGBTs 110a to 110f are connected to the control device 12, respectively. Further, the series connection points of the IGBTs 110a and 110d, the IGBTs 110b and 110e, and the IGBTs 110c and 110f that are connected in series are respectively connected to the vehicle drive motor M1.

  The current sense resistors 111a to 111f are elements for converting the current flowing through the IGBTs 110a to 110f into a voltage. Specifically, it is an element that converts a current flowing through a current sense terminal into a voltage. One ends of the current sense resistors 111a to 111f are connected to the current sense terminals of the IGBTs 110a to 110f, and the other ends are connected to the emitters of the IGBTs 110a to 110f, respectively. Further, both ends of the current sense resistors 111a to 111f are connected to the control device 12, respectively.

  The control device 12 is a device that controls the IGBTs 110a to 110f. The control device 12 is connected to the gates and emitters of the IGBTs 110a to 110f, respectively. Moreover, in order to detect the electric current which flows into IGBT110a-110f, it connects to the both ends of current sense resistance 111a-111f, respectively.

  Next, the control device will be described in detail with reference to FIG. Here, FIG. 2 is a circuit diagram of the control device in FIG. Specifically, it is a circuit diagram showing a circuit portion for one IGBT.

  As shown in FIG. 2, the control device 12 has a driving power supply circuit 120, an on driving circuit 121, an off driving circuit 122, an off holding circuit 123, and a blocking circuit 124, with respect to the IGBT 110 d. The overcurrent detection circuit 126, the short circuit detection circuit 127, and the control circuit 128 are provided. In the same manner, the control device 12 also applies to the other IGBTs 110a to 110c, 110e, and 110f, a driving power supply circuit, an on-driving circuit, an off-driving circuit, an off-holding circuit, and a shut-off circuit. An overcurrent detection circuit, a short circuit detection circuit, and a control circuit.

  The drive power supply circuit 120 is a circuit that supplies a voltage for driving the IGBT 110d. The driving power supply circuit 120 stabilizes and outputs the voltage supplied from the power supply circuit (not shown). Further, the operation is stopped based on an instruction from the control circuit 128. The input terminal of the driving power supply circuit 120 is connected to the power supply circuit. The positive terminal is connected to the ON drive circuit 121. Further, the negative terminal is connected to the ground for the high voltage battery insulated from the vehicle body, and is connected to the emitter of the IGBT 110d via the ground for the high voltage battery. In addition, the control terminal is connected to the control circuit 128.

  The on drive circuit 121 is a circuit for turning on the IGBT 110d. Specifically, this is a circuit that charges the gate of the IGBT 110d, sets the gate voltage higher than a threshold voltage for turning on and off, and turns on the IGBT 110d. The on drive circuit 121 includes an on drive FET 121a (on drive switching element) and an on drive resistor 121b.

  The on-drive FET 121a is a switching element that is driven by controlling the voltage of the gate and charges the gate of the IGBT when turned on. Specifically, it is a P-channel MOSFET. The source of the on-drive FET 121 a is connected to the positive terminal of the drive power supply circuit 120. The drain is connected to the gate of the IGBT 110d through the on-drive resistor 121b. Further, the gate is connected to the control circuit 128.

  The off drive circuit 122 is a circuit for turning off the IGBT 110d. Specifically, this is a circuit that discharges electric charges from the gate of the IGBT 110d, lowers the gate voltage below a threshold voltage for turning on and off, and turns off the IGBT 110d. The off drive circuit 122 includes an off drive FET 122a (off drive switching element) and an off drive resistor 122b.

  The off-drive FET 122a is a switching element that is driven by controlling the voltage of the gate, and discharges electric charges from the gate of the IGBT 110d when turned on. Specifically, it is an N-channel MOSFET. The source of the off drive FET 122a is connected to the ground for the high voltage battery insulated from the vehicle body, and is connected to the negative terminal of the drive power supply circuit 120 and the emitter of the IGBT 110d via the ground for the high voltage battery. The drain is connected to the gate of the IGBT 110d through the off-drive resistor 122b. Further, the gate is connected to the control circuit 128.

  The off-holding circuit 123 is a circuit that holds the off state of the IGBT 110d. Specifically, when the gate voltage of the IGBT 110d falls below an off-holding threshold value that is lower than the on / off threshold voltage, the gate voltage is quickly turned on / off by discharging charges from the gate of the IGBT 110d more quickly than the off drive circuit 122. This is a circuit that keeps the IGBT 110d in an OFF state by lowering the threshold voltage. The off holding circuit 123 includes an off holding FET 123a (off holding switching element) and a gate resistor 123b.

  The off-holding FET 123a is a switching element that is driven by controlling the voltage of the gate and discharges electric charges from the gate of the IGBT 110d when turned on. Specifically, it is an N-channel MOSFET. The source of the off-holding FET 123a is connected to the ground for the high voltage battery insulated from the vehicle body, and is connected to the negative terminal of the driving power supply circuit 120 and the emitter of the IGBT 110d via the ground for the high voltage battery. The drain is connected to the gate of the IGBT 110d. Furthermore, the gate is connected to the control circuit 128 via the gate resistor 123b.

  The cutoff circuit 124 is a circuit that turns off the IGBT 110d when an abnormal current flows through the IGBT 110d. Specifically, when an overcurrent or a short-circuit current flows in the IGBT 110d, the electric charge is discharged from the gate of the IGBT 110d more slowly than the off-drive circuit 122, and the gate voltage is made lower than the threshold voltage for turning on and off, and the IGBT 110d It is a circuit that turns off. The blocking circuit 124 includes a blocking FET 124a and a blocking resistor 124b.

  The blocking FET 124a is a switching element that is driven by controlling the voltage of the gate and discharges electric charges from the gate of the IGBT 110d when turned on. Specifically, it is an N-channel MOSFET. The source of the blocking FET 124a is connected to the ground for the high voltage battery insulated from the vehicle body, and is connected to the negative terminal of the driving power supply circuit 120 and the emitter of the IGBT 110d via the ground for the high voltage battery. Further, the drain is connected to the gate of the IGBT through the blocking resistor 124b. Further, the gate is connected to the control circuit 128.

  The overcurrent detection circuit 126 is a circuit that detects whether or not an overcurrent flows through the IGBT 110d. Specifically, the circuit determines that an overcurrent is flowing through the IGBT 110dT when the current flowing through the IGBT 110d becomes larger than the overcurrent threshold. The input terminal of the overcurrent detection circuit 126 is connected to one end of the current sense resistor 111d. The output terminal is connected to the control circuit 128.

  The short circuit detection circuit 127 is a circuit that detects whether or not the IGBT 110d is in a short circuit state. Specifically, when the current flowing through the IGBT 110d becomes larger than the short-circuit current threshold greater than the overcurrent threshold, both the IGBTs 110a and 110d are in a short-circuited state, and it is determined that a short-circuit current is flowing through the IGBT 110d. The input terminal of the short circuit detection circuit 127 is connected to one end of the current sense resistor 111d. The output terminal is connected to the control circuit 128.

  The control circuit 128 controls the on-drive circuit 121 and the off-drive circuit 122 based on a drive signal input from the outside to drive the IGBT 110d, and the off-hold circuit 123 based on the gate voltage of the IGBT 110d. This is a circuit that controls and maintains the off state of the IGBT 110d. Further, when a current greater than or equal to a predetermined threshold Ith (predetermined threshold) flows through the on-driving FET 121a for a predetermined time Tth or longer (predetermined time or longer), it is determined that the IGBT 110d is in an abnormal state, and This is also a circuit that turns off the IGBT 110d and outputs an abnormal signal to the outside. Further, the control circuit 128 controls the cutoff circuit 124 instead of the off drive circuit 122 to turn off the IGBT 110d when an abnormality such as an overcurrent flowing through the IGBT 110d or a short circuit state of the IGBT 110d occurs. It is also a circuit to do.

  Here, the predetermined threshold value Ith is set to a value equal to or smaller than the value of the current flowing through the on-drive FET 121a when both the on-drive FET 121a and the off-drive FET 122a are turned on. Specifically, in consideration of the detection error, when both the on-drive FET 121a and the off-drive FET 122a are turned on, the current value is set slightly lower than the current flowing through the on-drive FET 121a. The predetermined time Tth is set to a time longer than the time Ton required for charging the gate of the IGBT 110d by the on-drive FET 121a.

  The control circuit 128 is connected to the gates of the on-drive FET 121a and the off-drive FET 122a, respectively. In addition, the gate of the IGBT 110d is connected to the gate of the off-holding FET 123a through the gate resistor 123b. Further, it is connected to the drain of the on-drive FET 121 a and the control terminal of the drive power supply circuit 120. In addition, they are connected to the output terminals of the overcurrent detection circuit 126 and the short-circuit detection circuit 127 and the gate of the blocking FET 124a, respectively.

  Here, the drive power supply circuit 120, the ON drive FET 120a, the OFF drive FET 122a, the cutoff FET 124a, the overcurrent detection circuit 126, the short circuit detection circuit 127, and the control circuit 128 are integrally configured as an IC.

  Next, the operation of the motor control device will be described with reference to FIG. When the ignition switch (not shown) of the vehicle is turned on, the motor control device 1 shown in FIG. 1 starts its operation. The DC high voltage of the high voltage battery B1 is smoothed by the smoothing capacitor 10. The control device 12 controls the IGBTs 110a to 110f constituting the inverter device 11 based on a drive signal input from the outside. Specifically, the IGBTs 110a to 110f are turned on and off at a predetermined cycle. The inverter device 11 converts the DC high voltage smoothed by the smoothing capacitor 10 into a three-phase AC voltage and supplies it to the vehicle drive motor M1. In this way, the motor control device 1 controls the vehicle drive motor M1.

  Next, with reference to FIG. 2 to FIG. 5, the IGBT driving operation in a normal state and the operation when it is determined that the IGBT is in an abnormal state due to an on failure or the like of the on driving FET or the off driving FET are described. To do. Here, FIG. 3 shows a drive signal in a normal state, a timing chart of the on-drive FET and the off-drive FET, a current flowing through each FET, and a gate voltage waveform of the IGBT. FIG. 4 shows a drive signal, a timing chart of the on-drive FET and the off-drive FET, a current flowing through each FET, and a gate voltage waveform of the IGBT when the on-drive FET is turned on. FIG. 5 shows a drive signal, a timing chart of the on-drive FET and the off-drive FET, a current flowing through each FET, and a gate voltage waveform of the IGBT when the off-drive FET is turned on. 3 to 5, the current flowing in the on-drive FET and the current flowing in the off-drive FET are shown as positive in the direction of flowing into the gate of the IGBT and negative in the direction of flowing out of the gate of the IGBT. 4 and 5, the waveform drawn with a broken line is a waveform in a normal state. Also, t1 to t4 in FIG. 4 are the same timings as t1 to t4 in FIG. 3, and t1 and t2 in FIG. 5 are the same timings as t1 and t2 in FIG.

  In FIG. 2, the control circuit 128 drives the IGBT 110d by controlling the on-drive FET 121a and the off-drive FET 122a based on a drive signal input from the outside.

  As shown in FIG. 3, when the drive signal instructs to turn on the IGBT 110d (t1), the control circuit 128 turns off the off drive FET 122a and turns on the on drive FET 121a. As a result, current flows from the driving power supply circuit 120 to the gate of the IGBT 110d through the on-driving FET 121a and the on-driving resistor 121b for a time Ton, and charges are charged (t2). As a result, the gate voltage becomes higher than the threshold voltage for turning on and off, and the IGBT 110d is turned on. Here, the time Ton is a time required to charge the gate of the IGBT 110d.

  On the other hand, when the drive signal instructs to turn off the IGBT 110d (t3), the control circuit 128 turns off the on-drive FET 121a and turns on the off-drive FET 122a. As a result, current flows from the gate of the IGBT 110d through the off-drive resistor 122b and the off-drive FET 122a for a time Toff, and the charge is discharged (t4). As a result, the gate voltage becomes lower than the threshold voltage for turning on and off, and the IGBT 110d is turned off. Here, the time Toff is a time required for discharging the charge from the gate of the IGBT 110d.

  Then, when the gate voltage becomes equal to or lower than the off-holding threshold value lower than the on-off threshold voltage, the control circuit 128 turns on the off-holding FET 123a in FIG. As a result, a current flows from the gate of the IGBT 110d through the off-holding FET 123a, the electric charge is further discharged, and the off-state of the IGBT 110d is held.

  By the way, when the current flowing through the IGBT 110d becomes larger than the overcurrent threshold, the overcurrent detection circuit 126 determines that the overcurrent is flowing through the IGBT 110d. When the current flowing through the IGBT 110d becomes larger than the short-circuit current threshold, the short-circuit detection circuit 127 determines that both the IGBTs 110a and 110d are in a short-circuit state. When the control circuit 128 determines that an abnormality has occurred, such as an overcurrent flowing through the IGBT 110d or the IGBT 110d being short-circuited, the control circuit 128 turns on the blocking FET 124a instead of the off-driving FET 122a. As a result, electric charges are discharged from the gate of the IGBT 110d through the blocking resistor 124b. As a result, the gate voltage becomes lower than the threshold voltage at which the gate voltage is gradually turned on and off as compared with the off drive circuit 122, and the IGBT 110d is turned off.

  When the on-drive FET 121a is turned on due to an on-failure or malfunction, the drive signal instructs the IGBT 110d to turn off as shown in FIG. 4 (t3), and the control circuit 128 tries to turn off the on-drive FET 121a. However, the on-drive FET 121a cannot be turned off. Therefore, a current that does not flow in a normal state flows from the drive power supply circuit 120 to the gate of the IGBT 110d through the on-drive FET 121a and the on-drive resistor 121b. Further, even after the time Toff has elapsed, a current that does not flow in a normal state flows out from the gate of the IGBT 110d through the off-drive resistor 122b and the off-drive FET 122a. As a result, the gate voltage of the IGBT 110d does not sufficiently decrease, and an abnormal state in which the IGBT 110d cannot be turned off occurs.

  However, the control circuit 128 detects the current flowing through the on-driving FET 121a based on the voltage across the terminals of the on-driving resistor 121b. When a current equal to or greater than the predetermined threshold Ith flows through the on-drive FET 121a for a predetermined time Tth or more, it is determined that the gate voltage of the IGBT 110d does not decrease and the IGBT 110d is in an abnormal state. If it is determined that the IGBT 110d is in an abnormal state, the control circuit 128 stops the operation of the driving power supply circuit 120, cuts off the supply of voltage from the driving power supply circuit 120, and outputs an abnormal signal to the outside. As a result, the gate voltage becomes lower than the threshold voltage for turning on and off, and the IGBT 110d is turned off.

  Further, when the off drive FET 122a is turned on due to an on failure or malfunction, as shown in FIG. 5, the drive signal instructs to turn on the IGBT 110d (t1), and the control circuit 128 tries to turn off the off drive FET 122a. However, the off-drive FET 122a cannot be turned off. Therefore, even after the time Ton has elapsed, a current that does not flow in the normal state flows from the drive power supply circuit 120 to the gate of the IGBT 110d through the on-drive FET 121a and the on-drive resistor 121b. In addition, a current that does not flow in a normal state flows from the gate of the IGBT 110d through the off-drive resistor 122b and the off-drive FET 122a. As a result, the gate voltage of the IGBT 110d does not rise sufficiently, and an abnormal state in which the IGBT 110d cannot be turned on occurs.

  However, the control circuit 128 detects the current flowing through the on-driving FET 121a based on the voltage across the terminals of the on-driving resistor 121b. When a current equal to or greater than the predetermined threshold Ith flows through the on-drive FET 121a for a predetermined time Tth or more, it is determined that the gate voltage of the IGBT 110d does not increase and the IGBT 110d is in an abnormal state. If it is determined that the IGBT 110d is in an abnormal state, the control circuit 128 stops the operation of the driving power supply circuit 120, cuts off the supply of voltage from the driving power supply circuit 120, and outputs an abnormal signal to the outside. As a result, the gate voltage becomes lower than the threshold voltage for turning on and off, and the IGBT 110d is turned off.

  Next, the effect will be described. According to the first embodiment, as shown in FIG. 4, when the off drive FET 122a is turned on when the on drive FET 121a is turned on due to an on failure or malfunction, the gate voltage of the IGBT 110d does not decrease, and the IGBT 110d cannot be turned off. An abnormal condition occurs. Further, as shown in FIG. 5, when the on-drive FET 121a is turned on when the off-drive FET 122a is turned on due to an on-failure or malfunction, the gate voltage of the IGBT 110d does not increase and an abnormal state in which the IGBT 110d cannot be turned on occurs. . At these times, a current flows from the on-drive FET 121a to the off-drive FET 122a. In the on-drive FET 121a, a current that does not flow in a normal state and that has a predetermined threshold value Ith or more flows for a predetermined time Tth or more. Therefore, it can be determined that the IGBT 110d is in an abnormal state when a current equal to or greater than the predetermined threshold Ith flows through the on-drive FET 121a for a predetermined time Tth or longer.

  According to the first embodiment, when the on-drive FET 121a is turned on when the on-drive FET 121a is turned on due to an on-failure or malfunction, both the on-drive FET 121a and the off-drive FET 122a are turned on. In this case, a current equal to the current flowing flows. Further, when the on-driving FET 121a is turned on when the off-driving FET 122a is turned on due to an on-failure or malfunction, the on-driving FET 121a has a current that flows when both the on-driving FET 121a and the off-driving FET 122a are on. An equal current flows. Therefore, by setting the predetermined threshold value Ith to a value that is equal to or less than the value of the current flowing through the on-drive FET 121a when both the on-drive FET 121a and the off-drive FET 122a are turned on, the on-drive FET 121a is turned on due to an on failure or malfunction. It is possible to determine with certainty. Further, it can be reliably determined that the off-drive FET 122a is turned on due to an on-failure or malfunction.

  According to the first embodiment, when the on-driving FET 121a is turned on, a current flows through the on-driving FET 121a for a time Ton required to charge the gate of the IGBT 110d, and thereafter, the current flows. Absent. However, when the on-drive FET 121a is turned on due to an on-failure or malfunction, if the off-drive FET 122a is turned on, current continues to flow even after the time Ton has elapsed. Therefore, by setting the predetermined time Tth to be longer than the time Ton, it is possible to prevent erroneous determination due to the current that flows when charging the gate of the IGBT 110d.

  According to the first embodiment, when the control circuit 128 determines that the on-drive FET 121a or the off-drive FET 122a has an on-failure or the like, the control circuit 128 stops the operation of the drive power circuit 120 and drives the drive power circuit 120. The voltage supply from is cut off. As a result, the gate voltage becomes lower than the ON / OFF threshold voltage, and the IGBT 110d is turned OFF. Therefore, thermal destruction of the IGBT 110d can be prevented.

  According to the first embodiment, when the control circuit 128 determines that the on-drive FET 121a or the off-drive FET 122a has an on-failure, the control circuit 128 outputs an abnormal signal to the outside. Therefore, it is possible to notify the outside that the IGBT 110d is in an abnormal state.

  In the first embodiment, when the control circuit 128 determines that the on-driving FET 121a has an on-failure or the like, the control circuit 128 stops the operation of the driving power circuit 120 and supplies the voltage from the driving power circuit 120. Although the example which turns off IGBT110d by interrupting | blocking is given, it is not restricted to this. The IGBT 110d may be turned off by controlling the off-holding FET 123a. In this case, the IGBT 110d can be turned off by turning on the off-holding FET 123a and discharging the charge from the gate of the IGBT 110d. Therefore, thermal destruction of the IGBT 110d can be prevented.

  Further, the IGBT 110d may be turned on. When IGBT 110a shown in FIG. 2 is turned on, both IGBTs 110a and 110d connected in series are turned on, and a short-circuit current flows through IGBTs 110a and 110d. When a short-circuit current flows through the IGBT 110a, the control circuit (drive circuit) that controls the IGBT 110a turns off the IGBT 110a as in the case of the IGBT 110d. Therefore, the short circuit current flowing through the IGBT 110d can be cut off. Therefore, thermal destruction of the IGBT 110d can be prevented.

(Second Embodiment)
Next, the motor control device of the second embodiment will be described. The motor control device according to the second embodiment is different from the motor control device according to the first embodiment in that the IGBT is turned off by shutting off the drive power supply circuit when the off drive FET is turned on. The voltage is clamped below the off hold threshold, and the IGBT is turned off by the off hold circuit. The motor control device of the second embodiment has the same configuration as the motor control device of the first embodiment except for the control device.

  First, the configuration of the control device will be described with reference to FIG. Here, FIG. 6 is a circuit diagram of the control device in the second embodiment. Here, a different part from the control apparatus of 1st Embodiment is demonstrated, and description is abbreviate | omitted except a required part about a common part.

  As shown in FIG. 6, the control device 22 has a driving power supply circuit 220, an on driving circuit 221, an off driving circuit 222, an off holding circuit 223, and a blocking circuit 224 with respect to the IGBT 210 d. , An overcurrent detection circuit 226, a short circuit detection circuit 227, and a control circuit 228. Further, a voltage clamp circuit 229 is provided. The IGBT 210d and the current sense resistor 211d correspond to the IGBT 110d and the current sense resistor 111d of the first embodiment. The drive power supply circuit 220, the on drive circuit 221, the off drive circuit 222, the off hold circuit 223, the cutoff circuit 224, the overcurrent detection circuit 226, and the short circuit detection circuit 227 are the drive power supply circuit of the first embodiment. 120, the on-drive circuit 121, the off-drive circuit 122, the off-hold circuit 123, the cutoff circuit 124, the overcurrent detection circuit 126, and the short-circuit detection circuit 127.

  The voltage clamp circuit 229 is a circuit that clamps the gate voltage of the IGBT 210d below the off-hold threshold. The voltage clamp circuit 229 includes a voltage clamp FET 229a and a constant voltage diode 229b. The voltage of the constant voltage diode 229b is set to be a constant voltage equal to or lower than the off-holding threshold value. The voltage clamping FET 229a is a switching element that, when turned on, connects the constant voltage diode 229b to the gate of the IGBT 220d. Specifically, it is an N-channel MOSFET. The source of the voltage clamping FET 229a is connected to the ground for the high voltage battery insulated from the vehicle body, and is connected to the negative terminal of the driving power supply circuit 220 and the emitter of the IGBT 210d via the ground for the high voltage battery. The drain is connected to the gate of the IGBT 220d through the constant voltage diode 229b. Specifically, the anode of the constant voltage diode 229b is connected, and the cathode of the constant voltage diode 229b is connected to the gate of the IGBT 220d. Further, the gate of the voltage clamping FET 229 a is connected to the control circuit 228.

  Next, an operation when it is determined that the on-drive FET has an on-failure or the like will be described with reference to FIG. When the control circuit 228 determines that the on-drive FET 121a has an on-failure or the like, the control circuit 228 activates the voltage clamp circuit 229 so that the gate voltage of the IGBT 210d is equal to or less than the off-hold threshold. Specifically, the voltage clamping FET 229a is turned on, and the gate voltage of the IGBT 210d is set to be equal to or lower than the off holding threshold set by the constant voltage diode 229b. As a result, the off-holding FET 223a is turned on, the electric charge is discharged from the gate of the IGBT 210d, and the IGBT 210d is turned off.

  Next, the effect will be described. According to the second embodiment, when the control circuit 228 determines that the on-driving FET 121a has an on-failure or the like, the control circuit 228 activates the voltage clamp circuit 229 so that the gate voltage of the IGBT 210d is equal to or less than the off-hold threshold. Therefore, the charge can be discharged from the gate of the IGBT 210d by the off-holding FET 223a to turn off the IGBT 210d. Therefore, thermal destruction of the IGBT 210d can be prevented.

(Third embodiment)
Next, the motor control apparatus of 3rd Embodiment is demonstrated. The motor control device according to the third embodiment is different from the motor control device according to the first embodiment in that the IGBT is turned off by shutting off the drive power supply circuit in the event of an on failure of the off drive FET. Is cut off from the on-drive FET and the off-drive FET to block the IGBT. The motor control device of the third embodiment has the same configuration as the motor control device of the first embodiment except for the control device.

  First, the configuration of the control device will be described with reference to FIG. Here, FIG. 7 is a circuit diagram of the control device according to the third embodiment. Here, a different part from the control apparatus of 1st Embodiment is demonstrated, and description is abbreviate | omitted except a required part about a common part.

  As shown in FIG. 7, the control device 32 has a drive power supply circuit 320, an on drive circuit 321, an off drive circuit 322, an off hold circuit 323, and a cutoff circuit 324 with respect to the IGBT 310 d. The overcurrent detection circuit 326, the short circuit detection circuit 327, and the control circuit 328 are provided. Furthermore, a gate blocking FET 329 is provided. The IGBT 310d and the current sense resistor 311d correspond to the IGBT 110d and the current sense resistor 111d of the first embodiment. The drive power supply circuit 320, the on drive circuit 321, the off drive circuit 322, the off hold circuit 323, the cutoff circuit 324, the overcurrent detection circuit 326, and the short circuit detection circuit 327 are the drive power supply circuit of the first embodiment. 120, the on-drive circuit 121, the off-drive circuit 122, the off-hold circuit 123, the cutoff circuit 124, the overcurrent detection circuit 126, and the short-circuit detection circuit 127.

  The gate blocking FET 329 is a switching element that blocks the gate of the IGBT 310d from the on driving FET 321a and the off driving FET 322a. Specifically, it is an N-channel MOSFET. The source of the gate blocking FET 329 is connected to the gate of the IGBT 310d. The drain is connected to the on-drive FET 321a via the on-drive resistor 321b, and is connected to the off-drive FET 322a via the off-drive resistor 322b. Further, the gate is connected to the control circuit 328.

  Next, an operation when it is determined that the on-drive FET has an on-failure or the like will be described with reference to FIG. When the control circuit 328 determines that the on-drive FET 121a has an on-failure or the like, the control circuit 328 blocks the gate of the IGBT 310d from the on-drive FET 321a and the off-drive FET 322a. As a result, the supply of voltage to the gate for driving the IGBT 310d is cut off, and the IGBT 310d is turned off.

  Next, the effect will be described. According to the third embodiment, the control circuit 328 blocks the gate of the IGBT 310d from the on-driving FET 321a and the off-driving FET 322a when determining that the on-driving FET 121a has an on failure or the like. Therefore, the supply of voltage to the gate for driving IGBT 310d is interrupted, and IGBT 310d is turned off. Therefore, thermal destruction of the IGBT 310d can be prevented.

DESCRIPTION OF SYMBOLS 1 ... Motor control apparatus (electronic device), 10 ... Smoothing capacitor, 11 ... Inverter apparatus, 110a ... IGBT (2nd switching element), 110b, 110c, 110e, 110f ... IGBT, 110d ... IGBT (first switching element), 111a to 111f ... current sense resistor, 12, 22, 32 ... control device, 120, 220, 320 ... drive power supply circuit, 121, 221, 321... ON drive circuit, 121a, 221a, 321a... ON drive FET (ON drive switching element), 121b, 221b, 321b... ON drive resistance, 122, 222, 322. OFF driving circuit, 122a, 222a, 322a, ... OFF driving FET (OFF driving switching element), 122b, 22b, 322b... OFF driving resistance, 123, 223, 323... OFF holding circuit, 123a, 223a, 323a... OFF holding FET (OFF holding switching element), 123b, 223b, 323b. ..Gate resistance, 124, 224, 324... Circuit for blocking, 124a, 224a, 324a... FET for blocking, 124b, 224b, 324b. Current detection circuit, 127, 227, 327 ... short circuit detection circuit, 128, 228, 328 ... control circuit, 229 ... voltage clamp circuit, 229a ... voltage clamp FET, 329b ... constant voltage Diode, 329... Gate cutoff FET, B1... High voltage battery, M1.

Claims (10)

A first switching element driven by controlling the voltage of the control terminal;
An on-drive switching element that is connected to the control terminal of the first switching element and charges the control terminal of the first switching element by being turned on;
An off-drive switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element by being turned on;
Control for driving the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the input driving signal. Circuit,
In an electronic device comprising:
When both the on-drive switching element and the off-drive switching element are turned on, the threshold value is set to a value equal to or less than the value of the current flowing through the on-drive switching element,
It said control circuit, when the predetermined threshold value or more current to the on-drive switching element is flowing more than a predetermined time, an electronic device, characterized in that said first switching element is determined to be in an abnormal state. The predetermined time is, in claim 1, characterized in that it is set to be longer than the time required to charge the charge to the control terminal of the first switching element by the ON-drive switching element The electronic device described. A driving power supply circuit for supplying a voltage for driving the first switching element;
Said control circuit when said first switching element is determined to be in an abnormal state, according to claim 1, characterized in that turning off the first switching element to shut off the supply of voltage from the drive power supply circuit Or the electronic device of 2 . When the control circuit determines that the first switching element is in an abnormal state, the control circuit cuts off a control terminal of the first switching element from the on-drive switching element and the off-drive switching element. The electronic device according to claim 1 or 2 . A first switching element driven by controlling the voltage of the control terminal;
An on-drive switching element that is connected to the control terminal of the first switching element and charges the control terminal of the first switching element by being turned on;
An off-drive switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element by being turned on;
Control for driving the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the input driving signal. Circuit,
In an electronic device comprising:
An off-holding switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element by being turned on;
The control circuit controls the off-holding switching element to change the off state of the first switching element when a voltage at a control terminal of the first switching element is equal to or lower than an off-holding threshold lower than an on / off threshold voltage. And when the current exceeding the predetermined threshold flows through the on-drive switching element for a predetermined time or more, it is determined that the first switching element is in an abnormal state, and the first switching element is determined to be in an abnormal state. In this case, the electronic device is characterized in that the first switching element is turned off by controlling the off-holding switching element. A first switching element driven by controlling the voltage of the control terminal;
An on-drive switching element that is connected to the control terminal of the first switching element and charges the control terminal of the first switching element by being turned on;
An off-drive switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element by being turned on;
Control for driving the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the input driving signal. Circuit,
In an electronic device comprising:
An off-holding switching element that is connected to the control terminal of the first switching element and discharges the charge from the control terminal of the first switching element by being turned on;
A voltage clamping circuit that clamps a voltage of a control terminal of the first switching element to an off holding threshold value lower than an on / off threshold voltage;
Have
The control circuit controls the off-holding switching element to hold the off-state of the first switching element when the voltage at the control terminal of the first switching element is equal to or lower than an off-holding threshold, and the on-drive switching When a current exceeding a predetermined threshold flows through the element for a predetermined time or more, it is determined that the first switching element is in an abnormal state, and when it is determined that the first switching element is in an abnormal state, the voltage clamp circuit is An electronic device that is actuated to clamp a voltage at a control terminal of the first switching element below an off-holding threshold value. A first switching element driven by controlling the voltage of the control terminal;
An on-drive switching element that is connected to the control terminal of the first switching element and charges the control terminal of the first switching element by being turned on;
An off-drive switching element that is connected to the control terminal of the first switching element and discharges electric charge from the control terminal of the first switching element by being turned on;
Control for driving the first switching element by controlling the voltage of the control terminal of the first switching element by controlling the on-driving switching element and the off-driving switching element based on the input driving signal. Circuit,
In an electronic device comprising:
A second switching element driven by controlling the voltage of the control terminal and connected in series to the first switching element;
The second switching element is driven when the second switching element is driven by controlling the voltage of the control terminal of the second switching element based on the input drive signal, and when the abnormal current flows through the second switching element. A drive circuit for turning off,
Have
The control circuit determines that the first switching element is in an abnormal state and the first switching element is in an abnormal state when a current greater than or equal to a predetermined threshold flows through the on-drive switching element for a predetermined time or more. When the electronic device is determined, the electronic device turns on the first switching element. Wherein the predetermined threshold value, claim, wherein the on-drive switching element and the off-drive switching element is set to a value below the current value flowing through the on-drive switching element when both turn on 5 The electronic device of any one of -7 . The predetermined time is, claim 5, characterized in that it is set to be longer than the time required to charge the charge to the control terminal of the first switching element by the ON-drive switching element 9. The electronic device according to any one of 8 above. The electronic device according to claim 1 , wherein the control circuit outputs an abnormal signal to the outside when it is determined that the first switching element is in an abnormal state.

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