JP5195220B2 - Driving circuit for power conversion circuit - Google Patents

Description

  The present invention relates to a process of charging a charge for turning on a switching element to a conduction control terminal of the switching element, and the conduction control so as to turn on / off the voltage-controlled switching element included in the power conversion circuit. The present invention relates to a drive circuit of a power conversion circuit that performs a process of discharging the charge from a terminal.

  This type of driving circuit includes a switching element for charging a positive charge to the gate and a positive charge from the gate in order to turn on / off an insulated gate bipolar transistor (IGBT) as a switching element of a power conversion circuit. It is well known that it has a discharge switching element that discharges. That is, by turning off the discharge switching element and turning on the charging switching element, the gate of the IGBT is charged with a positive charge to turn it on, and the charging switching element is turned off. Further, by turning on the discharge switching element, positive charges are discharged from the gate of the IGBT, thereby turning it off.

  Parasitic capacitance exists between the gate and collector of the IGBT. For this reason, when noise is superimposed between the collector and emitter of the IGBT, etc., this noise propagates to the gate via the parasitic capacitance, so that a current flows through the electrical path connected to the gate. When current flows through the electrical path connected to the gate in this way, the voltage of the gate fluctuates due to the voltage drop. For this reason, when the IGBT is turned off and the gate voltage fluctuates due to the noise, the IGBT may be turned on erroneously.

Therefore, conventionally, for example, as seen in Patent Document 1 below, a switching element that short-circuits between the gate and the emitter of the IGBT is provided, and when the gate voltage of the IGBT becomes a predetermined value or less by turning on the discharge switching element, It has also been proposed to short-circuit the gate and emitter of the IGBT. Thereby, in the period in which the IGBT is turned off, fluctuations in the potential of the gate can be suitably suppressed, and consequently, the IGBT can be prevented from being turned on erroneously.
JP-A-8-18423

  By the way, in recent years, for the purpose of reducing the size of the drive circuit and the purpose of reducing the cost of the drive circuit, the drive circuit has been constituted by an integrated circuit (IC) integrated into one chip as much as possible. However, if a terminal for monitoring the gate voltage is added to incorporate the function of driving the switching element for short-circuiting the gate and emitter of the IGBT as described above into the IC, the number of terminals increases. It cannot be ignored that the IC becomes larger due to the above.

  The present invention has been made in order to solve the above-described problems, and the purpose thereof is to integrate even if the function of short-circuiting between the conduction control terminal and the output terminal of the switching element provided in the power conversion circuit is mounted. An object of the present invention is to provide a drive circuit for a power conversion circuit that can suppress an increase in circuit size as much as possible.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to the first aspect of the present invention, in order to turn on / off a voltage-controlled switching element included in a power conversion circuit, a process for charging a conduction control terminal of the switching element with an electric charge for turning on the switching element In the drive circuit of the power conversion circuit that performs the process of discharging the charge from the conduction control terminal, the conduction control terminal is connected to either the output terminal or the input terminal of the switching element during the on / off operation. The discharge switching element for discharging the electric charge from the conduction control terminal, the short-circuit switching element for short-circuiting the conduction control terminal and any one of the terminals, and the discharge switching element are incorporated 1 A chip integrated circuit, and the integrated circuit is a terminal connected to the conduction control terminal, and In addition to a terminal to which the discharging switching element is connected, a processing means is provided for performing a process of turning on the shorting switching element based on a voltage of a terminal for charging or discharging the conduction control terminal. And

  In the above invention, the number of terminals of the integrated circuit is reduced by diverting the other terminal as a terminal for monitoring the voltage of the conduction control terminal of the switching element in order to perform the process of turning on the short-circuit switching element. As a result, enlargement of the integrated circuit can be suppressed as much as possible.

  The impedance of the short-circuit path between the conduction control terminal via the short-circuit switching element and any one of the terminals is the impedance of the path between the conduction control terminal via the discharge switching element and any one of the terminals. Less than. In particular, the impedance of the short-circuit path between the conduction control terminal and any one of the terminals via the short-circuit switching element is the path having the smallest impedance among the paths that can be connected between the conduction control terminal and any one of the terminals. It is desirable that

  According to a second aspect of the present invention, in the first aspect of the invention, the integrated circuit includes a charging switching element for charging the electric charge in the conduction control terminal, and the other terminal is the It is a terminal for connecting the switching element for charging and the conduction control terminal.

  The charging switching element is turned off during the period in which the discharging switching element is turned on. For this reason, in the said invention, the voltage of a conduction | electrical_connection control terminal can be appropriately monitored by said another terminal in the period when the switching element for discharge is made into an ON state.

  According to a third aspect of the present invention, in the second aspect of the present invention, the terminal connected to the charging switching element is connected to the conduction control terminal via a charging resistor.

  In the said invention, the noise superimposed on another terminal can be reduced using the charging resistor which prescribes | regulates the charging speed of a conduction control terminal.

  According to a fourth aspect of the present invention, in the invention according to the second or third aspect, the processing means for prohibiting the on state during the period when the charging switching element is in the on state.

  In the above invention, it is possible to prevent the short-circuit switching element from being erroneously turned on based on the voltage of another terminal during the period in which the charging switching element is turned on.

  According to a fifth aspect of the present invention, in the invention according to the second or third aspect, the processing unit is prohibited from performing the on-state during a period in which the discharge switching element is in the off-state.

  In the above invention, it is possible to prevent the short-circuit switching element from being erroneously turned on based on the voltage of another terminal during the period in which the discharge switching element is in the off-state.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the processing means turns off the short-circuiting switching element in synchronization with the turning-off operation of the discharging switching element. It is characterized by that.

  When the switching element for discharge is turned off, it is considered that there is no need to short-circuit the conduction control terminal of the switching element and one of the terminals. In this regard, in the above-described invention, by turning off the short-circuit switching element in synchronization with the discharge switching element being turned off, the off-operation timing of the short-circuit switching element can be easily set.

  The invention according to claim 7 is a process of charging a conduction control terminal of the switching element with an electric charge for turning on the switching element so as to turn on / off the voltage-controlled switching element included in the power conversion circuit. And a short-circuit switching element that short-circuits either the output terminal or the input terminal of the switching element and the conduction control terminal in the drive circuit of the power conversion circuit that performs the process of discharging the charge from the conduction control terminal; A first integrated circuit connected to a path for operating the short-circuit switching element, and when the switching element of the power conversion circuit is turned on / off. A second terminal connected to a discharge path for discharging the charge charged in the conduction control terminal; and the power separately from the discharge path A third terminal connected to a path for charging or discharging the conduction control terminal of the switching element of the conversion circuit, and for the short circuit via the first terminal based on the voltage of the third terminal The switching element is turned on.

  In the above invention, the number of terminals of the integrated circuit is reduced by diverting the third terminal as a terminal for monitoring the voltage of the conduction control terminal of the switching element in order to perform the process of turning on the shorting switching element. As a result, enlargement of the integrated circuit can be suppressed as much as possible.

  The invention according to claim 8 is the invention according to claim 7, wherein the another path is a charge for charging the conduction control terminal with the charge when the switching element of the power conversion circuit is turned on / off. It is a route.

  During the discharge period of the conduction control terminal via the discharge path, the conduction control terminal is not charged via the charging path. For this reason, in the said invention, the voltage of a conduction control terminal can be appropriately monitored by the said 3rd terminal in the discharge period of a conduction control terminal.

  A ninth aspect of the invention is characterized in that, in the eighth aspect of the invention, a charging resistor is provided in the charging path.

  In the said invention, the noise superimposed on a 3rd terminal can be reduced using the resistor for charge which prescribes | regulates the charging speed of a conduction | electrical_connection control terminal.

  According to a tenth aspect of the present invention, in the invention according to any one of the seventh to ninth aspects, the integrated circuit terminates the state in which the electric charge is drawn into the second terminal via the discharge path. Synchronously, the short-circuit switching element is turned off.

  At the end of the state where the charge of the conduction control terminal is drawn into the second terminal via the discharge path, it is considered that there is no need to short-circuit the conduction control terminal of the switching element and one of the terminals. In this regard, in the above invention, the short-circuit switching element is turned off in synchronization with the end of the charge drawing state of the conduction control terminal to the second terminal via the discharge path. Timing can be set easily.

(First embodiment)
Hereinafter, a first embodiment in which a drive circuit of a power conversion circuit according to the present invention is applied to a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows the overall configuration of a motor generator control system according to this embodiment. The motor generator 10 is connected to a high voltage battery 12 via an inverter IV and a boost converter CV. Here, boost converter CV connects capacitor C, a pair of power switching elements Scp, Scn connected in parallel to capacitor C, a connection point between the pair of power switching elements Scp, Scn, and the positive electrode of high-voltage battery 12. And a reactor L. The voltage of the high-voltage battery 12 (for example, “288V”) is boosted up to a predetermined voltage (for example, “666V”) by turning on / off the power switching elements Scp, Scn. On the other hand, the inverter IV includes a series connection body of power switching elements Sup and Sun, a series connection body of power switching elements Svp and Svn, and a series connection body of power switching elements Swp and Swn. Body connection points are connected to the U, V, and W phases of motor generator 10, respectively. In the present embodiment, an insulated gate bipolar transistor (IGBT) is used as these power switching elements Sup, Sun, Svp, Svn, Swp, Swn, Scp, Scn. In addition, diodes Dup, Dun, Dvp, Dvn, Dwp, Dwn, Dup, and Dun are connected in antiparallel to these.

  The control device 16 is a control device that uses the low-voltage battery 14 as a power source. The controller 16 controls the motor generator 10 and operates the inverter IV and the converter CV to control the control amount as desired. Specifically, operation signals gcp and gcn are output to drive unit DU to operate power switching elements Scp and Scn of converter CV. Further, in order to operate the power switching elements Sup, Sun, Svp, Svn, Swp, Swn of the inverter IV, the operation signals gup, gun, gvp, gvn, gwp, gwn are output to the drive unit DU. Here, the high-potential side operation signals gcp, gup, gvp, gwp and the corresponding low-potential side operation signals gcn, gun, gvn, gwn are complementary signals. In other words, the power switching elements Scp, Sup, Svp, Swp on the high potential side and the corresponding power switching elements Scn, Sun, Svn, Swn on the low potential side are alternately turned on.

  FIG. 2 shows the configuration of the drive unit DU. Hereinafter, the power switching elements Sup, Sun, Svp, Svn, Swp, Swn, Scp, Scn are collectively referred to as the power switching element S, and the operation signals gup, gun, gvp, gvn, gwp, gwn, gcp , Gcn are collectively expressed as the operation signal g.

  As shown in the figure, the drive unit DU includes a drive IC 20 that is a one-chip semiconductor integrated circuit. The terminal T1 of the drive IC 20 is connected to the gate of the power switching element S via a charging resistor 30 for adjusting the gate charging speed. On the other hand, the drive IC 20 includes a power supply 26 that supplies electric charges for charging the conduction control terminal (gate) so as to turn on the power switching element S. The power source 26 is connected to the terminal T <b> 1 via the input terminal and the output terminal of the charging switching element 24.

  The terminal T2 of the drive IC 20 is connected to the gate of the power switching element S via a discharge resistor 34 for adjusting the discharge rate of the gate. On the other hand, the drive IC 20 includes a discharge switching element 32 that opens and closes between the terminal T5 and the terminal T2 connected to the emitter of the power switching element S.

  The drive IC 20 further includes a drive circuit 22 that drives the power switching element S. In the drive circuit 22, the charging switching element 24 and the discharging switching element 32 are complementarily turned on / off based on the operation signal g input to the drive unit DU via an insulating means such as a photocoupler (not shown). To drive the power switching element S. That is, when the operation signal g becomes logic “H” to indicate that the power switching element S is to be turned on, the charging switching element 24 is turned on and the discharging switching element 32 is turned off. Thus, a positive charge is charged to the gate of the power switching element S. Further, when the operation signal g becomes logic “L” to instruct to turn off the power switching element S, the charging switching element 24 is turned off and the discharging switching element 32 is turned on. Thus, positive charges are discharged from the gate of the power switching element S.

  The power switching element S includes a sense terminal ST that outputs a minute current having a correlation with a current (collector current) flowing between its input terminal (collector) and output terminal (emitter). The sense terminal ST is electrically connected to the emitter through a series connection body of resistors 40 and 42. As a result, a voltage drop occurs in the resistor 42 due to the current output from the sense terminal ST. Therefore, the amount of voltage drop due to the resistor 42 is correlated with the current flowing between the input terminal and the output terminal of the power switching element S. State quantity.

  The amount of voltage drop due to the resistor 42 is taken into the non-inverting input terminal of the comparator 44 via the terminal T4. On the other hand, a threshold voltage Vref is applied to the inverting input terminal of the comparator 44. Accordingly, when the collector current becomes equal to or greater than the threshold value, the comparator 44 is inverted from the logic “L” to the logic “H”. The logic “H” signal of the comparator 44 is taken into the delay 52 as the fail signal FL. The delay 52 outputs a logic “H” signal to the gate of the soft shut-off switching element 54 so that the power switching element S is forcibly turned off when the input signal becomes logic “H” for a predetermined time. And a stop signal AE to the drive circuit 22. Here, the stop signal AE is a signal for stopping the driving of the charging switching element 24 and the discharging switching element 32 by the driving circuit 22.

  The output terminal of the soft cutoff switching element 54 is connected to the terminal T5, and the input terminal is connected to the gate of the power switching element S via the soft cutoff resistor 56, the terminal T2, and the discharge resistor 34. Is done. As a result, the state where the collector current is equal to or greater than the threshold value continues for a predetermined time or longer, so that the soft cutoff switching element 54 is turned on, and the power switching element 56 and the discharge resistor 34 are connected via the soft cutoff resistor 56 and the discharge resistor 34. The charge on the gate of S is discharged. Here, the soft blocking resistor 56 is used to increase the resistance value of the discharge path. This is because, under a situation where the collector current is excessive, if the speed at which the power switching element S is switched from the on state to the off state, in other words, the cutoff speed between the collector and the emitter is increased, the surge becomes excessive. This is in view of the fear. For this reason, under the situation where the collector current is determined to be equal to or greater than the threshold value, the gate of the power switching element S is connected by a path having a larger resistance value than the discharge path including the discharge resistor 34 and the discharge switching element 32. Discharge.

  The output signal of the comparator 44 is further applied to the gate of the switching element 46. The switching element 46 has one terminal connected to the emitter of the power switching element S and the other terminal connected to the anode side of the Zener diode 50. The cathode side of the Zener diode 50 is connected to the terminal T2. Thereby, when the output signal of the comparator 44 becomes logic “H”, the switching element 46 is turned on, and therefore the voltage of the gate of the power switching element S is limited to about the breakdown voltage of the Zener diode 50. Become. This limits the collector current.

  According to such a configuration, when an overcurrent flows through the power switching element S, the Zener diode 50 is first turned on, so that the gate voltage of the power switching element S decreases. Thereby, the electric current which flows through the power switching element S can be restrict | limited. After that, when the overcurrent continues for a predetermined time, the soft cutoff switching element 54 is turned on, so that the power switching element S is forcibly turned off.

  The drive unit DU further includes an N-channel MOS field effect transistor (off-holding switching element 62) for short-circuiting the gate and emitter of the power switching element S. The off-holding switching element 62 is provided as close as possible to the power switching element S so as to connect the gate and emitter of the power switching element S with a low resistance. Of the paths connecting the gate and the emitter of the power switching element S, the impedance of the path including the off-holding switching element 62 is set to be lower than the impedance of the path including the discharge resistor 34. Yes. This is because when the power switching element S is turned off in accordance with the operation signal g, the input terminal (collector) of the power switching element S or the parasitic capacitance between the output terminal (emitter) and the gate is used. This is for avoiding that the power switching element S is erroneously turned on by superimposing high-frequency noise on the gate.

  That is, when a current flows from the gate of the power switching element S to the discharging resistor 34 due to high frequency noise, the voltage of the gate increases due to the voltage drop of the discharging resistor 34, so that the power switching element S is turned on. There is a risk of a situation. On the other hand, when the off-holding switching element 62 is provided, a current flows from the gate of the power switching element S to the off-holding switching element 62 due to high frequency noise. Since the impedance of this path is very small, the amount of increase in the gate voltage can be ignored, and the power switching element S can be held in the off state.

  The gate of the off-holding switching element 62 is connected to the off-holding circuit 60 in the drive IC 20 via the terminal T3. The off-holding circuit 60 monitors the gate voltage of the power switching element S based on the voltage applied to the terminal T1, and performs a process of turning on the off-holding switching element 62 when this voltage becomes a predetermined voltage. Is. In addition, a signal output from the drive circuit 22 to the gate of the discharge switching element 32 is monitored, and a process for turning off the off-holding switching element 62 is performed in synchronization with the discharge switching element 32 being turned off. But there is. Next, the processing of the off hold circuit 60 will be described with reference to FIG.

  FIG. 3 shows a process of the off-holding circuit 60 in a normal time when the power switching element S is operated by the operation signal g. Specifically, FIG. 3A shows the transition of the state of the charging switching element 24, FIG. 3B shows the transition of the state of the discharging switching element 32, and FIG. 3C shows the gate voltage. FIG. 3D shows the transition of the voltage state at the terminal T1, and FIG. 3E shows the transition of the gate voltage of the off-holding switching element 62. FIG.

  As shown in the figure, the off-holding switching element 62 is turned off in synchronization with the discharge switching element 32 being turned off. When the discharging switching element 32 is turned off, the charging switching element 24 is turned on after the elapse of a predetermined dead time. Thereby, the gate voltage of the power switching element S rises, and the power switching element S is switched on. Thereafter, the charge switching element 24 is turned off, and the positive charge is discharged from the gate of the power switching element S by turning on the discharge switching element 32 after a predetermined dead time has elapsed. Decreases. When the gate voltage decreases by a predetermined amount, the mirror period is reached, so that the rate of decrease of the gate voltage temporarily decreases. When the mirror period elapses, the gate voltage decrease rate increases, and the gate voltage decreases to substantially zero. At this time, the voltage at the terminal T1 also decreases to substantially zero. At this time, when the voltage at the terminal T1 becomes the threshold voltage, the off-holding switching element 62 is turned on. Here, in this embodiment, the threshold voltage is set to a predetermined voltage (here, 3.3 V) that the terminal T1 can take after the mirror period.

  As described above, since the power switching element S is substantially turned off and the gate and the emitter of the power switching element S are short-circuited by the off-holding switching element 62, the speed at which the power switching element S is turned off is It can be controlled by the resistor 34 for use. For this reason, since the OFF speed of the power switching element S does not become excessively large, a surge during the OFF operation of the power switching element S can be suppressed. Then, the switching element 62 for holding off is turned on in a state where the power switching element S is substantially in an off state, thereby suitably suppressing the gate voltage from rising due to high frequency noise thereafter. Can do.

  It is desirable that the timing for turning on the off-holding switching element 62 be performed as early as possible within a range in which the current flowing through the power switching element S is not suddenly interrupted. For this reason, it is desirable to turn off the off-holding switching element 62 based on the monitoring of the gate voltage of the power switching element S. However, as shown in FIG. 4, when the drive IC 20 is provided with a dedicated terminal T6 to monitor the gate voltage, the drive IC 20 may be increased in size due to an increase in the number of terminals of the drive IC 20 or the like. is there. In addition, in this case, it is desirable that a filter circuit is provided to remove noise from the voltage applied to the terminal T6 and that the voltage filtered by the filter circuit is taken into the off holding circuit 60.

  On the other hand, in the present embodiment, by monitoring the voltage at the terminal T1 that connects the charging switching element 24 and the power switching element S, an increase in the number of terminals can be avoided. Furthermore, by monitoring the voltage on the charging switching element 24 side with respect to the charging resistor 30, the filter effect by the resistor 30 can also be expected. That is, a parasitic capacitor exists in the electrical path between the charging resistor 30 and the off-holding circuit 60 as schematically shown by a broken line in FIG. For this reason, an RC series circuit is constituted by the parasitic capacitor and the charging resistor 30.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) Based on the voltage applied to the terminal T1 for connecting the charging switching element 24 and the gate of the power switching element S, the off-holding switching element 62 is turned on. Thereby, the number of terminals of the drive IC 20 can be reduced, and as a result, an increase in the size of the drive IC 20 can be suppressed as much as possible.

  (2) The terminal T1 connected to the charging switching element 24 is connected to the gate of the power switching element S via the charging resistor 30. Thereby, the gate voltage after reducing the noise superimposed on the gate of the power switching element S can be taken into the off hold circuit 60.

  (3) The off-holding switching element 62 is turned off in synchronization with the turning-off operation of the discharge switching element 32. Thereby, the off operation timing of the off-holding switching element 62 can be easily set.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 5 shows processing of the off hold circuit 60 according to the present embodiment. Here, FIGS. 5A to 5E correspond to FIGS. 3A to 3E.

  As shown in the figure, in this embodiment, the period during which the charging switching element 24 is turned on is the on-operation prohibition period of the off-holding switching element 62 by the off-holding circuit 60. Thereby, it is possible to suitably avoid that the off-holding circuit 60 malfunctions due to the influence of noise or the like and the off-holding switching element 62 is turned on during the period in which the power switching element S is to be turned on.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects (1) to (3) of the first embodiment.

  (4) During the period when the charging switching element 24 is in the on state, the process of turning on the off holding circuit 60 is prohibited. Thereby, it is possible to prevent the off-holding switching element 62 from being erroneously turned on based on the voltage at the terminal T1 during the period in which the charging switching element 24 is turned on.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 6 shows processing of the off hold circuit 60 according to the present embodiment. Here, FIGS. 6A to 6E correspond to FIGS. 3A to 3E.

  As shown in the figure, in the present embodiment, the period during which the discharge switching element 32 is in the OFF state is the ON operation prohibition period of the OFF holding switching element 62 by the OFF holding circuit 60. Thereby, it is possible to suitably avoid that the off-holding circuit 60 malfunctions due to the influence of noise or the like and the off-holding switching element 62 is turned on during a period in which the power switching element S should not be turned off.

  According to the present embodiment described above, the following effects can be obtained in addition to the effects (1) to (3) of the first embodiment.

  (5) During the period in which the discharge switching element 32 is in the off state, the process of turning on the off holding circuit 60 is prohibited. Thereby, it is possible to avoid that the off-holding switching element 62 is erroneously turned on based on the voltage at the terminal T1 during the period in which the discharge switching element 32 is turned off.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  In each of the above embodiments, the off-holding switching element 62 is configured by a discrete component, but is not limited thereto, and may be configured in the drive IC 20. Even in this case, the drive IC 20 can be downsized by diverting the terminal T1 connected to the charging switching element 24 as a terminal for monitoring the gate voltage of the power switching element S.

  In each of the above embodiments, the charging resistor 30 and the discharging resistor 34 are configured by discrete components. However, the present invention is not limited thereto, and may be configured in the drive IC 20.

  The method for turning off the off-holding switching element 62 in synchronization with the turning-off operation of the discharging switching element 32 is not limited to those exemplified in the above embodiments. For example, when the power switching element S is turned off, a signal to that effect is directly output from the drive circuit 22 to the off holding circuit 60, and the discharge switching element 32 has the voltage at the terminal T3 set to the logic “H” level. Thus, the on-operation may be performed.

  The terminal for monitoring the gate voltage of the power switching element S to turn on the off-holding switching element 62 is not limited to the terminal T1 to which the charging switching element 24 is connected. For example, the drive unit DU shown in FIG. 2 is modified so that a resistor connecting the Zener diode 50 and the gate of the power switching element S is separated from the discharge resistor 34, and the resistor and the Zener diode are connected. When a terminal for connecting to the terminal 50 is separately provided, this terminal may be used. Even in this case, the Zener diode 50 is also turned off when the power switching element S is turned off in a normal state in which the power switching element S is manipulated based on an operation signal from the control device 16. The voltage of the power switching element S can be appropriately monitored by the terminal.

  Further, for example, the drive unit DU shown in FIG. 2 is modified, and the soft cutoff resistor 56 is externally attached to the drive IC 20 as a discrete component, and the soft cutoff resistor and the soft cutoff switching element 54 are connected. If a separate terminal is provided, this terminal may be used. Even in this case, in the normal time when the power switching element S is operated based on the operation signal from the control device 16, the soft cutoff switching element 54 maintains the OFF state. The voltage of S can be monitored appropriately.

  The drive IC 20 may not include the soft cutoff switching element 54, the Zener diode 50, the switching element 46, and the like.

  The power switching element of the power conversion circuit is not limited to the inverter IV and the converter CV connected between the vehicle-mounted rotating machine and the battery. For example, it may be a power switching element that constitutes a DCDC converter that steps down the voltage of the high-voltage battery in order to supply the power of the on-vehicle high-voltage battery to the low-voltage battery.

  The power switching element of the power conversion circuit is not limited to the IGBT but may be, for example, a MOS field effect transistor.

1 is a system configuration diagram according to a first embodiment. FIG. The figure which shows the circuit structure of the drive circuit concerning the embodiment. The time chart which shows the OFF maintenance process of the power switching element concerning the embodiment. The figure which shows the circuit structure of the drive circuit used as the comparison object with the embodiment. The time chart which shows the off maintenance process of the power switching element concerning a 2nd embodiment. The time chart which shows the off maintenance processing of the power switching element concerning a 3rd embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 20 ... Drive IC, 32 ... Discharge switching element, 34 ... Discharge resistor, 60 ... Off holding circuit (one embodiment of processing means), 62 ... Off holding switching element (one embodiment of short circuit switching element) , S ... power switching element, IV ... inverter (one embodiment of power conversion circuit), CV ... converter (one embodiment of power conversion circuit).

Claims (10)

In order to turn on / off a voltage-controlled switching element included in the power conversion circuit, a process for charging the conduction control terminal of the switching element with a charge for turning on the switching element, and the charge from the conduction control terminal In the drive circuit of the power conversion circuit that performs the process of discharging
A discharging switching element for discharging the charge from the conduction control terminal by connecting either the output terminal or the input terminal of the switching element and the conduction control terminal during the on / off operation;
A short-circuit switching element that short-circuits the conduction control terminal and any one of the terminals;
A one-chip integrated circuit containing the discharge switching element,
The integrated circuit is a terminal connected to the conduction control terminal and the short circuit based on a voltage of a terminal for charging or discharging the conduction control terminal separately from a terminal connected to the discharging switching element. A drive circuit for a power conversion circuit, comprising processing means for performing processing for turning on a switching element for a power supply. The integrated circuit includes a charging switching element for charging the electric charge in the conduction control terminal,
The drive circuit of the power conversion circuit according to claim 1, wherein the another terminal is a terminal that connects the charging switching element and the conduction control terminal.   The drive circuit of the power conversion circuit according to claim 2, wherein a terminal connected to the charging switching element is connected to the conduction control terminal via a charging resistor.   4. The power conversion circuit drive circuit according to claim 2, wherein the processing unit prohibits the processing to turn on in the period when the charging switching element is turned on. 5.   4. The power conversion circuit drive circuit according to claim 2, wherein the processing means prohibits the processing to turn on during the period in which the discharge switching element is in the off state.   6. The power conversion circuit drive circuit according to claim 1, wherein the processing unit turns off the short-circuiting switching element in synchronization with the turning-off operation of the discharging switching element. . In order to turn on / off a voltage-controlled switching element included in the power conversion circuit, a process for charging the conduction control terminal of the switching element with a charge for turning on the switching element, and the charge from the conduction control terminal In the drive circuit of the power conversion circuit that performs the process of discharging
A short-circuit switching element that short-circuits either the output terminal or the input terminal of the switching element and the conduction control terminal;
An integrated circuit integrated into one chip,
The integrated circuit includes: a first terminal connected to a path for operating the short-circuit switching element; and the charge charged in the conduction control terminal when the switching element of the power conversion circuit is turned on / off. A second terminal connected to a discharge path for discharging the battery, and a third terminal connected to a path for charging or discharging the conduction control terminal of the switching element of the power conversion circuit separately from the discharge path. A power conversion circuit drive circuit comprising: turning on the short-circuit switching element via the first terminal based on a voltage of the third terminal.   8. The power conversion circuit according to claim 7, wherein the another path is a charging path for charging the electric charge to the conduction control terminal when the switching element of the power conversion circuit is turned on / off. Drive circuit.   9. The drive circuit for a power conversion circuit according to claim 8, wherein a charging resistor is provided in the charging path.   10. The integrated circuit according to claim 7, wherein the short-circuit switching element is turned off in synchronization with the end of the charge drawing state to the second terminal via the discharge path. The drive circuit of the power converter circuit of any one of Claims 1.

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