JP2011091923A - Drive circuit of voltage-driven switching device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a drive circuit of a voltage-driven switching device for making a turn-on gate current constant in an entire section including a mirror section. <P>SOLUTION: A gate drive constant current circuit is connected to a gate terminal of an IGBT1, and outputs a gate signal for turning on and off the IGBT1 to the gate terminal based on an on/off gate control signal of a pulse signal 2 for drive. The gate drive constant current circuit includes a constant voltage diode 14, a resistor 6, and a control signal transmission transistor 7 connected in series between a positive power supply 3 and GND potential 4, and a gate-on resistor 8 and a constant current output transistor 9 connected in series between the positive power supply 3 and the gate terminal of the IGBT1. A base terminal of the constant current output transistor 9 is connected between the constant voltage diode 14 and the resistor 6. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a drive circuit for a voltage-driven switching device, and more particularly to a drive circuit for a voltage-driven switching device used in a power converter that drives an inductive load such as a motor from a high-voltage DC power supply.

  The conditions required for a circuit that drives a voltage-driven switching device used in a power converter are that the voltage-driven switching device can be driven with low loss, and that the voltage utilization is high and that an inductive load such as a motor has a high output. In order to drive, it is required to be able to drive quickly in response to a command from the control device. As a driving method for reducing the switching loss of a voltage-driven switching device, even when the gate-emitter threshold voltage of an insulated gate bipolar transistor (hereinafter referred to as IGTB (Insulated Gate Bipolar Transistor)) varies, the turn-on loss varies. A constant current driving system effective for reduction is used. Here, the gate-emitter threshold voltage is the gate-emitter threshold when current begins to flow between the collector-emitter of the IGBT in a state where a predetermined output voltage (for example, 10 V) is applied between the collector-emitter of the IGBT. Refers to voltage.

  As shown in FIG. 5, in the constant current drive of the voltage driven switching device, it is desirable that the gate current is constant in the mirror section and other than the mirror section. If the gate current is too large, there will be problems due to increased radiation noise, and if the gate current is too small, the switching loss will increase at turn-on and the turn-on speed will be slower with respect to the ON command from the controller. The problem is that the voltage utilization rate is reduced and inductive loads such as motors cannot be driven at high output. Therefore, it is desirable that the gate current be as large as possible without affecting the radiation noise.

  By the way, Patent Document 1 proposes a drive circuit for a power semiconductor element that corrects an imbalance in output current even when the gate-emitter threshold voltage of power semiconductor elements connected in parallel varies. Yes. In this Patent Document 1, a current mirror circuit constituted by a PNP transistor is provided as a specific example of a drive circuit for a power semiconductor element, a Pch-MOSFET is provided as a specific example of an on signal transistor, and an off signal transistor is provided. A specific example using an Nch-MOSFET is disclosed. Moreover, the modification is also disclosed.

JP 2008-178248 A (paragraphs 0027 to 0030, FIGS. 5 and 6)

  However, in the power semiconductor element drive circuit disclosed in Patent Document 1, as shown in FIG. 6, the constant current value is different in the voltage-driven switching device except for the mirror section and the mirror section. There is a problem that cannot be reduced as intended. In addition, since the constant current value decreases outside the mirror section, there is a problem that it is impossible to quickly respond to a command from the control device, the voltage utilization rate is reduced, and the motor cannot be driven at a high output. Hereinafter, a mechanism in which the constant current value changes between the mirror section and other than the mirror section will be described.

  FIG. 7 is a diagram schematically illustrating the constant current driving circuit disclosed in Patent Document 1 (FIG. 6 of Patent Document 1). FIG. 7 shows a gate drive constant current circuit connected to the gate terminal of the IGBT 1 and outputting a gate signal for turning on / off the IGBT 1 to the gate terminal based on the on / off gate control signal of the driving pulse signal 2. .

  This gate drive constant current circuit includes a first resistor 5 and a second resistor 6 connected in series between the positive power supply 3 and the GND potential 4, a control signal transmission transistor 7, and the gate terminals of the positive power supply 3 and the IGBT 1. A gate-on resistor 8 and a constant current output transistor 9 are connected in series, and the gate terminal of the constant current output transistor 9 is connected between the first resistor 5 and the second resistor 6. Reference numeral 10 denotes an off signal transistor, 11 denotes an inverting element connected to the gate terminal of the off signal transistor 10, and 12 denotes a gate off resistance connected between the gate terminal of the IGBT 1 and the collector of the off signal transistor 10. Is shown.

In the constant current drive circuit of FIG. 7, the voltage of the positive power supply 3 is Vcc, the resistance value of the first resistor 5 is R1, the resistance value of the second resistor 6 is R2, the resistance value of the gate-on resistor 8 is Rg, and the constant current The collector-base capacitance of the output transistor 9 is C _CB , the base-emitter voltage of the constant current output transistor 9 is V _BE , the base current of the constant current output transistor 9 is I _B , and the current amplification factor of the constant current output transistor 9 is the gate of the h _FE, IGBT1 - when the emitter voltage using the gate current of Vg, IGBT1 and Ig, calculates the gate current Ig other than the gate current Ig (mirror) and mirror sections of the mirror section of IGBT1 by the circuit equations.

The gate current Ig outside the mirror interval is calculated. As a circuit equation for calculating the gate current Ig, first consider the base current I _B. The base current I _B is the sum of the current obtained by dividing the gate current Ig by the current amplification factor h _FE and the current that discharges the collector-base capacitor C _CB , and is given by Equation (1).

  Next, when a contact point equation is established for the connection point V2 between the first resistor 5 and the second resistor 6, equation (2) is obtained.

  Further, when the gate current Ig is Rg = 1, Expression (3) is obtained.

  Solving for the gate current Ig from the equations (1) to (3) gives the following.

  As shown in FIG. 6, since the gate-emitter voltage increases with a slope of dVg / dt outside the mirror interval, the gate current Ig decreases outside the mirror interval from Equation (4).

  Next, the gate current Ig (mirror) in the mirror section is calculated. As shown in FIG. 6, since dVg / dt = 0 in the mirror section, substituting dVg / dt = 0 into equation (4) yields equation (5).

  Therefore, the gate current Ig (mirror) increases in the mirror section from the equation (5).

8, a gate other than the mirror section and a mirror section of a conventional voltage-driven switching devices - emitter voltage Vg, the collector of the gate current Ig, IGBT 1 - is a schematic view of the emitter voltage V _CE. As shown in FIG. 8, there is a delay in increase of the period T1 in the gate current Ig after mirror section rush, IGBT 1 collector - becomes gentle descent emitter voltage V _CE, which is a factor of switching loss increase . Further, since the gate current Ig in section T2 after the end mirror section is reduced, the collector of the IGBT 1 - lowering of the emitter voltage _{V CE} becomes gentle, the collector of the IGBT 1 - quick saturation voltage _V CE emitter voltage VCE (sat) The voltage utilization factor decreases due to an increase in switching loss and deterioration of the responsiveness to the ON command from the control device, causing inductive loads such as motors to be driven at a high output. Yes.

  FIG. 9 is a diagram schematically showing a constant current driving circuit (FIG. 5 of Patent Document 1) configured by a current mirror system disclosed in Patent Document 1. The same reference numerals as those in FIG. 7 denote the same or corresponding parts. Is shown. In FIG. 9, a pair of constant current output transistors 9 as a current mirror is connected between a first resistor 5 and a second resistor 6 connected in series between a positive power supply 3 and a GND potential 4. The base terminals of the pair of transistors 13 are connected to the base terminal of the constant current output transistor 9 and the second resistor 6.

In the current mirror type constant current driving circuit shown in FIG. 9, the voltage of the positive power supply 3 is Vcc, the resistance value of the first resistor 5 is R1, the resistance value of the second resistor 6 is R2, and the resistance value of the gate-on resistance 8 Rg, the collector-base capacitance of the constant current output transistor 9 is C _CB , the base-emitter voltage of the constant current output transistor 9 and the pair of transistors 13 is V _BE , and the base current of the constant current output transistor 9 is I _B 2. The base current of the pair of transistors 13 is I _B 1, the constant current output transistor 9 and the current amplification factor of the pair of transistors 13 are h _FE , the gate-emitter voltage of the IGBT 1 is Vg, and the gate current of the IGBT 1 is Ig Then, the gate current Ig of the IGBT 1 is calculated by the circuit equation. Since the pair of transistors 13 used as current mirrors are manufactured on one chip and have substantially the same characteristics, the constant-current output transistor 9 and the base-emitter voltage V _BE and current amplification of the pair of transistors 13 are the same. Consider rate h _FE equal.

First, base currents I _B 1 and I _B 2 are considered as circuit equations for calculating the gate current Ig. When the connection point of the emitter terminal and the second resistor 6 of the transistor 13 of the pair was V3, base current I _{B 1} becomes the current obtained by dividing the collector current V3 / R2 in current amplification factor h _FE, the base current I _B 2 divided by current and collector gate current Ig in the current amplification factor h _FE - the sum of the current discharging the base capacitance C _CB, equation (6) becomes (7).

  Next, when a contact point equation is established for the connection point V3, Equation (8) is obtained.

  Further, the gate current Ig is represented by Expression (9).

  Solving for the gate current Ig from the equations (6) to (9) gives the following.

Here, when h _FE ≈h _FE −1, the following equation is obtained.

  Therefore, like the constant current drive circuit of FIG. 7 described above, since dVg / dt = 0 in the mirror section as shown in FIG. 6, even in the constant current drive circuit configured by the current mirror method, the mirror section and the mirror section Otherwise, the gate current Ig is different.

Further, in the constant current driving circuit shown in FIG. 7, the variation of the constant current setting value becomes large due to the variation of circuit components and the temperature drift. In the constant current drive circuit of FIG. 7, the voltage of the positive power supply 3 is Vcc, the resistance value of the first resistor 5 is R1, the resistance value of the second resistor 6 is R2, the resistance value of the gate-on resistor 8 is Rg, and the constant current the base of the output transistor 9 - when the emitter voltage is _{V bE,} the base current _{I B} of the constant current output transistor 9, the constant current set value Ig of the gate drive of IGBT1 becomes equation (10).

Here, the constant current set value Ig of the gate drive, the voltage Vcc of the positive power source 3, the base-emitter voltage V _BE of the constant current output transistor 9, the resistance value R1 of the first resistor 5, and the second resistor 6 resistance R2, the resistance value Rg of the gate resistance 8, and has a base current I received no value the influence of _B in the constant-current output transistor 9. For example, if Vcc = 15V, R1 = 20Ω, R2 = 130Ω, Rg = 1Ω, and V _BE at 25 ° C. = 0.7 V (typ), the Ig (typ) value at 25 ° C. is as follows: .

Usually, the base-emitter voltage V _BE of the transistor varies about ± 0.1 V, and V _BE has a temperature coefficient of −2 mV / ° C. The temperature range for -30 ° C. to 85 ° _C., to calculate the variation in the _{V BE.} The maximum variation is -30 ° C and the minimum value is 85 ° C.
V _BE (maximum value) = 0.7 + 0.1−0.002 × (−30−25) = 0.91V
V _BE (minimum value) = 0.7−0.1−0.002 × (85−25) = 0.48V
It becomes. Further, the voltage Vcc = 15V of the positive power supply 3 also usually has a variation of about ± 1V, and has a maximum value of 16V and a minimum value of about 14V. When the variation of the base-emitter voltage V _BE of the constant current driving transistor 9 and the variation of the voltage Vcc of the positive power supply 3 are substituted into the equation (10), the variation of the constant current setting value Ig of the gate drive is calculated.

It becomes. Therefore, the variation of the constant current set value Ig of the gate drive is
Variation + side = 1.65A / 1.3A = + 27%
Variation-side = 0.96A / 1.3A = -26%
And has a very large variation.

Further, as described above, the resistance value R1 of the first resistor 5, the resistance value R2 of the second resistor 6, is necessary to set the resistance value which is not affected by the base current I _B of the constant current drive transistor 9 Therefore, the power consumption at the resistance value R1 of the first resistor 5 and the resistance value R2 of the second resistor 6 is increased, and the power supply of the drive circuit is increased in size.

  On the other hand, in the case of the constant current drive circuit using the current mirror system shown in FIG. 9, the pair of transistors 13 used as the current mirror are manufactured on one chip and have almost the same characteristics, so the variation in the constant current set value is very large. Small. From the viewpoint of downsizing of the device and low power consumption, the mirror ratio of the current mirror circuit is not 1: 1, but is preferably as large as 1:10.

  However, when the mirror ratio of the current mirror circuit is increased to 1:10, there are no discrete parts that are mass-produced and can be obtained at low cost, and it is necessary to make a custom IC for exclusive use, which increases the cost. In addition, the gate drive circuit usually uses a dedicated gate drive IC, and it may be possible to incorporate a current mirror circuit in the gate drive custom IC, but the IGBT has a large capacity and a constant current value for gate drive. Is large, the chip size is very large in a custom IC in which a power transistor can be formed inside the IC only in a horizontal structure, resulting in an increase in cost.

  The present invention has been made to solve the above-described problem, and an object thereof is to obtain a drive circuit for a voltage-driven switching device that sets a gate current at turn-on to a desired current value with high accuracy. It is.

  A drive circuit for a voltage-driven switching device according to the present invention is connected to a gate terminal of a voltage-driven switching device, and receives a gate signal for turning on / off the switching device based on an on / off gate control signal of a driving pulse signal. In the drive circuit of the voltage-driven switching device that outputs to the gate terminal, a series connection body of a constant voltage diode, a resistor, and a control signal transmission transistor connected between a positive power source and a GND potential, the positive power source, and the switching device A gate-on resistance connected in series between the gate terminals and a series connection of constant current output transistors is provided, and a base terminal of the constant current output transistor is connected between the constant voltage diode and the resistor.

A driving circuit for a voltage-driven switching device according to another invention is connected to a gate terminal of the voltage-driven switching device and turns on / off the switching device based on an on / off gate control signal of a driving pulse signal. In a drive circuit for a voltage-driven switching device that outputs a gate signal to the gate terminal, a first resistor, a first transistor, a second resistor, and a control signal transmission transistor connected between a positive power supply and a GND potential A serial connection body, a serial connection body of a gate-on resistance and a constant current driving transistor connected between the positive power supply and the gate terminal of the switching device, and a connection between the gate-on resistance and the base terminal of the constant current driving transistor. A second transistor, and the first transistor Register, along with the short-circuited connecting the base and collector terminals, in which the base terminal of said second transistor connected between the second resistor and the first transistor.

  According to the voltage-driven switching device driving circuit of the present invention, the gate current at turn-on can be set to a desired current value with high accuracy, so that switching loss can be reduced.

It is a figure which shows the gate drive circuit of the voltage drive type switching device concerning Embodiment 1 of this invention. It is a figure which shows the Zener current-zener voltage characteristic of a constant voltage diode. It is a schematic diagram of the mirror section of the voltage drive type switching device according to the first embodiment of the present invention, the gate-emitter voltage other than the mirror section, the gate current, and the collector-emitter voltage of the IGBT. It is a figure which shows the gate drive circuit of the voltage drive type switching device concerning Embodiment 2 of this invention. It is a figure which shows the desirable behavior of the gate-emitter voltage and gate current in the gate drive circuit of a voltage drive type switching device. It is a figure which shows the behavior of the gate-emitter voltage and gate current in the gate drive circuit of the conventional voltage drive type switching device. It is a figure which shows the gate drive circuit of the conventional voltage drive type switching device. It is a schematic diagram of the mirror section of a conventional voltage-driven switching device, the gate-emitter voltage other than the mirror section, the gate current, and the collector-emitter voltage of the IGBT. It is a figure which shows the gate drive circuit by the current mirror system of the conventional voltage drive type switching device.

  Preferred embodiments of a gate drive circuit for a voltage-driven switching device according to the present invention will be described below with reference to the accompanying drawings. In the following, a case where an IGBT is used as the voltage-driven switching device will be described as an example. However, the voltage-driven switching device is not limited to the IGBT, and other voltage-driven switching devices such as SiC ( Silicon carbide) devices may be used as voltage driven switching devices.

Embodiment 1 FIG.
1 is a diagram showing a gate drive circuit of a voltage-driven switching device according to Embodiment 1 of the present invention. FIG. 1 shows a gate drive constant current circuit that is connected to the gate terminal of the IGBT 1 and outputs a gate signal for turning on / off the IGBT 1 to the gate terminal based on the on / off gate control signal of the driving pulse signal 2. Yes.

This gate drive constant current circuit includes a constant voltage diode 14 connected in series between a positive power source 3 and a GND potential 4, a resistor 6 corresponding to the second resistor in the prior art, a control signal transmission transistor 7, and a positive power source. 3 and a gate terminal of the IGBT 1 are connected in series between a gate-on resistor 8 and a constant current output transistor 9, and a base terminal of the constant current output transistor 9 is connected between the constant voltage diode 14 and the resistor 6. Reference numeral 10 denotes an off signal transistor, 11 denotes an inverting element connected to the gate terminal of the off signal transistor 10, and 12 denotes a gate off resistance connected between the gate terminal of the IGBT 1 and the collector of the off signal transistor 10. Is shown.

  FIG. 2 is a diagram illustrating a Zener voltage-zener current characteristic of the constant voltage diode 14. When the Zener voltage of the constant voltage diode 14 is Vz, the Zener current of the constant voltage diode is Iz, and the coefficient of the Zener voltage of the constant voltage diode is k, the following relational expression is established between the Zener voltage Vz and the Zener current Iz.

In the gate drive circuit of the voltage-driven switching device according to the first embodiment, the voltage of the positive power supply 3 is Vcc, the resistance value of the resistor 6 is R2, the resistance value of the gate-on resistance 8 is Rg, and the collector of the constant current output transistor 9 The base-to-base capacitance is C _CB , the constant-current output transistor 9 base-emitter voltage is V _BE , the constant-current output transistor 9 base current is I _B , the IGBT1 gate-emitter voltage is Vg, and the IGBT1 gate current is When Ig is used, the gate current Ig of the IGBT 1 is calculated from the circuit equation. First, when a contact equation is established for the connection point V1 between the constant voltage diode 14 and the resistor 15, equations (12) and (13) are established.

The gate current Ig is expressed by equation (14).

If V1 is eliminated from Equation (12) and Equation (13) and Ig is solved, Equation (15) is obtained.

Solving for Vz from Equation (11) to Equation (13) yields Equation (16).

When Expression (16) is substituted for Vz in Expression (15), Expression (17) is obtained.

Here, from k >> 1 / R2, Equation (17) becomes Equation (18).

Since k≈∞, Expression (18) becomes Expression (19).

  Therefore, from equation (19), the gate current Ig is constant regardless of dVg / dt, and the gate current Ig of the IGBT 1 is constant outside the mirror interval and the mirror interval.

3, a gate other than the mirror section and a mirror section of the voltage-driven switching device according to the first embodiment - is a schematic view of the emitter voltage V _CE - emitter voltage Vg, the collector of the gate current Ig, IGBT 1. As shown in FIG. 3, even interval T1 after the mirror section inrush, since the gate current Ig is constant, the collector of the IGBT 1 - no delay in falling of the voltage V _CE emitter. Further, since the gate current Ig does not decrease even outside the mirror interval, the collector-emitter voltage V _CE of the IGBT 1 can be quickly lowered to the saturation voltage V _CE (sat).

  As described above, according to the gate drive circuit of the voltage-driven switching device according to the first embodiment, the gate current Ig of the IGBT 1 can be made constant even outside the mirror interval and the mirror interval, and the switching loss at turn-on can be reduced. It can be reduced as intended. Further, since the gate current does not decrease even outside the mirror section, the voltage-driven switching device can be driven with good responsiveness, the voltage utilization rate can be improved, and an inductive load such as a motor can be driven with high output.

  Further, by combining the Zener voltage temperature coefficient of the constant voltage diode 14 and the temperature coefficient of the base-emitter voltage of the constant current output transistor 9, the accuracy of the constant current set value can be improved and loss variation can be reduced. it can.

Embodiment 2. FIG.
Next, a gate drive circuit for a voltage driven switching device according to Embodiment 2 of the present invention will be described. FIG. 4 is a diagram illustrating a gate drive circuit of the voltage-driven switching device according to the second embodiment. FIG. 4 shows a gate drive constant current circuit connected to the gate terminal of the IGBT 1 and outputting a gate signal for turning on / off the IGBT 1 to the gate terminal based on the on / off gate control signal of the driving pulse signal 2. ing. The gate drive constant current circuit includes a first resistor 5, a first transistor 15, a second resistor 6, a control signal transmission transistor 7, and a positive power supply 3 connected in series between the positive power supply 3 and the GND potential 4. And a constant current output transistor 9 connected in series between the gate terminals of the first transistor 15 and the IGBT 1, and the base terminal of the first transistor 15 is short-circuited to the collector terminal of the first transistor 15.

  The collector terminal of the second transistor 16 paired with the first transistor 15 is connected to the base terminal of the constant current output transistor 9, and the emitter terminal of the second transistor 16 is the gate-on resistor 8 and the constant current output transistor 9. The base terminal of the second transistor 16 is connected between the collector terminal of the first transistor 15 and the second resistor 6. Note that the first transistor 15 and the second transistor 16 have the same characteristics, for example, transistors of the same model name and the same production lot are used. Transistors of discrete components with uniform characteristics obtained by carrying out an operation for guaranteeing that they have been manufactured at the same time are used.

In the gate drive circuit of the voltage-driven switching device according to the second embodiment as described above, the voltage of the positive power supply 3 is Vcc, the resistance value of the first resistor 5 is R1, and the resistance value of the second resistor 9 is R2. , the resistance value of the gate-on resistor 8 Rg, the base of the first transistor 15 - emitter voltage _{V bE} 1, the base of the second transistor 16 - when the emitter voltage is _{V bE} 2, the gate drive IGBT1 The constant current set value Ig is expressed by equation (20).

Next, the variation of the constant current set value Ig in the circuit shown in FIG. 9 is calculated. The base-emitter voltage V _BE (typ) at 25 ° C. of the first transistor 15 and the second transistor 16 = 0.7V, the resistance value R1 of the first resistor 5 = 13Ω, and the resistance of the second resistor 6 Assuming that the value R2 = 150Ω, the resistance value Rg = 1Ω of the gate-on resistance 8, and the voltage Vcc of the positive power supply 3 = 15V, Ig (type) at 25 ° C. is as follows.

The variation of the base-emitter voltage of the first transistor 15 and the second transistor 16 is about ± 0.1 V and the temperature coefficient is −2 mV / ° C., but the first transistor 15 and the second transistor 16 By using the same model and the same production lot, the relative value of the variation in the base-emitter voltage V _BE of the first transistor 15 and the second transistor 16 can be suppressed to a very small value. The relative value is about 30 mV. Base of the first transistor 15 to be combined - emitter voltage V _{BE 1,} the base of the second transistor 16 - Maximum value of the emitter voltage V _{BE 2,} the minimum value is as follows.
V _BE 1 (maximum value) = V _BE 3 (maximum value) −0.003 = 0.88 V
V _BE 2 (maximum value) = 0.7 + 0.1−0.002 × (−30−25) = 0.91V
V _BE 1 (minimum value) = V _BE 3 (minimum value) + 0.003 = 0.51V
V _BE 2 (minimum value) = 0.7−0.1−0.002 × (85−25) = 0.48V
The variation of the voltage Vcc of the positive power source 3 is set to ± 1 V, the variation of the base-emitter voltage V _BE of the first and second transistors 15 and 16 and the variation of the voltage Vcc of the positive power source 3 are expressed by Equation (20). Substituting and calculating the variation of the constant current set value Ig

And the variation of the constant current set value Ig is
Variation + side = 1.44A / 1.3A = + 11%
Variation-side = 1.16A / 1.3A = -11%
Thus, the variation width is greatly reduced as compared with the conventional example.

Moreover, the base of the first transistor 15 - emitter voltage V _{BE 1,} the base of the second transistor 16 - emitter voltage V _{BE 2} is 1: for the first current mirror, widely available and inexpensive one When a double transistor configured on a chip is used, the relative values of V _BE 1 and V _BE 2 are further reduced to about 5 mV. When the variation of the constant current set value Ig in this case is calculated,

And the variation of the constant current set value Ig is
Variation + side = 1.42A / 1.3A = + 9%
Variation-side = 1.19A / 1.3A = -9%
Thus, higher accuracy can be achieved.

  In addition, since the first transistor 15 and the second transistor 16 that determine the accuracy of the constant current set value Ig can be configured by small-capacity transistors, the gate drive and protection functions can be provided at low cost without increasing the chip size. The constant current set value Ig can be made highly accurate by configuring the first transistor 15 and the second transistor 16 on the same chip.

  Further, the resistance value R1 of the first resistor 5 and the resistance value R2 of the second resistor 6 in FIG. 9 may be values which are not affected by the base current of the second transistor 16, and the first resistor 5 The resistance value R1 of the second resistor 6 and the resistance value R2 of the second resistor 6 are about 100 times the resistance value R1 of the first resistor 5 and the resistance value R2 of the second resistor 6 in FIG. Can be. Therefore, the power consumption at the resistance value R1 of the first resistor 5 and the resistance value R2 of the second resistor 6 is reduced, and a reduction in power consumption of the drive circuit can be achieved.

  As described above, according to the gate drive circuit of the voltage-driven switching device according to the second embodiment, it is possible to realize a gate constant current drive circuit with a low power consumption and a highly accurate constant current value. Loss variation can be greatly reduced, contributing to higher efficiency and lower cost of the power converter. Further, since it can be realized with only discrete components that are generally widely available at low cost without requiring expensive dedicated components, it is possible to contribute to cost reduction of the drive circuit.

1 IGBT
2 Driving pulse signal 3 Positive power supply 4 GND potential 5 First resistor 6 Second resistor 7 Control signal transmission transistor 8 Gate on resistance 9 Constant current output transistor 10 Off signal transistor 11 Inversion element 12 Gate off resistor 13 Constant current output transistor A pair of transistors 14 a constant voltage diode 15 a first transistor 16 a second transistor paired with a first transistor

Claims (8)

Drive circuit for voltage-driven switching device, connected to the gate terminal of the voltage-driven switching device, and outputs a gate signal for turning on / off the switching device to the gate terminal based on the on / off gate control signal of the driving pulse signal In
A series connection body of a constant voltage diode, a resistor, and a control signal transmission transistor connected between a positive power source and a GND potential;
A series connection of a gate-on resistance and a constant current output transistor connected between the positive power supply and the gate terminal of the switching device,
A gate drive circuit for a voltage driven switching device, wherein a base terminal of the constant current output transistor is connected between the constant voltage diode and the resistor.   2. The gate drive circuit for a voltage-driven switching device according to claim 1, wherein a Zener voltage temperature coefficient of the constant voltage diode is combined with a temperature coefficient of a base-emitter voltage of the constant current output transistor. Drive circuit for voltage-driven switching device, connected to the gate terminal of the voltage-driven switching device, and outputs a gate signal for turning on / off the switching device to the gate terminal based on the on / off gate control signal of the driving pulse signal In
A series connection of a first resistor, a first transistor, a second resistor, and a control signal transmission transistor connected between a positive power supply and a GND potential;
A series connection of a gate-on resistance and a constant current driving transistor connected between the positive power source and the gate terminal of the switching device,
A second transistor connected between the gate-on resistance and a base terminal of the constant current drive transistor;
The first transistor has a base terminal and a collector terminal connected in a short circuit, and a base terminal of the second transistor is connected between the first transistor and the second resistor. Gate drive circuit of drive type switching device.   4. The gate drive circuit for a voltage driven switching device according to claim 3, wherein the first transistor and the second transistor are transistors having uniform characteristics.   5. The gate drive circuit for a voltage driven switching device according to claim 4, wherein the first transistor and the second transistor are transistors of the same model name and the same manufacturing lot.   4. The first transistor and the second transistor are configured by incorporating a transistor on the same chip of a custom IC having a function of driving and protecting the voltage-driven switching device. 5. A gate driving circuit of the voltage driven switching device according to 4.   The gate drive circuit for a voltage driven switching device according to any one of claims 1 to 6, wherein the voltage driven switching device is an insulated gate bipolar transistor.   The gate drive circuit for a voltage-driven switching device according to any one of claims 1 to 6, wherein the voltage-driven switching device is a SiC device.

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