JP2001223571A - Gate driving device for voltage driving-type semiconductor element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inexpensively provide a driving circuit where the voltage driving- type element of a main circuit can be driven with low loss and low noise and driving ability can arbitrarily be changed. SOLUTION: In a gate driving device, on-voltage is applied to the gate of a voltage driving-type semiconductor element (IGBT1) based on the no-command of a driving signal via a first switching means for on (M1 and M2) and the voltage of a gate is pulled out via a second switching means for off (M3 and M4) based on an off-command, plural output stage units (output stages 1 to 3 and 1a to 3a) constituted of the first switching means for on and the second switching means for off exist. The input side terminal (A to E) of the plural output stage units are connected in parallel. Output side terminals (output signals) are independently installed. The output side terminals are arbitrarily connected to one voltage driving-type semiconductor element (IGBT1). Thus, driving ability can arbitrarily be changed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate drive device for a voltage-driven semiconductor device such as an IGBT or MOSFET which constitutes a power conversion device used for inverter control or NC control of a motor control, an air conditioner or the like.

[0002]

2. Description of the Related Art In recent years, in a power conversion device using a semiconductor device, it has been required to reduce noise generated due to a switching operation of the voltage-driven semiconductor device constituting the power conversion device due to various legal regulations. Is required. FIG. 4 is a circuit configuration diagram showing a conventional example of this type of power converter. In FIG. 4, reference numeral 1 denotes an IGBT as a voltage-driven semiconductor element of the power converter, and 2 denotes an inductive load such as a motor, and power is supplied from the main circuit power supply VM to the inductive load 2 based on ON / OFF of the IGBT 1. Is supplied.
In an actual inverter circuit, three series circuits in which two IGBTs 1 are connected in series are connected in parallel, and the midpoint of each series circuit is connected to an inductive load such as a motor as an output. The driving circuit for turning on / off the IGBT 1 includes:
P-channel MOSFET 11 and N-channel MOSFET connected in series between drive circuit power supply VDD and a reference potential point (emitter potential or ground potential of IGBT 1)
T12 and MOSFETs 11, 12 based on the drive signal.
And a control circuit including inverting elements 21a to 21e for controlling 3 is a gate resistance. M for P channel
The number of inverting elements on the OSFET 11 side and the N-channel MOSFET 12 side is different at the same time
This is because there is a time lag for preventing the short circuits 1 and 12 from being turned on. In this circuit, MOS
FETs 11 and 12 are used by selecting low on-resistance elements,
The driving capability of the IGBT 1 is set high, and the value of the gate resistor 3 is adjusted so that the IGBT 1 can be used at a lower driving capability. In such a circuit, the circuit configuration is simple,
When the switching operation of the IGBT 1 is accelerated, the change of the collector current Ic and the collector-emitter voltage VCE of the IGBT 1 at the time of turn-on and turn-off becomes steep, so that the collector current Ic causes an oscillation phenomenon to generate noise. It should be noted that the present invention is characterized by a gate drive device for a voltage-driven semiconductor device, and therefore, the following description is given by describing only one IGBT 1 as a main switching device. The circuit of FIG. 5 is provided as a means for reducing the noise in FIG. FIG. 5 is a circuit configuration diagram showing a different conventional example.
No. 47015, JP-A-10-32976, JP-A-11
No. 97994). In FIG. 5, M1 is a P-channel MOSFET having a low on-resistance, M2 is an N-channel MOSFET having a high on-resistance, M3 is an N-channel MOSFET having a low on-resistance, and M4 is a P-channel MOSFET having a high on-resistance. M5 is an N-channel MOSFET having a lower on-resistance than M3. Then, the MOSFETs M1 and M2 are connected in parallel,
FETs M3, M4, and M5 are connected in parallel, and one end of these parallel-connected MOSFETs M1 and M2 is
One end of M3, M4, M5 is connected in series. MOS
The other ends of the FETs M1 and M2 are connected to the drive circuit power supply VDD, and the other ends of the MOSFETs M3, M4 and M5 are connected to a reference potential point (IG
BT1 (emitter potential or ground potential). This series connected midpoint is connected to the gate of IGBT1. The gates of the MOSFETs M1 to M5 are individually controlled by drive signals via a pre-driver. When the collector current IC drives the IGBT 1 of 50 A, the ON resistance of each MOSFET is 17
Ω, M4 is set to 220 Ω, M5 is set to 2 Ω, and M1 and M2 are set to 34 Ω with both turned on.

[0003]

In the drive circuit shown in FIG. 5, the timing at which each MOSFET is turned on (details will be described later) is changed by a signal output from the pre-driver in response to the drive signal, and the drive circuit is transiently driven. The drive capability is changed by changing the on-resistance (high drive capability results in low loss and low switching loss, and low drive capability results in low noise) to achieve low loss and low noise. However, in this drive circuit, the IGB to be driven is controlled by the ON resistance of each MOSFET.
Since the driving capability for T1 is determined, the on-resistance of each MOSFET must be set according to the type of IGBT1. In the drive circuit of FIG.
When it is attempted to change the driving capability using the gate resistor 3 as shown in FIG. 4, the on-resistances of the MOSFETs M1 and M2 are considerably different, for example, 100Ω and 1KΩ. Since the ratio is increased, it is not possible to simply add the gate resistor 3. FIG. 6 is a circuit configuration diagram for changing the driving capability of FIG. FIG. 6 is different from FIG.
1 to M5 are connected to the IGBT 1 via gate resistors 3a to 3e having different resistance values, respectively. In this circuit configuration, the driving capability can be arbitrarily set by individually setting the values of the gate resistors.
However, although this drive circuit is usually formed as an IC,
The number of pins of the IC is increased to connect to each gate resistor, and the gate resistor is required for the terminals, resulting in an increase in cost.

An object of the present invention is to provide a low-cost drive circuit capable of driving a voltage-driven element of a main circuit with low loss and low noise.

[0005]

In order to achieve the above object, the present invention provides a first method for turning on an on-state voltage to a gate of a voltage-driven semiconductor device (IGBT1) based on an on-command of a drive signal. In the gate drive device, which is applied through the switching means (M1, M2) and pulls out the gate voltage via the second switching means for turning off (M3, M4) based on the off command, the first switching for turning on is performed. There are a plurality of output stage units (output stages 1 to 3 and 1a to 3a) each of which comprises a switch and a second switching unit for turning off, and the input terminals (A to E) of the plurality of output stage units are connected in parallel, The output side terminal (output signal) is provided independently.
It is effective that the output side terminal is arbitrarily connected to one voltage-driven semiconductor element (IGBT1). Also,
The first switching means for turning on is a P-channel MOSFET.
T (M1) is a parallel connection circuit of an N-channel MOSFET (M2), and the second switching means for turning off is a P-channel MOSFET (M4) and an N-channel MOSFET
It is effective that the circuit is connected in parallel with (M3). P
The channel MOSFETs (M1, M4) have a high on-resistance, and the N-channel MOSFETs (M2, M3) have a low on-resistance. Further, it is effective to provide an N-channel MOSFET (M5) having an on-resistance lower than the N-channel MOSFET of the second switching means for turning off between the gate of the IGBT1 and the reference potential. is there. The output values of the output terminals of the plurality of output stage units are different.

According to the present invention, by arbitrarily connecting the terminal of the IC from which the output terminal of the output stage unit is drawn out, the driving capability of the IC can be easily changed without impairing low loss and low noise. .

[0007]

FIG. 1 is a circuit diagram of a power converter showing a first embodiment of the present invention. FIG. 1 (a) is a drive circuit diagram, and FIG. 1 (b) is an output stage 1 of FIG. 5 is a partially enlarged view, and the same reference numerals are given to those having the same functions as those of the conventional circuit shown in FIG. That is, in FIG. 1, units including output stages 1 to 3 are connected in parallel in the IC. The circuit configuration of these output stages 1 to 3 is as shown in FIG.
It has the same circuit configuration as that of FIG. However, the ON resistances of the MOSFETs M1 to M5 in the output stages 1 to 3 are different, and the output signals of the output stages 1 to 3 have different driving capabilities. First, the operation of the partially enlarged view of FIG. 1B will be described below with reference to the operation waveform diagram shown in FIG.
A MOSFET M for realizing the operation waveform of FIG.
The selection conditions of 1 to M5 are the same as the selection conditions of the on-resistance in FIG. First, a drive signal (see FIG. 2 (f)) is turned on from off to on (T
When the ON command is issued to the IGBT 1 at one point in time, the signal at the terminal A of M1 changes from high to low (see FIG. 2A), and the signal at the terminal B of M2 changes from low to high (see FIG. 2). (See (b)), and M1 and M2 change from the off state to the on state. During this on state, M3 to M5 are turned off (see FIGS. 2C to 2E). As a result IGB
T1 is turned on by the gate voltage from the driving circuit power supply VGG via M1 and M2, and the gate voltage V of the IGBT1 is
G rises rapidly, and the IGBT 1 starts a turn-on operation while exceeding a threshold VG 1 of the IGBT 1 and entering a flat period (a mirror capacitor charging period of the IGBT 1). In this Miller capacitance charging period, M1 is turned off at the time T2, and M1 and M2 contribute to the gate capacitance charging between the times T1 and T2, so that the time is shortened. Then, IGBT
As the gate voltage of 1 (see FIG. 2 (g)) approaches VG1, the gate-source voltage of M2 approaches the threshold value of M2 and turns off. Therefore, in the region where the gate voltage of IGBT1 is equal to or higher than VG1, only M1 turns on. As a result, as shown in the figure, dV / dt of the gate voltage VG of the IGBT 1 decreases, and the changes in the collector current Ic (not shown) and the collector-emitter voltage VCE (see FIG. 2 (h)) of the IGBT 1 become gentle. . Next, when the drive signal changes from on to off (at time T3) and an off command is issued to the IGBT 1, M3 to M5 change from off to on. During this ON state, M1 and M2 are turned OFF. As a result, the gate voltage VGE of the IGBT 1 rapidly falls, and the IGBT 1 starts a turn-off operation while slightly leaving a flat period (a mirror capacitance discharging period of the IGBT 1).
This Miller capacitance discharge period can be shortened by turning off M5 at the time of T4, and only M3 and M4 are once turned on. As a result, dV / dt of the gate voltage VG of the IGBT1 decreases as shown in the figure. , IGBT1
Collector current Ic and collector-emitter voltage VCE
Changes slowly. When the gate voltage drops to VG2 (about 5 V) at time T5, M5 is turned on again, M3 to M5 are turned on, the drop of the gate voltage VG is accelerated, and the turn-off time of the IGBT1 is shortened and held off. Returning to FIG. 1 again, the output stages 1 to 3
Since it is only necessary to change the on-resistance of the ET, it can be easily realized in the IC. In this example, three output terminals are provided to output the output signals of the output stages 1 to 3, and the number of pins of the IC is increased by two. For example, when the collector current Ic is 25 A, 50 A, and 75 A, the output terminals are changed. For example, seven types of driving capabilities can be realized by combining the connection pins to the IGBT1. And if there are four output stage units, 15
Different driving capabilities can be realized. In these, it is not necessary to provide external gate resistors individually as shown in FIG. 6, so that the number of components is not increased. 3A and 3B show different embodiments, in which FIG. 3A is a drive circuit diagram, and FIG. 3B is a partially enlarged view of the output stage 1a of FIG. 3 is different from FIG. 1 in that the MOSs provided in each of output stages 1 to 3 are provided.
The point is that FET M5 is taken out and M5 is provided independently.
This M5 is called a sinker and is an IGBT to be driven.
1 is a transistor having a low on-resistance for holding 1 off. In this case, since the gate of the IGBT 1 only needs to have a low resistance and fall to the reference potential (ground), the driving capability does not have to be changed for each driving target. Therefore, M of each output stage
5 are integrated into one output terminal. This output terminal may be a terminal for detecting the voltage of the gate. As described above, in the present invention, the means for changing the ON resistance of each MOSFET has been described. However, a resistance value may be set by inserting a diffusion resistance or a polysilicon resistance in each MOSFET in series.

[0008]

According to the present invention, it is possible to provide an inexpensive drive circuit capable of driving the voltage drive type element of the main circuit with low loss and low noise and capable of arbitrarily changing the drive capability.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention;
(A) is a drive circuit diagram, (b) is a partially enlarged view of (a).

FIG. 2 is a waveform chart illustrating the operation of FIG.

FIG. 3 is a circuit diagram showing another embodiment of the present invention;
(A) is a drive circuit diagram, (b) is a partially enlarged view of (a).

FIG. 4 is a circuit configuration diagram showing a conventional example.

FIG. 5 is a circuit diagram showing another conventional example.

FIG. 6 is a circuit diagram showing a reference example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 IGBT 2 Inductive load 11, 12, M1-M5 MOSFET 21a-21e Inverting element 3, 3a-3e Gate resistance

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H740 BA11 BA12 BB10 HH05 KK01 5J055 AX08 AX12 AX25 AX44 AX65 BX16 BX18 CX07 CX13 CX20 DX09 DX13 DX14 DX22 DX55 DX56 DX73 DX83 GX01 GX02 GX04

Claims (6)

[Claims] An on-state voltage is applied to a gate of a voltage-driven semiconductor device via a first on-state switching means based on an on-command of a drive signal, and a second off-state switching means is provided based on an off instruction. In the gate driving device for extracting the voltage of the gate through the gate driver, there are a plurality of output stage units including the first switching means for turning on and the second switching means for turning off, and the input terminals of the plurality of output stage units are connected in parallel. Wherein the output side terminal is provided independently and the output side terminal is arbitrarily connected to one voltage driven type semiconductor element. 2. The first switching means for turning on is a parallel connection circuit of a P-channel MOSFET and an N-channel MOSFET, and the second switching means for turning off is a parallel connection circuit of a P-channel MOSFET and an N-channel MOSFET. A gate driving device for a voltage-driven semiconductor device according to claim 1. 3. The P-channel MOSFET has a high on-resistance and the N-channel MOSFET has a low on-resistance.
A gate drive device for a voltage-driven semiconductor device according to claim 1. 4. The gate drive device for a voltage-driven semiconductor device according to claim 2, wherein the gate drive device is an IC. 5. An N-channel MOS having an on-resistance lower than that of an N-channel MOSFET of a second switching means for turning off.
3. An FET provided between the gate and a reference potential.
A gate drive device for a voltage-driven semiconductor device according to claim 1. 6. The gate drive device for a voltage-driven semiconductor device according to claim 1, wherein output values of output terminals of the plurality of output stage units are different.