JP3399737B2 - Gate drive and power module - Google Patents

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 driving a power switching element and a power module incorporating the gate drive device, and more particularly,
The present invention relates to an improvement for shortening an unstable period at turn-off.

[0002]

2. Description of the Related Art FIG. 10 is a circuit diagram showing a configuration of a conventional power module which is the background of the present invention. In FIG. 10, 250 is a power module, and 150 is a gate drive device. Further, 51 is a power switching element to be driven by the device 150, and 55 amplifies an input signal Vin input from the outside through a terminal 61 and outputs the amplified signal to a terminal 62 connected to a gate electrode G of the power switching element 51. It is an amplifier that outputs a gate voltage Vg. The power switching element 51 includes a gate electrode G,
IGB provided with collector electrode C and emitter electrode E
The threshold voltage Vth is usually 3
It is set to a value within the range of V to 6V.

Further, 56 is a terminal 63 connected to the terminal 62 and the emitter electrode E of the power switching element 51.
And 53 is a gate-sink switching element, and 53 is a logic circuit having two inputs connected to terminals 61 and 62 and an output connected to the base electrode of the gate-sink switching element 56.

The logic circuit 53 is configured as a two-input NOR circuit, and only when both of the two input signals Vin and Vg have a low level value below a threshold voltage peculiar to the logic circuit 53. , A high level signal is output as the output signal Vn, and the gate sink switching element 5
Turn on 6. Since a bipolar transistor is used in the logic circuit 53, the threshold voltage of the logic circuit 53 is usually about 0.8V.

When a high level value is input as the input signal Vin, the amplifier 55 outputs a high level value exceeding the threshold voltage Vth peculiar to the power switching element 51 as the gate voltage Vg. As a result, the power switching element 51 is turned on. When the input signal Vin is at high level, the output signal Vn of the logic circuit 53 becomes low level regardless of the value of the gate voltage Vg.
Therefore, the gate sink switching element 56 is turned off.

Next, when the input signal Vin changes from the high level to the low level, at the same time, the logic circuit 5
One of the two input signals to 3 (input signal Vin) becomes low level. The gate voltage Vg, which is another input signal to the logic circuit 53, transitions from a high level value exceeding the threshold voltage Vth toward a low level (zero voltage) value in response to a change in the input signal Vin. To do.

FIG. 11 is a timing chart showing the transition process. When the gate voltage Vg reaches the threshold voltage of the logic circuit 53 in the process of transitioning toward the zero voltage, the input signal Vin, which is one input of the logic circuit 53, is already at the low level. The output signal Vn changes from low level to high level. As a result, the gate sink switching element 56 becomes conductive,
The gate voltage Vg is reduced to zero voltage.

[0008]

The height of the gate voltage Vg when the output signal Vn of the logic circuit 53 of FIG. 10 is inverted from low level to high level, that is, the sink voltage Vs (FIG. 11) is It is equal to the threshold voltage of the logic circuit 53. Then, this sink voltage Vs
The value of is usually about 0.8V. On the other hand, the threshold voltage Vth of the power switching element 51 is 3V to 6V.
Because of this, the transition period Ts (FIG. 11), that is, the period until the gate sink switching element 56 operates after the input signal Vin changes from the high level to the low level, becomes long.

During the transition period Ts, the state of the power switching element 51 is unstable. The potential of the collector electrode C rises with the transition of the power switching element 51 from on to off, but the parasitic capacitance existing between the collector electrode C and the gate electrode G is accordingly increased in the transition period Ts. Therefore, the gate voltage Vg easily rises.

The power modules 250 are usually used in a form in which two power modules are connected in series between a high potential side power source line and a low potential side power source line. Then, the two power modules 250 connected in series are driven so as to be turned on and off alternately. At this time, when one of the power modules 250 should be turned off, if its gate voltage Vg carelessly rises and returns to the on state, a short circuit is caused between the high potential side and low potential side power supply lines.

In order to prevent this short circuit, one power module 250 passes through the transition period Ts, and the gate sink switching element 56 is operated to move to a stable off state until the other power module 250 is activated. It is necessary to extend the time when the 250 is turned on.
As described above, when switching between the on / off states, a period in which both power modules 250 are not operating, that is, a dead time is required. Since this dead time is defined by the transition period Ts described above, the conventional power module 250 requires a long dead time.

As described above, in the conventional gate driving device and the power module incorporating the same, generally,
In the process of transition from the ON state to the OFF state, that is, in the process of turn-off, there is a problem that the transition period in which the state of the power switching element is not stable is long and the dead time is long accordingly.

The present invention has been made in order to solve the above-mentioned problems in the conventional device, and can shorten the period during which the power switching element is in an unstable state during the turn-off process and the power module. The purpose is to provide.

[0014]

The device of the first invention is a gate drive device for driving a voltage-driven power switching device, which is connectable to a gate electrode and a main electrode of the power switching device, respectively. The magnitude of the voltage between the first and second terminals, the gate sink switching element that is interposed between the first and second terminals, and the first and second terminals is determined by the threshold voltage of the power switching element. in response to below the sink voltage defined so as to be substantially coincident, and control means for controlling so as to conduct the gate sink switching device, from the outside
A third terminal for relaying a supplied input signal;
Inserted between the third and first terminals and inserted into the third terminal
Amplifies the input signal applied and outputs it to the first terminal
Further comprising an amplifier for
Force is connected to the third terminal and the gate sink switch is
Two-input type having a predetermined threshold voltage for driving a switching element
Logic circuit and the other input of the first terminal and the logic circuit
Is connected to the output of the amplifier and converts the output of the amplifier to the other input.
And a conversion circuit for inputting the input to the input circuit,
With reference to the second terminal of one input and the other input
The magnitude of the applied voltage is less than or equal to the predetermined threshold voltage.
Switching device for the gate sink only at certain times
Switching element for the gate sink so that
The conversion circuit drives the sink voltage to the predetermined voltage.
Is set to a value exceeding the threshold voltage of
The magnitude of the voltage between the second terminals is greater than the sink voltage.
When it is larger, a voltage larger than the predetermined threshold voltage is
Input to the other input of the logic circuit,
Voltage smaller than the predetermined threshold voltage
It is characterized by inputting .

[0015]

The apparatus of the second invention, in the gate driving apparatus of the first aspect of the invention, the conversion circuit comprises a dividing resistor element first and second resistive elements, which are connected in series, the divided resistance element Is interposed between the first and second terminals, and the connecting portion of the first and second resistance elements is connected to the other input of the logic circuit. .

The apparatus of the third invention, in the gate driving apparatus of the first aspect of the invention, the conversion circuit, a reference voltage corresponding to the magnitude of the voltage between said first and second terminals to the sink voltage and In comparison, it is characterized by including a comparator for inputting a voltage higher or lower than the threshold voltage to the other input of the logic circuit, respectively, depending on whether the former is higher or lower than the latter.

According to a fourth aspect of the present invention, in the gate drive apparatus according to the first aspect of the present invention, the conversion circuit includes a diode element, and the diode element has the first terminal and the other input of the logic circuit. And is inserted in a direction in which the voltage of the first terminal is higher than the voltage of the other input of the logic circuit by the amount of the forward voltage with respect to the second terminal. It is characterized by

According to a fifth aspect of the invention, in the gate driving device of the first aspect of the invention, a plurality of unit conversion circuits that include the conversion circuit and have the same configuration as the conversion circuit but different sink voltages are provided. Further, each of these unit conversion circuits can be connected to the first terminal through a connection wiring, and only one of the unit conversion circuits can be selectively used as the conversion circuit. It is characterized in that it is connected to the first terminal through the connection wiring.

According to a sixth aspect of the present invention, in the gate drive apparatus according to the first aspect of the invention, the conversion circuit includes a diode element whose one end is connected to the other input of the logic circuit, and the diode element is , A plurality of unit diode elements connected in series with each other, and the other end of the diode element and a connection portion between the plurality of unit diode elements are both connected to the first terminal via connection wiring. The other end and only one of the connection portions are selectively connected to the first terminal via the connection wiring, and the direction of the plurality of unit diode elements is It is characterized in that the voltage of the first terminal is higher than the voltage of the other input of the logic circuit by the amount of the forward voltage with reference to the second terminal.

The device of the seventh invention is, in a power module, the gate drive device according to any one of the first to sixth inventions, and the gate electrode and the gate electrode at the first and second terminals of the gate drive device. The voltage-driven power switching element, to which main electrodes are respectively connected, is provided.

[0022]

DETAILED DESCRIPTION OF THE INVENTION

<First Embodiment> FIG. 1 is a circuit diagram showing a configuration of a power module according to a first embodiment. As shown in FIG. 1, the power module 121 includes a power switching element 1 for turning on (conducting) and turning off (cutting off) a main current, and a gate driving device 101 for driving the element 1. The power switching element 1 includes a gate electrode G,
IGB provided with collector electrode C and emitter electrode E
Composed of T.

The power module 121 is further provided with a pair of main terminals 25 and 26. The collector electrode C of the power switching element 1 is connected to one main terminal 25, and the emitter electrode E is connected to the other main terminal 26. External power supplies and loads are connected to the main terminals 25 and 26. As a result, the main current modulated and controlled by the on / off operation (switching operation) of the power switching element 1 is supplied to the load.

The device 101 is provided with terminals 22 and 23. Among these, the terminal (first terminal) 22 is connected to the gate electrode G of the power switching element 1, and the terminal (second terminal) 23 is connected to the emitter electrode E. The device 101 is provided with another terminal (third terminal) 21, through which an external input signal V
in is input.

The device 101 further includes an amplifier 5, a dividing resistance element 2, a logic circuit 3, and a gate sink switching element 6. Of these, the amplifier 5
Is inserted between the terminals 21 and 22, and amplifies the input signal Vin inputted through the terminal 21 to generate a gate voltage (gate-emitter voltage) Vg for switching the power switching element 1. , To the terminal 22.

The gate sink switching element 6 is composed of a bipolar transistor, and its collector electrode and emitter electrode are connected to the terminal 22 and the terminal 23, respectively. The output of the logic circuit 3 configured as a 2-input NOR circuit is connected to the base electrode of the gate sink switching element 6.

The dividing resistance element 2 is composed of a first serially connected first resistance element.
And the second resistance element 2a, 2b, the terminal 2
It is inserted between 2 and 23. The connection portion of the first and second resistance elements 2a and 2b is connected to one of the two inputs of the logic circuit 3. That is, a divided voltage signal obtained by dividing the gate voltage Vg by the first and second resistance elements 2a and 2b is input to one of the two inputs of the logic circuit 3 as the input signal Vm.

The other of the two inputs of the logic circuit 3 has terminals 21,
That is, it is connected to the input of the amplifier 5. That is,
Input signals Vin and Vm are input to the two inputs of the logic circuit 3, respectively.

FIG. 2 is a circuit diagram showing the internal structure of the amplifier 5. As shown in FIG. 2, the amplifier 5 includes two-stage unit amplifiers that are connected in cascade. The unit amplifier in the latter stage has a pair of transistors 32 and 33 connected in series, and the non-inverting output and the inverting output of the unit amplifier 31 in the preceding stage are connected to the base electrodes of the transistors 32 and 33, respectively. There is. Also, the transistors 32 and 3
A gate resistor 34 that regulates the output current of the amplifier 5 is connected to the connection portion of 3.

The unit amplifier 31 includes transistors 32 and 3 so that one of the transistors 32 and 33 is turned on and the other is turned off according to the value of the input signal Vin.
Drive 3 That is, when the input signal Vin has a high level value, the transistors 32 and 33 are turned on and off, respectively, and as a result, a high level signal is output as the output of the amplifier 5. Conversely, the input signal Vi
When n is a low level value, the transistor 3
2 and 33 are turned off and on, respectively, and as a result, a low level signal is output as the output of the amplifier 5.

FIG. 3 is a circuit diagram showing the internal structure of the logic circuit 3. As shown in FIG. 3, the logic circuit 3 includes a pair of transistors 41 and 42 connected in parallel, and resistance elements 43 and 4 whose one ends are connected to their base electrodes, respectively.
4, and a resistance element 45 interposed between the collector electrodes of the pair of transistors 41 and 42 and the external power supply Vcc.
Is equipped with.

The potentials of the collector electrodes of the transistors 41 and 42 are output as the output signal Vn of the logic circuit 3.
The two input signals Vin and Vm of the logic circuit 3 are input to the other ends of the resistance elements 43 and 44, respectively. Therefore, the value of the output signal Vn becomes high level only when both of the two input signals Vin and Vm are low level values. That is, the logic circuit 3 functions as a 2-input NOR circuit.

Further, the transistors 41 and 42 are formed of bipolar transistors and have a 2-input signal Vi.
The threshold voltage of n and Vm is about 0.8V. That is, if the two input signals Vin and Vm are higher than 0.8 V, the transistors 41 and 42 are turned on, and if they are low, they are turned off.

Returning to FIG. 1, the operation of the power module 121 will be described. When a high level value is input as the input signal Vin, the amplifier 5 outputs a high level value exceeding the threshold voltage Vth peculiar to the power switching element 1 as the gate voltage Vg. As a result, the power switching element 1 is turned on. The threshold voltage Vth of the power switching element 1 composed of the IGBT is preferably set to about 3 to 6V.

When a low level value is input as the input signal Vin, the amplifier 5 outputs the gate voltage Vg as
Outputs zero voltage. As a result, the power switching element 1 is turned off. In this way, the power switching element 1 is turned on / off according to the level of the input signal Vin.

FIG. 4 is a block diagram showing a typical usage pattern of the power module 121. As shown in FIG. 4, the power module 121 is normally connected in series between the high-potential-side power supply line and the low-potential-side power supply line (ground line), and one end of the load 28 is connected to these connection parts. To be done. When the power module 121 on the high potential side is turned on, the power module 121 on the low potential side is
It is turned off, and as a result, the main current Ic is supplied from the high-potential-side power supply line to the load 28.

When the low potential side power module 121 is turned on, the high potential side power module 121 is turned off, and as a result, the main current Ic flows from the load 28 to the low potential side power supply line. In this way, the input signal Vin is individually input to each power module 121 so that the pair of power modules 121 connected in series are alternately turned on and off. Further, normally, another pair of power modules 121 connected in series is further prepared, and the other end of the load 28 is connected to this another pair in the same manner as in FIG.

Returning to FIG. 1, when the input signal Vin is at high level, regardless of the value of the gate voltage Vg,
The output signal Vn of the logic circuit 3 becomes low level. Therefore, the gate sink switching element 6 is turned off. That is, when the input signal Vin is at the high level, the gate sink switching element 6 does not interfere with the operation of the power switching element 1.

Next, when the input signal Vin changes from the high level to the low level, at the same time, the logic circuit 3
One of the two input signals (input signal Vin) to the signal goes low. Further, the gate voltage Vg which is the output signal of the amplifier 5 transitions from the high level value to the low level (zero voltage) value in response to the change of the input signal Vin.

First and Second Components of Dividing Resistance Element 2
The ratio of the resistance values of the resistance elements 2a and 2b is 2 of the logic circuit 3.
Each input threshold voltage Vbt, power switching element 1
With respect to the threshold voltage Vth of Vbt≈Vth × Rb / (R
a + Rb) ... (Equation 1). Here, the resistance values Ra and Rb are the resistance values of the first and second resistance elements 2a and 2b, respectively. In other words, the resistance ratio Ra / Rb is Ra / Rb≈ (Vth / Vb
t) −1 ... (Equation 2).

That is, the gate voltage Vg is equal to the threshold voltage Vth.
The resistance ratio Ra / Rb is set so that the input signal Vm substantially coincides with the threshold voltage Vbt. As described above, since the threshold voltage Vbt of the logic circuit 3 is about 0.8V, if the threshold voltage Vth is any value in the range of 3V to 6V described above, the resistance ratio Ra /
Rb is set to any value within the range of about 2.5 to 6.5.

FIG. 5 is a timing chart showing changes in the gate voltage Vg and the output signal Vn as the input signal Vin changes from the high level to the low level. When the gate voltage Vg reaches a certain voltage Vs called a sink voltage in the process of transition from a high level value exceeding the threshold voltage Vth toward a low level value, that is, a zero voltage, it is input to the logic circuit 3. Input signal V
m reaches the threshold voltage Vbt.

Since the input signal Vin which is the other input of the logic circuit 3 is already at the low level, the output signal Vn of the logic circuit 3 is at the low level at the same time when the input signal Vin crosses the threshold voltage Vbt in the process of the decrease of the input signal Vm. To high level. As a result, the gate sink switching element 6 becomes conductive, and the gate voltage Vg is reduced to zero voltage. That is, since the gate electrode G and the emitter electrode E of the power switching element 1 are short-circuited by the gate sink switching element 6, the power switching element 1 is in a stable cutoff state.

The sink voltage Vs corresponds to the value of the gate voltage Vg when the input signal Vm matches the threshold voltage Vbt. Therefore, when the resistance ratio Ra / Rb is given by Expression 1 or Expression 2, the sink voltage Vs substantially matches the threshold voltage Vth of the power switching element 1. That is, in this power module 121, when the gate voltage Vg decreases, when the voltage value substantially corresponding to the threshold voltage Vth is crossed, the gate sink switching element 6 operates and the power switching element 1 stabilizes. Be cut off. Therefore, after the input signal Vin changes from the high level to the low level, the period until the power switching element 1 is stably shut off, that is, the transition period T
s is shortened compared to the conventional module 250 (FIG. 10).

In the usage pattern shown in FIG. 4, the transition period Ts
Defines the waiting time before one power module can be turned off and the other power module can be turned on, that is, the dead time. Therefore, in the power module 121, since the transition period Ts is shortened, the dead time in the usage pattern of FIG. 4 is also shortened.

The entire gate drive device 101 can be constructed by one chip (single semiconductor chip). Further, in the gate driving device 101, the part excluding the dividing resistance element 2 may be integrated into one chip, and the dividing resistance element 2 may be configured by an individual element. With this configuration, it is possible to easily select the resistance ratio of the divided resistance element 2 so as to match the threshold voltage Vth of the power switching element 1 in the manufacturing process of the gate driving device 101 or the power module 121. Benefits are obtained.

<Second Embodiment> FIG. 6 is a circuit diagram showing a structure of a power module according to a second embodiment. In the following drawings, the same parts or corresponding parts (parts having the same functions) as those of the device of the first embodiment shown in FIG. 1 are designated by the same reference numerals, and detailed description thereof will be omitted. Figure 6
As shown in FIG. 3, the power module 122 includes the power switching element 1 and the gate drive device 102 that drives the power switching element 1. The device 102 is characteristically different from the device 101 in that a comparator 4 is provided instead of the divided resistance element 2 of FIG.

The comparator 4 has a gate voltage Vg and a reference voltage Vg.
Compared with ref, if the former is higher than the latter, a high level signal is output as the input signal Vm to the logic circuit 3, and if it is low, a low level signal is output. Therefore, in this device 101, the reference voltage Vref defines the sink voltage Vs.

The magnitude of the reference voltage Vref is set to a value that substantially matches the threshold voltage Vth of the power switching element 1. For example, the threshold voltage Vt of the power switching element 1
If h is any value in the range of 3V to 6V, the reference voltage Vref is set to any value in the range of about 3V to 6V.

Therefore, in the process in which the power switching element 1 makes a transition from conduction to interruption, the gate sink switching element 6 becomes conductive at the time when the gate voltage Vg approximately crosses the threshold voltage Vth, as in the device 101 of FIG. Then
The power switching element 1 shifts to a stable cutoff state. That is, the timing chart showing this process is similar to that of FIG. 5, and the sink voltage Vs substantially matches the threshold voltage Vth, as in the first embodiment.

As described above, also in the power module 122 of this embodiment, the transition period Ts is shortened as compared with the conventional power module 250 (FIG. 10), and the dead time is similarly shortened.

<Third Embodiment> FIG. 7 is a circuit diagram showing a structure of a power module according to a third embodiment. As shown in FIG. 7, the power module 123 includes a power switching element 1 and a gate driving device 10 that drives the power switching element 1.
3 and 3. The device 103 is characteristically different from the device 101 in that a diode element 7 is provided instead of the divided resistance element 2 in FIG.

That is, the terminal 22 and one input of the logic circuit 3 are connected via the diode element 7. Moreover, the diode element 7 is connected in the direction in which the forward current flows from the terminal 22 to the logic circuit 3. That is, the anode electrode is connected to the terminal 22 and the cathode electrode is connected to the input of the logic circuit 3. Further, the diode element 7 may be composed of a single unit diode element, or may be composed of a series circuit of a plurality of unit diode elements as illustrated in FIG. 7.

Since the diode element 7 is inserted between the terminal 22 and the one input of the logic circuit 3, the one input corresponds to the forward voltage of the diode element 7 rather than the gate voltage Vg. A voltage signal that is only low is input as the input signal Vm. Moreover, the forward voltage of the diode element 7 is set to substantially match the difference between the threshold voltage Vth of the power switching element 1 and the threshold voltage Vbt of the logic circuit 3. The forward voltage of the diode element 7 can be easily set by adjusting the number of unit diode elements forming the diode element 7.

Therefore, in the process in which the power switching element 1 makes a transition from conduction to interruption, the gate sink switching element 6 becomes conductive at the time when the gate voltage Vg approximately crosses the threshold voltage Vth, as in the device 101 of FIG. Then
The power switching element 1 shifts to a stable cutoff state. That is, the timing chart showing this process is similar to that of FIG. 5, and the sink voltage Vs substantially matches the threshold voltage Vth, as in the first embodiment.

As described above, also in the power module 123 of this embodiment, the transition period Ts is shortened as compared with the conventional power module 250, and the dead time is also shortened.

By inserting a Zener diode instead of the diode element 7 in the direction opposite to that of the diode element 7, the potential difference between the gate voltage Vg and the input signal Vm is determined by the forward voltage of the diode element 7. Instead of, a Zener voltage may be used for generation. Further, it is also possible to use a general element such as a varistor that generates a constant voltage.

The gate drive device 103 can be constructed as a single chip. Further, in the gate drive device 103, the portion excluding the diode element 7 may be integrated into a single chip, and the diode element 7 may be configured by an individual element. With this configuration, the forward voltage of the diode element 7 is appropriately selected according to the magnitude of the threshold voltage Vth of the power switching element 1 in the manufacturing process of the gate driving device 103 or the power module 123. The advantage is that it can be done easily.

<Fourth Embodiment> FIG. 8 is a circuit diagram showing a structure of a power module according to a fourth embodiment. As shown in FIG. 8, the power module 124 includes a power switching element 1 and a gate driving device 10 for driving the power switching element 1.
4 and. The device 104 has a plurality of divided resistance elements 12, 1 whose one end is commonly connected to the terminal 23.
3 and 14 are characteristically different from the device 101 of FIG.

Each of the divided resistance elements 12, 13 and 14 is
Similar to the divided resistance element 2, it has two unit resistance elements connected in series. Then, the divided resistance elements 12, 1
The connection portion of the two unit resistance elements forming each of the elements 3 and 14 is commonly connected to one input of the logic circuit 3. Then, only one of the divided resistance elements 12, 13, 14 is selected, and the other end is connected to the amplifier 5 through the connection wiring 11.
Is connected to the connection wiring 15 that connects the terminal 22 to the terminal 22. The remaining other ends of the divided resistive elements 12, 13 and 14 which are not selected remain open.

The resistance ratios of the two unit resistance elements provided in each of the divided resistance elements 12, 13 and 14 are set to be different from each other. That is, the divided resistance elements 12, 13, 1
4 is prepared so that a plurality of different input signals Vm can be generated. Then, in the manufacturing process of the gate driving device 104 or the power module 124, according to the magnitude of the threshold voltage Vth of the power switching element 1,
One of the plurality of divided resistance elements 12, 13, and 14 is selected and connected by using the connection wiring 11.

As described above, in the device 104 or the power module 124, one of the plurality of divided resistance elements 12, 13, and 14 prepared in advance is selectively connected by the connection wiring 11, so that there are a plurality of ways. One of the sink voltages Vs can be arbitrarily selected.
That is, it is possible to assemble various power modules 124 having the power switching elements 1 having different threshold voltages Vth by only preparing one type of device 104. From this, it can be said that the device 104 and the power module 124 are suitable for high-mix low-volume production.

The entire gate drive device 104 can be constructed in one chip. At this time, a part of the connection wiring 15 and the divided resistance elements 12, 13, 1
It is advisable to form pads on the other ends of the wirings 4, use bonding wires as the connection wirings 11, and connect the connection wirings 11 by wire bonding. Thus, well known wafer process techniques can be used.

Alternatively, in the device 104, the portions other than the divided resistance elements 12, 13, 14 may be integrated into one chip, and the divided resistance elements 12, 13, 14 may be configured by individual elements. At this time, a normal jumper wire can be used as the connection wiring 11.

Further, in FIG. 8, the three divided resistance elements 1
Although the example including 2, 13, and 14 is shown, it is generally possible to configure to include a plurality of divided resistance elements. It is needless to say that the larger the number of dividing resistance elements is, the more various threshold voltages Vth can be supported.

<Fifth Embodiment> FIG. 9 is a circuit diagram showing a structure of a power module according to a fifth embodiment. As shown in FIG. 9, the power module 125 includes a power switching element 1 and a gate driving device 10 for driving the power switching element 1.
5 and. Then, the device 105 becomes the device 103
Similarly to the above, the diode element 7 is provided.

In this device 105, the diode element 7
Has a plurality of unit diode elements connected in series, and is connected not only to the side opposite to one end of the diode element 7 connected to the logic circuit 3 but also to the connecting portion of each unit diode element. Pads that can be connected by the wiring 11 are provided. Then, another pad provided on the connection wiring 15 and one of the plurality of pads provided on the diode element 7 are selectively connected by the connection wiring 11.

That is, in the manufacturing process of the device 105,
The pad provided on the connection wiring 15 and the diode element 7
One of the plurality of pads provided on the connection wiring 11
It is possible to arbitrarily select the magnitude of the difference between the input signal Vm input to one side of the logic circuit 3 and the gate voltage Vg by selectively connecting by using the.
In other words, it is possible to arbitrarily select a plurality of sink voltages Vs.

Therefore, similar to the device 104, it is possible to assemble a variety of power modules 125 having the power switching elements 1 having different threshold voltages Vth just by preparing one type of device 105.

The device 105 may be entirely integrated into a single chip and a bonding wire may be used as the connection wiring 11. Alternatively, a part of the device 105 other than the diode element 7 may be integrated into a single chip and the diode element 7 may be formed. May be composed of individual elements. In the latter case, a normal jumper wire can be used as the connection wiring 11.

Further, instead of forming a pad to which the connection wiring 11 can be connected at the connection portion of the plurality of unit diode elements constituting the diode element 7, one end of the plurality of diode elements 7 having different forward voltages is logically connected. It is also possible to configure the gate drive device so as to be commonly connected to one input of the circuit 3. At this time, the plurality of diode elements 7
One of them is selected, and the other end and the connection wiring 15 are connected by the connection wiring 11.

However, in the form of the device 105 in which a plurality of pads are provided in one diode element 7, the number of diode elements 7 can be small, and the chip area of the device 105 can be reduced accordingly. There is an advantage of getting.

<Modification> (1) In each of the above embodiments, the transistors 41 and 42 (FIG. 3) included in the logic circuit 3 are bipolar transistors, and the threshold voltage Vbt thereof is approximately 0.8V. An example was given. However, in the present invention, the threshold voltage Vth of the power switching element 1 and the threshold voltage Vbt of the logic circuit 3 are set.
, And the latter is generally applicable to power modules in which the latter has a lower relationship than the former. For example, transistor 4
1, 42, the threshold voltage V of the power switching element 1
An FET having a threshold voltage Vb lower than th may be used.

(2) The gate-sink switching element 6 is not limited to a bipolar transistor, but any element that performs a switching operation can be used. For example, FE
It is possible to use T. However, in order to facilitate the manufacturing process of the gate driving device, the gate sink switching element 6 and the transistor 4 included in the logic circuit 3 are included.
It is desirable that 1 and 42 are the same kind as each other.
That is, the gate sink switching element 6 is an FET
If so, it is desirable that the transistors 41 and 42 are also FETs, and if the gate sink switching element 6 is a bipolar transistor, the transistors 41 and 42 are
Is also a bipolar transistor from the viewpoint of the manufacturing process.

(3) In each of the above embodiments, an n-channel type IGBT was described as an example of the power switching element 1, but the present invention can be similarly applied to a p-channel type IGBT. is there. When the power switching element 1 is a p-channel type IGBT, the potential of the terminal 23, which is the reference potential of the gate driving devices 101 to 105, is not the ground potential but the high power supply side potential, and as the gate sink switching element 6, for example, A pnp type bipolar transistor is used. Further, for example, in the devices 103 and 105, the direction of the diode element 7 is opposite to that in FIGS. 7 and 9.

(4) Further, the power switching element 1 is not limited to the IGBT illustrated in each of the above-described first to fifth embodiments, but a voltage drive type power switching element in general can be used. For example, an FET may be used as the power switching element 1.

(5) The divided resistance element 2, the comparator 4, the diode element 7, and the divided resistance elements 12, 13, and 14 illustrated in each of the above-described embodiments are all gates based on the potential of the terminal 23. It is a specific example of a kind of conversion circuit for converting the voltage Vg into the input signal Vm. This conversion circuit is not limited to the form illustrated in each embodiment, but generally,
If the magnitude (absolute value) of the sink voltage Vs is set larger than the magnitude (absolute value) of the threshold voltage Vbt, the same effect is obtained.

However, the configurations illustrated in the devices 101 to 105 are advantageous in that the configuration of the conversion circuit is simple and the manufacture is easy, and the chip area can be reduced when the conversion circuit and the conversion circuit are integrated into one chip. There is. In particular, the effects are remarkable in the devices 101 and 104 using the split resistance element 2 and the devices 103 and 105 using the diode element 7.

(6) A plurality of conversion circuits (unit conversion circuits) having mutually different sink voltages Vs are provided corresponding to the device 104 of the fourth embodiment, and only one of them is connected via the connection wiring 11. The gate driving device selectively connected to the terminal 22 has the same effect as the device 104. For example, a plurality of comparators 4 having different reference voltages Vref (FIG. 6)
May be provided, only one of which may be selectively connected to the terminal 22. In the device 104 shown in FIG.
Three unit conversion circuits are provided, and three resistance elements that are interposed between one input of the logic circuit 3 and the terminal 23 and connected in parallel with each other are provided between these three unit conversion circuits. Shared in.

[0080]

The device of the first invention is used in a form in which the gate electrode and the main electrode of the power switching element are connected to the first and second terminals, respectively. Then, when the power switching element is turned off, the voltage between the first and second terminals changes from the magnitude exceeding the threshold voltage of the power switching element toward the zero voltage. When the voltage between the first and second terminals falls below the sink voltage during this transition process, the gate sink switching element becomes conductive and the power switching element shifts to a stable cutoff state. Since the sink voltage is set so as to substantially match the threshold voltage of the power switching element, the operation at the time of turning off the power switching element is stabilized earlier than in the conventional device.

Further, when the input signal input from the outside to the third terminal changes to turn off the power switching element, the magnitude of the output voltage of the amplifier based on the second terminal is then changed to the power switching element. The voltage that exceeds the threshold voltage of is attenuated to zero voltage. In this process, if the magnitude of the output voltage exceeds the sink voltage and falls below, a voltage lower than the threshold voltage is input to one input of the logic circuit by the function of the conversion circuit. As a result, the logic circuit drives the gate sink switching element to be conductive.

That is, when the output voltage falls below the sink voltage larger than the threshold voltage of the logic circuit, the gate sink switching element becomes conductive, and the power switching element shifts to a stable cutoff state. Therefore, the operation at the time of turning off the power switching element having a threshold voltage higher than the threshold voltage of the logic circuit can be stabilized early.

In the device of the second aspect of the invention, since the conversion circuit is constituted by the resistance element which is a simple element, the manufacturing is easy and the cost is low, and the chip area is small when the device is constituted by one chip. Can be made smaller.

In the device of the third invention, since the conversion circuit is composed of the comparator, the structure is relatively simple and the manufacturing is relatively easy.

In the device of the fourth aspect of the present invention, since the conversion circuit is constituted by the diode element which is a simple element, the manufacturing is easy and the cost is low, and the chip area is small when the device is constructed in one chip. Can be made smaller.

In the device of the fifth aspect of the invention, a plurality of unit conversion circuits having mutually different sink voltages are provided, and all of them can be connected to the first terminal. Therefore, it is possible to arbitrarily select one of the plurality of unit conversion circuits according to the threshold voltage of the power switching element to be connected. That is, it is possible to adapt to a power switching element having a plurality of threshold voltages with a single configuration.

In the device of the sixth invention, a plurality of unit diode elements connected to each other in series are provided, and both ends and connecting portions thereof can be connected to the first terminal. Therefore, it is possible to select one of a plurality of types of forward voltages according to the threshold voltage of the power switching element to be connected. That is, it is possible to adapt to a power switching element having a plurality of threshold voltages with a single configuration.

In the device of the seventh invention, since the sink voltage of the gate drive device is set so as to be substantially equal to the threshold voltage of the power switching device, the unstable period at the time of turning off the power switching device is most likely. An effectively shortened power module is realized.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a device according to a first embodiment.

2 is a circuit diagram of the amplifier of FIG.

FIG. 3 is a circuit diagram of the logic circuit of FIG.

4 is a block diagram showing a usage pattern of the apparatus of FIG. 1. FIG.

5 is a timing chart of the apparatus of FIG.

FIG. 6 is a circuit diagram of the device according to the second embodiment.

FIG. 7 is a circuit diagram of the device according to the third embodiment.

FIG. 8 is a circuit diagram of the device according to the fourth embodiment.

FIG. 9 is a circuit diagram of the device according to the fifth embodiment.

FIG. 10 is a circuit diagram of a conventional device.

11 is a timing chart of the conventional device of FIG.

[Explanation of symbols]

1 power switching element, 2 divided resistance elements, 2a
First resistance element, 2b second resistance element, 3 logic circuit, 4
Comparator, 5 amplifier, 6 gate sink switching element, 7 diode element, 11 connection wiring, 12,
13 and 14 divided resistance elements, 22, 23 and 21 terminals (first, second and third terminals).

Claims (7)

(57) [Claims] 1. A gate drive device for driving a voltage-driven power switching element, comprising: first and second terminals respectively connectable to a gate electrode and a main electrode of the power switching element; and the first and second terminals. A gate sink switching element inserted between the second terminals, and a sink voltage determined such that the magnitude of the voltage between the first and second terminals substantially matches the threshold voltage of the power switching element. Responsive to falling below, control means for controlling the gate sink switching element to conduct, and a third terminal for relaying an input signal supplied from the outside.
And the third terminal inserted between the third and first terminals,
To the first terminal by amplifying the input signal input to
An amplifier for outputting, wherein the control means has one input connected to the third terminal, and the gate sink
Having a predetermined threshold voltage for driving the switching element for use 2
An input type logic circuit , connected to the first terminal and the other input of the logic circuit,
The output of the amplifier is converted and input to the other input.
And a logic circuit , wherein the logic circuit is provided in front of the one input and the other input.
The voltage magnitude with respect to the second terminal is
The gate sink is provided only when it is below a predetermined threshold voltage.
Gate sink so that the switching element for
Driving the switching element for the conversion circuit , and the conversion circuit changes the sink voltage to the predetermined threshold voltage.
It is set to exceed the size of the first and second terminals.
When the voltage between the two is greater than the sink voltage
A voltage greater than the predetermined threshold voltage is applied to the logic circuit.
Input to the other input of and less than the sink voltage
A gate driving device characterized in that a voltage smaller than the predetermined threshold voltage is inputted at times . 2. The gate drive device according to claim 1 , wherein the conversion circuit includes a dividing resistance element in which first and second resistance elements are connected in series, and the dividing resistance element is the first resistance element. And a second terminal, and a connecting portion of the first and second resistance elements is connected to the other input of the logic circuit. 3. The gate drive device according to claim 1 , wherein the conversion circuit compares the magnitude of the voltage between the first and second terminals with a reference voltage corresponding to the sink voltage, A gate drive device for inputting to the other input of the logic circuit a voltage greater than or less than the threshold voltage, respectively, depending on whether or not is greater than the latter. 4. The gate drive device according to claim 1 , wherein the conversion circuit includes a diode element, and the diode element is interposed between the first terminal and the other input of the logic circuit. And is inserted in a direction in which the voltage of the first terminal is higher than the voltage of the other input of the logic circuit by a forward voltage with reference to the second terminal. And gate drive device. 5. The gate driving device according to claim 1 , further comprising a plurality of unit conversion circuits each including the conversion circuit and having the same configuration as the conversion circuit but different in the sink voltage from each other. Any of the unit conversion circuits can be connected to the first terminal through a connection wiring, and only one of the unit conversion circuits can be selectively connected to the first terminal as the conversion circuit. A gate drive device, which is connected through connection wiring. 6. The gate drive device according to claim 1 , wherein the conversion circuit includes a diode element whose one end is connected to the other input of the logic circuit, and the diode element is connected in series with each other. A plurality of unit diode elements are provided, and any of the other end of the diode element and a connecting portion between the plurality of unit diode elements can be connected to the first terminal via a connection wiring. Moreover, only one of the other end and the connection portion is selectively connected to the first terminal through the connection wiring, and the direction of the plurality of unit diode elements is set to the second terminal. As a reference, the gate driving device is characterized in that the voltage of the first terminal is higher than the voltage of the other input of the logic circuit by a forward voltage. 7. claims 1 and gate driving apparatus according to claim 6, said first and second terminals of the gate driving unit, the said gate electrode and the main electrode is connected A power module comprising: a voltage drive type power switching element;