JPH04354156A - Semiconductor switching device - Google Patents

Abstract

PURPOSE:To realize a semiconductor switching device which can reduce its switching loss without increasing the number of its components. CONSTITUTION:This semiconductor switching device is provided with an IGBT 111 and MOSFET 112 using a high-speed diode 113 as its internal parasitic diode and the gate of the IGBT 111 is connected to a gate G5 through an input resistance 114a, with the gate of the MOSFET 112 being connected to the gate G5 through another input resistance 114b having a resistance value higher than that of the resistance 114a. Because of a voltage drop caused by the resistance values of the input resistances, the MOSFET 112 is turned off after the IGBT ill is turned off. The collector current of this semiconductor switching device is shared by both the IGBT 111 and MOSFET 112. The chips of the IGBT 111 and MOSFET 112 are connected in parallel with each other in a container.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a switching device using a semiconductor chip, and in particular to an IGBT chip and a MOS switching device.
The present invention relates to a semiconductor switching device having a composite switching circuit with a FET chip.

0002

[Prior Art] Switching devices using semiconductor elements are also used in switching circuits such as chopper circuits and half-bridge circuits in power supplies, etc., and a typical example is an insulated gate bipolar device shown in FIG. There are semiconductor switching devices that utilize transistors (hereinafter referred to as IGBTs). In the figure, 201 is a semiconductor switching device, and an insulating substrate 203 is fixed on the bottom plate 202 of the container. This insulating substrate 203 has a first external gate terminal 204a on its surface.
conductor pattern 204b and external collector terminal 205a
and a third conductor pattern 206b including an emitter terminal 206a. Here, the collector electrode of the IGBT chip 207 and the anode electrode of the high-speed diode chip 208 are fixed to the surface of the second conductor pattern 205b. Further, the emitter electrode of the IGBT chip 207 and the cathode electrode of the high-speed diode chip 208 are both electrically connected to the third conductor pattern 206b by aluminum wires 209a and 209b. The gate electrode portion of the IGBT chip 207 is also electrically connected to the first conductor pattern 204b via the aluminum wire 209c, and the semiconductor switching device 201
constitutes the equivalent circuit shown in FIG.

In this equivalent circuit, the gate G6 of the IGBT 211 is driven by the gate drive circuit to supply or disconnect the current from the collector C to the emitter E, and the high speed diode 212 is used to circulate the current from the load side. Acts as a freewheeling diode.

0004

[Problems to be Solved by the Invention] When the semiconductor switching device 201 having such a configuration is used, for example, in a chopper circuit, and the IGBT 211 is turned off from the on state (period T11) to the period 12, the state shown by the dashed-dotted line 220 in FIG. As shown, the collector-emitter current IC0 of the IGBT 211 decreases and the IGBT 211 is turned off. However, since a tail current IC0' is generated in the IGBT 211, which is a minority carrier element, at turn-off, a large turn-off loss occurs in the semiconductor switching device 201. This turn-off loss reduces the conversion efficiency of the power supply device as a switching loss in proportion to the switching frequency. Therefore, it is necessary to reduce the turn-off loss by shortening the fall time of the current IC0 of the IGBT 211. Generally speaking, when the current fall time of the IGBT 211 is shortened, its saturation voltage (on operation period T1 shown by the solid line 221)
1) increases, and conversely, the on-loss increases. That is, in the IGBT 211, since there is a trade-off relationship between the fall time and the saturation voltage, it is difficult to reduce both the turn-off loss and the on-loss. For this reason, when a conventional switching device using the IGBT 211 is used, there is a limit to increasing the switching frequency of the power supply device to a high frequency, which is an obstacle to improving conversion efficiency.

[0005] Therefore, a method can be considered in which a MOSFET chip, which is a majority carrier element, is used in the switching device instead of an IGBT chip. When this method is adopted, no tail current is generated in the MOSFET chip at turn-off, as shown by the broken line 222 in FIG.
Turn-off loss can be reduced to a fraction of that of IGBT. However, in FIG.
The current-saturation voltage characteristics of ET are shown, and the broken line 224 indicates IGB
As shown in the current-saturation voltage characteristics of T, the saturation voltage in the large current region of MOSFET is higher than the saturation voltage of IGBT, so when a large current flows under heavy load, the on-loss increases, On the contrary, there is a problem in that the switching loss of the power supply device increases.

[0006] In order to solve the above problems, the inventors
We construct a switching circuit using IGBTs and MOSFETs, and propose a circuit configuration that reflects the low saturation voltage in the high current region of IGBTs and the low turn-off loss of MOSFETs, but when each chip is mounted on a wiring board, , due to the problem of an increase in the number of mounted parts,
Not desirable from a practical standpoint.

[0007] Therefore, the problem of the present invention is to
By modularizing SFET, IGBT chips and MOS can be combined without increasing the number of mounted components.
The object of the present invention is to realize a semiconductor switching device that can reduce switching loss by configuring a circuit that reflects the features of FET chips.

[0008]

[Means for Solving the Problems] In order to solve the above problems, in a semiconductor switching device using an IGBT chip and a MOSFET chip, the means taken by the present invention is to separately connect the IGBT chip and the MOSFET chip to a wiring board. IGBT chip and MOSFET without being mounted on top
The chip is stored inside a container, and inside this container, the IGB
While electrically connecting the collector electrode of the T chip and the drain electrode of the MOSFET chip to an external collector terminal,
By electrically connecting the emitter electrode of the IGBT chip and the source electrode of the MOSFET chip to an external emitter terminal,
This is to connect a GBT chip and a MOSFET chip in parallel. Electrical connections in this configuration include, for example, IGB
It is possible to employ a structure in which both the collector electrode of the T chip and the drain electrode of the MOSFET chip are fixed on the conductor pattern on the bottom side of the container.

Here, in order to drive the IGBT chip and the MOSFET chip by a common gate drive circuit, the gate electrode of the IGBT chip and the MOSFET chip are placed inside the container.
A common drive signal supplied to the gate electrode of the FET is controlled to turn off the MOSFET after the turn-off operation of the MOSFET.
It is preferable to have drive signal control means for turning off the T-chip. In this case, as the drive signal control means, for example, the threshold voltage of the MOSFET chip, which is lower than the threshold voltage of the IGBT chip, or the
MOS that is large compared to the input resistance on the gate electrode side of the chip
The input resistance on the FET side can be used. Note that the external gate terminals of the IGBT chip and the MOSFET chip can be either a common terminal or formed as separate terminals.

Furthermore, in the present invention, MOSFET
Preferably, the internal parasitic diodes formed within the chip are fast diodes.

[0011]

[Operation] In the semiconductor switching device according to the present invention, the collector electrode of the IGBT chip and the drain electrode of the MOSFET chip are electrically connected to an external emitter terminal, and the emitter electrode of the IGBT chip and the MOS
The source electrode of the FET chip is electrically connected to the external collector electrode and connected in parallel. Therefore, the collector-emitter current of the semiconductor switching device is divided into the IGBT chip and MOSFET chip that are connected in parallel. Here, in the small current region, MOSFET is better than IG.
The saturation voltage is lower than that of BT, and conversely, in the large current region,
IBGT has a lower saturation voltage than MOSFET. Therefore, under small current conditions such as during light load, the current between the collector and emitter of the semiconductor switching device is
On the other hand, under large current conditions such as during heavy loads, the IG
Flows to the BT side. In other words, the semiconductor switching device exhibits the saturation voltage of the semiconductor chip with the lower saturation voltage in response to the current level, so the saturation voltage of the semiconductor switching device is low over a wide range of conditions from small current conditions to large current conditions. . Therefore, since the on-loss can be reduced, the conversion efficiency of the power supply device can be increased.

Here, the sequence of the gate drive circuit is as follows:
If you turn off the IGBT first and then turn off the MOSFET chip, even if a tail current occurs when the IGBT turns off, the MOSFET chip will turn off.
Since ET is in the on state, turn-off loss due to tail current does not occur in the semiconductor switching device.

That is, when the MOSFET turns off, the semiconductor switching device turns off, and since the semiconductor switching device substantially has the turn-off characteristics of a MOSFET, the turn-off loss is also low. Therefore, since switching loss can be reduced, conversion efficiency can be further improved.

Moreover, since the MOSFET and IGBT are housed inside the container and are modularized, there is no need to mount them individually on the wiring board, and the number of parts does not increase. Moreover, the circuit configuration can also be simplified.

[0015] Here, the MO is lower than that of the IGBT chip.
A MOSFE that is larger than the threshold voltage of the SFET chip or the input resistance on the gate electrode side of the IGBT chip.
If the T-chip has a drive signal control means such as an input resistor on the gate electrode side, even if the same gate drive circuit is used, the IGBT will always turn off first and the MOS will always turn off.
Since it is possible to configure a sequence in which the FET is turned off later, it is possible to realize a common gate drive circuit.

Furthermore, in order to pass the current flowing back from the reactance on the load side of the switching device at the time of turn-off, the IGB is used in the chopper circuit, etc.
Connect a high speed diode in parallel with T to make it a freewheeling diode. In addition, if the reverse recovery time of the internal parasitic diode of the MOSFET is long, the MOSFET may be damaged due to the current circulating from the load side, so connect a reverse blocking diode in series with the MOSFET. , to prevent internal parasitic diodes from functioning. Here, if the internal parasitic diode of the MOSFET is formed as a high-speed diode with good reverse recovery characteristics, this internal parasitic diode can be used as a free-wheeling diode connected in parallel to the IGBT,
Since these diodes function as reverse blocking diodes for the internal parasitic diodes, these diodes can be omitted. Moreover, since the forward voltage drop of the diodes connected in series with the MOSFET can be removed, the on-voltage on the MOSFET side does not increase, and the on-loss can be kept low.

[0017]

【Example】

[Embodiment 1] Next, a semiconductor switching device according to Embodiment 1 of the present invention will be described with reference to FIG.

FIG. 1 is a perspective view showing the inside of the semiconductor switching device of this example with side plates and a cover plate removed.

In the figure, reference numeral 1 denotes a semiconductor switching device, and an insulating substrate 3 is fixed on the bottom plate 2 of the container. This insulating substrate 3 has, on its surface, a first conductor pattern 4b having a first external gate terminal 4a, and a second conductor pattern 4b.
a second conductor pattern 5b having an external gate terminal 5a;
, a third conductor pattern 6b having an external collector terminal 6a, a fourth conductor pattern 7b having an emitter terminal 7a, and a fifth conductor pattern 8 to which a MOSFET chip is fixed. Here, the collector electrode of the IGBT chip 9 is provided on the surface of the third conductor pattern 6b,
The anode electrode of the high-speed diode chip 10 as a freewheel diode and the cathode electrode of the Schottky barrier diode chip 11 as a reverse blocking diode for the internal parasitic diode of the MOSFET chip are fixed and electrically connected. Furthermore, the drain electrode of the MOSFET chip 12 is fixed to the surface of the fifth conductive pattern 8 and electrically connected thereto. This fifth conductor pattern 8 and the anode electrode of the Schottky barrier diode chip 11 are connected to an aluminum wire 13a.
is electrically connected to the MOSFET chip 12
and the Schottky barrier diode chip 11 are connected in series. Here, the gate electrode of the MOSFET chip 12 and the second conductor pattern 5b are electrically connected by the aluminum wire 13b, and the MOSFET chip 12 is driven by a signal from the second external gate terminal 5a. ing. On the other hand, IGBT chip 9
The gate electrode is electrically connected to the first conductor pattern 4b by an aluminum wire 13c, so that the IGBT chip 9 is driven by a signal from the first external gate terminal 4a. Furthermore, IGBT chip 9
The emitter electrode of the high-speed diode chip 10, the cathode electrode of the high-speed diode chip 10, and the source electrode of the MOSFET chip 12 are all electrically connected to the fourth conductor pattern 7b by aluminum wires 13d, 13e, and 13f.

FIG. 2 shows an equivalent circuit of the semiconductor switching device 1 having this configuration.

In this equivalent circuit, IGBT21 and M
It is connected in parallel with OSFET23, and IGBT21
The emitter of the MOSFET 23 and the source of the MOSFET 23 are connected to the emitter E of the semiconductor switching device 1 at the same potential, and the IG
The collector of BT21 and the drain side of MOSFET23 are connected to collector C of semiconductor switching device 1. Further, the gate of the IGBT 21 is connected to the first gate drive circuit via the first gate G1 of the semiconductor switching device 1, and the gate of the MOSFET 23 is connected to the second gate drive circuit via the second gate G2 of the semiconductor switching device 1. It is designed to be connected to the drive circuit. here,
High-speed diode 22 connected in parallel to IGBT 21
functions as a freewheeling diode for the current flowing back from the emitter E, which is the load side. On the other hand, M
The Schottky barrier diode 24 connected in series to the OSFET 23 is configured so that the current flowing back from the load side at turn-off is connected to the internal parasitic diode 25 of the MOSFET 23.
Even if the reverse recovery time of the internal parasitic diode 25 is long, increasing switching loss and element breakdown are prevented.

Next, the operation when the semiconductor switching device 1 is used in a chopper circuit will be explained with reference to FIGS. 2 and 3.

FIG. 3 is a timing chart showing the operating state of the semiconductor switching device 1. FIG. 3(a) shows the voltage/current characteristics of the semiconductor switching device 1, and FIG. 3(b) shows the voltage/current characteristics of the semiconductor switching device 1.
Figure 3(c) shows the voltage/current characteristics of the MOSFET23, Figure 3(d) shows the voltage/current characteristics of the IGBT21, and Figure 3(d) shows the voltage/current characteristics of the MOSFET23.
The gate voltage VG1 that drives FET23 is shown in FIG. 3(e).
2 shows the gate voltage VG2 that drives the IGBT 21. Note that in FIGS. 3(a) to 3(e), solid lines indicate voltage waveforms, and broken lines indicate current waveforms.

As shown in FIGS. 3(d) and 3(e),
The gate voltages of MOSFET 23 and IGBT 21 are equal to the gate voltage VG1 of MOSFET 23 during period T1.
After reaching the threshold voltage VM1, a period T2 elapses,
In the period T3, the gate voltage G2 of the IGBT 21 reaches the threshold voltage VI1 with a delay. Further, after the period T4, the gate voltage decreases, and in the period T5, the IGB
After the gate voltage G2 of T21 drops to the threshold voltage VI1, a period T6 elapses, and in a period T7, the MOSF
The gate voltage VG1 of ET23 reaches the threshold voltage VM with a delay.
It drops to 1. Therefore, at turn-on, IGBT 21 is turned on with a delay after MOSFET 23 is turned on, and conversely, at turn-off, after IGBT 21 is turned off, MOSFET 23 is turned off with a delay.

Therefore, as shown in FIGS. 3(a) to 3(c), the current/voltage characteristics during the operation of the semiconductor switching device 1 from turn-on to steady state are as follows.
In period T1, the gate voltage G1 of the MOSFET 23 reaches the threshold voltage VM1, the current ID1 flows to the MOSFET 23 side, and the voltage VT1 of the semiconductor switching device 1 increases.
decreases. Thereafter, when the gate voltage VG2 of the IGBT 21 reaches the threshold voltage VI1 in the period T3, the current IT1 is shunted and the current IC1 is also applied to the IGBT 21 side.
flows.

On the other hand, during turn-off from the steady state, when the gate voltage VG2 of the IGBT 21 decreases to the threshold voltage VI1 in the period T5, the current IC1 on the IGBT 21 side decreases and the tail current IC1'
However, this current fluctuation is absorbed by the current ID1 of the MOSFET 23, and the current flowing through the semiconductor switching device 1 is maintained in a steady state. That is, at this point, the semiconductor switching device 1 is in the on state, and no turn-off loss occurs due to the tail current IC1'.

After this, in period T7, the MOSFET
When the gate voltage VG1 of MOSFET 23 decreases to the threshold voltage VM1, the current ID1 on the MOSFET 23 side also decreases, the current IT1 flowing through the semiconductor switching device 1 decreases, and the MOSFET 23 becomes in an off state.

As described above, in the semiconductor switching device 1 of this example, the transient characteristics at the time of turn-off depend on the MOS
The turn-off characteristics of the FET 23 are reflected and the turn-off characteristics of the IGBT 21, which has a large turn-off loss, are not expressed, so even if the switching frequency is high, the switching loss is small, so the conversion efficiency of the power supply device can be increased. Further, in the semiconductor switching device 1 of this example, the collector current IT1 is divided into the MOSFET 23 and the IGBT 21 in a steady state, and the chip with the lower saturation voltage shares a large current. Here, the relationship between the current level and saturation voltage of each chip is shown in Figure 12.
As mentioned above based on the above, in the small current region, MO
The saturation voltage of the SFET 23 is low, and the saturation voltage of the IGBT 21 is low in the large current region. Therefore, under conditions of low load and small current level, a large current flows to MOSFET23, and under conditions of high load and large current, IGBT2
Since a large current flows toward the semiconductor switching device 1, the saturation voltage of the semiconductor switching device 1 is low over a wide current range, as shown by the solid line 225 in FIG. The on-loss that occurs is also small. Therefore, the conversion efficiency of the power supply device can be further improved. Moreover, since both chips are fixed inside the container and made into modules, even when mounted on a wiring board, only one component is required as a switching device, so the mounting space is small and components can be mounted efficiently. can be done. In addition, since the wiring length is also shortened, the L component due to the wiring is low, so it is possible to suppress the occurrence of surge voltages, vibrations, etc. due to the L component.

[Embodiment 2] Next, a semiconductor switching device according to Embodiment 2 of the present invention will be described with reference to FIG. 4.

FIG. 4 is a perspective view showing the inside of the semiconductor switching device of this example with the side plate and cover plate removed.

In the figure, 31 is a semiconductor switching device, and an insulating substrate 33 is fixed to the bottom plate 32 of the container.
has an external gate terminal 34a on its surface.
a second conductor pattern 35b including an external collector terminal 35a, and an emitter terminal 36a.
and a fourth conductor pattern 37 to which a MOSFET chip is fixed. Here, similarly to the semiconductor switching device 1 of the first embodiment, an IGBT is provided on the surface of the second conductor pattern 35b.
Collector electrode of chip 38 and high speed diode chip 3
The anode electrode of 9 and the cathode electrode of the Schottky barrier diode chip 40 are fixed and electrically connected. Further, on the surface of the fourth conductor pattern 37, M
The drain electrode of the OSFET chip 41 is fixed and electrically connected.

Here, the IGBT chip 38 and the MOSFE
As the T-chip 41, one in which the threshold voltage of the IGBT chip 38 is higher than that of the MOSFET chip 41 is used. Further, both the gate electrode of the IGBT chip 38 and the gate electrode of the MOSFET chip 41 are connected to the aluminum wires 42a and 42.
b is electrically connected to the first conductor pattern 34b. The other configurations are the same as those of the semiconductor switching device 1 of Example 1, and description thereof will be omitted.

The equivalent circuit of the semiconductor switching device 1 having this configuration is as shown in FIG.
The structure is similar to that shown in FIG. 2, including an ET52, a high-speed diode 53, a Schottky barrier diode 54, and an internal parasitic diode 55 of the MOSFET52, but the IGB
Both the gate of T51 and MOSFET52 are connected to the gate drive circuit via the gate G3, and the IGBT
51 and MOSFET 52 are configured to be driven by a common gate drive circuit.

Next, the operation when the semiconductor switching device 31 is used in a chopper circuit will be explained with reference to FIGS. 5 and 6.

FIG. 6 is a timing chart showing the operating state of the semiconductor switching device 31, and FIG. 6(a) shows the voltage/current characteristics of the semiconductor switching device 31.
b) shows the voltage/current characteristics of MOSFET53, and Fig. 6(c) shows the voltage/current characteristics of MOSFET53.
) shows the voltage/current characteristics of IGBT51, and Fig. 6(d) shows the voltage/current characteristics of IGBT51.
The gate voltage VG3 that drives the OSFET 53 and IGBT 51 is shown. Note that also in FIGS. 6(a) to 6(d), the voltage waveform is shown by a solid line, and the current waveform is shown by a broken line.

Here, as shown in FIG. 6(d), the MOS
The gate voltage VG3 of the FET 53 and the IGBT 51 is equal to the threshold voltage V of the MOSFET 53 during the period T11.
After reaching M2, a period T12 elapses, and the threshold voltage VI2 of the IGBT 51 is reached in a period T13. Further, after the period T14 passes, the gate voltage VG3 decreases, and in the period T15, the gate voltage VG3 increases to the IGBT51.
After decreasing to the threshold voltage VI2, a period T16 elapses, and in a period T17, the gate voltage of the MOSFET 53 decreases to the threshold voltage VM2. In this way, in the semiconductor switching device 1, the MOSFET
53 and IGBT51 have the same gate drive circuit, but the threshold voltage VI2 of IGBT51 is different from that of MOSFET
Since the threshold voltage VM2 is higher than that of 53, the MOS
After the FET 53 is turned on, the IGBT 51 is turned on with a delay, and at turn-off, after the IGBT 51 is turned off, the MOSFET 53 is turned off with a delay.

Therefore, as shown in FIGS. 6(a) to 6(c), in the steady state from turn-on of the semiconductor switching device 31, the current ID2 flows to the MOSFET 53 side in the period T11, and then the current ID2 flows in the period T13. The current I at
T2 is shunted and current IC2 flows to the IGBT 51 side.

On the other hand, in the turn-off operation from the steady state, during the period T15, the current IC2 on the IGBT51 side
A tail current IC2' is generated during this period, but the current IT2 and voltage VT2 of the semiconductor switching device 31 are
It is kept in a steady on state. After this, in period T17, when the gate voltage decreases to the threshold voltage VM2 of MOSFET 53, current ID2 on the side of MOSFET 53 also decreases, current IT2 flowing through semiconductor switching device 31 decreases, and it becomes an OFF state.

Therefore, the semiconductor switching device 3 of this example
In No. 1, the difference in threshold voltage between IGBT 51 and MOSFET 53 is used to adjust the transient characteristics at turn-off.
Since the turn-off characteristics of the MOSFET 53 are reflected and the turn-off characteristics of the IGBT 51, which has a large turn-off loss, are absorbed, the switching loss is low, and since control is performed by a common gate drive circuit, the circuit configuration can be simplified. Also, in the semiconductor switching device 31 of this example, under the condition of a small current level, the MOSFET 53
A large current flows towards the IGB, and under large current conditions, the IGB
Since a large current flows toward T51, the loss generated in the semiconductor switching device 31 is small in any current region, so that the conversion efficiency of the power supply device can be increased.

Moreover, since the switching device is modularized, the mounting space is small and components can be easily mounted.

[Embodiment 3] Next, a semiconductor switching device according to Embodiment 3 of the present invention will be described with reference to FIG.

FIG. 7 is a perspective view showing the inside of the semiconductor switching device of this example with the side plate and cover plate removed.

In the figure, 61 is a semiconductor switching device, and an insulating substrate 63 on the container bottom plate 6 is provided with a first conductor pattern 64b having an external gate terminal 64a and an external collector terminal 65a on its surface. A third conductor pattern including a second conductor pattern 65b and an emitter terminal 66a.
conductor pattern 36b, and a fourth conductor pattern 67 to which a MOSFET chip is fixed. here,
Similar to the semiconductor switching devices of Examples 1 and 2, the collector electrode of the IGBT chip 68 and the high-speed diode chip 69 are provided on the surface of the second conductor pattern 65b.
The anode electrode of the Schottky barrier diode chip 70 and the cathode electrode of the Schottky barrier diode chip 70 are fixed and electrically connected,
The drain electrode of the MOSFET chip 71 is fixed to the surface of the fourth conductive pattern 67 and electrically connected thereto.

Here, resistor chips 72a and 72b are fixed and electrically connected to the surface of the first conductor pattern 64b, and the gate electrode of the IGBT chip 68 is connected to the resistor chip 72a, and the MOSFET is connected to the resistor chip 72b. Gate electrodes of the chip 71 are electrically connected by aluminum wires 73a and 73b, respectively. Among these resistor chips 72a and 72b, the resistor chip 72b has a resistance value larger than that of the resistor chip 72a. In addition, IGBT chip 68
The MOSFET chip 71 is different from the IGBT chip 38 and the MOSFET chip 41 of the second embodiment, and has threshold voltages of approximately the same level. The other configurations are the same as those of the semiconductor switching device 1 of Example 1, and description thereof will be omitted.

The equivalent circuit of the semiconductor switching device 1 having this configuration is as shown in FIG.
ET82, high speed diode 83, Schottky barrier diode 84, parasitic diode 8 of MOSFET82
The gate of the IGBT 81 is connected to the gate G4 via a small input resistance 86a, and the gate of the MOSFET 82 is connected to the gate G4 via a large input resistance 86b. A drive circuit is connected.

Also in the turn-off operation of this semiconductor switching device 61, MOSFET 82 and IGBT 8
After the IGBT 81 is turned off due to a voltage drop based on the resistance values of the resistors 86a and 86b, the gate voltage of 1 is
After a delay, MOSFET 82 is controlled to turn off.

Therefore, like the semiconductor switching device 31 of the second embodiment, even if the gate drive circuit is shared, the IG
The tail current of BT81 is the semiconductor switching device 61.
Since the turn-off characteristics of the semiconductor switching device 61 exhibits the turn-off characteristics of the MOSFET 82 without affecting the turn-off characteristics of the MOSFET 82, a semiconductor switching device with small switching loss can be realized. Also, in the semiconductor switching device 61 of this example, M
Since the OSFET 82 and the IGBT 81 share the current, and a larger current always flows in the one with the lower saturation voltage, the on-loss is low over a wide current range, and the conversion efficiency of the power supply device can be improved. Moreover, since the switching device 61 is modularized and the gate drive circuit is also shared, the circuit configuration can be simplified.

[Embodiment 4] Next, a semiconductor switching device according to Embodiment 4 of the present invention will be described with reference to FIG. 9.

FIG. 9 is a perspective view showing the inside of the semiconductor switching device of this example with the side plate and cover plate removed.

In the figure, 91 is a semiconductor switching device, and an insulating substrate 93 on the container bottom plate 92 has a first conductor pattern 94b with an external gate terminal 94a and an external collector terminal 95a on its surface. It has a second conductor pattern 95b and a third conductor pattern 96b including an emitter terminal 96a.

[0051] Here, the collector electrode of the IGBT chip 97 and the MOS
Only the drain electrode of the FET chip 98 is fixed and electrically connected, and the emitter electrode of the IGBT chip 97 and the source electrode of the MOSFET 98 are electrically connected to the third conductive pattern 96b by aluminum wires 99a and 99b. . In addition, the first conductor pattern 94b
As in the third embodiment, on the surface of the resistor chip 100a,
and a resistor chip 100b having a larger resistance value than the resistor chip 100a are fixed and electrically connected, and the gate electrode of the IGBT chip 97 is connected to the resistor chip 100.
The gate electrode of the MOSFET chip 98 is electrically connected to the resistor chip 100b by an aluminum wire 99d. Furthermore, MOSFETs have internal parasitic diodes, but the MOSFETs used in this example
The internal parasitic diode of the ET chip 98 is a high-speed diode in which the diode portion in the semiconductor substrate is doped with a heavy metal to shorten the lifetime of minority carriers.

Therefore, the equivalent circuit of the semiconductor switching device 91 having this configuration is as shown in FIG.
, MOSFET112, and a high-speed diode 113 which is an internal parasitic diode of MOSFET112. Here, the gate of the IGBT 111 is connected to the gate through a small input resistance 114a, and the gate of the MOSFET 112 is connected to the gate through a large input resistance 114b.
5, and a gate drive circuit is connected to this gate G5.

In the turn-off operation of this semiconductor switching device 91, even if the common gate drive circuit is used, after the IGBT 111 is turned off, the MOS
Since the FET 112 is turned off, the turn-off characteristics of the semiconductor switching device 91 exhibit the turn-off characteristics of the MOSFET 112, so a semiconductor switching device with small switching loss can be realized. Further, the semiconductor switching device 61 of this example also includes a MOSFET 82 and an IG
Since the BT81 shares the current and a larger current always flows to the side with a lower saturation voltage, the on-loss is also small and the conversion efficiency of the power supply device can be increased. Moreover, since the switching device is modularized and the gate drive circuit is also shared, the circuit configuration is simplified.

Furthermore, when a bridge circuit or the like is configured using the semiconductor switching device 91 having this configuration, even if current flows back from the reactance on the load side in the freewheel mode, the current is diverted to the high speed diode 113.
Since it is possible to commutate the current to can be reduced. Moreover, since there is no diode connected in series to MOSFET 112, no forward voltage drop occurs due to this diode, and the on-state voltage on the MOSFET 112 side is low, so that on-loss can be further reduced. Furthermore, since the mounting space for components is small, there is a high degree of freedom in designing inside the container, and for example, a plurality of switching circuits can be accommodated.

As described above, in any of the embodiments, IGBT and MOSFET are used together, and the IGBT has a low saturation voltage in a large current region, and the MOSFET has a low saturation voltage in a small current region.
Reflecting the low saturation voltage of the SFET, it is possible to reduce the on-loss of the semiconductor switching device over a wide current range. Also, in turn-off operation,
Since the turn-off operation of the MOSFET is delayed with respect to the turn-off operation of the IGBT, the semiconductor switching device exhibits the turn-off characteristics of a MOSFET with small turn-off loss. Therefore, the conversion efficiency of the power supply device can be increased. Moreover, since the switching device is modularized into one component, the mounting space on the wiring board is small and the work efficiency for mounting the components is high.

Although the above embodiments have all been explained using chopper circuits as an example, they can also be applied to high frequency switching circuits such as inverter circuits and converter circuits.

[0057]

[Effects of the Invention] As described above, in the semiconductor switching device according to the present invention, the IGBT chip and the MOSFE
The T-chip is stored inside the container, and the IG
The feature is that the BT chip and the MOSFET chip are connected in parallel, so the following effects are achieved.

[0058] Since the IGBT chip and the MOSFET chip are connected in parallel, under small current conditions, the current flows to the MOSFET chip, which has a lower saturation voltage in the small current region, and under large current conditions, the current flows toward the MOSFET chip, which has a lower saturation voltage in the large current region. The voltage flows to the side of the IGBT chip where the voltage is lower. Therefore, since the on-state voltage of the semiconductor switching device is low regardless of the current level, the on-state loss can be reduced over a wide current range, and the conversion efficiency of the power supply device can be improved.

■ By turning off the MOSFET chip with small turn-off loss after the IGBT chip is turned off, the turn-off characteristics of the semiconductor switching device can be made to be the turn-off characteristics of the MOSFET, so even in high frequency switching, the switching The loss is small, and the conversion efficiency of the power supply device can be further improved.

[0060] Since the IGBT chip and the MOSFET chip are housed inside the container in a parallel-connected state, the number of parts mounted on the wiring board can be reduced and the circuit configuration can be simplified. Furthermore, since the wiring length can be shortened, the L component caused by the wiring can also be reduced, and the occurrence of surge voltages, oscillations, etc. can also be suppressed.

■ The threshold voltage of the IGBT chip is M
When the threshold voltage is higher than the threshold voltage of the OSFET chip, or when a larger input resistance is connected to the MOSFET side than to the IGBT side, the drive signal control means for controlling the signal from the gate drive circuit is installed inside the container. If you have
Since the MOSFET chip and the IGBT chip can be driven by a common gate drive circuit so that the MOSFET is turned off after the IGBT, the circuit configuration can be further simplified.

[0062] When the internal parasitic diode in the MOSFET chip is a high-speed diode, the reverse recovery characteristics are good. does not require. Therefore, the number of parts and assembly man-hours can be reduced, and M
Since the ON voltage on the OSFET side can be lowered, the ON loss can be further reduced. In addition, since the mounting space for components is small, the degree of freedom in design is increased, such as by incorporating multiple circuits inside the container.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the internal configuration of a semiconductor switching device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing the configuration of a semiconductor switching device according to Example 1 of the present invention.

FIG. 3 is a timing chart showing the operating state of the semiconductor switching device according to the first embodiment of the present invention.

FIG. 4 is a perspective view showing the internal configuration of a semiconductor switching device according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram showing the configuration of a semiconductor switching device according to Example 2 of the present invention.

FIG. 6 is a timing chart diagram showing the operating state of the semiconductor switching device according to the second embodiment of the present invention.

FIG. 7 is a perspective view showing the internal configuration of a semiconductor switching device according to a third embodiment of the present invention.

FIG. 8 is a circuit diagram showing the configuration of a semiconductor switching device according to Example 3 of the present invention.

FIG. 9 is a perspective view showing the internal configuration of a semiconductor switching device according to a fourth embodiment of the present invention.

FIG. 10 is a circuit diagram showing the configuration of a semiconductor switching device according to a fourth embodiment of the present invention.

FIG. 11 is a graph diagram showing current/voltage characteristics in turn-off operations of IGBTs and MOSFETs.

FIG. 12 is a graph diagram showing the relationship between current and saturation voltage of IGBT and MOSFET.

FIG. 13 is a perspective view showing the internal configuration of a conventional semiconductor switching device.

FIG. 14 is a circuit diagram showing the configuration of a conventional semiconductor switching device.

[Explanation of symbols]

1, 31, 61, 91... semiconductor switching device 9
, 38, 68, 97... IGBT chip 12, 41,
71,98...MOSFET chip 10,39,69
,97...Schottky barrier diode chip

Claims (5)

[Claims] Claim 1: IGBT chip and MOSFE inside the container.
The T-chip is stored inside this container, and the IGBT
The collector electrode of the chip and the drain electrode of the MOSFET chip are electrically connected to an external collector terminal, and the emitter electrode of the IGBT chip and the source electrode of the MOSFET chip are electrically connected to the external emitter terminal. Semiconductor switching device. 2. In claim 1, a common drive signal supplied to the gate electrode of the IGBT chip and the gate electrode of the MOSFET is controlled in the interior of the container, so that the MOSFE
A semiconductor switching device comprising drive signal control means for turning off a T-chip. 3. The semiconductor switching device according to claim 2, wherein the drive signal control means has a threshold voltage of the MOSFET chip that is lower than a threshold voltage of the IGBT chip. 4. The semiconductor switching device according to claim 2, wherein the drive signal control means is an input resistance on the gate electrode side of the MOSFET that is larger than an input resistance on the gate electrode side of the IGBT chip. Device. 5. The semiconductor switching device according to claim 1, wherein the internal parasitic diode of the MOSFET chip is a high speed diode.