JP2021044871A - Semiconductor device and power conversion apparatus - Google Patents

Abstract

To provide a semiconductor device and a power conversion apparatus in which electromotive voltage which is generated in a semiconductor switching element when the element is switched can be suppressed, and which have excellent reliability and excellent low loss properties.SOLUTION: A semiconductor device 1 includes a semiconductor switching element 2, and a control circuit 3 that is connected to a gate terminal G and a source terminal S or an emitter terminal of the semiconductor switching element, and performs on/off control on the semiconductor switching element. The control circuit includes a determination circuit 22 that detects a control terminal voltage Vg between the gate terminal and the source terminal or the emitter terminal, and a gate driving circuit 28 that is capable of controlling the voltage value of the control terminal voltage. In a case where an increase value of the control terminal voltage detected by the determination circuit becomes greater than a prescribed threshold, the control terminal voltage is increased to a control terminal voltage that is higher than the detected one.SELECTED DRAWING: Figure 1

Description

The present invention relates to the configuration of a semiconductor device and its control, and particularly relates to a technique effective when applied to a power semiconductor device mounted on a power conversion device.

In power semiconductor switching elements used in power conversion devices such as DC-DC converters and inverters, the maximum voltage that can be applied is specified from the viewpoint of reliability and destruction prevention.

In such a power conversion device, the current value changes by the switching operation by driving the main semiconductor switching element on and off. For example, in the case of turn-off operation in which the current is cut off, when the main semiconductor switching element cuts off the current by a control command to the control terminal, the inductance in the circuit is increased according to the amount of current change in the unit time. Since an electromotive voltage is generated in, a voltage higher than the power supply voltage is applied between the main terminals that control the electric power.

At this time, if this electromotive voltage becomes excessive, an overvoltage exceeding the withstand voltage of the element is applied between the main terminals, a withstand voltage breakdown phenomenon occurs in the element, and the leakage current becomes excessively increased. Therefore, in order to avoid such a situation, it is common to limit the switching operation speed to some extent and suppress the electromotive voltage. However, if the switching speed is simply set low, the switching speed tends to be low even under the condition that no overvoltage occurs, so that the switching loss tends to be high.

For the purpose of avoiding such a problem, an active clamp is widely used as a method of lowering the switching speed only under the condition where an overvoltage occurs. As an example of the active clamp (active clamp circuit), for example, there is a technique as described in Patent Document 1.

In this method, when a certain voltage or more is applied between the main terminals, the voltage of the control terminal is changed in the on direction and a current is passed through the element to change the rate of change of the current due to switching per unit time. Overvoltage is prevented by limiting the voltage so that it does not drop or exceed a certain value, and suppressing the electromotive voltage of the inductance to a certain value or less.

Japanese Unexamined Patent Publication No. 2001-245466 Japanese Unexamined Patent Publication No. 7-235674

In the method as described in Patent Document 1, a circuit for detecting an overvoltage is required, and a circuit configuration in which a constant voltage diode is combined with the outside of the main semiconductor switching element is used. However, in such a case, it is necessary to consider the variation in the overvoltage determination voltage and the variation in the withstand voltage of the main semiconductor switching element, and in order to secure a margin, an excessive voltage is applied to the actual main semiconductor switching element and the leakage current rises. It is necessary to suppress the overvoltage to a lower voltage level with respect to the voltage. In this case, the switching speed will be set too low and the loss will increase.

Therefore, in the power conversion device, the switching loss increases as compared with the case where the overvoltage is suppressed until the actual device withstand voltage is reached. Then, in order to suppress heat generation due to switching loss, it is necessary to take measures such as reducing the total loss by using a main semiconductor switching element having a larger area with a lower conduction loss, or suppressing the temperature rise by a cooling device having a lower thermal resistance. Therefore, it becomes difficult to reduce the size and improve the efficiency of the power conversion device.

As a method for reducing the influence of the withstand voltage variation and reducing the loss while suppressing the overvoltage, for example, a method as described in Patent Document 2 is known. In this method, overvoltage protection is performed by using the leakage current generated by the breakdown of the junction termination region of the main semiconductor switching element due to the overvoltage and turning it on.

Since a part for detecting overvoltage is provided in the main semiconductor switching element, the voltage for determining overvoltage fluctuates in the same tendency with respect to fluctuations in withstand voltage such as chip thickness and impurity concentration of the main semiconductor switching element. The influence of variation is small, and the margin of the voltage for determining the overvoltage with respect to the withstand voltage of the main semiconductor switching element and protecting it can be set low.

However, in the case of the method as in Patent Document 2, the on-drive to the control terminal for overvoltage protection and the off-output from the control circuit that controls the on / off state of the main semiconductor switching element conflict with each other. A large leakage current is required to turn it on. Therefore, the delay time until the ON state is turned on becomes long, the ON drive cannot be completed in time, and it becomes difficult to suppress the overvoltage.

In addition, since an excessive leakage current is required to prevent this delay, a high-energy charge is generated by this leakage current and injected into the gate oxide film of the element, which lowers the reliability of the main semiconductor switching element. There is a possibility of letting you.

In addition, a method for improving these problems by using an auxiliary drive circuit is also disclosed, but other factors such as an increase in the element area due to mounting the auxiliary drive circuit and a large current being required for the power supply of the auxiliary drive circuit. It is difficult to apply it because of the problems of.

Therefore, an object of the present invention is to provide a power semiconductor device capable of suppressing an electromotive voltage generated in a semiconductor switching element and having excellent reliability and low loss, and a power conversion device using the same. It is in.

In order to solve the above problems, the present invention includes a semiconductor switching element, a gate terminal of the semiconductor switching element, and a control circuit connected to a source terminal or an emitter terminal to control the semiconductor switching element on and off. The control circuit includes a determination circuit that detects the control terminal voltage between the gate terminal, the source terminal or the emitter terminal, and a gate drive circuit that can control the voltage value of the control terminal voltage, and is detected by the determination circuit. When the rising value of the control terminal voltage exceeds a predetermined threshold value, the control terminal voltage is increased to a higher value than the detected control terminal voltage.

According to the present invention, it is possible to realize a power semiconductor device capable of suppressing an electromotive voltage generated in a semiconductor switching element and having excellent reliability and low loss, and a power conversion device using the same. ..

As a result, the power conversion device can be miniaturized and highly efficient.

Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is a figure which shows the circuit structure of the semiconductor device which concerns on Example 1 of this invention. It is a figure which shows the operating voltage and current sequence of the semiconductor device of FIG. It is a figure which shows the cross-sectional structure of the main semiconductor switching element of FIG. It is a figure which shows the cross-sectional structure of the main semiconductor switching element which concerns on Example 2 of this invention. It is a figure which shows the structure of the semiconductor device which concerns on Example 3 of this invention. It is a figure which shows the structure of the power conversion apparatus which concerns on Example 4 of this invention. It is a figure which shows the structure of the main semiconductor switching element which concerns on Example 5 of this invention.

Hereinafter, examples of the present invention will be described with reference to the drawings. In each drawing, the same components are designated by the same reference numerals, and the detailed description of overlapping portions will be omitted.

The semiconductor device according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 3. FIG. 1 is a diagram showing a circuit configuration of a semiconductor device in this embodiment. The semiconductor device 1 of this embodiment is connected to a main semiconductor switching element 2, a gate terminal G (6) which is a control terminal thereof, and a source terminal S (4), and is connected to a control circuit 3 which controls the on / off of the main semiconductor switching element 2. It is configured.

The main semiconductor switching element 2 is an n-ch type power MOSFET M1 (11) which is an insulated gate type switching element, and a diode Di (12) which shares a drain terminal D (5) and a cathode in the same semiconductor chip. ), The diode 14 provided between the anode of the diode Di (12) and the gate terminal G (6) of the power MOSFET M1 (11) in the direction of connecting the diode Di (12) and the anode terminal, and the diode Di. It is composed of a diode Rs (13) connected between the anode terminal and the source terminal S (4) of (12).

Further, the structure of the diode Di (12) is set so as to be a certain amount lower than the withstand voltage of the power MOSFET M1 (11) portion. Further, the gate resistor Rgin (15) built in the power MOSFET M1 (11) has a shape like a parasitic resistor or an oscillation prevention limiting resistor between the gate of the power MOSFET M1 (11) and the gate terminal G (6). It is provided in.

The control circuit 3 is a gate composed of an input circuit 21, a determination circuit 22, a MOSFET M2 (23), a MOSFET M3 (24), a MOSFET M4 (25), a compression type MOSFET M5 (26), and a gate resistance Rg (27). It is composed of a drive circuit 28, operates by a power supply applied between the power supply (Vcc) terminal 9 and the Ssense terminal 8, and is an input signal between the signal input terminal IN7 and the Ssense terminal 8 to generate a power MOSFET M1 (11). Controls on / off.

Here, when a voltage exceeding the withstand voltage of the diode Di (12) is applied between the DSs of the power MOSFET M1 (11) due to the turn-off operation in a power converter or the like, the leakage current of the diode Di (12) increases. Due to the voltage drop of the resistor Rs due to the current, the leakage current flows through the diode 14 to the gate of the power MOSFET M1 (11), and the potential of the gate terminal G (6) changes in the direction of increasing.

At this time, when the determination circuit 22 determines in the determination circuit 22 that the amount of boosting of the potential of the gate terminal G (6), which is the control terminal, (“first amount”) is a certain amount or more, the control circuit 3 gates. The drive circuit 28 is provided with another boosting structure that further increases the control terminal voltage Vg by a "second amount".

As a result, it is possible to raise the control terminal voltage Vg to a certain amount at high speed with a small leakage current of the diode Di (12), and it is possible to suppress the overvoltage at high speed and with higher accuracy. It is possible to reduce the loss of the element while avoiding the deterioration of the property.

FIG. 2 shows the operating voltage and current sequence of the semiconductor device 1 of this embodiment during the turn-off operation. As shown in FIG. 2, the control terminal voltage Vg increases as the main terminal voltage Vds exceeds the withstand voltage Vds1 of the diode Di (12) while the control terminal voltage Vg of the control terminal G is decreasing when the current is cut off. A certain amount of ΔV1 rises. Here, ΔV1 is generated when the leakage current of the diode Di (12) flows in, so that the current Ishink flowing into the off drive circuit of the control circuit 3 rises, and the voltage drop due to the resistance of the control circuit 3 rises.

This ΔV1 is detected by the determination circuit 22, and the control terminal voltage Vg is additionally increased to ΔV2 by the gate drive circuit 28. At this time, the control terminal voltage Vg increases as shown in FIG. 2, but since there is a voltage drop of the built-in gate resistor Rgin (15) of the power MOSFET M1 (11), the authenticity of the power MOSFET M1 (11) inside the semiconductor chip The gate voltage of is in the range where the decrease gradient becomes gentle and the switching speed becomes slow, but it does not change until it increases.

As a result, the current change rate of the main current Id flowing through the power MOSFET M1 (11), that is, the gradient of the current is reduced as shown by the broken line in FIG. 2, and overvoltage is prevented.

Further, when the overvoltage is determined by this ΔV1, the main terminal voltage Vds between the source terminal S (4) and the drain terminal D (5) is in a certain range with respect to the withstand voltage Vds1 of the diode Di (12), for example, Vds ≧. If the judgment circuit 22 is set to judge the overvoltage only when a certain condition such as Vds1 × 0.8 is satisfied, the influence of noise etc. can be eliminated and the overvoltage judgment can be made more accurately, and the main terminal can be judged with low loss and high reliability. It is possible to limit the overvoltage applied to.

As a method of the determination circuit 22 for determining the rise of ΔV1, for example, the control terminal voltage Vg is differentiated by the differentiating circuit during the off operation to detect that the gradient of Vg is in the rising direction, and the control terminal from that point in time. The amount of change ΔV of the voltage Vg can be determined by integrating the differential value of the control terminal voltage Vg with an integrator circuit and comparing it with the set value of ΔV1.

Further, as an equivalent and simple method, it is determined by detecting that the period in which the differential value (“first amount”) of the control terminal voltage Vg exceeds a certain value continues for more than a certain time. You may.

As a method of the gate drive circuit 28 that further increases the control terminal voltage Vg by a “second amount”, when it is determined that the amount of increase in the control terminal voltage Vg is equal to or higher than a certain level, the power MOSFET M1 is used during turn-off control. By turning off the MOSFET M3 (24) that flows the current Ishink1 that discharges the electric charge from the gate of (11) and turning on the MOSFET M4 (25), the MOSFET M4 (25) that discharges at the lower current Ishink2, the depletion. The resistance of the discharge circuit may be increased by switching only to the current path consisting of the type MOSFET M5 (26).

Here, the depletion type MOSFET M5 (26) is a short circuit between the gate and the source of the depletion type MOSFET, functions as a constant current element, and limits the current in the path of Ishink2, so that a diode is used under the condition of Vds ≧ Vds1. The leakage current of Di (12) can be reduced.

Further, as a method for further reducing the leakage current of the diode Di (12), the MOSFET M3 (24) is turned off when it is determined that the amount of increase in the control terminal voltage Vg is equal to or higher than a certain level, and the MOSFET M4 (25) is turned off. In addition to the operation of switching to only the current path consisting of the MOSFET M4 (25) and the depletion type MOSFET M5 (26) by turning on the MOSFET M2 (23), the leakage current from the diode Di (12) can be detected by turning on the MOSFET M2 (23). Instead, the control terminal voltage Vg may be further increased by a certain amount by flowing a current from the power supply Vcc in the direction of increasing the control terminal voltage Vg.

That is, in the control circuit 3, for example, when the increase value of the control terminal voltage Vg exceeds a predetermined threshold value during the off control of the main semiconductor switching element 2 (during the off control period), the power supply connected to the gate drive circuit 28 (during the off control period) A function to increase the voltage value of the control terminal voltage Vg by performing at least one of control of supplying current from Vcc) and control of increasing the resistance value of the discharge circuit that discharges electric charge from the gate of the semiconductor switching element 2. Is configured with.

If the increase in the control terminal voltage Vg becomes excessive by turning on the MOSFET M2 (23), instead of the MOSFET M2 (23) M2, use an on-side drive circuit using a MOSFET with a lower current drive capability. It may be provided and boosted by this.

As a result, it is possible to raise the control terminal voltage Vg to a certain amount at higher speed with a small leakage current of the diode Di (12), and it is possible to suppress overvoltage at higher speed and with higher accuracy, and reliability. And loss reduction can be realized to a higher degree.

FIG. 3 is a partial cross-sectional view of the main semiconductor switching element 2 in the semiconductor device 1 of the present embodiment shown in FIG. 1, and shows a power MOSFET as an example.

The main semiconductor switching element 32 includes a main MOSFET portion including a source electrode 42, a drain electrode 43, and a gate electrode (trench gate electrode) 41, a drain electrode and a gate electrode common to the main MOSFET portion, and an independent sense electrode 51. A portion 54 corresponding to the electrode Di (12) of FIG. 1 is provided.

In this example, the main MOSFET portion is a trench gate MOSFET having a striped structure, and the n-layer 45, which is a drift layer on the substrate n + layer 44, has a p-channel diffusion layer 46 and a source diffusion layer (n + layer). 47, a p + layer 48 is provided at the source electrode contact portion with the p-channel diffusion layer 46, and a trench gate electrode 41 is provided via a gate oxide film 49.

On the other hand, the portion 54 that becomes the diode Di is a high-concentration p + layer 57 that is a contact portion between the p-diffusion layer ps52 and the sense electrode 51 and the p-diffusion layer ps52 that are not in direct contact with the p-channel diffusion layer 46. To be equipped.

The p-diffusion layer ps 52 may be separated (insulated) from the p-channel diffusion layer 46, and there is no problem even if the layout patterns on the chip are formed separately in the same process. A trench gate electrode is also provided, which is connected to or independently of the main MOSFET section, but has a common gate potential or is the same as the sense electrode 51 at the portion 54 that becomes the diode Di. It may be an electric potential. The resistor Rs55 and the diode 56 may be formed by using polysilicon deposited on the insulating film or the like.

Here, at the portion 54 serving as the diode Di, an n-diffusion layer 53 having a higher concentration than the drift layer (n-layer) 45 is provided at the boundary between the p-diffusion layer ps 52 and the drift layer (n-layer) 45.

With such a configuration, the withstand voltage of the portion 54 that becomes the diode Di decreases by a certain amount with respect to the main MOSFET portion that does not have the n layer due to the increase in the electric field strength due to the n layer, and the drift layer (n-layer). ) Even if the withstand voltage of the main MOSFET section fluctuates due to fluctuations in the thickness of 45 and its concentration, the withstand voltage can be set low by a certain amount with high accuracy.

Further, even when a voltage exceeding the withstand voltage of this portion 54 is applied and the leakage current increases, the leakage current flows in the vicinity of the n-layer, so that high-energy electrons or holes due to the leakage current are the gate oxide film of the trench gate electrode. Since it is difficult to inject into 49, it is not easily damaged and high reliability can be obtained.

In addition, in order to reduce the withstand voltage of the portion 54 serving as the diode Di by a certain amount, a p-type diffusion layer may be provided instead of the n layer.

Further, in this embodiment, an example in which an n-ch type power MOSFET M1 (11) is used as the main semiconductor switching element is shown, but as will be described later in Examples 4 and 5, an IGBT (Insulated Gate Bipolar) is used. A transistor) may be used. In this case, the control circuit 3 is connected to the gate terminal and the emitter terminal of the IGBT.

As described above, the semiconductor device 1 of this embodiment is connected to the main semiconductor switching element 2, the gate terminal G (6) of the main semiconductor switching element 2, and the source terminal S (4) (or emitter terminal). A control circuit 3 that controls the main semiconductor switching element 2 on and off is provided, and the control circuit 3 detects the control terminal voltage Vg between the gate terminal G (6) and the source terminal S (4) (or emitter terminal). When the determination circuit 22 and the gate drive circuit 28 capable of controlling the voltage value of the control terminal voltage Vg are provided and the increase value of the control terminal voltage Vg detected by the determination circuit 22 exceeds a predetermined threshold value, the detection is detected. Increase to a control terminal voltage higher than the control terminal voltage Vg.

Further, the determination circuit 22 sets the main terminal voltage Vds between the source terminal S (4) and the drain terminal D (5) (or between the emitter terminal and the collector terminal) of the main semiconductor switching element 2 (power MOSFET M1 (11)). When the main terminal voltage Vds detected by the determination circuit 22 is within a predetermined voltage range and the control terminal voltage Vg detected by the determination circuit 22 exceeds a predetermined threshold value, the control circuit 3 detects the control terminal. Increase the voltage Vg.

As a result, it is possible to realize a power semiconductor device having excellent reliability and low loss that can suppress the electromotive force generated in the device when the semiconductor switching element is switched.

The semiconductor device according to the second embodiment of the present invention will be described with reference to FIG. FIG. 4 shows another embodiment of the cross-sectional structure of the main semiconductor switching element of the semiconductor device according to the present invention.

In this embodiment, as shown in FIG. 4, the portion 62 serving as the diode Di of the main semiconductor switching element 34 is insulated under the gate pad electrode 61 for mounting and connecting the trench gate electrode 41 of the MOSFET by wire bonding or the like. A high-concentration p + layer 65 and a p-diffusion layer (ps layer) 64 are provided so as to sandwich the film 63.

In FIG. 4, the contact portion of the wiring electrode of the portion 62 that becomes the diode Di is omitted. In this embodiment, since the trench gate electrode is not formed in the portion 62 to be the diode Di, the electric field relaxation by the trench gate electrode does not occur, so that the withstand voltage is lowered by a certain amount from the main MOSFET portion, and the diode is used. The withstand voltage of the portion 62 that becomes Di is adjusted. Of course, it goes without saying that the withstand voltage may be adjusted by providing n layers or the like.

Further, since the trench gate electrode is not provided in the forming region of the portion 62 serving as the diode Di, damage to the trench gate oxide film due to the leakage current does not occur.

Further, since the portion 62 which becomes the diode Di is provided under the gate pad electrode where the element is not normally provided, the element area does not increase and the chip size can be reduced. Further, by providing the high-concentration p + layer 65, the series resistance of the portion 62 serving as the diode Di is reduced, and the leakage current can be uniformly flowed over a wide area under the gate pad electrode.

As a result, overvoltage detection level fluctuations due to excessive temperature rise due to leakage current concentration and wiring deterioration due to local current concentration can be prevented, and low loss can be realized with higher accuracy and reliability.

Needless to say, the structure of the drain portion (drain electrode 43) of the MOSFET of this embodiment is changed to the collector structure of the IGBT, and the structure of the source portion (source electrode 42) is changed to the emitter structure of the IGBT. By doing so, the same effect can be expected in the case of IGBT.

The semiconductor device according to the third embodiment of the present invention will be described with reference to FIG. FIG. 5 shows an example of mounting the semiconductor device 71 according to the present invention, in which the semiconductor device of the present invention is mounted in a three-terminal package, taking as an example a case where a MOSFET is used for the main semiconductor switching element 72.

An IC chip 81 in which the control circuit 73 and the power supply circuit 74 are integrated is arranged on the circuit pattern 75 connected to the source terminal S (77) of the main semiconductor switching element 72, and the drain terminal D is further provided by the bonding wire 76. The potential of (78) is supplied to the control circuit 73 and the power supply circuit 74.

Here, the power supply circuit 74 is a circuit that generates a power supply voltage to the control circuit 73 from the drain-source voltage of the main semiconductor switching element 72.

In the semiconductor device 71 of this embodiment, the main current is controlled to be turned on and off by applying a signal to the gate terminal G (79). With such a configuration, it is possible to provide the function intended by the present invention in the form of three terminals having the same configuration and function as the widely used conventional element and having easy-to-use functions.

Further, by mounting the main semiconductor switching element 72, the control circuit 73, and the power supply circuit 74 in the same package, it is possible to avoid the influence of noise due to the parasitic wiring inductance and determine the amount of voltage rise of the control terminal voltage Vg with high accuracy. The function of the present invention can be realized with high accuracy.

The power conversion device according to the fourth embodiment of the present invention will be described with reference to FIG. FIG. 6 is an embodiment of a power conversion device using a semiconductor device according to the present invention. As will be described later in Example 5 (FIG. 7), a three-phase inverter 101 in the case where an IGBT is used for the main semiconductor switching element 131 is shown as an example.

The power conversion device (three-phase inverter) 101 of this embodiment is an inverter composed of main circuits of U-phase 107, V-phase 108, and W-phase 109 that supply power from the DC power supply 105 to the load 106 according to a command from the logic unit 102. The semiconductor devices 111 and 121 of the present invention are provided on the upper and lower arms, as shown in detail in the main circuit of the U-phase 107.

The basic configurations and functions of the semiconductor devices 111 and 121 are the same as when the power MOSFET described above is used, but since the main semiconductor switching elements 112 and 122 are IGBTs, the overvoltage is detected by the leakage current. A diode 145 formed by a pn junction on the collector side of the IGBT is connected in series to the diode Di141 provided in the IGBT so that its cathode faces each other.

In this case as well, if the withstand voltage of the diode Di141 is set lower than that of the IGBT portion by a certain amount, the same effect as when the power MOSFET is used can be obtained. Further, in this case, by setting the withstand voltage of the diode Di136 connected in parallel to the IGBT higher than the withstand voltage of the diode Di141, it is possible to prevent the application of an overvoltage to the diode connected in parallel with the IGBT.

The semiconductor device according to the fifth embodiment of the present invention will be described with reference to FIG. 7. FIG. 7 shows an example in which all of the IGBT, diode Di, and resistance element constituting the main semiconductor switching element 131 are integrated on one chip.

As shown in FIG. 7, it is possible to integrate all of them on one chip. Although the IGBT 135 and the diode Di141 need to be integrated on the same chip, some of the other parts need to be integrated. It can also be configured in combination with another element.

With the configuration as shown in FIG. 7, the starting voltage surge of the parasitic inductance Ls (see FIG. 6) of the main circuit applied to the turned-off IGBT 135 and the diode provided in parallel with the IGBT of the opposite arm of the turned-on IGBT 135. Less semiconductor when overvoltage is applied, such as an inductive voltage surge of parasitic inductance Ls during reverse recovery operation, and a voltage surge due to a large current cutoff due to a protection operation when a load short circuit occurs or a vertical arm short circuit occurs. By detecting the overvoltage with high accuracy from the leakage current of the switching element and raising the control terminal voltage Vg by an appropriate amount, it is possible to prevent the overvoltage from being applied to the main semiconductor switching element.

In this way, by using the semiconductor device of the present invention, switching operation can be performed at high speed and with high accuracy so that the electromotive voltage generated at the parasitic inductance Ls103 (FIG. 6) of the main circuit during switching is within an appropriate range. It is possible to provide a more reliable, low-loss, compact power converter with a controllable and simple configuration.

The method of appropriately controlling the overvoltage of the main semiconductor switching element with low loss in the semiconductor device according to the present invention and the power conversion device using the same has been described above. Needless to say, this method can be applied to other types of power switching elements other than those described above and other power conversion systems. For example, when applied to a DC-DC converter, the same applies to the reverse recovery operation of the MOSFET of the synchronous rectifier circuit, which is widely used when the diode rectifier operation is low loss, in addition to the switching element that turns the current on and off. The effect of can be expected.

The present invention is not limited to the above-described embodiment, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to the one including all the described configurations. It is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add / delete / replace a part of the configuration of each embodiment with another configuration.

1,31,71,111,121 ... Semiconductor device 2,32,34,72,112,122,131 ... Main semiconductor switching element 3,33,73,113,123 ... Control circuit 4,77 ... Source terminal S
5,78 ... Drain terminal D
6,79,134 ... Gate terminal G
7 ... Signal input terminal 8 ... Ssense terminal 9 ... Power supply (Vcc) terminal 11 ... Power MOSFET
12, 54, 62, 141 ... Diode (Di)
13, 55, 142 ... Resistance 14, 56, 143 ... Diode 15, 144 ... Built-in gate resistance 21 ... Input circuit 22 ... Judgment circuit 23, 24, 25 ... MOSFET
26 ... Depression type MOSFET
27 ... Gate resistance Rg
28 ... Gate drive circuit 41 ... Gate electrode (trench gate electrode)
42 ... Source electrode 43 ... Drain electrode 44 ... Substrate n + layer 45 ... Drift layer (n-layer)
46 ... p-channel diffusion layer 47 ... source diffusion layer (n + layer)
48, 57, 65 ... p + layer 49 ... Gate oxide film 51 ... Sense electrode 52, 64 ... p diffusion layer (ps layer)
53 ... n Diffusion layer 61 ... Gate pad electrode 63 ... Insulation film 74 ... Power supply circuit 75 ... Circuit pattern 76 ... Bonding wire 81 ... IC chip 101 ... Power converter (3-phase inverter)
102 ... Logic part 103 ... Parasitic inductance Ls (of main circuit)
104 ... Smoothing capacitor 105 ... DC power supply 106 ... Load 107, 108, 109 ... Inverter main circuit (U phase, V phase, W phase)
132 ... Emitter terminal 133 ... Collector terminal 135 ... IGBT
136 ... Parallel diode 145 ... Collector side pn diode

Claims (12)

Semiconductor switching elements and
A control circuit connected to a gate terminal of the semiconductor switching element and a source terminal or an emitter terminal to control the semiconductor switching element on and off is provided.
The control circuit includes a determination circuit for detecting the control terminal voltage between the gate terminal, the source terminal or the emitter terminal, and a gate drive circuit capable of controlling the voltage value of the control terminal voltage.
A semiconductor device characterized in that when the increase value of the control terminal voltage detected by the determination circuit exceeds a predetermined threshold value, the control terminal voltage is increased to a higher value than the detected control terminal voltage. The semiconductor device according to claim 1.
The semiconductor switching element is a semiconductor device having an insulated gate type switching element. The semiconductor device according to claim 2.
The insulated gate type switching element is a semiconductor device characterized by being a MOSFET or an IGBT. The semiconductor device according to claim 2.
The semiconductor switching element has a diode that is connected in parallel with the insulated gate type switching element and has a withstand voltage lower than the withstand voltage of the insulated gate type switching element.
A semiconductor device characterized in that a control terminal voltage is increased by flowing a leakage current of the diode into the gate terminal. The semiconductor device according to claim 1.
The control circuit is a semiconductor device characterized in that the control terminal voltage is increased when a state in which the voltage gradient of the control terminal voltage detected by the determination circuit exceeds a predetermined threshold value continues for a certain period of time. The semiconductor device according to claim 1.
The determination circuit detects the main terminal voltage between the source terminal and the drain terminal of the semiconductor switching element or between the emitter terminal and the collector terminal, and detects the main terminal voltage.
The control circuit increases the control terminal voltage when the main terminal voltage detected by the determination circuit is within a predetermined voltage range and the control terminal voltage detected by the determination circuit exceeds a predetermined threshold value. A semiconductor device characterized by. The semiconductor device according to claim 1.
The control circuit controls to supply a current from a power source connected to the gate drive circuit when the increase value of the control terminal voltage exceeds a predetermined threshold value when the semiconductor switching element is turned off, and the semiconductor switching element. A semiconductor device characterized in that the voltage value of the control terminal voltage is increased by performing at least one of the controls for increasing the resistance value of the discharge circuit that discharges the charge from the gate. The semiconductor device according to claim 4.
The semiconductor switching element has a trench gate electrode and has a trench gate electrode.
The diode is formed in a part of the trench gate electrode in the channel width direction, and has an n-type or p-type conductive type high-concentration diffusion layer at the boundary between the channel diffusion layer and the drift layer at that portion. A semiconductor device characterized by this. The semiconductor device according to claim 4.
The diode is a semiconductor device characterized in that it is arranged below a gate pad electrode. The semiconductor device according to claim 1.
A semiconductor device characterized in that the semiconductor switching element and the control circuit are integrated in the same mounting structure. The semiconductor device according to claim 10.
A semiconductor device characterized in that a power supply circuit that generates a power supply for the control circuit from a terminal voltage of the semiconductor switching element is integrated in the same mounting structure. A power conversion device according to any one of claims 1 to 11, wherein the semiconductor device is used.

Images