Semiconductor device

Abstract

To provide a semiconductor device with a simple circuit structure and including a self-generation type power supply with wide applicability.SOLUTION: A power module 40 includes one semiconductor switching element QH, QC, and at least one output terminal, and a voltage change occurs at the output terminal by a connection relationship change with a power supply line 4 according to turning on / off of the semiconductor switching element. A power supply self-generation circuit 50 includes: an input node Ni connected to the output terminal through a capacitor 15; a diode 17 connected between the input node Ni and an output node No in a predetermined connection direction; a capacitor 20 connected between the output node No and a reference node Nr; and a resistor 18 connected between the input node Ni and a ground line 5. The capacitor 20 maintains a voltage with a polarity according to the connection direction of the diode 17 between the reference node Nr and the output node No.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a semiconductor device.

Background Art

[0002] For a circuit group for controlling the on / off of a power semiconductor device, for example, a drive circuit (such as a gate driver), it is necessary to prepare a control power supply voltage that is lower than the main circuit voltage for comparison.

[0003] For example, Japanese Patent Laid-Open No. 8-308253 (Patent Document 1) describes that two capacitors are connected in series via a diode between the main electrodes (collector-emitter) of a semiconductor device that is on / off controlled by a drive circuit, thereby configuring a self-generating type power supply circuit for the drive circuit.

[0004] The power supply circuit described in Patent Document 1 generates a control power supply voltage for the drive circuit by dividing the voltage between the main electrodes during the off period of the semiconductor device by the capacitive coupling of two capacitors. Thereby, without using a transformer, which is disadvantageous in terms of system miniaturization and noise generation, a self-generating type power supply circuit composed of simple circuit elements can supply the control power supply voltage.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the power supply circuit of Patent Document 1, since the power supply is generated by dividing the voltage between the main electrodes during the off period of the semiconductor element, it is difficult to generate a negative voltage. Therefore, among the circuit groups including the drive circuit, the power supply circuit of Patent Document 1 composed of simple circuit elements cannot be applied to the circuit using the negative voltage as the power supply.

[0007] The present disclosure has been made to solve such problems, and an object of the present disclosure is to provide a semiconductor device including a self - generating power supply circuit with a simple circuit configuration and a wide application range.

Means for Solving the Problems

[0008] In one aspect of the present disclosure, a semiconductor device is provided. The semiconductor device includes a power module incorporating at least one semiconductor switching element, and a power self - generating circuit connected to the power module. The power module has at least one output terminal. The connection relationship between the output terminal and a power supply line that supplies a DC voltage is switched according to the on - off state of the semiconductor switching element, thereby causing a voltage change. The power self - generating circuit includes an input node, a diode, a capacitor, and a resistor. The input node is connected to the output terminal or the power supply line via a capacitor. The diode is connected between the output node and the input node in a predetermined connection direction. The capacitor is connected between a reference node and the output node. The resistor is connected between the input node and a ground line. The capacitor holds a voltage with a polarity corresponding to the connection direction of the diode between the reference node and the output node.

Effects of the Invention

[0009] According to the present disclosure, since output voltages of different polarities are generated at the output node according to the connection direction of the diode in the power self - generating circuit, a semiconductor device including a self - generating power supply circuit with a simple circuit configuration and a wide application range can be provided.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the following, the same or corresponding parts in the drawings are denoted by the same reference numerals, and the description thereof will not be repeated in principle.

[0012] Embodiment 1. FIG. 1 is a circuit diagram for explaining a configuration example of a semiconductor device according to Embodiment 1.

[0013] Referring to FIG. 1, a semiconductor device 100 according to Embodiment 1 includes a power module 40 and a power self-generation circuit 50. The power module 40 is configured to include a high-side semiconductor switching element QH and a low-side semiconductor switching element QL that are serially connected between a power line 4 and a ground line 5. A freewheeling diode FWD is reversely connected in parallel to each of the semiconductor switching element QH and the semiconductor switching element QL.

[0014] In the example of FIG. 1, the power module 40 is a three-phase inverter having a U-phase circuit 30U, a V-phase circuit 30V, and a W-phase circuit 30W that are connected in parallel between the power line 4 and the ground line 5. Each of the U-phase circuit 30U, the V-phase circuit 30V, and the W-phase circuit 30W has a high-side semiconductor switching element QH and a low-side semiconductor switching element QL. In each of the U-phase circuit 30U, the V-phase circuit 30V, and the W-phase circuit 30W, the connection point of the semiconductor switching element QH and the semiconductor switching element QL is connected to the output terminal of each phase (U, V, W).

[0015] In FIG. 1, each of the semiconductor switching elements QH and QL is exemplified by a Si-IGBT (Silicon Insulated Gate Bipolar Transistor). However, instead of the IGBT, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) can also be used, and any semiconductor element that can be turned on and off can be applied. It is also possible to configure the semiconductor switching elements QH and QL using a WBG (Wide Band Gap) device typified by a SiC (Silicon Carbide)-MOSFET.

[0016] The semiconductor switching element QH is turned on and off according to a control signal (not shown) by the high-side gate driver GDH. Similarly, the semiconductor switching element QL is turned on and off according to a control signal (not shown) by the low-side gate driver GDL. Although not shown, high-side gate drivers GDH and low-side gate drivers GDL are also arranged for the semiconductor switching elements QH and QL of the V-phase circuit 30V and the W-phase circuit 30W, and the six semiconductor switching elements in FIG. 1 are individually turned on and off controlled.

[0017] On the power supply side of the power module 40, the output voltage of the AC power supply 1 is rectified by the diode bridge 2 and applied to the smoothing capacitor 3 connected between the power supply line 4 and the ground line 5. Thereby, based on the ground line 5 that supplies the ground voltage GND, a DC voltage VDC corresponding to the main circuit voltage is supplied by the power supply line 4.

[0018] A control power supply 7 for driving the gate drivers GDL and GDH included in the power module 40 may be arranged. In this case, for the low-side gate driver GDL, the output voltage of the control power supply 7 is supplied, while the high-side gate driver GDH is connected to the control power supply 7 via a limiting resistor 8 and a bootstrap diode 9. Further, a bootstrap capacitor 10 is connected between the power supply line of the gate driver GDH and the negative electrode (emitter in the case of an IGBT, source in the case of a MOSFET) of the high-side semiconductor switching element QH.

[0019] With the "bootstrap circuit" composed of the limiting resistor 8, the bootstrap diode 9, and the bootstrap capacitor 10, gate driving for turning on the high-side semiconductor switching element QH can be enabled by using the charge stored in the bootstrap capacitor 10 during the on period of the low-side semiconductor switching element QL. Note that for the limiting resistor 8 and the bootstrap diode 9, although they are shown as external elements of the power module 40 in FIG. 1, they may be incorporated into the power module 40. Also, in FIG. 1, a circuit configuration using the above-described bootstrap circuit is illustrated to reduce the number of control power supplies, but a configuration in which a control power supply for the high-side gate driver GDH is further arranged separately from the control power supply 7 in FIG. 1 is also acceptable in terms of circuit operation.

[0020] Note that although not shown in FIG. 1, in the V-phase circuit 30V and the W-phase circuit 30 to W as well, peripheral elements similar to those of the U-phase circuit 30U are arranged for the high-side semiconductor switching element QH and the low-side semiconductor switching element QL.

[0021] The output terminals (U, V, W) of the power module 40 are connected to an inductive load 14 typified by a three-phase motor via wirings 11 to 13. The power self-generation circuit 50 is connected to one of the output terminals of the three-phase output terminals (U-phase in the example of FIG. 1) via a capacitor 15. The capacitor 15 is connected between the above-described power module 40 and the input node Ni of the power self-generation circuit 50.

[0022] The power supply self-generation circuit 50 includes a diode 17 connected between the input node Ni and the output node No, a resistor 18 connected between the input node Ni and the ground line 5, and a capacitor 20 connected between the output node No and the reference node Nr. Furthermore, a Zener diode 21 may be disposed between the output node No and the reference node Nr to stabilize the voltage of the output node No, i.e., the output voltage of the power supply self-generation circuit 50. In the first embodiment, the reference node Nr is connected to the ground line 5.

[0023] 1, the diode 17 is arranged in a connection direction (first connection direction) in which the anode is connected to the input node Ni and the cathode is connected to the output node No. The Zener diode 21 is arranged in a connection direction in which the anode is grounded and the cathode is connected to the output node No.

[0024] 1, when the power module 40 operates as an inverter, the turn-on and turn-off of the six built-in semiconductor switching elements is controlled by the gate drivers (GDH, GDL) of the power module 40. As a result, the semiconductor device 100 converts the DC voltage of the power line 4 into an AC voltage (DC / AC power conversion) to drive the inductive load 14. Although not shown in FIG. 1, the timing at which the gate drivers GDH, GDL of each phase turn on and off the corresponding semiconductor switching elements QH, QL is instructed by a control signal (not shown) transmitted to the power module 40 from a system control unit such as a microcomputer (not shown).

[0025] During the DC / AC power conversion, for example, the on / off timing of the semiconductor switching elements QH and QL is determined by PWM (Pulse Width Modulation) control, which compares a carrier wave having a predetermined carrier frequency with an AC command value. The carrier frequency is usually a high frequency of several kHz to several tens of kHz.

[0026] As a result, the voltages at the output terminals of each phase and the wirings 11 to 13 connecting the output terminals and the inductive load 14 vary in a manner of swinging between the DC voltage VDC of the power line 4 and the ground voltage GND of the ground line 5 by the on / off of the semiconductor switching elements according to the carrier frequency. The voltage fluctuations generated in the wirings 11 to 13 during such switching (when the semiconductor switching elements are turned on and off) are determined by the characteristics of the semiconductor switching elements (QH, QL) built in the power module 40 and the inductive load 14. For example, each time switching occurs, a high-speed voltage fluctuation (dV / dt) of about several (kV / μs) occurs.

[0027] The above-described voltage fluctuation (dV / dt) generated in the wiring 11 is transmitted to the input node Ni of the power self-generation circuit 50 by the coupling by the capacitor 15. Note that the capacitor 15 is arranged to electrically separate the wiring 11 handling high voltage and the power self-generation circuit 50 handling low voltage. Therefore, the capacitance value of the capacitor 15 may be about several (nf) as long as insulation is ensured.

[0028] Note that, in the wirings 11 to 13 of each phase, when the high-side semiconductor switching element QH is turned on, the voltage rises from the ground voltage GND to the DC voltage VDC, so a positive voltage fluctuation ((dv / dt)>0) is input to the power self-generation circuit 50 (input node Ni).

[0029] Conversely, when the high-side semiconductor switching element QH is turned off, the voltages of the wirings 11 to 13 decrease from the DC voltage VDC to the ground voltage GND, so a negative voltage fluctuation ((dv / dt)<0) is input to the power self-generation circuit 50 (input node Ni).

[0030] The diode 17 allows one of the positive voltage fluctuation and the negative voltage fluctuation to pass through depending on the connection direction, and charges the capacitor 20 with the amount of charge determined by |dV / dt|. The amount of charge Q charged in the capacitor 20 is expressed as dQ / dt = C×|dv / dt| per unit time, where C is the capacitance value of the capacitor 20.

[0031] In the connection direction of the diode 17 in the example of FIG. 1, while the capacitor 20 is charged by the positive voltage fluctuation ((dv / dt)>0), the negative voltage fluctuation ((dv / dt)<0) is not transmitted to the capacitor. As a result, even when a negative voltage fluctuation ((dv / dt)<0) is input, the discharge of the capacitor 20 is blocked by the diode 17. As a result, a positive voltage is generated as the output voltage of the power supply self-generation circuit 50 at the output node No connected to the capacitor 20.

[0032] The arrangement of the resistor 18 makes it possible to secure a discharge path for the capacitor 15 when a voltage fluctuation of a polarity that does not pass through the diode 17 (in the example of FIG. 1, a negative voltage fluctuation) occurs at the input node Ni. As a result, the charging of the capacitor 20 can be stabilized. The resistance value of the resistor 18 can be determined so as not to overly limit the charge and discharge current of the capacitor 15, and is, for example, on the order of several (Ω).

[0033] The Zener diode 21 is arranged in a connection direction in which the cathode is connected to the output node No in order to stabilize the voltage of the output node No and prevent overvoltage.

[0034] Incidentally, the connection direction of the diode 17 can be reversed from the example of FIG. 1, with the anode connected to the output node No and the cathode connected to the input node Ni (second connection direction). In this case, while the diode 17 transmits the negative voltage fluctuation ((dv / dt)<0) to the capacitor 20, the positive voltage fluctuation ((dv / dt)>0) is not transmitted to the capacitor 20. Therefore, while the capacitor 20 is charged by the negative voltage fluctuation ((dv / dt)<0), even when a positive voltage fluctuation ((dv / dt) > 0) is input, the discharge of the capacitor 20 is blocked by the diode 17. As a result, a negative voltage is generated as the output voltage of the power supply self-generation circuit 50 at the output node No connected to the capacitor 20.

[0035] When the diode 17 is connected in the second connection direction described above, the Zener diode 21 is also arranged in the connection direction opposite to that in FIG. 1. Specifically, the Zener diode 21 is arranged in a connection direction in which the anode is connected to the output node No and the cathode is connected to the ground line 5.

[0036] In this way, in the semiconductor device according to the first embodiment, the simple configuration power supply self-generation circuit 50 including the diode 17, the resistor 18, and the capacitor 20 outputs a low-voltage output voltage from the output voltage (high voltage) from the power module 40. node It can be generated. In particular, in the power supply self-generation circuit 50 of the present embodiment, either a positive voltage or a negative voltage can be output depending on the connection direction of the diode 17, and the power supply destination, that is, the applicable range becomes wider. Also, the absolute value of the output voltage can be appropriately adjusted in a range of, for example, several (V) to a dozen or so (V) by designing each constant.

[0037] The output voltage of the power supply self-generation circuit 50 can be used, for example, as the power supply voltage of an arbitrary circuit represented by other circuits (not shown) inside the power module 40. For example, it can be effectively used for a function that operates with a minute amount of power such as the Fo signal that notifies abnormality detection in the function mounted on DIPIPM (Dual Inline Package Intelligent Power Module) (registered trademark). In this case, by supplying the power of the circuit related to the Fo signal from the power supply self-generation circuit 50, there is no need to prepare an extra transformer or the like for the control power supply for the Fo signal, which can contribute to the miniaturization and cost reduction of the system.

[0038] Moreover, even when the semiconductor switching elements incorporated in the power module 40 are composed of WBG devices, it is possible to generate the output voltage by the power self-generation circuit 50 having the same configuration. Since the WBG device enables faster switching compared to Si devices (e.g., general Si-IGBT elements), the absolute value of the voltage change (dV / dt) becomes larger. As a result, it is easy to secure the amount of charge for charging the capacitor 20, so that the power self-generation circuit 50 can operate more efficiently.

[0039] In the first embodiment, the power self-generation circuit 50 can be provided corresponding to the output terminal of any phase of the power module 40, and it is also possible to provide the power self-generation circuit 50 in a plurality of phases.

[0040] Embodiment 2. FIG. 2 is a circuit diagram for explaining a configuration example of the semiconductor device according to the second embodiment.

[0041] Referring to FIG. 2, the semiconductor device 101 according to the second embodiment includes a power module 40 similar to that in FIG. 1 and a power self-generation circuit 51.

[0042] The power self-generation circuit 51 has the same circuit configuration as the power self-generation circuit 50 shown in FIG. 1, but is different from the power self-generation circuit 50 in that it is connected to all of the wirings 11 to 13 via the capacitors 15, 22, and 23. On the other hand, also in the power self-generation circuit 51, the reference node Nr is connected to the ground line 5.

[0043] Therefore, in the power self-generation circuit 51, not only the voltage change (dV / dt) generated in each of the wirings 11 to 13 but also all of the voltage changes (dV / dt) generated in each of the wirings 11 to 13 are transmitted to the input node Ni. That is, all of the voltage changes ((dV / dt)<0) from VDC to GND and the voltage changes ((dV / dt)>0) from GND to VDC generated at the output terminals of each of the three phases (U, V, W) of the power module 40 are transmitted to the input node Ni.

[0044] The operation of the power self-generation circuit 51 is the same as that of the power self-generation circuit 50 described above. That is, in the connection direction of the diode 17 shown in FIG. 2, a positive voltage is generated at the output node No by charging the capacitor 20 with the amount of charge associated with the positive voltage change in the wirings 11 to 13.

[0045] On the other hand, when the connection direction of the diode 17 is reversed from that in FIG. 2, a negative voltage is generated at the output node No by charging the capacitor 20 with the amount of charge associated with the negative voltage change in the wirings 11 to 13.

[0046] In the power self-generation circuit 51, since the charging charge of the capacitor 20 is ensured using the three-phase voltage change (dV / dt), the capacitor 20 can be charged at high speed. For this reason, the power that can be supplied as a power source also increases. Therefore, compared with the first embodiment, it becomes possible to supply the power supply voltage to a circuit with high power consumption, and the applicable range as a power supply circuit can be expanded. For example, when the power self-generation circuit 51 is mounted on the above-described DIPIPM (registered trademark), it can also be used for a circuit such as a gate driver configured by a built-in IC (Integrated Circuit) with a certain degree of high power consumption.

[0047] Embodiment 3. FIG. 3 is a circuit diagram for explaining a configuration example of a semiconductor device according to Embodiment 3.

[0048] Referring to FIG. 3, a semiconductor device 102 according to Embodiment 3 includes the same power module 40 as in FIG. 1 and a power self-generation circuit 52.

[0049] The power self-generation circuit 52 includes a diode 17, a resistor 18, and a capacitor 20, and preferably further includes a Zener diode 21, in the same manner as the power self-generation circuits 50 and 51. The connection of the diode 17, the resistor 18, the capacitor 20, and the Zener diode 21 to the input node Ni, the output node No, and the reference node Nr inside the power self-generation circuit 52 is the same as that of the power self-generation circuits 50 and 51, so a detailed description will not be repeated.

[0050] On the other hand, the power self-generation circuit 52 has a connection relationship with the outside that is different from those of the power self-generation circuits 50 and 51. Specifically, the input node Ni is connected to the power line 4 (DC voltage VDC) via the capacitor 24, and the reference node Nr is connected to one phase of the three-phase wirings 11 to 13 (the three-phase output terminals of the power module 40).

[0051] In the power self-generation circuit 52 according to the third embodiment, a floating power supply with the potential of the output terminal (U phase, V phase, or W phase) of the power module 40 as a reference can be self-generated using the same circuit configuration as the power self-generation circuits 50 and 51. At this time, the power supply voltage can be appropriately adjusted, for example, in the range of several (V) to several tens (V). When the power self-generation circuit 52 is mounted on the above-mentioned DIPIPM (registered trademark), the power self-generation circuit 52 can be used as an auxiliary power supply for the high-side control power supply or the control power supply itself.

[0052] In the third embodiment, the power self-generation circuit 52 can be provided corresponding to the output terminal of any phase of the power module 40, and it is also possible to provide the power self-generation circuit 52 in each of a plurality of phases.

[0053] In addition, in this embodiment, an example of the power module 40 incorporating six semiconductor switching elements that constitute a three-phase inverter has been described, but the configuration of the power module 40 is arbitrary including the number of semiconductor switching elements. Also in this case, since there is at least one output terminal that generates a voltage change by switching the connection relationship with the power line according to the on / off of the semiconductor switching element, at least any one of the power self-generation circuits 50 to 52 described in this embodiment can be applied.

[0054] The embodiments disclosed this time should be considered illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the above description but by the claims, and it is intended that all modifications within the meaning and scope equivalent to the claims be included.

Description of Reference Numerals

[0055] 1 AC power supply, 2 diode bridge, 3 smoothing capacitor, 4 power line, 5 ground line, 7 control power supply, 8 limiting resistor, 9 bootstrap diode, 10 bootstrap capacitor, 11 to 13 wirings, 14 inductive load, 15, 20, 24 capacitors, 17, FWD diode, 18 resistor, 21 Zener diode, 30U U-phase circuit, 30V V-phase circuit, 30W W-phase circuit, 40 power module, 50, 51, 52 power self-generation circuit, 100, 101, 102 semiconductor devices, GDH gate driver (high side), GDL gate driver (low side), GND ground voltage, Ni input node, No output node, Nr reference node, QH, QL semiconductor switching elements, VDC DC voltage.

Claims

1. A power module incorporating at least one semiconductor switching element, and a power self-generation circuit connected to the power module, wherein the power module has at least one output terminal at which a voltage change occurs by switching a connection relationship with a power line that supplies a DC voltage according to on / off of the semiconductor switching element, and the power self-generation circuit has an input node connected to the output terminal or the power line via a capacitor, a diode connected between the output node and the input node in a predetermined connection direction, a capacitor connected between a reference node and the output node, and a resistor connected between the input node and a ground line without passing through a rectifying element, wherein the capacitor holds a voltage having a polarity corresponding to the connection direction of the diode between the reference node and the output node, a semiconductor device.

2. The input node is connected to the output terminal, the diode is arranged in a first connection direction in which an anode is connected to the input node while a cathode is connected to the output node, the reference node is connected to the ground line, and a positive voltage is generated at the output node, the semiconductor device according to Claim 1.

3. A power module incorporating at least one semiconductor switching element, and a power self-generation circuit connected to the power module, wherein the power module has at least one output terminal at which a voltage change occurs by switching a connection relationship with a power line that supplies a DC voltage according to on / off of the semiconductor switching element, and the power self-generation circuit has an input node connected to the output terminal or the power line via a capacitor, a diode connected between the output node and the input node in a predetermined connection direction, a capacitor connected between a reference node and the output node, and a resistor connected between the input node and a ground line, wherein the capacitor holds a voltage having a polarity corresponding to the connection direction of the diode between the reference node and the output node, the input node is connected to the output terminal, and the diode is arranged in a second connection direction in which a cathode is connected to the input node while an anode is connected to the output node, A semiconductor device in which the reference node is connected to the ground line and a negative voltage is generated at the output node. **Claim 4** The power module has a plurality of output terminals whose connection relationship with the power line is switched according to the on / off states of the different semiconductor switching elements. The semiconductor device according to claim 2 or 3, wherein the input node is connected to the plurality of output terminals via different capacitors respectively. **Claim 5** The reference node is connected to the output terminal. The semiconductor device according to claim 1, wherein the input node is connected to the power line. **Claim 6** The power self-generation circuit The semiconductor device according to claim 2 or 5, further comprising a Zener diode having an anode connected to the reference node and a cathode connected to the output node. **Claim 7** The power self-generation circuit The semiconductor device according to claim 3, further comprising a Zener diode having an anode connected to the output node and a cathode connected to the reference node.

Images