Semiconductor switch device and power distribution device

Abstract

To provide a semiconductor switch device capable of detecting an abnormal state of a power distribution device without interrupting power supply to a load side.SOLUTION: The switch device 100 includes a main switch device 110 and a sense MOS111 connected in parallel with the main switch device 110. The semiconductor switch device 100 also includes a first current detection circuit 120 that detects a current between the input terminal and the output terminal, and a second current detection circuit 130 that detects a current flowing through the semiconductor switch device 100. The semiconductor switch device 100 also includes: A drive circuit 140 is provided for controlling on / off of the main switch device 110 and the sense MOS111. The semiconductor switch device 100 includes a diagnosis circuit 160 for diagnosing abnormality of the power distribution device 10 on the basis of a value of a first voltage corresponding to the current detected by the first current detection circuit 120 and a value of a second voltage corresponding to the current detected by the second current detection circuit 130 or a predetermined reference voltage.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor switch device and a power distribution device. [Background technology]

[0002] Conventionally, technology has been proposed relating to a semiconductor switch device that cuts off the power supply and performs protective operation when an abnormality occurs between a power source and a load device that uses power supplied from the power source via a wire harness. Patent Document 1 discloses a semiconductor abnormality detection circuit that is configured with a semiconductor switch element and a circuit with a current sensing function. The semiconductor abnormality detection circuit disclosed in Patent Document 1 determines whether the semiconductor circuit is operating normally based on the on / off voltage levels applied to the control input terminal of the semiconductor switch element and the voltage value of the sense signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-115692 Summary of the Invention [Problem to be solved by the invention]

[0004] However, some load devices require constant power supply under normal conditions. Therefore, when the semiconductor abnormality detection circuit disclosed in Patent Document 1 is applied to a load device that requires constant power supply, it cannot be turned off, and therefore it is not possible to test for a short circuit between the input and output (a short to power).

[0005] The present disclosure has been made in consideration of the problems inherent in the conventional technology, and an object of the present disclosure is to provide a semiconductor switch device that can detect an abnormal state of a power distribution device without interrupting the power supply to the load side. [Means for solving the problem]

[0006] A semiconductor switch device according to an aspect of the present disclosure is a semiconductor switch device that is provided in a power distribution device and protects the power distribution device in the event of an abnormality, and includes: a main switch element that is connected to an input terminal connected to a power source and an output terminal connected to a load device and controls the on / off of power supplied from the input terminal to the output terminal; a sense MOS connected in parallel with the main switch element; a first current detection circuit that is connected to the load device and detects the current flowing through the load device; a second current detection circuit that is connected to the output terminal and the sense MOS and detects the current flowing through the semiconductor switch device; a drive circuit that controls the on / off of the main switch element and the sense MOS; and a diagnostic circuit that diagnoses an abnormality in the power distribution device based on a first voltage value corresponding to the current detected by the first current detection circuit and a second voltage value or a predetermined reference voltage corresponding to the current detected by the second current detection circuit.

[0007] A power distribution device according to another aspect of the present disclosure includes the semiconductor switch device described above, a power source connected to an input terminal of the semiconductor switch device, and a load device connected to an output terminal of the semiconductor switch device. [Effects of the Invention]

[0008] According to the present disclosure, it is possible to provide a semiconductor switch device that can detect an abnormal state of a power distribution device without interrupting the power supply to the load side. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a semiconductor switch device according to this embodiment. [Figure 2] FIG. 2 is a schematic diagram for explaining a circuit model in the case where a short circuit to the power supply occurs between the input and output. [Figure 3] FIG. 3 is a diagram showing the relationship between the short-to-power resistance and the load current, load voltage, and output current when a short-to-power occurs between the input and output. [Figure 4] FIG. 4 is a diagram showing the relationship between the power short resistance and the short-circuit current. [Figure 5]FIG. 5 is a diagram showing the relationship between the load resistance and the voltage in the open state. [Figure 6] FIG. 6 is a diagram for explaining power short detection and open detection according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, a semiconductor switch device 100 and a power distribution device 10 according to several embodiments of the present disclosure will be described in detail with reference to the drawings. The same or equivalent parts in the drawings of the semiconductor switch device 100 and the power distribution device 10 according to each embodiment will be denoted by the same reference numerals, and their description will be omitted.

[0011] 1 is a diagram showing the connection state between the internal blocks of a semiconductor switch device 100 according to this embodiment and a power supply 200 and a load device 300. The configuration including the semiconductor switch device 100, the power supply 200, and the load device 300 corresponds to a power distribution device 10.

[0012] The semiconductor switch device 100 is connected to a power supply 200 from an input terminal (VB terminal) which is a power supply terminal, via a wire harness. The semiconductor switch device 100 is also connected to a load device 300 from an output terminal (OUT terminal) via another wire harness. The semiconductor switch device 100 is provided in a power distribution device 10, and protects the power distribution device 10 in the event of an abnormality.

[0013] 2 is a schematic diagram of a circuit model showing a power short resistance Rshort and a short-circuit current Ishort flowing through the power short resistance Rshort when a short circuit (power short) occurs between the input and output. In this specification, a power short refers to a state in which a terminal, a wiring pattern, or a wire harness connected to the terminal is shorted to the power supply. As shown in FIG. 2, when a power short occurs, part of the current flowing through the semiconductor switch device 100 under normal conditions flows through the power short resistance Rshort, thereby reducing the current flowing through the semiconductor switch device 100.

[0014] 3 is a diagram showing the relationship between the power short resistance Rshort and the load current Iload, the load voltage Vout, and the output current Io when a power short occurs between the input and output. As shown in FIG. 3, when a power short occurs, as the power short resistance Rshort decreases, the current flowing through the semiconductor switch device 100 flows through the power short resistance Rshort. Therefore, the current flowing through the semiconductor switch device 100 decreases as shown by the IPD output current in FIG. 3 (IPD: Intelligent Power Device).

[0015] 4 is a diagram showing the relationship between the power short resistance Rshort and the short-circuit current Ishort. As shown in Fig. 4, when a power short occurs, as the power short resistance Rshort decreases, the current flowing through the semiconductor switch device 100 flows through the power short resistance Rshort, and the value of the short-circuit current Ishort increases.

[0016] In the case of a short-to-power state, the semiconductor switch device 100 according to this embodiment detects the short-to-power state by utilizing the decrease in the value of the current flowing through the semiconductor switch device 100. Specifically, a short-to-power state is determined by the difference in voltage corresponding to the current detected by the first current detection circuit 120 and the second current detection circuit 130 shown in FIG.

[0017] Furthermore, the semiconductor switch device 100 according to this embodiment can also detect that the load device 300 is in an open state. FIG. 5 is a diagram showing the relationship between the load resistance when the load device 300 is in an open state and the first voltage V1 and the second voltage V2 shown in FIG. 1. As shown in FIG. 5, when the load device 300 is in an open state and the resistance on the load side increases, both the first voltage V1 and the second voltage V2 decrease. The semiconductor switch device 100 according to this embodiment detects the open state by utilizing the fact that, in the case of this open state, the voltage value corresponding to the value of the current flowing through the semiconductor switch device 100 decreases.

[0018] Next, the semiconductor switch device 100 will be described in detail.

[0019] (Configuration of semiconductor switching device 100) The semiconductor switch device 100 includes a main switch element 110, a sense MOS 111, a first current detection circuit 120, a second current detection circuit 130, a drive circuit 140, a control circuit 150, and a diagnostic circuit 160.

[0020] The main switching element 110 is a switch that turns off in the event of an abnormality to cut off power supplied to the load device 300. That is, the main switching element 110 controls the on / off of power supplied from an input terminal (VB terminal) connected to the power supply 200 to an output terminal (OUT terminal) connected to the load device 300. In this embodiment, the main switching element 110 is configured, for example, by a MOS (Metal-Oxide-Semiconductor) transistor.

[0021] The sense MOS 111 is a control element for detecting the current flowing through the semiconductor switch device 100. The sense MOS 111 is connected in parallel with the main switch element 110. In this embodiment, the sense MOS 111 is formed of, for example, a MOS transistor.

[0022] The first current detection circuit 120 detects the current flowing through the load device 300. The first current detection circuit 120 is configured by a general operational amplifier with a positive terminal connected to the load device 300 and a negative terminal connected to ground. The first current detected by the first current detection circuit 120 is sent to the diagnostic circuit 160.

[0023] The second current detection circuit 130 detects the current flowing through the semiconductor switch device 100. The second current detection circuit 130 is configured by a general operational amplifier having a positive terminal connected to the main switch element 110 and a negative terminal connected to the sense MOS 111. The second current detected by the second current detection circuit 130 is sent to the diagnostic circuit 160.

[0024] The drive circuit 140 generates signals that determine the on / off states of the main switching element 110 and the sense MOS 111. The control circuit 150 gives the drive circuit 140 an on / off control instruction in accordance with a control instruction from an external terminal IN.

[0025] The diagnostic circuit 160 diagnoses an abnormality in the power distribution device 10 based on the value of the first voltage V1 corresponding to the current detected by the first current detection circuit 120 and the value of the second voltage V2 corresponding to the current detected by the second current detection circuit or a predetermined reference voltage Vref.

[0026] Specifically, the diagnostic circuit 160 compares the value of the first voltage V1 with the value of the second voltage V2 using the first comparator 171, and diagnoses that the power distribution device 10 is in a short-to-power state if the value of the first voltage V1 is greater than the value of the second voltage V2. The result of the diagnosis of a short-to-power state by the diagnostic circuit 160 is notified to the outside of the semiconductor switch device 100 via the external output terminal OUT1.

[0027] The second current sent from the second current detection circuit 130 may have the current supplied from the constant current source 180 added as an offset. This allows the diagnostic circuit 160 to adjust the point at which it is determined that a short to power has occurred due to the offset when comparing the voltage values ​​of the first voltage V1 and the second voltage V2 corresponding to the first current and the second current, making it possible to more accurately determine the short to power state.

[0028] Furthermore, the diagnostic circuit 160 compares the value of the first voltage V1 with the value of the reference voltage Vref using the second comparator 172, and if the value of the first voltage V1 is lower than the value of the reference voltage Vref, diagnoses that the power distribution device 10 is in an open state. The result of the diagnosis of an open state by the diagnostic circuit 160 is notified to the outside of the semiconductor switch device 100 via the external output terminal OUT2.

[0029] FIG. 6 is a diagram for explaining power short detection and open circuit detection according to this embodiment, and is a diagram for explaining the operation of the diagnostic circuit 160.

[0030] As shown in FIG. 6, when V1 > V2 (first current > second current), the first comparator 171 of the diagnostic circuit 160 outputs "Short_det." as high. Also, when V1 ≤ V2, the first comparator 171 of the diagnostic circuit 160 outputs "Short_det." as low.

[0031] As shown in FIG. 6, when a short circuit occurs, the short - circuit current Ishort increases and the current flowing through the semiconductor switch device 100 decreases. Therefore, the second current decreases and becomes smaller than the current between the input and output. In this case, the diagnostic circuit 160 sets "Short_det." to high and detects the short - circuit state.

[0032] Also, when V1 < Vref, the second comparator 172 of the diagnostic circuit 160 outputs "Open_det." as high. Also, when V1 ≥ Vref, the second comparator 172 of the diagnostic circuit 160 outputs "Open_det." as low.

[0033] As shown in FIG. 6, when an open circuit occurs, the load resistance increases and the current flowing through the whole decreases. Therefore, the corresponding first voltage V1 and second voltage also decrease. When the decreased first voltage V1 becomes lower than a predetermined reference voltage Vref, the diagnostic circuit 160 sets "Open_det." to high and detects the open - circuit state.

[0034] As described above, the semiconductor switch device 100 is provided in the power distribution device 10 and protects the power distribution device 10 in the event of an abnormality. The semiconductor switch device 100 includes a main switch element 110 connected to an input terminal connected to a power source 200 and an output terminal connected to a load device 300, and controls the on / off of power supplied from the input terminal to the output terminal. The semiconductor switch device 100 also includes a sense MOS 111 connected in parallel with the main switch element 110. The semiconductor switch device 100 also includes a first current detection circuit 120 connected to the load device 300 and detecting a current flowing through the load device 300. The semiconductor switch device 100 also includes a second current detection circuit 130 connected to the output terminal and the sense MOS 111 and detecting a current flowing through the semiconductor switch device 100. The semiconductor switch device 100 also includes a drive circuit 140 that controls the on / off of the main switch element 110 and the sense MOS 111. The semiconductor switch device 100 includes a diagnostic circuit 160 that diagnoses abnormalities in the power distribution device 10 based on a first voltage value corresponding to the current detected by the first current detection circuit 120 and a second voltage value corresponding to the current detected by the second current detection circuit 130 or a predetermined reference voltage.

[0035] This allows the semiconductor switch device 100 to detect an abnormal state of the power distribution device 10 without interrupting the power supply to the load side.

[0036] Furthermore, the diagnostic circuit 160 of the semiconductor switch device 100 may include a first comparator 171 that compares the value of the first voltage V1 with the value of the second voltage V2. Furthermore, the first comparator 171 of the diagnostic circuit 160 may diagnose that the power distribution device 10 is in a short-to-power state when the value of the first voltage V1 is greater than the value of the second voltage V2. This enables the semiconductor switch device 100 to detect a short-to-power state without cutting off the power supply to the load side.

[0037] The semiconductor switch device 100 may further include a constant current source 180 provided between the second current detection circuit 130 and the first comparator 171. The second voltage V2 of the semiconductor switch device 100 may be a voltage corresponding to a current obtained by adding the current supplied from the constant current source 180 to the current detected by the second current detection circuit 130. In this case, the current supplied from the constant current source 180 is added as an offset to the second current sent from the second current detection circuit 130. This enables the semiconductor switch device 100 to adjust the point at which it is determined that a short to power has occurred due to the offset when comparing the first voltage V1 and the second voltage V2 corresponding to the first current and the second current, thereby making it possible to more accurately determine a short to power state.

[0038] Furthermore, the diagnostic circuit 160 of the semiconductor switch device 100 may compare the value of the first voltage V1 with the value of the reference voltage Vref, and may diagnose that the power distribution device 10 is in an open state if the value of the first voltage V1 is lower than the value of the reference voltage Vref. This enables the semiconductor switch device 100 to detect an open state without interrupting the power supply to the load side.

[0039] (Other embodiments) Although the embodiments have been described in detail with reference to the drawings, the present embodiments are not limited to the contents described in the above embodiments. Furthermore, the components described above include those that can be easily imagined by a person skilled in the art and those that are substantially the same. Furthermore, the configurations described above can be combined as appropriate. Furthermore, various omissions, substitutions, or modifications of the configurations can be made without departing from the spirit of the embodiments.

[0040] The features of the semiconductor switch device 100 and the power distribution device 10 will be described below.

[0041] A semiconductor switch device 100 according to a first aspect is provided in a power distribution device 10 and protects the power distribution device 10 in the event of an abnormality. The semiconductor switch device 100 includes a main switch element 110 connected to an input terminal connected to a power source 200 and an output terminal connected to a load device 300, and controls on / off of power supplied from the input terminal to the output terminal. The semiconductor switch device 100 also includes a sense MOS 111 connected in parallel with the main switch element 110. The semiconductor switch device 100 also includes a first current detection circuit 120 connected to the load device 300 and detecting a current flowing through the load device 300. The semiconductor switch device 100 also includes a second current detection circuit 130 connected to the output terminal and the sense MOS 111 and detecting a current flowing through the semiconductor switch device 100. The semiconductor switch device 100 also includes a drive circuit 140 that controls on / off of the main switch element 110 and the sense MOS 111. The semiconductor switch device 100 includes a diagnostic circuit 160 that diagnoses abnormalities in the power distribution device 10 based on a first voltage value corresponding to the current detected by the first current detection circuit 120 and a second voltage value corresponding to the current detected by the second current detection circuit 130 or a predetermined reference voltage.

[0042] This configuration enables the semiconductor switch device 100 to detect an abnormal state of the power distribution device 10 without interrupting the power supply to the load side.

[0043] The diagnostic circuit 160 of the semiconductor switch device 100 according to the second aspect may include a first comparator 171 that compares the value of the first voltage V1 with the value of the second voltage V2. Furthermore, the first comparator 171 of the diagnostic circuit 160 may diagnose that the power distribution device 10 is in a short-to-power state when the value of the first voltage V1 is greater than the value of the second voltage V2.

[0044] This configuration enables the semiconductor switch device 100 to detect a power short state without interrupting the power supply to the load side.

[0045] The diagnostic circuit 160 of the semiconductor switch device 100 according to the third aspect may further include a constant current source 180 provided between the second current detection circuit 130 and the first comparator 171. The second voltage of the semiconductor switch device 100 may be a voltage corresponding to a current obtained by adding the current detected by the second current detection circuit 130 to the current supplied from the constant current source 180.

[0046] With this configuration, in the semiconductor switch device 100, the current supplied from the constant current source 180 is added as an offset to the second current sent from the second current detection circuit 130. This enables the semiconductor switch device 100 to adjust the point at which it is determined that a short to power has occurred due to the offset when comparing the values ​​of the first voltage V1 and the second voltage V2 corresponding to the first current and the second current, thereby making it possible to more accurately determine a short to power state.

[0047] The diagnostic circuit 160 of the semiconductor switch device 100 according to the fourth aspect may compare the value of the first voltage V1 with the value of the reference voltage Vref, and diagnose that the power distribution device 10 is in an open state if the value of the first voltage V1 is lower than the value of the reference voltage Vref.

[0048] This configuration enables the semiconductor switch device 100 to detect an open state without interrupting the power supply to the load side.

[0049] The power distribution device 10 according to the fifth aspect includes the semiconductor switch device 100 described above, a power source 200 connected to the input terminal of the semiconductor switch device 100, and a load device 300 connected to the output terminal of the semiconductor switch device 100.

[0050] This configuration enables the power distribution device 10 to detect an abnormal state of the power distribution device 10 without interrupting the power supply to the load side. [Explanation of symbols]

[0051] 10 Power distribution equipment 100 Semiconductor switch device 110 Main switch element 111 Sense MOS 120 First current detection circuit 130 Second current detection circuit 140 Drive Circuit 150 control circuit 160 Diagnostic Circuit 171 First comparator 172 Second comparator 180 constant current source 200 power supply 300 load device

Claims

1. A semiconductor switch device that is provided in a power distribution device and protects the power distribution device in the event of an abnormality, a main switch element connected to an input terminal connected to a power supply and an output terminal connected to a load device, for controlling on / off of power supplied from the input terminal to the output terminal; a sense MOS connected in parallel with the main switching element; a first current detection circuit connected to the load device and detecting a current flowing through the load device; a second current detection circuit connected to the output terminal and the sense MOS, for detecting a current flowing through the semiconductor switch device; a drive circuit for controlling the main switching element and the sense MOS to be turned on and off; a diagnostic circuit that diagnoses an abnormality in the power distribution device based on a first voltage value corresponding to the current detected by the first current detection circuit and a second voltage value corresponding to the current detected by the second current detection circuit or a predetermined reference voltage; A semiconductor switch device comprising:

2. the diagnostic circuit includes a first comparator that compares the value of the first voltage with the value of the second voltage; 2. The semiconductor switch device according to claim 1, wherein the first comparator of the diagnostic circuit diagnoses that the power distribution device is in a short-to-power state when the value of the first voltage is greater than the value of the second voltage.

3. the diagnostic circuit further includes a constant current source provided between the second current detection circuit and the first comparator; 3. The semiconductor switch device according to claim 2, wherein the second voltage is a voltage corresponding to a current obtained by adding the current detected by the second current detection circuit to the current supplied from the constant current source.

4. 2. The semiconductor switch device according to claim 1, wherein the diagnostic circuit compares the value of the first voltage with the value of the reference voltage, and diagnoses that the power distribution device is in an open state if the value of the first voltage is lower than the value of the reference voltage.

5. The semiconductor switch device according to any one of claims 1 to 4, the power supply connected to the input terminal of the semiconductor switch device; the load device connected to the output terminal of the semiconductor switch device; A power distribution device comprising:

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