Semiconductor switch device, power distribution device, and short-circuit detection method

Abstract

To provide a semiconductor switch device capable of detecting a short-to-power state without interrupting power supply to a load side.SOLUTION: A semiconductor switch device 100 includes a main switch element 110 for controlling on / off of power supplied from a power supply terminal connected to a power supply 200 to an output terminal connected to a load device 300. In addition, the semiconductor switch device 100 includes a drive circuit 120 that applies a voltage lower than that in the normal operation to the main switch element 110 in the short-to-power detection operation. Further, the semiconductor switch device 100 includes a short-to-power detection means 150 for detecting whether or not the output voltage of the output terminal has a sufficient potential difference with respect to the power supply voltage of the power supply terminal in the case of the short-to-power detection operation. In addition, the semiconductor switch device 100 includes a diagnosis circuit 140 that diagnoses a power supply short-circuit state when it is detected that the output voltage does not have a sufficient potential difference with respect to the power supply voltage in the power supply short-circuit detection operation, and outputs the diagnosis result to the outside.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a semiconductor switch device, a power distribution device, and a method for detecting a short to power. [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 view of the problems inherent in the conventional technology, and an object of the present disclosure is to provide a semiconductor switch device that is capable of detecting a power short state 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 controls on / off of power supplied from a power supply terminal connected to a power source to an output terminal connected to a load device; a drive circuit that, in the case of a power short detection operation, applies a voltage to the main switch element that is lower than in the case of normal operation so that the main switch element is in a predetermined constant voltage regulation state; a control circuit that instructs the drive circuit to perform normal operation or power short detection operation; power short detection means that, in the case of a power short detection operation, detects whether the output voltage of the output terminal has a sufficient potential difference with respect to the power supply voltage of the power supply terminal; and a diagnostic circuit that, in the case of a power short detection operation, detects that there is a power short state if it is detected that the output voltage does not have a sufficient potential difference with respect to the power supply voltage, and outputs the diagnostic result to the outside.

[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 a power supply terminal of the semiconductor switch device, and a load device connected to an output terminal of the semiconductor switch device.

[0008] A power fault detection method according to another aspect of the present disclosure is a power fault detection method that is executed in a semiconductor switch device including a main switch element that controls on / off of power supplied from a power supply terminal connected to a power supply to an output terminal connected to a load device, and detects a power fault between the power supply terminal and the output terminal, wherein in the case of power fault detection operation, a voltage lower than that in normal operation is applied to the main switch element so that the main switch element is in a predetermined constant voltage regulation state, in the case of power fault detection operation, it detects whether the output voltage of the output terminal has a sufficient potential difference with respect to the power supply voltage of the power supply terminal, and in the case of power fault detection operation, if it is detected that the output voltage does not have a sufficient potential difference with respect to the power supply voltage, it diagnoses a power fault state and outputs the diagnosis result to the outside. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to provide a semiconductor switch device that can detect a power short state without interrupting the power supply to the load side. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a semiconductor switch device according to this embodiment. [Figure 2A] FIG. 2A is a diagram showing an example of processing of the semiconductor switch device according to this embodiment. [Figure 2B] FIG. 2B is a diagram showing an example of processing of the semiconductor switch device according to this embodiment. [Figure 3] FIG. 3 is a diagram for explaining a comparative example of power fault detection. [Figure 4] FIG. 4 is a diagram for explaining power fault detection according to this embodiment. [Figure 5] FIG. 5 is a flowchart showing an example of processing of a power fault detection method using the semiconductor switch device according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] 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.

[0012] 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.

[0013] The semiconductor switch device 100 is connected to a power supply 200 from a power supply terminal (VB terminal) which is an input 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.

[0014] The semiconductor switch device 100 includes a main switch element 110, a drive circuit 120, a control circuit 130, a diagnostic circuit 140, a power short detection means 150, a dummy load 160, and an input / output interface 170.

[0015] 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 a power supply 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.

[0016] The drive circuit 120 is connected to the charge pump 180 and generates a signal that determines whether the main switch element 110 is turned on or off. The control circuit 130 instructs the drive circuit 120 to perform normal operation or power short detection operation. For example, in the case of normal operation, the control circuit 130 instructs the drive circuit 120 to perform normal operation by turning on a control signal S1. In the case of power short detection operation, the control circuit 130 instructs the drive circuit 120 to perform power short detection operation by turning on a control signal S2. In this specification, a power short refers to a state in which a terminal, a wiring pattern, or a wire harness connected to a terminal is shorted to a power supply.

[0017] The diagnostic circuit 140 performs a power short detection process in response to an instruction from the control circuit 130, and outputs the diagnosis results to the outside via the input / output interface 170 and the DIAG terminal. The power short detection means 150 performs a power short detection process based on an instruction from the diagnostic circuit 140 or the control circuit 130. The dummy load 160 discharges the charge accumulated in the capacitance component present in the load device 300 in accordance with an instruction from the power short detection means 150. The dummy load 160 may be used as an option that can be set to be used or not depending on the abnormal state. The dummy load 160 may also be a voltage dividing resistor that detects the output voltage or input voltage.

[0018] The input / output interface 170 sends control instructions input from the outside via the IN terminal and the MODE terminal to the control circuit 130. For example, the control instruction input to the IN terminal is an instruction to turn on or off the semiconductor switch device 100. The control instruction input to the MODE terminal may also be information indicating a normal operation mode or a power fault detection operation mode. The charge pump 180 corresponds to a power supply supplied to the drive circuit 120. It is assumed that a voltage higher than the power supply voltage VB is supplied from the charge pump 180.

[0019] (Normal operation mode) 2A is a diagram showing an example of processing of the semiconductor switch device 100 according to this embodiment, and is a diagram for explaining operation during normal operation. When the control signal from the control circuit 130 turns on, the drive signal of the drive circuit 120 turns on (time T1). This turns on the main switch element 110, and the output voltage of the OUT terminal becomes the power supply voltage VB. Note that in FIG. 2A, "Out signal" indicates the output voltage of the output terminal (OUT terminal) (the same applies hereinafter in FIGS. 2B to 4).

[0020] Furthermore, when the control signal from the control circuit 130 turns off (GND level), the drive signal of the drive circuit 120 turns off (GND level) (time T2), which turns off the main switch element 110, the output voltage of the OUT terminal becomes a voltage of the GND level, and the power supply to the load device 300 is cut off.

[0021] 2B is a diagram showing an example of processing of the semiconductor switch device 100 according to this embodiment, and is a diagram for explaining operation during a short-to-power condition. As in the case of FIG. 2A, when the control signal from the control circuit 130 is turned on, the drive signal of the drive circuit 120 is turned on (time T3). This turns on the main switch element 110, and the output voltage of the OUT terminal becomes the power supply voltage VB.

[0022] 2B, a short-to-power anomaly occurs. In this case, for example, when the control signal from the control circuit 130 turns off (GND level), the drive signal of the drive circuit 120 turns off (GND level) (time T4). However, due to the short-to-power anomaly, power continues to be supplied even when the main switching element 110 turns off, and the output voltage of the OUT terminal does not drop to the GND level.

[0023] (Power fault detection process in comparative example) 3 is a diagram illustrating the process of power short detection in the semiconductor abnormality detection circuit disclosed in Patent Document 1 as a comparative example. Under normal conditions, when the power short detection control signal turns on at time T5, the drive signal turns off (GND level). In this case, the supply of power to the load device is cut off, and the output voltage of the OUT terminal also becomes GND level (off).

[0024] On the other hand, if a short to power occurs at time T7, when the control signal for power short detection turns on, the drive signal turns off (GND level). In this case, the power supply to the load device is not cut off due to the power short, so the output voltage of the OUT terminal does not drop and remains at the power supply voltage VB. This makes it possible for a conventional semiconductor abnormality detection circuit to detect a short to power.

[0025] However, some load devices require constant power supply under normal conditions. Therefore, when a load device that requires constant power supply is applied to a conventional semiconductor abnormality detection circuit, the semiconductor switch element cannot be turned off, and it is not possible to test for a short circuit between the input and output (a short to power).

[0026] The semiconductor switch device 100 according to this embodiment realizes a semiconductor switch device 100 that can detect a power short state without interrupting the power supply to the load side.

[0027] (Power Short Detection Processing in Semiconductor Switch Device 100) Next, a method for detecting a short to power on the input side and the output side in the semiconductor switch device 100 according to this embodiment will be described below. Fig. 4 is a diagram for explaining the short to power detection according to this embodiment.

[0028] When the control circuit 130 outputs a signal instructing a power short detection operation (turns on the control signal S2), the drive circuit 120 outputs a signal with a lower voltage than a normal on signal, which causes the main switching element 110 to enter a predetermined constant voltage regulation state (time T9). In this embodiment, the predetermined constant voltage regulation state is a state in which the main switching element 110 is in an on state and the output voltage (Vout) of the output terminal (OUT terminal) is lower than the power supply voltage VB.

[0029] Specifically, in the case of a short-to-power detection operation, the drive circuit 120 applies a voltage lower than the voltage applied during normal operation to the gate of the main switching element 110. For example, the voltage lower than the voltage applied during normal operation is a voltage with the same voltage value as the power supply voltage VB.

[0030] Furthermore, drive circuit 120 operates dummy load 160 to discharge the charge accumulated in the capacitance component present in load device 300. As a result, a certain potential difference occurs between the VB terminal and the OUT terminal (time T9 to time T10).

[0031] However, if the VB terminal and the OUT terminal are shorted to the power supply (short-circuited), even if the charge is discharged by the dummy load 160, the charge is immediately charged from the short-circuit path, and therefore no potential difference occurs between the VB terminal and the OUT terminal (time T11 to time T12, the dashed line is the expected value of the voltage of the OUT terminal). Therefore, the semiconductor switch device 100 can detect the presence or absence of a short circuit by measuring the potential between the VB terminal and the OUT terminal at this time.

[0032] (Outline of processing flow of semiconductor switching device 100) Next, the flow of power fault detection processing in the semiconductor switch device 100 will be described using the flowchart shown in Figure 5. The series of operations of the semiconductor switch device 100 shown in the flowchart in Figure 5 begins when the semiconductor switch device 100 is started, and ends when the operation is completed. The processing in the flowchart shown in Figure 5 also ends when the power is turned off or an interrupt occurs to end the processing. In addition, in the following description of the flowchart, content that is the same as that described in the above description of the semiconductor switch device 100 will be omitted or simplified.

[0033] In step S501, the control circuit 130 determines whether or not an instruction to perform a power fault detection operation has been received. If the control circuit 130 determines in step S501 that an instruction to perform a power fault detection operation has been received (step S501: YES), the process proceeds to step S502. On the other hand, if the control circuit 130 determines in step S501 that an instruction to perform a power fault detection operation has not been received (step S501: NO), the process returns to step S501, and the process from step S501 is repeated. That is, the semiconductor switch device 100 performs normal operation until an instruction to perform a power fault detection operation is received.

[0034] In step S502, the control circuit 130 controls the drive circuit 120. Specifically, the control circuit 130 turns on the control signal S2 to instruct the drive circuit 120 to perform a power short detection operation. In response to this control instruction, the drive circuit 120 outputs a signal with a lower voltage than a normal ON signal, which signal puts the main switching element 110 into a predetermined constant voltage regulation state. Then, the process proceeds to step S503.

[0035] In step S503, the driving circuit 120 operates the dummy load 160 to discharge the charge accumulated in the capacitance component present in the load device 300. Thereafter, the process proceeds to step S504.

[0036] In step S504, the power fault detection means 150 determines whether the output voltage (Vout) of the VOUT terminal has a sufficient potential difference with respect to the power supply voltage VB of the VB terminal. In this specification, a "sufficient potential difference" corresponds to a potential difference that can be detected by the power fault detection means 150. For example, a "sufficient potential difference" may be a potential corresponding to a voltage that is 10% or more of the voltage between the VB terminal and GND. Alternatively, a "sufficient potential difference" may be a potential difference of 1 V or more with respect to the voltage between the VB terminal and GND.

[0037] In step S504, if the power fault detection means 150 determines that the output voltage (Vout) of the VOUT terminal has a sufficient potential difference with respect to the power supply voltage VB of the VB terminal (step S504: YES), the process proceeds to step S506. On the other hand, in step S504, if the power fault detection means 150 determines that the output voltage (Vout) of the VOUT terminal does not have a sufficient potential difference with respect to the power supply voltage VB of the VB terminal (step S504: NO), the process proceeds to step S505.

[0038] In step S505, the diagnostic circuit 140 determines that the power distribution device 10 is in a short-to-power state, and notifies the outside via the input / output interface 170 and the DIAG terminal that the power distribution device 10 is in a short-to-power state. Then, the process ends.

[0039] In step S506, the diagnostic circuit 140 determines that the power distribution device 10 is in a normal state, not a power fault state, and notifies the outside via the input / output interface 170 and the DIAG terminal that the power distribution device 10 is in a normal state. Then, the processing ends. Note that the notification of the normal state in step S506 is not necessarily required as long as the notification of the power fault state in step S505 is implemented.

[0040] (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.

[0041] In the above-described embodiment, the drive circuit 120 outputs a signal to the main switching element 110 during power short detection operation, the signal having a voltage lower than that of the ON signal, so that the main switching element 110 enters a predetermined constant voltage regulation state. Specifically, the drive circuit 120 controls the main switching element 110 to enter the above state by applying a voltage equal to the power supply voltage VB to the gate of the main switching element 110. This configuration does not limit the configuration of the embodiment. For example, the drive circuit 120 may drive the main switching element 110 so that the voltage at the VOUT terminal becomes a voltage that is a predetermined percentage of the voltage between the VB terminal and GND. For example, the predetermined percentage may be a voltage that is approximately 80% of the voltage between the VB terminal and GND. Alternatively, the predetermined percentage may be a voltage that is 80% or more of the voltage between the VB terminal and GND.

[0042] Furthermore, a computer program (power fault detection program) that causes a computer to execute the processing (power fault detection method) in the semiconductor switch device 100 described above, and a computer-readable recording medium on which the program is recorded, are included in the scope of this embodiment. Here, any type of computer-readable recording medium may be used. Furthermore, the computer program is not limited to being recorded on the recording medium described above, and may be transmitted via a telecommunications line, a wireless or wired communication line, a network such as the Internet, or the like.

[0043] The following describes the features of the semiconductor switch device 100, the power distribution device 10, and the power short detection method.

[0044] A semiconductor switch device 100 according to a first aspect is provided in a power distribution device and protects the power distribution device in the event of an abnormality. The semiconductor switch device 100 includes a main switch element 110 that controls on / off of power supplied from a power supply terminal connected to a power supply 200 to an output terminal connected to a load device 300. The semiconductor switch device 100 also includes a drive circuit 120 that, in a power short detection operation, applies a voltage to the main switch element 110 that is lower than that in a normal operation so that the main switch element 110 is in a predetermined constant voltage regulation state. The semiconductor switch device 100 also includes a control circuit 130 that issues an instruction to the drive circuit 120 to perform normal operation or a power short detection operation. The semiconductor switch device 100 also includes a power short detection means 150 that, in a power short detection operation, detects whether the output voltage of the output terminal has a sufficient potential difference with respect to the power supply voltage of the power supply terminal. Furthermore, the semiconductor switch device 100 includes a diagnostic circuit 140 that, in the case of a power short detection operation, diagnoses a power short state when it is detected that the output voltage does not have a sufficient potential difference with respect to the power supply voltage, and outputs the diagnostic result to the outside.

[0045] With this configuration, the semiconductor switch device 100 performs power short detection while keeping the main switch element 110 in the on state, that is, the constant voltage regulation state, and therefore, it is possible to detect a power short state without cutting off the power supply to the load side.

[0046] The drive circuit 120 of the semiconductor switch device 100 according to the second aspect may apply a voltage to the gate of the main switch element 110 that is the same as the power supply voltage of the power supply terminal in the case of a power short detection operation.

[0047] With this configuration, the semiconductor switch device 100 can appropriately maintain the main switch element 110 in the ON state, ie, the constant voltage regulation state, when detecting a short to power.

[0048] The drive circuit 120 of the semiconductor switch device 100 according to the third embodiment may drive the main switch element 110 in the case of a power short detection operation so that the output voltage becomes lower than the voltage between the power supply voltage and GND.

[0049] With this configuration, the semiconductor switch device 100 performs power short detection while keeping the main switch element 110 in the ON state, and therefore, it is possible to detect a power short state without cutting off the power supply to the load side.

[0050] The drive circuit 120 of the semiconductor switch device 100 according to the fourth aspect may drive the main switch element 110 in the case of a power short detection operation so that the output voltage becomes a voltage having a value equal to or greater than 80% of the voltage between the power supply voltage and GND.

[0051] With this configuration, the semiconductor switch device 100 can more accurately perform power short detection while keeping the main switch element 110 in the on state, making it possible to detect a power short state without cutting off the power supply to the load side.

[0052] The semiconductor switch device 100 according to the fifth aspect may further include a dummy load 160 connected to the output terminal. In addition, the power short detection means 150 may operate the dummy load to discharge charges accumulated in a capacitance component present in the load device 300 in the case of a power short detection operation.

[0053] With this configuration, the semiconductor switch device 100 can more reliably discharge the charge accumulated in the capacitance component present in the load device 300, thereby enabling more accurate short-to-power detection.

[0054] The power distribution device 10 according to the sixth aspect includes the semiconductor switch device 100 described above, a power supply 200 connected to the power supply terminal of the semiconductor switch device 100, and a load device 300 connected to the output terminal of the semiconductor switch device 100.

[0055] With this configuration, the power distribution device 10 performs power short detection while keeping the main switch element 110 in the on state, which is a constant voltage regulation state, and therefore it is possible to detect a power short state without cutting off the power supply to the load side.

[0056] A power short detection method according to a seventh aspect is a power short detection method executed in a semiconductor switching device 100 including a main switching element 110 that controls on / off of power supplied from a power supply terminal connected to a power supply 200 to an output terminal connected to a load device 300. The power short detection method detects a power short between a power supply terminal and an output terminal. In a power short detection operation, the power short detection method applies a voltage to the main switching element 110 that is lower than that in normal operation so that the main switching element 110 is in a predetermined constant voltage regulation state. In a power short detection operation, the power short detection method detects whether the output voltage of the output terminal has a sufficient potential difference with respect to the power supply voltage of the power supply terminal. In a power short detection operation, the power short detection method diagnoses a power short state when it is detected that the output voltage does not have a sufficient potential difference with respect to the power supply voltage, and outputs the diagnosis result to the outside.

[0057] With this configuration, the power short detection method performs power short detection while keeping the main switch element 110 in the on state, which is the constant voltage regulation state, and therefore makes it possible to detect a power short state without cutting off the power supply to the load side. [Explanation of symbols]

[0058] 10 Power distribution equipment 100 Semiconductor switch device 110 Main switch element 120 Drive Circuit 130 control circuit 140 Diagnostic Circuit 150 Power fault detection means 160 dummy load 170 Input / Output Interface 180 Charge Pump 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 that controls on / off of power supplied from a power supply terminal connected to a power supply to an output terminal connected to a load device; a drive circuit that applies a voltage lower than that in normal operation to the main switching element so that the main switching element is in a predetermined constant voltage regulation state during a power short detection operation; a control circuit that instructs the drive circuit to perform the normal operation or the power short detection operation; a power short detection means for detecting whether or not an output voltage of the output terminal has a sufficient potential difference with respect to a power supply voltage of the power supply terminal in the case of the power short detection operation; and a diagnostic circuit that, when it is detected that the output voltage does not have a sufficient potential difference from the power supply voltage during the power short detection operation, diagnoses the state as being a power short and outputs the diagnostic result to the outside.

2. 2. The semiconductor switch device according to claim 1, wherein the drive circuit applies a voltage having the same value as the power supply voltage of the power supply terminal to the gate of the main switch element in the case of the power short detection operation.

3. 2. The semiconductor switch device according to claim 1, wherein the drive circuit drives the main switch element in the case of the power short detection operation so that the output voltage becomes lower than a voltage between the power supply voltage and GND.

4. 4. The semiconductor switch device according to claim 3, wherein the drive circuit drives the main switch element so that the output voltage becomes a voltage having a value equal to or greater than 80% of a voltage between the power supply voltage and GND during the power short detection operation.

5. a dummy load connected to the output terminal; 2. The semiconductor switch device according to claim 1, wherein the power short detection means operates the dummy load in the case of the power short detection operation, thereby discharging charges accumulated in a capacitance component present in the load device.

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

7. 1. A power fault detection method that is executed in a semiconductor switch device including a main switch element that controls on / off of power supplied from a power supply terminal connected to a power supply to an output terminal connected to a load device, and detects a power fault between the power supply terminal and the output terminal, In the case of a power short detection operation, a voltage lower than that in the case of a normal operation is applied to the main switching element so that the main switching element is in a predetermined constant voltage regulation state; In the case of the power short detection operation, detecting whether or not the output voltage of the output terminal has a sufficient potential difference with respect to the power supply voltage of the power supply terminal; In the case of the power short detection operation, if it is detected that the output voltage does not have a sufficient potential difference with respect to the power supply voltage, a power short detection state is diagnosed and the diagnosis result is output to the outside.

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