JP2021189006A - Short circuit detector - Google Patents

Abstract

To provide a short circuit detector that can detect a short circuit between terminals when the terminals are used.SOLUTION: A control unit acquires outputs of a first sensor and a second sensor before a voltage gain of a first terminal unit is changed (S1). After that, the voltage gain of the first terminal unit is changed (S3) and the control unit acquires outputs of the first sensor and the second sensor after the voltage gain of the first terminal unit is changed (S5). The control unit determines whether the output of the second sensor has changed beyond a threshold value (S7). When the output of the second sensor has changed beyond the threshold value, generation of a short circuit between the terminals is determined (S9). When the output of the second sensor has not changed beyond the threshold value, generation of a short circuit between the terminals is not determined (S11).SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a short circuit detection device.

Japanese Patent Application Laid-Open No. 2019-46515 (Patent Document 1) discloses an abnormality detection circuit that detects a short circuit between adjacent terminals of an FPC (Flexible Printed Circuit) used in a disk device. This abnormality detection circuit is used when the disk device is in the test mode (mode in which the disk is not written or read), a voltage is applied between the terminals, and the detected voltage between the terminals is compared with the reference voltage. By doing so, a short circuit between the terminals is detected (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2019-46515

Since the abnormality detection circuit disclosed in Patent Document 1 applies a voltage between the terminals, it can be used only in the test mode. That is, in the disk device, for example, when control is performed using the monitor result of the terminal signal (hereinafter, also referred to as "when the terminal is used (when monitoring)"), an abnormality detection circuit is used between the terminals. Short circuit cannot be detected. In general, short circuits between terminals are likely to occur when the terminals are used. If a short circuit occurs between the terminals when using the terminals, it is desirable to detect the occurrence of the short circuit immediately.

The present disclosure has been made to solve the above problems, and an object thereof is to provide a short circuit detection device capable of detecting a short circuit between terminals when the terminals are used.

The short circuit detection device according to this disclosure detects a short circuit between the first terminal and the second terminal. This short-circuit detection device includes a control device that receives signals from the first terminal and the second terminal, and a changing means for changing the voltage gain of the first terminal. The control device controls the changing means. The control device detects a short circuit between the first terminal and the second terminal based on the change in the signal level of the second terminal when the voltage gain of the first terminal is changed.

According to the above configuration, the control device changes the voltage gain of the first terminal by controlling the changing means. When the first terminal and the second terminal are short-circuited, the level of the signal from the second terminal to the control device changes as the voltage gain of the first terminal changes. On the other hand, when the first terminal and the second terminal are not short-circuited, the level of the signal from the second terminal to the control device does not change even if the voltage gain of the first terminal changes. Therefore, the control device can detect a short circuit between the terminals based on the change in the signal level from the second terminal when the voltage gain of the first terminal is changed. Since the short circuit between the terminals is detected based on the change in the signal level, the short circuit between the terminals can be detected when the first terminal and the second terminal are used.

According to the present disclosure, it is possible to provide a short circuit detection device capable of detecting a short circuit between terminals when the terminals are used.

It is an overall block diagram of the sensor device which concerns on embodiment. It is a figure for demonstrating the output of the 1st sensor and the 2nd sensor at the time of a normal operation that a short circuit does not occur between terminals. It is a figure for demonstrating the output of the 1st sensor and the 2nd sensor at the time of an abnormality in which a short circuit occurs between terminals. It is a functional block diagram of the control part which concerns on embodiment. It is a flowchart which shows the procedure of the short circuit detection processing executed in the control part. It is an overall block diagram of the sensor device which concerns on modification 3. FIG. It is an overall block diagram of the sensor device which concerns on a comparative example.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same or corresponding parts in the drawings are designated by the same reference numerals and the description thereof will not be repeated.

<Overall configuration of sensor device>
FIG. 1 is an overall configuration diagram of the sensor device 10 according to the present embodiment. The sensor device 10 includes a first terminal unit 20, a second terminal unit 30, a first input circuit 40, a second input circuit 50, and a control unit 60. The first sensor 70 is connected to the first terminal portion 20. A second sensor 80 is connected to the second terminal portion 30. The first sensor 70 and the second sensor 80 are, for example, temperature sensors. The sensor device 10 converts the detection signal (voltage) of the first sensor 70 into a temperature, and outputs the converted temperature as a detection value of the first sensor 70 to an external device (not shown). The sensor device 10 converts the detection signal (voltage) of the second sensor 80 into a temperature, and outputs the converted temperature as a detection value of the second sensor 80 to an external device. The first sensor 70 and the second sensor 80 are not limited to the temperature sensor, and may be various sensors. Further, the first sensor 70 and the second sensor 80 are not limited to the same type of sensor, and may be different types of sensors.

The first terminal portion 20 includes a first positive electrode terminal 21 and a first negative electrode terminal 22. The first positive electrode terminal 21 is connected to the control unit 60 via the first input circuit 40. Specifically, the first positive electrode terminal 21 is electrically connected to the input portion of the first input circuit 40 by the signal line L11. The output unit of the first input circuit 40 is electrically connected to the input port of the control unit 60 by the signal line L12. The first negative electrode terminal 22 is grounded.

The second terminal portion 30 includes a second positive electrode terminal 31 and a second negative electrode terminal 32. The second positive electrode terminal 31 is connected to the control unit 60 via the second input circuit 50. Specifically, the second positive electrode terminal 31 is electrically connected to the input portion of the second input circuit 50 by the signal line L21. The output unit of the second input circuit 50 is electrically connected to the input port of the control unit 60 by the signal line L22. The second negative electrode terminal 32 is grounded.

The first input circuit 40 is electrically connected between the first positive electrode terminal 21 and the control unit 60. The first input circuit 40 converts the analog signal from the first sensor 70 into a digital signal and outputs it to the control unit 60. The details of the first input circuit 40 will be described later.

The second input circuit 50 is electrically connected between the second positive electrode terminal 31 and the control unit 60. The second input circuit 50 converts the analog signal from the second sensor 80 into a digital signal and outputs it to the control unit 60. The second input circuit 50 includes a power supply 51, a pull-up resistor 52, a resistor 53, and an ADC (Analog-to-Digital Converter) 54.

The power supply 51 supplies a power supply voltage to the signal line L21. One end of the pull-up resistor 52 is connected to the power supply 51, and the other end is connected to the connection point X2 on the signal line L21.

The input unit of the ADC 54 is connected to the connection point X2 on the signal line L21 via the resistor 53. The output unit of the ADC 54 is connected to the signal line L22. The ADC 54 converts the analog signal from the second sensor 80 input from the second terminal unit 30 into a digital signal and outputs it to the control unit 60. The circuit configuration of the second input circuit 50 is not limited to the above, and for example, the same configuration as that of the first input circuit 40 (details will be described later) can be adopted.

The control unit 60 includes a CPU (Central Processing Unit) that performs various processes, a memory that includes a ROM (Read Only Memory) that stores programs and data, a RAM (Random Access Memory) that stores the processing results of the CPU, and the like. Includes input / output ports for exchanging information with the outside (none of them are shown). A signal line L12 and a signal line L22 are connected to the input port. For example, a signal line (not shown) connected to an input port of an external device is connected to the output port. The CPU expands the program stored in the ROM into the RAM and executes it. The CPU executes a predetermined arithmetic process based on the signal input from the input port and the information stored in the memory, and outputs the arithmetic result from the output port. It should be noted that these controls are not limited to software processing, but can also be constructed and processed by dedicated hardware (electronic circuit).

The control unit 60 converts the detected value (voltage value) of the first sensor 70 received via the signal line L12 into a temperature. In the following, the detection signal from the first sensor 70 input to the control unit 60 via the signal line L12 is also referred to as “output of the first sensor 70”. The control unit 60 converts the output of the first sensor 70 into temperature by using, for example, a first map that defines the relationship between the voltage value and the temperature, which is stored in the memory in advance. The control unit 60 outputs the converted temperature as the detection temperature of the first sensor 70 to an external device.

Further, the control unit 60 converts the detection signal (voltage) of the second sensor 80 received via the signal line L22 into a temperature. In the following, the detection signal of the second sensor 80 input to the control unit 60 via the signal line L22 is also referred to as “output of the second sensor 80”. The control unit 60 converts the output of the second sensor 80 into temperature by using, for example, a second map that defines the relationship between the voltage value and the temperature, which is stored in the memory in advance. The control unit 60 outputs the converted temperature as the detection temperature of the second sensor 80 to an external device.

In the external device, for example, predetermined control using the detection temperature of the first sensor 70 and the detection temperature of the second sensor 80 is executed. That is, in the sensor device 10 and the external device, control using the monitor results of the signals from the first terminal unit 20 and the second terminal unit 30 (control using the monitor results of the signals from the terminals) is performed.

<Short circuit detection process>
Here, a short circuit may occur between adjacent terminals such as the first terminal portion 20 and the second terminal portion 30. The short circuit between the terminals is, for example, when the control is performed using the monitoring result of the signal from the terminals (first terminal portion 20 and the second terminal portion 30) (when the terminals are used), that is, the sensor (the first terminal portion 30). It is likely to occur when monitoring 1 sensor 70 and 2nd sensor 80). Therefore, it is desirable to be able to detect a short circuit between terminals when monitoring the sensor (when using the terminals).

Therefore, the control unit 60 according to the present embodiment is configured to be able to execute the short circuit detection process. The short circuit detection process is a process for detecting a short circuit between terminals when monitoring the sensors (first sensor 70 and second sensor 80). Hereinafter, the short circuit detection process will be described step by step.

The first input circuit 40 according to the present embodiment includes a power supply 41, a gain changing unit 42, a resistor 44, and an ADC 45.

The power supply 41 supplies a power supply voltage to the signal line L11. A gain changing unit 42 is electrically connected between the power supply 41 and the signal line L12.

The gain changing unit 42 includes a switch 43, a resistor R1, and a resistor R2.
The resistance R1 and the resistance R2 have different resistance values. In the present embodiment, the resistance value of the resistor R1 has a value smaller than the resistance value of the resistor R2. The resistance R1 and the resistance R2 may have different resistance values, and the values are not particularly limited. For example, the resistance value of the resistor R1 may have a value larger than the resistance value of the resistor R2.

The switch 43 is a so-called c-contact switch. The switch 43 has three contacts 43a, 43b, 43c. The contact 43a is electrically connected to the power supply 41. The contact 43b is electrically connected to one end of the resistor R1. The other end of the resistor R1 is electrically connected to the connection point X1 on the signal line L11. The contact 43c is electrically connected to one end of the resistor R2. The other end of the resistor R2 is electrically connected to the connection point X1.

The switch 43 is configured to be switchable between a first state for connecting the contact 43a and the contact 43b and a second state for connecting the contact 43a and the contact 43c. The switch 43 switches between the first state and the second state according to the control signal from the control unit 60. The voltage supplied to the signal line L11 differs between the case where the switch 43 is in the first state and the case where the switch 43 is in the second state. That is, when the connection state of the switch 43 is switched, the voltage gain of the first terminal portion 20 is changed. The gain changing unit 42 corresponds to an example of the "changing means" according to the present disclosure. In the present embodiment, the first state is the default state of the switch 43, and the switch 43 is switched to the second state when the short circuit detection process is executed.

The input unit of the ADC 45 is connected to the connection point X1 on the signal line L11 via the resistor 44. The output unit of the ADC 45 is connected to the signal line L12. The ADC 45 converts the analog signal from the first sensor 70 input from the first terminal unit 20 into a digital signal and outputs it to the control unit 60.

The control unit 60 controls the first input circuit 40 to execute the short circuit detection process. The short circuit detection process is started while monitoring the sensors (first sensor 70 and second sensor 80). At the time of monitoring the sensor, the switch 43 of the first input circuit 40 is in the first state. That is, the voltage gain of the first terminal portion 20 is a voltage gain determined by the resistor R1.

Then, at the time of monitoring the sensor, the control unit 60 switches the switch 43 of the gain changing unit 42 from the first state to the second state. As a result, the voltage gain of the first terminal portion 20 becomes the voltage gain determined by the resistor R2. As the voltage gain of the first terminal unit 20 changes, the level of the signal input to the control unit 60 via the signal line L12 (output of the first sensor 70) changes.

Here, between the first terminal portion 20 and the second terminal portion 30 (more specifically, between the first positive electrode terminal 21 of the first terminal portion 20 and the second positive electrode terminal 31 of the second terminal portion 30). ), The level of the signal input to the control unit 60 via the signal line L22 (output of the second sensor 80) changes with the voltage gain of the first terminal unit 20. do. On the other hand, when there is no short circuit between the first terminal portion 20 and the second terminal portion 30, the output of the second sensor 80 does not change.

The control unit 60 monitors the output of the second sensor 80 after changing the voltage gain of the first terminal unit 20, and when the output of the second sensor 80 changes by a threshold value or more, the first terminal unit 20 It is determined that a short circuit has occurred between the second terminal portion 30 and the second terminal portion 30.

The threshold value is calculated, for example, by multiplying the output of the second sensor 80 before changing the voltage gain of the first terminal portion 20 by a predetermined rate of change. The rate of change can be predetermined, for example, based on the respective values of the power supply 41, the resistor R1 and the resistor R2.

FIG. 2 is a diagram for explaining the outputs of the first sensor 70 and the second sensor 80 in a normal state in which a short circuit does not occur between the terminals. FIG. 3 is a diagram for explaining the outputs of the first sensor 70 and the second sensor 80 when a short circuit occurs between the terminals. The horizontal axis of FIGS. 2 and 3 shows the time, and the vertical axis shows the output of the sensor. The solid line L1 in FIG. 2 and the solid line L3 in FIG. 3 indicate the output of the first sensor 70. The solid line L2 in FIG. 2 and the solid line L4 in FIG. 3 indicate the output of the second sensor 80.

First, referring to FIG. 2, from time t0 to time t1, the switch 43 of the gain changing unit 42 is in the first state. At time t1, the switch 43 is switched from the first state to the second state. As a result, the voltage gain of the first terminal portion 20 is changed. Since the voltage gain of the first terminal portion 20 has been changed, the output (signal level) of the first sensor 70 is reduced at time t1. On the other hand, since no short circuit has occurred between the terminals, even if the voltage gain of the first terminal portion 20 is changed, the output of the second sensor 80 is not affected by the change. Therefore, the output of the second sensor 80 does not change more than the threshold value before and after the time t1.

Next, with reference to FIG. 3, from time t10 to time t12, the switch 43 of the gain changing unit 42 is in the first state. Here, at time t11, between the first terminal portion 20 and the second terminal portion 30 (more specifically, the first positive electrode terminal 21 of the first terminal portion 20 and the second positive electrode terminal of the second terminal portion 30). There is a short circuit between (31) and (31). Therefore, at time t11, the output of the first sensor 70 and the output of the second sensor 80 have the same value. In this state, at time t12, the switch 43 is switched from the first state to the second state. Since the voltage gain of the first terminal portion 20 has been changed, the output of the first sensor 70 and the output (signal level) of the second sensor 80 have decreased with the change of the voltage gain. In this case, the output of the second sensor 80 changes by the threshold value or more before and after the time t12.

As described above, the control unit 60 monitors the outputs of the second sensor 80 before and after changing the voltage gain of the first terminal unit 20 between the first terminal unit 20 and the second terminal unit 30. It is possible to determine whether or not a short circuit has occurred.

In the short-circuit detection method between terminals in the present embodiment, although the voltage gain of the first terminal portion 20 changes by switching the switch 43, the monitoring of the sensors (first sensor 70 and second sensor 80) is interrupted. It does not have to be. Therefore, in order to detect a short circuit between the terminals, it is not necessary to interrupt the control using the monitor result of the signal from the terminals (first terminal portion 20 and second terminal portion 30).

After the voltage gain of the first terminal unit 20 is changed (switch 43: second state), the control unit 60 replaces the above-mentioned first map with a third map according to the changed voltage gain (switch 43: second state). The output of the first sensor 70 may be converted into temperature by using a map) that defines the relationship between the voltage value and the temperature.

<Functional block of control unit>
FIG. 4 is a functional block diagram of the control unit 60 according to the present embodiment. With reference to FIG. 4, the control unit 60 includes an execution start unit 61, a switch switching unit 62, a first acquisition unit 63, a second acquisition unit 64, a determination unit 65, and an output unit 66.

The execution start unit 61 determines the start of the short circuit detection process. The execution start unit 61 determines, for example, to start the short-circuit detection process when a predetermined time has elapsed from the execution of the previous short-circuit detection process. Alternatively, the execution start unit 61 may decide to start the short circuit detection process when, for example, an execution instruction is received from a higher-level device of the sensor device 10. When the start of the short circuit detection process is determined, the execution start unit 61 outputs a connection state switching instruction to the switch switching unit 62.

Upon receiving the switching instruction, the switch switching unit 62 generates and outputs a control signal for switching the connection state of the switch 43 of the gain changing unit 42 from the first state to the second state. Further, the switch switching unit 62 outputs a change signal indicating that the connection state of the switch 43 of the gain changing unit 42 has been switched, that is, the voltage gain of the first terminal unit 20 has been changed, to the determination unit 65.

The first acquisition unit 63 acquires the output of the first sensor 70 and outputs it to the determination unit 65.
The second acquisition unit 64 acquires the output of the second sensor 80 and outputs it to the determination unit 65.

The determination unit 65 receives the output of the first sensor 70 and the output of the second sensor 80. The determination unit 65 is located between the first terminal unit 20 and the second terminal unit 30 (more specifically, the first positive electrode terminal 21 of the first terminal unit 20 and the second positive electrode terminal 31 of the second terminal unit 30). (Between) and determine whether or not a short circuit has occurred. When the determination unit 65 receives a change signal from the switch switching unit 62 and the output of the second sensor 80 changes by a threshold value or more, a short circuit occurs between the first terminal unit 20 and the second terminal unit 30. It is determined that there is. The determination unit 65 outputs the determination result (whether or not there is a short circuit between the terminals) to the output unit 66. When the determination unit 65 receives the change signal from the switch switching unit 62 and the output of the second sensor 80 has not changed by the threshold value or more, the determination unit 65 short-circuits between the first terminal unit 20 and the second terminal unit 30. Is not generated.

The determination unit 65 receives a change signal from the switch switching unit 62, the output of the first sensor 70 changes by the first threshold value or more, and the output of the second sensor 80 changes by the second threshold value or more. , It may be determined that a short circuit has occurred between the first terminal portion 20 and the second terminal portion 30. For example, when the detection target of the second sensor 80 changes significantly, the output of the second sensor 80 may fluctuate beyond the threshold value. In such a case, it may not be possible to accurately determine the occurrence of a short circuit between the terminals by monitoring only the fluctuation of the output of the second sensor 80. By considering the fluctuation of the output of the first sensor 70 in addition to the fluctuation of the output of the second sensor 80, the occurrence of a short circuit between the terminals can be determined more accurately. The first threshold value is calculated, for example, by multiplying the output of the first sensor 70 before changing the voltage gain of the first terminal portion 20 by the above-mentioned rate of change. The second threshold value is calculated, for example, by multiplying the output of the second sensor 80 before changing the voltage gain of the first terminal portion 20 by the above-mentioned rate of change.

The output unit 66 outputs the determination result received from the determination unit 65 to an external device.
<Process executed by the control unit>
FIG. 5 is a flowchart showing a procedure of the short circuit detection process executed by the control unit 60. The flowchart shown in FIG. 5 is called from the main routine when the start of execution of the short circuit detection process is determined, and is executed by the control unit 60. A case where each step of the flowchart shown in FIG. 5 (hereinafter, the step is abbreviated as “S”) is realized by software processing by the control unit 60 will be described, but a part or all of the steps are manufactured in the control unit 60. It may be realized by the hardware (electric circuit).

The control unit 60 starts the flowchart when a predetermined time has elapsed from the execution of the previous short-circuit detection process or when an execution instruction is received from the host device, and the output of the first sensor 70 and the output of the second sensor 80 Acquire the output (S1). The control unit 60 stores the acquired value as the value before the change of the voltage gain of the first terminal unit 20.

Next, the control unit 60 changes the voltage gain of the first terminal unit 20 (S3). Specifically, the control unit 60 changes the connection state of the switch 43 of the gain changing unit 42 from the first state to the second state. As a result, the voltage gain of the first terminal portion 20 is changed.

Next, the control unit 60 acquires the output of the first sensor 70 and the output of the second sensor 80 (S5). The control unit 60 stores the acquired value as the value after the voltage gain of the first terminal unit 20 is changed.

The control unit 60 determines whether or not the output of the second sensor 80 has changed by a threshold value or more before and after the change of the voltage gain of the first terminal unit 20 (S7). When the output of the second sensor 80 changes by the threshold value or more (YES in S7), the control unit 60 determines an abnormality and is between the first terminal unit 20 and the second terminal unit 30 (more specifically, more specifically). It is determined that a short circuit has occurred between the first positive electrode terminal 21 of the first terminal portion 20 and the second positive electrode terminal 31 of the second terminal portion 30 (S9).

If the output of the second sensor 80 has not changed by the threshold value or more before and after the change of the voltage gain of the first terminal portion 20 (NO in S7), the control unit 60 determines to be normal, and the first terminal portion 20 and It is determined that no short circuit has occurred with the second terminal portion 30 (S11).

In S7, the control unit 60 changes the output of the first sensor 70 by the first threshold value or more, and the output of the second sensor 80 changes by the second threshold value or more, the first terminal unit 20 and the second. It may be determined that a short circuit has occurred between the terminal portion 30 and the terminal portion 30. By considering the fluctuation of the output of the first sensor 70 in addition to the fluctuation of the output of the second sensor 80, the occurrence of a short circuit between the terminals can be determined more accurately.

The control unit 60 outputs the determination result in S7 or S9 (S13).
As described above, in the sensor device 10 according to the present embodiment, the first terminal portion 20 and the second terminal are monitored by monitoring the output of the second sensor 80 before and after the change of the voltage gain of the first terminal portion 20. Whether or not a short circuit has occurred with the unit 30 is determined. In the short-circuit detection method between terminals in the present embodiment, although the voltage gain of the first terminal portion 20 changes by switching the switch 43, the monitoring of the sensors (first sensor 70 and second sensor 80) is interrupted. It does not have to be. Therefore, it is not necessary to interrupt the control using the monitor result of the signal from the first terminal portion 20 and the second terminal portion 30 in order to detect the short circuit between the terminals.

<Modification 1>
In the embodiment, an example in which the sensor device 10 has two terminal portions, a first terminal portion 20 and a second terminal portion 30, has been described. However, the number of terminal portions is not limited to two. The sensor device 10 may have three or more terminal portions. Even when the sensor device 10 has three or more terminal portions, the occurrence of a short circuit between adjacent terminals can be detected by providing the first input circuit 40 for each terminal portion.

<Modification 2>
In the embodiment, the gain changing unit 42 includes the switch 43, the resistor R1 and the resistor R2, and changes the connection state of the switch 43 to change the voltage gain of the first terminal unit 20. In the second modification, another example of changing the voltage gain of the first terminal portion 20 will be described.

For example, a so-called a-contact switch or a b-contact switch can be used instead of the switch 43. In the second modification, an example in which the a-contact switch is used will be described as an example.

In the second modification, one end of the resistor R1 is electrically connected to the power supply 41. The other end of the resistor R1 is electrically connected to the connection point X1 on the signal line L11. The resistor R2 is connected in parallel with the resistor R1 between the power supply 1 and the connection point X1. One end of the resistor R2 is electrically connected to the connection point between the power supply 41 and one end of the resistor R1 via the a contact switch. Specifically, the a-contact switch has a first contact and a second contact. The first contact is, for example, electrically connected to a connection point between the power supply 41 and one end of the resistor R1. The second contact is electrically connected to one end of the resistor R2. The other end of the resistor R2 is electrically connected to the connection point between the other end of the resistor R1 and the connection point X1.

In the second modification, the voltage gain of the first terminal portion 20 can be changed by switching between the cutoff and the connection of the a-contact switch. That is, also in the second modification, the voltage gain of the first terminal portion 20 can be changed by controlling the connection state of the a-contact switch as in the embodiment. Therefore, even in the configuration of the modified example 2, the same effect as that of the embodiment can be obtained. The voltage gain of the first terminal portion 20 may be appropriately set by appropriately changing the resistance values of the resistors R1 and R2.

<Modification 3>
In the embodiment, the gain changing unit 42 includes the switch 43, the resistor R1 and the resistor R2, and changes the connection state of the switch 43 to change the voltage gain of the first terminal unit 20. In the third modification, another example of changing the voltage gain of the first terminal portion 20 will be described.

FIG. 6 is an overall configuration diagram of the sensor device 10A according to the modified example 3. The sensor device 10A is obtained by changing the first input circuit 40 to the first input circuit 40A with respect to the sensor device 10 according to the embodiment. Since the other configurations of the sensor device 10A are the same as those of the sensor device 10, they will not be described repeatedly.

The first input circuit 40A includes a first power supply 46, a gain changing unit 47, a resistor R3, a resistor 44, and an ADC 45. The gain changing unit 47 includes a second power supply 48 and a switch 49.

The first power source 46 and the second power source 48 have different potentials. That is, the first power supply 46 and the second power supply 48 supply different voltages to the signal line L11. In the third modification, the first power source 46 has a higher potential than the second power source 48. The first power supply 46 and the second power supply 48 may have different potentials from each other, and the values thereof are not particularly limited. For example, the first power supply 46 may have a lower potential than the second power supply 48.

The switch 49 is a so-called c-contact switch. The switch 49 has three contacts 49a, 49b, 49c. The contact 49a is electrically connected to one end of the resistor R3. The other end of the resistor R3 is electrically connected to the connection point X3 on the signal line L11. The contact 49b is electrically connected to the first power supply 46. The contact 49c is electrically connected to the second power supply 48. The switch 49 is configured to be switchable between a third state in which the contact 49a and the contact 49b are connected and a fourth state in which the contact 49a and the contact 49c are connected. The switch 49 switches between the third state and the fourth state according to the control signal from the control unit 60. The voltage supplied to the signal line L11 differs between the case where the switch 49 is in the third state and the case where the switch 49 is in the fourth state. That is, when the connection state of the switch 49 is switched, the voltage gain of the first terminal portion 20 is changed. The gain changing unit 47 corresponds to an example of the "changing means" according to the present disclosure. In the third modification, the third state is the default state of the switch 49, and the switch 49 is switched to the fourth state when the short circuit detection process is executed.

Since the first input circuit 40A has the above-mentioned configuration, the voltage gain of the first terminal portion 20 can be changed by controlling the connection state of the switch 49 as in the embodiment. The sensor device 10A according to the third modification can also have the same effect as the sensor device 10 according to the embodiment.

<Comparison example>
For example, in the sensor device 10 according to the first embodiment, in order to detect a short circuit between the first terminal portion 20 and the second terminal portion 30, an input circuit having another configuration is adopted instead of the first input circuit 40. It is also possible to do.

FIG. 7 is an overall configuration diagram of the sensor device 100 according to the comparative example. The sensor device 100 includes a first terminal unit 200, a second terminal unit 300, a first input circuit 400, a second input circuit 500, and a control unit 600. The first sensor 700 is connected to the first terminal portion 200. A second sensor 800 is connected to the second terminal portion 300. The first terminal portion 200, the second terminal portion 300, the second input circuit 500, the first sensor 700, and the second sensor 800 are the first terminal portion 20 and the second terminal portion 30 of the sensor device 10 according to the embodiment. It has the same configuration as the second input circuit 50, the first sensor 70, and the second sensor 80, respectively. Therefore, the description of the first terminal portion 200, the second terminal portion 300, the second input circuit 500, the first sensor 700, and the second sensor 800 will not be repeated.

The first input circuit 400 includes a power supply 410, a resistor R4, a resistor 440, an ADC 450, and a switch 460.

The power supply 410 supplies a power supply voltage to the signal line L110. The power supply 410 is electrically connected to the signal line L110 via the resistor R4. Specifically, one end of the resistor R4 is electrically connected to the power supply 410, and the other end is electrically connected to the connection point X10 on the signal line L110.

The input portion of the ADC 450 is electrically connected to the connection point X10 between the other end of the resistor R3 and the signal line L31 via the resistor 440. The ADC 450 converts the analog signal from the first sensor 700 input from the first terminal unit 200 into a digital signal and outputs it to the control unit 600.

The switch 460 is a switch for grounding the first terminal portion 200 (first positive electrode terminal 210). When the switch 460 is closed, the first positive electrode terminal 210 is grounded. The switch 460 switches between an open state and a closed state according to a control signal from the control unit 600.

When the control unit 600 detects a short circuit between the first terminal unit 200 and the second terminal unit 300, the control unit 600 controls the switch 460 of the first input circuit 400 to be in the closed state. As a result, the level of the signal input to the control unit 600 via the signal line L120, that is, the output of the first sensor 700 (the signal level of the first terminal unit 200) is fixed to zero.

The control unit 600 monitors the output of the second sensor 800 (the signal level of the second terminal unit 300) with the switch 460 closed and the output of the first sensor 700 fixed to zero. Temporarily between the first terminal portion 200 and the second terminal portion 300 (more specifically, between the first positive electrode terminal 210 of the first terminal portion 200 and the second positive electrode terminal 310 of the second terminal portion 300). When a short circuit occurs, the signal level of the first terminal portion 200 is fixed to zero, so that the signal level of the second terminal portion 300 also becomes zero. On the other hand, when there is no short circuit between the first terminal portion 200 and the second terminal portion 300, even if the signal level of the first terminal portion 200 is fixed to zero, the signal level of the second terminal portion 300 Will not be zero. The control unit 600 monitors the signal level of the second terminal unit 300 in a state where the signal level of the first terminal unit 200 is fixed to zero, thereby between the first terminal unit 200 and the second terminal unit 300. The presence or absence of a short circuit can be detected.

However, in this case, in order to fix the signal level of the first terminal portion 200 to zero, it is required to interrupt the monitoring of the sensors (first sensor 70 and second sensor 80). Therefore, for example, it is required to provide a test mode for determining the presence or absence of a short circuit between terminals, and to interrupt the control using the detection value of the sensor when the test mode is selected. In the sensor device 100 according to the comparative example, unlike the sensor device 10 of the embodiment, it is not possible to determine whether or not a short circuit has occurred between the terminals while continuing the control using the detection value of the sensor.

In addition, even if a short circuit occurs between the terminals, a terminal that may cause a fatal failure if a short circuit occurs so as not to cause a fatal failure in the sensor device and / or an external device. It is also conceivable to design so that they are not adjacent to each other. However, in this case, the arrangement of terminals is restricted.

It is also conceivable to estimate the occurrence of a short circuit based on the output of a sensor that behaves physically similar. As an example of a sensor that behaves physically similar, for example, assuming that a sensor device is mounted on a vehicle, a water temperature sensor that detects the temperature of engine cooling water and an oil that detects the temperature of engine oil. An example is a temperature sensor. It is considered that there is a certain correlation between the output of the water temperature sensor and the output of the oil temperature sensor. As described above, when there is a sensor that behaves physically similar, it is conceivable to estimate the occurrence of a short circuit in the other sensor based on the result of the occurrence of a short circuit in one sensor. However, depending on the type of sensor, there may be no sensor that behaves physically similar. In such a case, the occurrence of a short circuit cannot be estimated based on the results of other sensors.

As described above, by using the first input circuit 40 in the embodiment, it is possible to detect the presence or absence of a short circuit between the terminals without interrupting the control using the detection value of the sensor.

The embodiments disclosed this time should be considered to be exemplary and not restrictive in all respects. The scope of the present disclosure is set forth by the claims rather than the description of the embodiments described above, and is intended to include all modifications within the meaning and scope of the claims.

10, 10A sensor device, 20 1st terminal, 21 1st positive electrode terminal, 22 1st negative electrode terminal, 30 2nd terminal, 31 2nd positive electrode terminal, 32 2nd negative electrode terminal, 40, 40A 1st input circuit, 41 power supply, 42 gain change unit, 43 switch, 44 resistance, 45 ADC, 46 first power supply, 47 gain change unit, 48 second power supply, 49 switch, 50 second input circuit, 51 power supply, 52 pull-up resistance, 53 Resistance, 54 ADC, 60 Control unit, 61 Execution start unit, 62 Switch switching unit, 63 1st acquisition unit, 64 2nd acquisition unit, 65 Judgment unit, 66 Output unit, 70 1st sensor, 80 2nd sensor, 100 Sensor device, 200 1st terminal, 210 1st positive terminal, 300 2nd terminal, 310 2nd positive terminal, 400 1st input circuit, 410 power supply, 440 resistance, 450 ADC, 460 switch, 500 2nd input circuit , 600 Control unit, 700 1st sensor, 800 2nd sensor, L11, L12, L21, L22, L31, L110, L120 signal line, R1, R2, R3, R4 resistance.

Claims (1)

A short-circuit detection device that detects a short circuit between the first terminal and the second terminal.
A control device that receives signals from the first terminal and the second terminal,
It is provided with a changing means for changing the voltage gain of the first terminal.
The control device controls the changing means,
The control device is a short-circuit detection device that detects a short circuit between the first terminal and the second terminal based on a change in the signal level of the second terminal when the voltage gain of the first terminal is changed. ..

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