Sensor device for vehicles

Abstract

To provide a sensor device for vehicles that does not require a control unit to store a threshold related to determination of the luminous energy of external light.SOLUTION: A sensor device 10 for vehicles comprises: a phototransistor 30 for outputting a detection current Id corresponding to the luminous energy of external light from an output terminal 30o; a limiting resistor R1 connected to the output terminal 30o; a detection circuit 21 for outputting a Hi or a Lo signal depending on whether or not the detection current Id greater than or equal to a threshold; and a control unit 20 having a general-purpose input port P1 for inputting the Hi or Lo signal and determining whether or not the detection current Id is greater than or equal to the threshold depending on whether the inputted signal is a Hi or a Lo signal. The detection circuit 21 includes a base resistor R3 connected to the limiting resistor R1 and having a resistance value corresponding to a threshold, a pullup resistor R7, and a transistor 21T having a base terminal to which the base resistor R3 is connected, a collector terminal connected between the pullup resistor R7 and the general-purpose input port P1, and an emitter terminal connected to ground.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a sensor device for a vehicle. [Background technology]

[0002] The vehicle display device described in Patent Document 1 includes an illuminance detection means for changing an output current based on the illuminance of external light, a conversion circuit for converting the change in current value detected by the illuminance detection means into a plurality of voltage values ​​for output, and a control means having first and second input ports for inputting the voltage values ​​from the conversion circuit and adjusting the output brightness of a backlight that illuminates the display means in accordance with the voltage values. The control means sets a predetermined switching threshold for the first input port or the second input port, between a lower limit (0V) and an upper limit (5V), and calculates the illuminance based on the voltage value input to the other input port when one of the input ports exceeds the switching threshold (see paragraph 0027 of Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-6462 Summary of the Invention [Problem to be solved by the invention]

[0004] In the configuration of Patent Document 1, the storage capacity is occupied by the thresholds stored in advance in the control means. The present disclosure has been made in consideration of the above-described circumstances, and aims to provide a sensor device for a vehicle that does not require a control unit to store a threshold value for determining the amount of external light. [Means for solving the problem]

[0005] In order to achieve the above object, a vehicle sensor device according to the present disclosure includes: a phototransistor that outputs a detection current from an output terminal according to the amount of external light; a limiting resistor connected to the output terminal; a light amount detection circuit that outputs a Hi signal or a Lo signal depending on whether the detected current is equal to or greater than a first threshold; a control unit having a first general-purpose input port to which the Hi signal or the Lo signal from the light amount detection circuit is input, and determining whether the detection current is equal to or greater than the first threshold value depending on whether the signal input to the first general-purpose input port is the Hi signal or the Lo signal; The light amount detection circuit a first base resistor connected to the limiting resistor and having a resistance value according to the first threshold; a first pull-up resistor; a first switch element having a base terminal to which the first base resistor is connected, a collector terminal connected between the first pull-up resistor and the first general-purpose input port, and an emitter terminal connected to ground. [Effects of the Invention]

[0006] According to the present disclosure, there is no need to store a threshold value for determining the amount of external light in the control unit. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a block diagram of a lighting system according to an embodiment of the present disclosure. [Figure 2] 10 is a timing chart showing the detected current (Id), the input signal of each port (P1 to P4), and the lighting luminance state according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0008] A lighting system having a vehicle sensor device according to an embodiment of the present disclosure will be described with reference to the drawings. The lighting system is mounted on a vehicle, for example, a saddle-type vehicle such as a motorcycle, and turns on a lighting fixture at a brightness corresponding to the illuminance of external light.

[0009] As shown in FIG. 1, the lighting system 1 includes a vehicle sensor device 10, a backlight device 50, and a backlight driving unit 55.

[0010] The vehicle sensor device 10 includes a control unit 20, a phototransistor 30, detection circuits 21 to 24, a gain adjustment circuit 25 including a gain adjustment resistor R2, and a limiting resistor R1.

[0011] The backlight device 50 is a lighting device that illuminates a liquid crystal display panel (not shown). The backlight driving unit 55 is a driver with a PWM dimming function that drives the backlight device 50 to light up based on a PWM (Pulse Width Modulation) signal from the control unit 20. The backlight device 50 includes a plurality of light-emitting diodes (LEDs) that serve as light sources. The backlight device 50 lights up at a brightness that corresponds to the duty ratio of the PWM signal.

[0012] The phototransistor 30, which is an illuminance detection sensor, has an input terminal to which a constant voltage (5V) is applied from a power supply V, and an output terminal 30o that outputs a detection current Id of an amount corresponding to the amount of incident external light. The phototransistor 30 is mounted on the back side of the meter dial (not shown), which is made of a printed, translucent colored diffusion plate. The mounting position of the phototransistor 30 is not limited to this example, and may be any position.

[0013] The limiting resistor R1 is connected to adjust the gain (sensitivity) of the phototransistor 30 and the amount of current flowing through it. One end of the limiting resistor R1 is connected to the output terminal 30o of the phototransistor 30. The other end of the limiting resistor R1 is connected to each of the detection circuits 21 to 24. The resistance value of the limiting resistor R1 is determined appropriately according to the amount of current and the gain. This resistance value is set to, for example, 5 to 15 Ω, e.g., 10 Ω.

[0014] Each of the detection circuits 21-24 outputs either a Hi signal or a Lo signal to the corresponding general-purpose port P1-P4 depending on whether the detection current Id of the phototransistor 30 is equal to or greater than one of the different thresholds Th1-Th4. In this example, a Hi signal is output when the detection current Id is less than one of the thresholds Th1-Th4, and a Lo signal is output when the detection current Id is equal to or greater than one of the thresholds Th1-Th4. Each of the detection circuits 21-24 is an external circuit of the control unit 20.

[0015] As shown in FIG. 2, the magnitude relationship between the thresholds Th1 to Th4 is set as "Th3>Th1>Th2>Th4". The threshold value Th3 is set between the lower limit of a large current that can occur in the event of a short circuit and the upper limit of the detection current Id of the phototransistor 30 at the illuminance of outside light in the daytime (the upper limit of the high light intensity range L3). The threshold value Th1 is set between the lower limit value of the detection current Id of the phototransistor 30 at the illuminance of external light in the daytime (the lower limit value of the high light range L3) and the upper limit value of the detection current Id of the phototransistor 30 at the illuminance of external light in the evening (the upper limit value of the medium light range L2). The threshold value Th2 is set between the lower limit value of the detection current Id of the phototransistor 30 at the illuminance of external light in the evening (the lower limit value of the medium light range L2) and the upper limit value of the detection current Id of the phototransistor 30 at the illuminance of external light at night (the upper limit value of the low light range L1). The threshold value Th4 is set between the lower limit of the detected current Id of the phototransistor 30 at nighttime external light illuminance (the upper limit of the low light level range L1) and the upper limit of the small current that can occur in the event of an open circuit failure.

[0016] The detection circuit 24 is configured to output a Hi signal to the general-purpose port P4 when the detected current Id is less than a threshold value Th4, and to output a Lo signal to the general-purpose port P4 when the detected current Id is equal to or greater than the threshold value Th4.

[0017] The detection circuit 24 includes a transistor 24T and a pull-up resistor R10. The base terminal of the transistor 24T is connected to a limiting resistor R1. The base terminal of the transistor 24T is connected to either no base resistor or a base resistor with a resistance of zero (0 Ω). The emitter terminal of the transistor 24T is connected to ground. The pull-up resistor R10 is connected between a power supply V and the collector terminal of the transistor 24T. The general-purpose port P4 is connected between the collector terminal of the transistor 24T and the pull-up resistor R10. The pull-up resistor R10 is provided to apply a Hi signal to the general-purpose port P4 based on a constant voltage from the power supply V when the transistor 24T is off.

[0018] When a detection current Id less than a threshold value Th4 is supplied to the base terminal of the transistor 24T, the transistor 24T is off. When the transistor 24T is off, the general-purpose port P4 is in a high potential state based on the constant voltage from the power supply V, and a Hi signal is output to the general-purpose port P4. When a detection current Id greater than or equal to the threshold value Th4 is supplied to the base terminal of the transistor 24T, the transistor 24T is turned on, and current from the power supply V flows to ground via the pull-up resistor R10 and the transistor 24T, so that the general-purpose port P4 is in a low potential state and a Lo signal is output to the general-purpose port P4.

[0019] The detection circuit 23 is configured to output a Hi signal to the general-purpose port P3 when the detected current Id is less than a threshold value Th3, and to output a Lo signal to the general-purpose port P3 when the detected current Id is equal to or greater than the threshold value Th3.

[0020] The detection circuit 23 includes a transistor 23T, a base resistor R5, and a pull-up resistor R9. The detection circuit 23 will be described below, focusing on the differences from the above-mentioned detection circuit 24. The general-purpose port P3 is connected between the collector terminal of the transistor 23T and the pull-up resistor R9. The base resistor R5 is connected between the base terminal of the transistor 23T and the limiting resistor R1. The resistance value of the base resistor R5 is set to a value corresponding to the threshold value Th3 at which the transistor 23T switches between on and off. The resistance value of the base resistor R5 is set to 0.5 to 1.5 MΩ, for example, 1 MΩ.

[0021] The detection circuit 22 is configured to output a Hi signal to the general-purpose port P2 when the detected current Id is less than the threshold value Th2, and to output a Lo signal to the general-purpose port P2 when the detected current Id is equal to or greater than the threshold value Th2.

[0022] The detection circuit 22 includes a transistor 22T, a base resistor R4, and a pull-up resistor R8. The detection circuit 22 will be described below, focusing on the differences from the above-mentioned detection circuit 23. The general-purpose port P2 is connected between the collector terminal of the transistor 22T and the pull-up resistor R8. The base resistor R4 is connected between the base terminal of the transistor 22T and the limiting resistor R1. The resistance value of the base resistor R4 is set to a value corresponding to the threshold value Th2 at which the transistor 22T switches between on and off. The resistance value of the base resistor R4 is set to 0.5 to 1.5 KΩ, for example, 1 KΩ.

[0023] The detection circuit 21 is configured to output a Hi signal to the general-purpose port P1 when the detected current Id is less than the threshold value Th1, and to output a Lo signal to the general-purpose port P1 when the detected current Id is equal to or greater than the threshold value Th1.

[0024] The detection circuit 21 includes a transistor 21T, a base resistor R3, and a pull-up resistor R7. The detection circuit 21 will be described below, focusing on the differences from the above-mentioned detection circuit 23. The general-purpose port P1 is connected between the collector terminal of the transistor 21T and the pull-up resistor R7. The base resistor R3 is connected between the base terminal of the transistor 21T and the limiting resistor R1. The resistance value of the base resistor R3 is set to a value corresponding to the threshold value Th1 at which the transistor 21T switches between on and off. The resistance value of the base resistor R3 is set to 50 to 150 kΩ, for example, 100 kΩ. The magnitude relationship between the resistance values ​​of the base resistors R3 to R5 is set to "resistance value of R5>resistance value of R3>resistance value of R4". The base terminal of the transistor 24T may also be provided with a base resistor having a resistance value smaller than that of the base resistors R3 to R5. By changing the resistance constants of the base resistors R3 to R5 of the detection circuits 21 to 24, the threshold values ​​Th1 to Th4 can be set to any values ​​without setting them in the control unit 20.

[0025] The gain adjustment circuit 25 is a circuit that adjusts the gain of the detection current Id of the phototransistor 30. The gain adjustment circuit 25 includes a gain adjustment resistor R2, a transistor 25T, and a base resistor R6. The base terminal of the transistor 25T is connected to a port P5 via the base resistor R6. The collector terminal of the transistor 25T is connected to the gain adjustment resistor R2. The gain adjustment resistor R2 is connected in parallel to the limiting resistor R1. The emitter terminal of the transistor 25T is connected to ground.

[0026] The transistor 25T is switched between on and off by a control signal S5 from a port P5. When the transistor 25T is off, no current flows through the gain adjustment resistor R2, and the gain adjustment resistor R2 is in an inactive state. When the transistor 25T is on, a current flows through the gain adjustment resistor R2, placing the gain adjustment resistor R2 in an active state. In this active state, a portion of the detection current Id from the phototransistor 30 flows to ground via the gain adjustment resistor R2 and the transistor 25T. This weakens the amount of detection current Id flowing through each of the detection circuits 21-24, raising the thresholds Th1-Th4 at which the transistors 21T-24T of each of the detection circuits 21-24 are turned on. Whether the gain adjustment resistor R2 is in an active or inactive state is determined during the inspection process to suppress variations in the sensor sensitivity of the phototransistor 30. These variations in sensor sensitivity are caused by unevenness in the printing of the dial, which is a translucent colored diffusion plate, and individual differences between phototransistors.

[0027] Next, the operation of the vehicle sensor device 10 in each state will be described. When an open circuit fault occurs, the detection current Id of the phototransistor 30 becomes less than the threshold value Th4, the detection circuits 21 to 24 (transistors 21T to 24T) turn off, and the general-purpose input ports P1 to P4 receive a Hi signal (time T1 in Figure 2).

[0028] At night, the detection current Id of the phototransistor 30 is within the low light range L1, the detection circuit 24 (transistor 24T) is turned on, the other detection circuits 21 to 23 (transistors 21T to 23T) are turned off, the general-purpose input ports P1 to P3 receive a Hi signal, and the general-purpose input port P4 receives a Lo signal (time T2 in Figure 2).

[0029] In the evening, the detection current Id of the phototransistor 30 falls within the medium light range L2, the detection circuits 22 and 24 (transistors 22T and 24T) turn on, the detection circuits 21 and 23 (transistors 21T and 23T) turn off, the general-purpose input ports P1 and P3 input a Hi signal, and the general-purpose input ports P2 and P4 input a Lo signal (time T3 in Figure 2).

[0030] During the daytime, the detection current Id of the phototransistor 30 is within the high light range L3, the detection circuits 21, 22, 24 (transistors 21T, 22T, 24T) are turned on, the detection circuit 23 (transistor 23T) is turned off, the general-purpose input port P3 receives a Hi signal, and the general-purpose input ports P1, P2, P4 receive a Lo signal (time T4 in Figure 2).

[0031] When a short circuit fault occurs, the detection current Id of the phototransistor 30 becomes an overcurrent equal to or greater than the threshold value Th3, the detection circuits 21 to 24 (transistors 21T to 24T) turn on, and the general-purpose input ports P1 to P4 receive a Lo signal (time T5 in Figure 2).

[0032] The control unit 20 is made up of a microcomputer, and controls the lighting and brightness of the backlight device 50 via the backlight driving unit 55. The control unit 20 also displays vehicle information such as vehicle speed on a liquid crystal display panel (not shown).

[0033] The control unit 20 has general-purpose input ports P1 to P4 and output ports P5 and Pa. The general-purpose input ports P1 to P4 realize the function of the control unit 20 to recognize a logic "Hi" if the applied voltage is equal to or greater than a threshold voltage, and to recognize a logic "Lo" if the applied voltage is less than the threshold voltage. The control unit 20 inputs Hi or Lo signals from the detection circuits 21 to 24 via general-purpose input ports P1 to P4, and determines whether the amount of external light falls within ranges L1 to L3 and whether there is an open circuit fault or a short circuit fault, based on the combination of Hi or Lo signals input at the general-purpose input ports P1 to P4.

[0034] When the control unit 20 receives a Hi signal at all of the general-purpose input ports P1 to P4 (see time T1 in FIG. 2), it determines that an open circuit fault has occurred and performs a predetermined safety operation. An example of this predetermined safety operation is turning off the backlight device 50. However, this predetermined safety operation is not limited to this, and may also be turning on the backlight device 50 at a medium brightness, or notifying the driver of the open circuit fault via a notification means.

[0035] When the control unit 20 receives a Hi signal at the general-purpose input ports P1 to P3 and a Lo signal at the general-purpose input port P4 (see time T2 in Figure 2), it determines that the detected current Id is in the low light intensity range L1 and turns on the backlight device 50 at low brightness.

[0036] When the control unit 20 receives a Hi signal at the general-purpose input ports P1 and P3 and a Lo signal at the general-purpose input ports P2 and P4 (see time T3 in Figure 2), it determines that the detected current Id is in the medium light intensity range L2 and turns on the backlight device 50 at medium brightness.

[0037] When the control unit 20 receives a Hi signal at the general-purpose input port P3 and a Lo signal at the general-purpose input ports P1, P2, and P4 (see time T4 in Figure 2), it determines that the detected current Id is in the high light intensity range L3 and turns on the backlight device 50 at high brightness.

[0038] When the control unit 20 receives Lo signals at all of the general-purpose input ports P1 to P4 (see time T5 in FIG. 2), it determines that a short circuit fault has occurred in the circuit and performs the predetermined safety operation described above.

[0039] (effect) According to the embodiment described above, the following effects are achieved. (1) The vehicle sensor device 10 includes a phototransistor 30 that outputs a detection current Id from an output terminal 30o that corresponds to the amount of external light, a limiting resistor R1 connected to the output terminal 30o, detection circuits 21 and 22 that are an example of a light amount detection circuit that outputs a Hi signal or a Lo signal depending on whether the detection current Id is equal to or greater than thresholds Th1 and Th2 that are an example of a first threshold, and a control unit 20 that has general-purpose input ports P1 and P2 that are an example of a first general-purpose input port that inputs the Hi signal or Lo signal from the detection circuits 21 and 22, and determines whether the detection current Id is equal to or greater than thresholds Th1 and Th2 that are an example of a first threshold depending on whether the signal input to the general-purpose input ports P1 and P2 is a Hi signal or a Lo signal. The detection circuits 21, 22 include base resistors R3, R4, which are examples of first base resistors connected to the limiting resistor R1 and have resistance values ​​corresponding to the thresholds Th1, Th2, pull-up resistors R7, R8, which are examples of first pull-up resistors, and transistors 21T, 22T, which are examples of first switch elements, having base terminals to which the base resistors R3, R4 are connected, collector terminals connected between the pull-up resistors R7, R8 and the general-purpose input ports P1, P2, and emitter terminals connected to ground. According to this configuration, the thresholds Th1 and Th2 are determined by the resistance values ​​of the base resistors R3 and R4 without any setting by the control unit 20, so there is no need to store thresholds for determining the amount of light in the control unit 20. Therefore, pressure on the storage capacity of the control unit 20 is suppressed. The detection current Id of the phototransistor 30 can be input to the general-purpose input ports P1 and P2, which makes it possible to prevent a shortage of AD ports. In a conventional configuration where the detection current of a phototransistor is acquired at an AD port, the voltage drop at the phototransistor is large, making it impossible to fully utilize the AD conversion resolution. Specifically, if the supply voltage is 5V and the phototransistor drops by about 0.5V, a 10-bit AD converter can only use a resolution of 926 out of a resolution of 1024. In this regard, with the above configuration, the resistance values ​​of the base resistors of the detection circuits 21 and 22 are adjusted to anticipate the voltage drop at the phototransistor 30, eliminating the need to consider the voltage drop.

[0040] (2) The plurality of detection circuits 21, 22 include base resistors R3, R4 having different resistance values ​​so as to have different threshold values ​​Th1, Th2. According to this configuration, it is possible to determine which of the ranges L1 to L3 the detected current Id of the phototransistor 30 is in without using an AD port.

[0041] (3) The vehicle sensor device 10 further includes a detection circuit 23, an example of a short-circuit detection circuit, that outputs a Hi signal or a Lo signal depending on whether the detection current Id is equal to or greater than a threshold value Th3, an example of a second threshold value that is greater than the threshold values ​​Th1 and Th2. The control unit 20 has a general-purpose input port P3, an example of a second general-purpose input port, that inputs the Hi signal or the Lo signal from the detection circuit 23, and determines whether a short-circuit fault exists based on whether the Hi signal or the Lo signal input to the general-purpose input port P3 is a Hi signal or a Lo signal. The detection circuit 23 includes a base resistor R5, an example of a second base resistor, connected to the limiting resistor R1 and having a resistance greater than the resistances of the base resistors R3 and R4 of the detection circuits 21 and 22, a pull-up resistor R9, an example of a second pull-up resistor, and a transistor 23T, an example of a second switch element, having a base terminal connected to the base resistor R5, a collector terminal connected between the pull-up resistor R9 and the general-purpose input port P3, and an emitter terminal connected to ground. According to this configuration, the control unit 20 can determine whether a short circuit has occurred without storing a threshold value for determining the amount of light in the control unit 20.

[0042] (4) The vehicle sensor device 10 further includes a detection circuit 24, which is an example of an open circuit detection circuit, that outputs a Hi signal or a Lo signal depending on whether the detected current Id is equal to or greater than a threshold value Th4, which is an example of a third threshold value that is smaller than the threshold values ​​Th1 and Th2. The control unit 20 has a general-purpose input port P4, which is an example of a third general-purpose input port, that inputs the Hi signal or the Lo signal from the detection circuit 24, and determines whether an open fault exists depending on whether the signal input to the general-purpose input port P4 is a Hi signal or a Lo signal. The detection circuit 24 includes a pull-up resistor R10, which is an example of a third pull-up resistor, and the detection circuit 24, which is an example of a third switch element, having a base terminal connected to the limiting resistor R1, a collector terminal connected between the pull-up resistor R10 and the general-purpose input port P4, and an emitter terminal connected to ground. According to this configuration, the control unit 20 can determine an open circuit failure without storing a threshold value for determining the amount of light in the control unit 20.

[0043] (5) The vehicle sensor device 10 further includes a gain adjustment circuit 25 that can adjust the detection current Id that flows through the limiting resistor R1. According to this configuration, it is possible to apply an offset to the threshold values ​​Th1 to Th4.

[0044] (6) The gain adjustment circuit 25 includes a gain adjustment resistor R2 connected in parallel with the limiting resistor R1 at the output terminal 30o, and a transistor 25T, which is an example of a gain adjustment transistor, connected between the gain adjustment resistor R2 and ground. The control unit 20 controls the transistor 25T to be switched on and off. According to this configuration, it is possible to simply apply an offset to the threshold values ​​Th1 to Th4.

[0045] (Variation) The present disclosure is not limited to the above-described embodiments and drawings. Modifications (including deletion of components) may be made as appropriate within the scope of the present disclosure. An example of such a modification is described below.

[0046] In the above embodiment, the control unit 20 controls the backlight device 50 as the control target, but the control target is not limited to this and may also be a headlight device or a wiper driving device. If the control target is a headlight device, the control unit 20 may turn on the headlight device when the detected current Id of the phototransistor 30 is within the low light level range L1 or the medium light level range L2, and may turn off the headlight device when the detected current Id is within the high light level range L3.

[0047] Either one of the two detection circuits 21 and 22 in the above embodiment may be omitted. Also, either one or both of the two detection circuits 23 and 24 may be omitted. In the above embodiment, the gain adjustment circuit 25 may be omitted.

[0048] In the above embodiment, the detection circuits 21-24 are configured to output a Lo signal to the general-purpose input ports P1-P5 when the detection current Id is equal to or greater than the thresholds Th1-Th4, and to output a Hi signal to the general-purpose input ports P1-P5 when the detection current Id is less than the thresholds Th1-Th4. However, the detection circuits 21-24 may be configured to output a Hi signal to the general-purpose input ports P1-P5 when the detection current Id is equal to or greater than the thresholds Th1-Th4, and to output a Lo signal to the general-purpose input ports P1-P5 when the detection current Id is less than the thresholds Th1-Th4. In this case, the specific configuration of the detection circuits 21-24 can be modified as appropriate, and the detection circuits 21-24 may be configured so that a Hi signal is input to the general-purpose input ports P1-P4 when the transistors 21T-24T are turned on, and a Lo signal is input to the general-purpose input ports P1-P4 when the transistors 21T-24T are turned off. This modification discloses, for example, the technical idea described in the following Supplementary Note 1. Note that Supplementary Note 1 is not to be construed as limiting the present invention in any way. (Appendix 1) a phototransistor that outputs a detection current from an output terminal according to the amount of external light; a limiting resistor connected to the output terminal; a light amount detection circuit that outputs a Hi signal or a Lo signal depending on whether the detected current is equal to or greater than a first threshold; a control unit having a first general-purpose input port to which the Hi signal or the Lo signal from the light amount detection circuit is input, and determining whether the detection current is equal to or greater than the first threshold value depending on whether the signal input to the first general-purpose input port is the Hi signal or the Lo signal; The light amount detection circuit a first base resistor connected to the limiting resistor and having a resistance value according to the first threshold; a base terminal to which the first base resistor is connected; a first switch element that switches between on and off depending on the value of a current supplied to the base terminal, thereby switching a signal to be output to the first general-purpose input port between the Hi signal and the Lo signal; Vehicle sensor device. [Explanation of symbols]

[0049] 1...Lighting system 10...Sensor device for vehicle 20...Control unit 21 to 24: Detection circuit, 21T to 25T: Transistor 25...Gain adjustment circuit 30...Phototransistor, 30o...Output terminal 50...backlight device, 55...backlight driving section L1: Low light range, L2: Medium light range, L3: High light range R1: Limiting resistor R2: Gain adjustment resistor R3~R6: Base resistors R7~R10: Pull-up resistors P1 to P4: General-purpose input ports P5,Pa...Output port V…Power supply S5…Control signal Id: Detection current Th1~Th4...Threshold

Claims

1. a phototransistor that outputs a detection current from an output terminal according to the amount of external light; a limiting resistor connected to the output terminal; a light amount detection circuit that outputs a Hi signal or a Lo signal depending on whether the detected current is equal to or greater than a first threshold; a control unit having a first general-purpose input port to which the Hi signal or the Lo signal from the light amount detection circuit is input, and determining whether the detection current is equal to or greater than the first threshold value depending on whether the signal input to the first general-purpose input port is the Hi signal or the Lo signal, The light amount detection circuit a first base resistor connected to the limiting resistor and having a resistance value according to the first threshold; a first pull-up resistor; a first switch element having a base terminal to which the first base resistor is connected, a collector terminal connected between the first pull-up resistor and the first general-purpose input port, and an emitter terminal connected to ground; Vehicle sensor device.

2. the plurality of light amount detection circuits each include the first base resistor having a different resistance value so as to have a different first threshold value; The sensor device for a vehicle according to claim 1 .

3. a short-circuit detection circuit that outputs a Hi signal or a Lo signal depending on whether the detected current is equal to or greater than a second threshold value that is greater than the first threshold value; the control unit has a second general-purpose input port to which the Hi signal or the Lo signal from the short circuit detection circuit is input, and determines whether a short circuit fault exists based on whether the signal input to the second general-purpose input port is the Hi signal or the Lo signal; The short circuit detection circuit a second base resistor connected to the limiting resistor and having a resistance value greater than a resistance value of the first base resistor of the light amount detection circuit; A second pull-up resistor; a second switch element having a base terminal to which the second base resistor is connected, a collector terminal connected between the second pull-up resistor and the second general-purpose input port, and an emitter terminal connected to ground; The sensor device for a vehicle according to claim 1 .

4. an open circuit detection circuit that outputs a Hi signal or a Lo signal depending on whether the detected current is equal to or greater than a third threshold value that is smaller than the first threshold value; the control unit has a third general-purpose input port to which the Hi signal or the Lo signal from the open detection circuit is input, and determines whether an open fault exists based on whether the signal input to the third general-purpose input port is the Hi signal or the Lo signal; The open detection circuit a third pull-up resistor; a third switch element having a base terminal connected to the limiting resistor, a collector terminal connected between the third pull-up resistor and the third general-purpose input port, and an emitter terminal connected to ground; The sensor device for a vehicle according to claim 1 .

5. further comprising a gain adjustment circuit capable of adjusting the detection current flowing through the limiting resistor; The sensor device for a vehicle according to claim 1 .

6. the gain adjustment circuit includes a gain adjustment resistor connected to the output terminal in parallel with the limiting resistor, and a gain adjustment transistor connected between the gain adjustment resistor and ground, the control unit controls the gain adjustment transistor to switch between on and off. The sensor device for a vehicle according to claim 5 .

Images