Light source control device

Abstract

A light source control device is provided that can reduce costs even if it has a structure with a temperature-sensitive resistor and a momentary switch. The light source control device (1) is configured to include a control unit (110), an LED power supply circuit (10), a PWM control circuit (11), a detection circuit (12), an LED (211), a momentary switch (213), and a temperature-sensitive resistor (214). In the control unit (110), one terminal is used to detect the operation detection of the momentary switch (213) and the temperature detection based on the temperature-sensitive resistor (214). When the momentary switch (213) is operated, the control unit (110) controls the lighting and extinguishing of the LED (211), and then the PWM control circuit (11) controls the brightness of the LED (211) according to the temperature detection result.

Description

Technical Field

[0001] The invention relates to a light source control device. Background Art

[0002] In vehicle lamps, the use of LEDs as light sources is becoming more and more common. However, due to the heat generated by the LED, the LED itself or components mounted around the LED may deteriorate. For this reason, as in the prior art literature, the following device is proposed: a temperature-sensitive resistor is provided to detect the temperature near the LED, and the supply current to the LED is reduced based on the detected temperature, thereby suppressing the heat generation of the LED.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2018-134981 Summary of the invention

[0006] (Problems to be solved by the invention)

[0007] However, in the interior lighting for lighting the interior of the vehicle, as in the case of vehicle lamps, the use of LED as a light source is becoming popular, and in order to make the interior brighter, the improvement of the brightness of the LED is sought. If the brightness of the LED is increased, the heat generated by the LED increases, so as in the case of vehicle lamps, a temperature-sensitive resistor for detecting the temperature near the LED needs to be provided. In addition, it is configured as follows: a control unit is provided in the interior lighting device arranged in front of the ceiling portion, and the interior lighting device in the center of the ceiling portion separated from the front of the ceiling portion is controlled by the control unit in front of the ceiling portion. In this case, the control unit and the LED of the interior lighting device in the center of the ceiling portion are provided on different substrates. Furthermore, the interior lighting device in the center of the ceiling portion is configured as follows: a momentary switch is provided on the substrate on which the LED and the temperature-sensitive resistor are installed, and the LED is turned on and off according to its operation. Therefore, not only the number of connector connections increases, but also a wiring harness is required for connecting the substrate on which the control unit in front of the ceiling portion is provided and the substrate on which the LED of the interior lighting device in the center of the ceiling portion is installed, thereby increasing the cost.

[0008] Therefore, the present invention takes the above-mentioned facts into consideration and provides a light source control device that can reduce costs even if it has a structure including a temperature-sensitive resistor and a momentary switch.

[0009] (Technical solutions to solve problems)

[0010] The light source control device involved in the first embodiment of the present invention comprises: a light source; a momentary switch, one end of which is connected to a power supply via a pull-up resistor and the other end is connected to the ground, the momentary switch conducts the one end and the other end when it is operated, and disconnects the one end and the other end when it is not operated; and a control unit, which has an input terminal connected to one end of the momentary switch and inputs a switch signal corresponding to the operation state of the momentary switch, when it is detected from the switch signal that the momentary switch is operated, the power supply to the light source is controlled to switch the light source to a lighting state or an extinguishing state, the light source control device also comprises a temperature-sensitive resistor, one end of the temperature-sensitive resistor is connected to one end of the momentary switch, the other end of the temperature-sensitive resistor is connected to the ground, and the resistance value of the temperature-sensitive resistor changes with temperature, the switch signal of the momentary switch or the voltage-divided signal after the power supply is divided by the pull-up resistor and the temperature-sensitive resistor is input to the input terminal of the control unit, and the control unit controls the brightness of the light source according to the voltage-divided signal.

[0011] The light source control device involved in the first embodiment includes a light source, a momentary switch, a control unit, and a temperature-sensitive resistor. The operation of the momentary switch is detected at the input terminal of the control unit, and when the momentary switch is not operated, the voltage-divided signal after the power supply is divided by the pull-up resistor and the temperature-sensitive resistor is detected. The control unit controls the lighting and extinguishing of the light source when the momentary switch is operated based on the detection result of the input terminal, and further controls the brightness of the light source based on the voltage-divided signal. Therefore, according to this structure, one input terminal of the control unit can be used to operate the momentary switch and detect the temperature near the light source, thereby reducing the cost of the light source control device.

[0012] The light source control device involved in the second embodiment of the present invention comprises: a light source; a momentary switch, one end of which is connected to a power source via a pull-up resistor and the other end is connected to ground, the momentary switch conducts between the one end and the other end when it is operated, and disconnects between the one end and the other end when it is not operated; and a control unit, which has an input terminal connected to one end of the momentary switch and inputs a switch signal corresponding to the operation state of the momentary switch, and when it is detected from the switch signal that the momentary switch is operated, controls the power supply to the light source to switch the light source to a lighting state or an extinguishing state, and the light source The control device also includes a temperature-sensitive resistor, one end of which is connected to one end of the momentary switch, and the other end of the temperature-sensitive resistor is connected to the ground, and the resistance value of the temperature-sensitive resistor changes with temperature. The light source control device is composed of a first substrate and a second substrate that are separated and arranged at different positions from each other. A control unit is provided on the first substrate, and a light source, a momentary switch and a temperature-sensitive resistor are provided on the second substrate. The switching signal of the momentary switch or the voltage-divided signal after the power supply is divided by the pull-up resistor and the temperature-sensitive resistor is input to the input terminal of the control unit, and the control unit controls the brightness of the light source according to the voltage-divided signal.

[0013] The light source control device involved in the second embodiment includes a light source, a momentary switch, a control unit, a temperature-sensitive resistor, a first substrate and a second substrate. The first substrate and the second substrate are configured to be separated from each other, the control unit is provided on the first substrate, and the light source, the momentary switch and the temperature-sensitive resistor are provided on the second substrate. The operation of the momentary switch is detected at the input terminal of the control unit, and when the momentary switch is not operated, the voltage-divided signal after the power supply is divided by the pull-up resistor and the temperature-sensitive resistor is detected. According to the detection result of the input terminal, the control unit controls the lighting and extinguishing of the light source when the momentary switch is operated, and further controls the brightness of the light source according to the voltage-divided signal. Therefore, according to this structure, one input terminal of the control unit can be used to operate the momentary switch and detect the temperature near the light source, so the number of wiring harnesses can be reduced, and the cost of the light source control device can be reduced.

[0014] The light source control device involved in the third embodiment is based on the light source control device involved in the first embodiment or the second embodiment. The light source control device has a switching unit, which is arranged between the other end of the temperature-sensitive resistor and the ground, and switches the temperature-sensitive resistor between a state where current flows and a state where no current flows.

[0015] The light source control device involved in the third embodiment is based on the light source control device involved in the first embodiment or the second embodiment, and further includes a switch unit. By providing a switch unit for switching the current flowing in the temperature sensing resistor, when temperature detection based on the temperature sensing resistor is not required, the switch unit is controlled so that no current flows in the temperature sensing resistor. Therefore, according to this structure, it is possible to prevent an increase in power consumption.

[0016] A light source control device according to a fourth embodiment is the light source control device according to the third embodiment, and further includes a power supply unit that supplies power to the switch unit in conjunction with power supply to the light source.

[0017] The light source control device involved in the fourth embodiment is based on the light source control device involved in the third embodiment, and further includes a power supply unit that is linked to the power supply to the light source. Power is supplied from the power supply unit to the switch unit to control the switch unit. Since a power supply unit that supplies power to the switch unit in linkage with the power supply state to the light source is provided, when the light source is in an off state and there is no need for a current for temperature detection to flow through the temperature sensing resistor, the switch unit is linked to the power supply state to the light source and switches the temperature sensing resistor to a state where no current flows. Therefore, according to this structure, there is no need to provide a control terminal for controlling the switch unit in the control unit, and an increase in power consumption can be prevented without increasing costs.

[0018] (Effects of the Invention)

[0019] According to the embodiment of the present invention, it is possible to provide a light source control device that can reduce costs even if the device has a configuration including a temperature-sensitive resistor and a momentary switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a diagram showing the configuration of a light source control device 1 according to the first embodiment of the present invention.

[0021] Figure 2 It is a circuit configuration diagram of a light source control device 1 according to the first embodiment of the present invention.

[0022] Figure 3 1 is a diagram showing the relationship between the momentary switch operation and the input voltage to the control unit of the light source control device 1 according to the first embodiment of the present invention.

[0023] Figure 4 This is a graph showing the relationship between the temperature and the input voltage to the control unit of the light source control device 1 according to the first embodiment of the present invention.

[0024] Figure 5 4 is a graph showing the relationship between the temperature and the PWM duty ratio of the light source control device 1 according to the first embodiment of the present invention. DETAILED DESCRIPTION

[0025] [First embodiment]

[0026] use Figure 1 as well as Figure 2 A light source control device 1 according to a first embodiment of the present invention will be described.

[0027] (Configuration of Light Source Control Device 1)

[0028] Figure 1 1 is a diagram showing the structure of the light source control device 1 of the present embodiment mounted on a vehicle V. The vehicle V equipped with the light source control device 1 is, for example, a four-wheeled vehicle, including a vehicle powered by an internal combustion engine such as a diesel engine or a gasoline engine, an electric vehicle powered by an electric motor, a hybrid vehicle having both an internal combustion engine and an electric motor, and the like.

[0029] The light source control device 1 is configured using a control unit substrate 100 and an LED substrate 200 , and the control unit substrate 100 and the LED substrate 200 are connected to each other via a harness 150 .

[0030] The control unit substrate 100 is arranged in front of the ceiling portion of the vehicle V, and the LED substrate 200 is arranged in the center of the ceiling portion of the vehicle V. A control unit for controlling the interior lighting of the vehicle is embedded in the control unit substrate 100, and LEDs and operation switches for lighting the interior of the vehicle at night are embedded in the LED substrate 200.

[0031] In addition, the control unit substrate 100 may also be provided with a circuit configuration for lighting the interior of the vehicle, similarly to the LED substrate 200. In the present embodiment, this configuration is omitted to avoid complicating the description.

[0032] [Configuration of the Control Unit Board 100]

[0033] The control unit substrate 100 is configured by a control unit 110 , an LED power supply circuit 10 , a PWM control circuit 11 , a detection circuit 12 , and connection terminals 101 to 103 .

[0034] The control unit 110 includes terminals 104 to 106 .

[0035] The LED power supply circuit 10 is formed by transistors 111 to 112 and resistors 113 to 115 .

[0036] The emitter of the transistor 111 is connected to one end of the resistor 113 and a power source for lighting the LED. Although it is connected to the positive electrode of the battery mounted on the vehicle V, it can also be connected to the output of a stabilized power supply circuit that supplies voltage from the battery mounted on the vehicle V. The base of the transistor 111 is connected to the other end of the resistor 113 and the collector of the transistor 112. The collector of the transistor 111 is connected to the connection terminal 101. The emitter of the transistor 112 is connected to the ground, and the base of the transistor 112 is connected to one end of the resistor 114 and one end of the resistor 115. The other end of the resistor 114 is connected to the terminal 104, and the other end of the resistor 115 is connected to the ground.

[0037] The PWM control circuit 11 is formed by a transistor 116, a resistor 117, and a resistor 118. The collector of the transistor 116 is connected to the connection terminal 102, the emitter is connected to the ground, and the base is connected to one end of the resistor 117 and one end of the resistor 118. The other end of the resistor 117 is connected to the terminal 105, and the other end of the resistor 118 is connected to the ground.

[0038] The detection circuit 12 is configured using a resistor 119 as a pull-up resistor. One end of the resistor 119 is connected to the terminal 106 and the connection terminal 103. Although not shown, the other end of the resistor 119 is pulled up and connected to the output of a stabilized power supply circuit supplied with power from a battery of the vehicle V. For example, in this embodiment, the voltage is 5V, and the same voltage is also supplied to the control unit 110.

[0039] [Configuration of LED Substrate 200]

[0040] The LED substrate 200 is composed of an LED 211 as a light source, a resistor 210 , a momentary switch 213 , a temperature-sensitive resistor 214 , a switch circuit 20 , and connection terminals 201 to 203 .

[0041] The connection terminal 201 is connected to one end of the resistor 210. In addition, the connection terminal 201 is connected to one end of the resistor 216 via a power supply line 218 as a power supply unit.

[0042] The other end of the resistor 210 is connected to the anode of the LED 211 , and the connection terminal 202 is connected to the cathode.

[0043] The connection terminal 203 is connected to one end of a momentary switch 213 and one end of a temperature sensing resistor 214 . The other end of the momentary switch 213 is connected to the ground, and the other end of the temperature sensing resistor 214 is connected to the collector of the transistor 215 .

[0044] The switch circuit 20 as a switch unit is formed by a transistor 215 , a resistor 216 , and a resistor 217 .

[0045] The emitter of the transistor 215 is grounded, and the base is connected to the other end of the resistor 216 and one end of the resistor 217. The other end of the resistor 217 is grounded.

[0046] The connection terminals 201 to 203 are connected to the connection terminals 101 to 103 of the control unit substrate 100 via the harness 150 , respectively.

[0047] (Operation of Light Source Control Device 1)

[0048] The control unit 110 is composed of, for example, a microcomputer and has input and output terminals. The terminal 106 as an input terminal of the control unit 110 is an analog input terminal, and although not shown, the voltage input to the terminal is converted from analog to digital, and the input voltage value is taken into the control unit 110. The LED substrate 200 is mounted on the terminal 106, and a switch signal corresponding to the operation state of the momentary switch 213 is input.

[0049] Figure 3 The voltage values ​​input to the terminal 106 when the momentary switch 213 is in the on state and the off state are shown. When the momentary switch 213 is operated, the switch is in the on state, and the terminal 106 is short-circuited to the ground. When the momentary switch 213 is not operated, the switch is in the off state, and a voltage of 5V is input to the terminal 106. In addition, when the LED power supply circuit 10 described later is in the on state, the voltage obtained by dividing the 5V by the temperature-sensitive resistor 214 and the resistor 119 is input. Therefore, in Figure 3In FIG. 1 , when the momentary switch 213 is in the off state, a voltage of about 5 V is input to the terminal 106 , but the voltage level of this voltage varies with the temperature.

[0050] Figure 4 The temperature near the temperature-sensing resistor 214 and the voltage value input to the terminal 106 are shown. In the present embodiment, the temperature-sensing resistor 214 is implemented by using a thermistor to realize the circuit configuration. The temperature-sensing resistor 214 is a thermistor with a negative temperature characteristic, which has a characteristic that the resistance value decreases as the temperature increases. Therefore, if the temperature increases, the input voltage value of the terminal 106 decreases. The control unit 110 can detect the temperature near the LED 211 based on the voltage input to the terminal 106. At this time, the LED power supply circuit 10 described later needs to be set to the on state in the temperature detection.

[0051] The on / off of the LED power circuit 10 is controlled by the output signal of the terminal 104 of the control unit 110. When the control unit 110 detects that the momentary switch 213 is operated based on the signal input to the terminal 106 thereof, the control unit 110 outputs a high-level control signal from the terminal 104 to turn on the LED power circuit. When the LED power circuit 10 is turned on, a voltage is supplied to the connection terminal 201 of the LED substrate 200 via the connection terminal 101 and the harness 150. The voltage supplied to the connection terminal 201 is supplied to the switch circuit 20 via the power supply line 218, so that the transistor 215 is turned on.

[0052] The PWM control circuit 11 controls the current flowing through the LED 211 by outputting the PWM control signal from the terminal 105 of the control unit 110. The duty ratio of the PWM control signal is changed according to the temperature detection result near the LED 211. When the PWM control circuit 11 is turned on based on the PWM control signal from the terminal 105, current flows through the resistor 210 and the LED 211, and the LED lights up.

[0053] Figure 5The relationship between the temperature near LED211 and the duty cycle of the PWM control signal in this embodiment is shown. When the temperature converted from the voltage value input to terminal 106 is below 85°C, the PWM control signal output of terminal 105 is output at a 100% duty cycle. When it exceeds 85°C, it is output at a 50% duty cycle, and when it exceeds 90°C, it is output at a 5% duty cycle. This control is performed during the temperature rise process, and the duty cycle is changed with hysteresis during the temperature drop process. When the temperature drops below 85°C, the duty cycle is changed from 5% to 50%, and when the temperature drops below 80°C, the duty cycle is changed from 50% to 100%. The control unit 110 monitors the temperature near LED211, and controls the duty cycle of the PWM control circuit 11 in accordance with its temperature, thereby controlling the brightness (heat generation) of LED211.

[0054] (Effect)

[0055] The light source control device 1 according to this embodiment is as follows Figure 2 As shown, the structure includes a control unit substrate 100 , an LED substrate 200 , and a harness 150 .

[0056] The control unit substrate 100 includes a control unit 110 , an LED power supply circuit 10 , a PWM control circuit 11 , and a detection circuit 12 .

[0057] The LED substrate 200 includes an LED 211 , a momentary switch 213 , and a temperature-sensitive resistor 214 .

[0058] When the momentary switch 213 is operated, the control unit 110 of the light source control device 1 thus configured controls the lighting and extinguishing of the LED 211, and further controls the brightness of the LED 211 using the PWM control circuit 11 according to the temperature detection result. In addition, since the operation detection of the momentary switch 213 and the temperature detection based on the temperature sensing resistor 214 can be detected using one terminal 106, the number of terminals used in the control unit can be reduced, and the cost can be reduced.

[0059] In addition, even when the LED substrate 200 as the second substrate on which the LED 211, the momentary switch 213 and the temperature sensing resistor 214 are mounted and the control unit substrate 100 as the first substrate are arranged at different positions separated from each other, the operation detection of the momentary switch 213 and the temperature detection based on the temperature sensing resistor 214 can be detected by using one terminal 106, so the number of wire harnesses 150 can be reduced, and the cost can be reduced. Furthermore, since the number of connections of the wire harness can be reduced, the wire harness wires can be reduced, and the weight of the light source control device 1 can be reduced at the same time.

[0060] In addition, a switch circuit 20 is also embedded in the LED substrate 200. By providing a switch circuit 20 that switches the current flowing in the temperature-sensing resistor 214, when temperature detection based on the temperature-sensing resistor 214 is not required, the switch circuit 20 is controlled so that no current flows in the temperature-sensing resistor 214. Therefore, according to this structure, the power consumption of the light source control device 1 can be reduced. Furthermore, by controlling the switch circuit 20 with a voltage supplied from the LED power supply circuit 10 via the power supply line 218, it is not necessary to provide a control terminal in the control unit 110, which can reduce costs. Furthermore, since the number of connections of the wiring harness can be reduced, the wiring harness wires can be reduced, and the weight of the light source control device 1 can be reduced at the same time.

[0061] [Other embodiments]

[0062] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the invention.

[0063] Regarding the on / off control of the LED power supply circuit 10 of the present invention described above, an example in which it is linked to the operation of the momentary switch 213 is described, but it can also be controlled in conjunction with the on / off of an auxiliary power supply of the vehicle V.

[0064] (Number Description)

[0065] 1 light source control device, 10 LED power supply circuit, 11 PWM control circuit, 12 detection circuit, 150 wiring harness, 100 control unit substrate, 101, 102, 103, 201, 202, 203 connection terminals, 104, 105, 106 terminals, 110 control unit, 20 switch circuit, 200 LED substrate, 211 LED, 213 momentary switch, 214 temperature sensing resistor, 218 power supply line, V vehicle.

Claims

1. A light source control device, characterized in that: have: light source; a momentary switch having one end connected to a power source via a pull-up resistor and the other end connected to ground, the momentary switch conducting the one end and the other end when operated and disconnecting the one end and the other end when not operated; and a control unit having an input terminal connected to the one end of the momentary switch and inputting a switch signal corresponding to an operation state of the momentary switch, and controlling the power supply to the light source to switch the light source to a lighting state or an extinguishing state when the momentary switch is detected to be operated from the switch signal, The light source control device further comprises a temperature sensing resistor, one end of which is connected to the one end of the momentary switch, the other end of which is connected to the ground, and the resistance value of which changes with temperature. The switch signal of the momentary switch or the voltage-divided signal obtained by dividing the power supply by the pull-up resistor and the temperature-sensitive resistor is input to the input terminal of the control unit. The control unit controls the brightness of the light source according to the divided voltage signal.

2. A light source control device, characterized in that: have: light source; a momentary switch having one end connected to a power source via a pull-up resistor and the other end connected to ground, the momentary switch conducting the one end and the other end when operated and disconnecting the one end and the other end when not operated; and a control unit having an input terminal connected to the one end of the momentary switch and inputting a switch signal corresponding to an operation state of the momentary switch, and controlling the power supply to the light source to switch the light source to a lighting state or an extinguishing state when the momentary switch is detected to be operated from the switch signal, The light source control device further comprises a temperature sensing resistor, one end of which is connected to the one end of the momentary switch, the other end of which is connected to the ground, and the resistance value of which changes with temperature. The light source control device is composed of a first substrate and a second substrate which are separately arranged at different positions from each other. The control unit is provided on the first substrate. The light source, the momentary switch and the temperature-sensitive resistor are arranged on the second substrate. The switch signal of the momentary switch or the voltage-divided signal obtained by dividing the power supply by the pull-up resistor and the temperature-sensitive resistor is input to the input terminal of the control unit. The control unit controls the brightness of the light source according to the divided voltage signal.

3. The light source control device according to claim 1 or 2, characterized in that: The light source control device includes a switch unit that is provided between the other end of the temperature-sensitive resistor and the ground and switches the temperature-sensitive resistor between a state in which current flows and a state in which current does not flow.

4. The light source control device according to claim 3, characterized in that: The light source control device is provided with a power supply unit, and the power supply unit supplies power to the switch unit in conjunction with the power supply to the light source.

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