JP7359689B2 - Light source control device - Google Patents

Description

The present invention relates to a light source control device.

2. Description of the Related Art Vehicle lamps using LEDs as light sources are becoming popular. However, the heat generated by the LED may deteriorate the LED itself or components mounted around the LED. Therefore, as described in prior art documents, a device has been proposed that includes a temperature-sensitive resistor that detects the temperature near the LED and reduces the current supplied to the LED based on the detected temperature, thereby suppressing the heat generation of the LED. has been done.

JP2018-134981A

By the way, in the same way as vehicle lamps, the use of LEDs as a light source is becoming popular for vehicle interior lighting that illuminates the interior of the vehicle, and there is a need to increase the brightness of LEDs to brighten the interior of the vehicle. . When the brightness of the LED is increased, the amount of heat generated by the LED increases, so it is necessary to provide a temperature-sensitive resistor to detect the temperature near the LED, similar to a vehicle lamp. In addition, a control unit is provided in the interior lighting device located in front of the ceiling, and the interior lighting device in the center of the ceiling, which is located apart from the front of the ceiling, is controlled by the control unit in front of the ceiling. There is. In this case, the control unit and the LED of the vehicle interior lighting device in the center of the ceiling are provided on different boards. Further, the vehicle interior lighting device in the center of the ceiling is configured such that a momentary switch is provided on a substrate on which an LED and a temperature-sensitive resistor are mounted, and the LED is turned on and off in accordance with the operation of the momentary switch. As a result, the number of connector connections increases, and a harness is also required to connect the board in front of the ceiling where the control unit is installed and the board in the center of the ceiling where the LED of the vehicle interior lighting system is mounted, which increases costs. It will happen.

Therefore, in consideration of the above facts, the present invention provides a light source control device that can reduce costs even if it has a configuration including a temperature-sensitive resistor and a momentary switch.

The light source control device according to the first embodiment of the present invention includes a light source, one end of which is connected to a power source via a pull-up resistor, and the other end of which is connected to ground, and the one end and the other end are connected to each other during operation. The switch has a momentary switch that is conductive and cuts off one end and the other end when not operated, and an input terminal that is connected to one end of the momentary switch and receives a switch signal according to the operating state of the momentary switch. A light source control device, comprising: a control section that controls power supply to a light source so as to switch the light source to a lighting state or a non-lighting state when detecting operation of a momentary switch from a signal, one end of which is a momentary switch; It is connected to one end of the switch and the other end is connected to ground, and is equipped with a temperature-sensitive resistor whose resistance value changes depending on the temperature.The input terminal of the control section is connected to the switch signal of the momentary switch or the pull-up resistor. A divided voltage signal obtained by dividing the voltage of the power supply by the temperature-sensitive resistor is input, and the control section controls the brightness of the light source based on the divided voltage signal.

The light source control device according to the first embodiment includes a light source, a momentary switch, a control section, and a temperature-sensitive resistor. At the input terminal of the control section, operation of the momentary switch is detected, and when the momentary switch is not operated, a divided voltage signal obtained by dividing the voltage of the power supply using the pull-up resistor and the temperature-sensitive resistor is detected. The control section controls turning on and off 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 partial voltage signal. Therefore, according to this configuration, since the momentary switch can be operated and the temperature near the light source can be detected using one input terminal of the control section, the cost of the light source control device can be reduced.

In the light source control device according to the second embodiment of the present invention, one end of the light source is connected to a power source via a pull-up resistor, and the other end is connected to ground, and the one end and the other end are connected to each other during operation. The switch has a momentary switch that is conductive and cuts off one end and the other end when not operated, and an input terminal that is connected to one end of the momentary switch and receives a switch signal according to the operating state of the momentary switch. A control unit that controls the power supply to the light source so that when it detects that the momentary switch has been operated from the signal, the light source is switched on or off.One end is connected to one end of the momentary switch, and the other end is connected to ground. A light source control device comprising a first substrate and a second substrate, which are spaced apart from each other and are arranged at different positions, and a temperature-sensitive resistor whose resistance value changes depending on the temperature. The first board is provided with a control unit, the second board is provided with a light source, a momentary switch, and a temperature-sensitive resistor, and the input terminal of the control unit receives a switch signal of the momentary switch or A divided voltage signal obtained by dividing the voltage of the power supply is inputted by the pull-up resistor and the temperature-sensitive resistor, and the control unit controls the brightness of the light source based on the divided voltage signal.

The light source control device according to the second embodiment includes a light source, a momentary switch, a control section, a temperature-sensitive resistor, a first substrate, and a second substrate. The first substrate and the second substrate are arranged apart from each other, the first substrate is provided with a control section, and the second substrate is provided with a light source, a momentary switch, and a temperature-sensitive resistor. At the input terminal of the control section, operation of the momentary switch is detected, and when the momentary switch is not operated, a divided voltage signal obtained by dividing the voltage of the power supply using the pull-up resistor and the temperature-sensitive resistor is detected. The control section controls turning on and off 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 partial voltage signal. Therefore, according to this configuration, since the momentary switch can be operated and the temperature near the light source can be detected with one input terminal of the control section, the number of harnesses can be reduced, and the cost of the light source control device can be reduced.

The light source control device according to the third embodiment is the light source control device according to the first embodiment or the second embodiment, and is provided between the other end of the temperature-sensitive resistor and the ground, and is arranged so that a current flows through the temperature-sensitive resistor. A switching means is provided for switching between a state in which current flows and a state in which current does not flow.

The light source control device according to the third embodiment is the light source control device according to the first embodiment or the second embodiment, and further includes switching means. By providing a switching means for switching the current flowing through the temperature-sensitive resistor, the switching means is controlled so that the current does not flow through the temperature-sensitive resistor when temperature detection by the temperature-sensitive resistor is unnecessary. Therefore, according to this configuration, an increase in power consumption can be prevented.

The light source control device according to the fourth embodiment is the light source control device according to the third embodiment, and is provided with power supply means for supplying power to the switching means in conjunction with power supply to the light source.

The light source control device according to the fourth embodiment is the light source control device according to the third embodiment, and further includes power supply means linked to power supply to the light source. Electric power is supplied from the power supply means to the switching means to control the switching means. Since a power supply means is provided that supplies power to the switching means in conjunction with the state of power supply to the light source, the switching means is linked to the state of power supply to the light source, and switches the temperature-sensitive resistor to a state where no current flows. Therefore, according to this configuration, there is no need to provide the control unit with a control terminal for controlling the switching means, and an increase in power consumption can be prevented without increasing cost.

According to the embodiments of the present invention, it is possible to provide a light source control device that can reduce costs even if it has a configuration including a temperature-sensitive resistor and a momentary switch.

1 is a configuration diagram of a light source control device 1 according to a first embodiment of the present invention. FIG. 1 is a circuit configuration diagram of a light source control device 1 according to a first embodiment of the present invention. FIG. 3 is a diagram showing the relationship between momentary switch operation and input voltage to the control unit of the light source control device 1 according to the first embodiment of the present invention. FIG. 2 is a relationship diagram between the temperature of the light source control device 1 and the input voltage to the control unit according to the first embodiment of the present invention. FIG. 3 is a relationship diagram between temperature and PWM duty ratio of the light source control device 1 according to the first embodiment of the present invention.

[First embodiment]
A light source control device 1 according to a first embodiment of the present invention will be described using FIGS. 1 and 2.
(Configuration of light source control device 1)
FIG. 1 is a configuration diagram of a light source control device 1 of this embodiment mounted on a vehicle V. The vehicle V on which the light source control device 1 is installed is, for example, a four-wheel vehicle, and includes 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, or an internal combustion engine. Also includes hybrid vehicles that are equipped with electric motors.

The light source control device 1 includes a control unit board 100 and an LED board 200, and the control unit board 100 and the LED board 200 are connected to each other by a harness 150.
The control unit board 100 is disposed in front of the ceiling in the vehicle interior of the vehicle V, and the LED board 200 is disposed in the center of the ceiling in the vehicle interior. The control unit board 100 incorporates a control unit that controls vehicle interior lighting, and the LED board 200 incorporates LEDs and operation switches for illuminating the vehicle interior at night.
Note that the control unit board 100 may also be provided with a circuit configuration for illuminating the interior of the vehicle similarly to the LED board 200. In this embodiment, the explanation will be omitted because it is complicated.

[Configuration of control unit board 100]
The control unit board 100 includes 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.

The control unit 110 includes terminals 104 to 106.
The LED power supply circuit 10 is composed of transistors 111-112 and resistors 113-115.

The emitter of the transistor 111 is connected to one end of a 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 may also be connected to the output of a stabilized power supply circuit supplied with 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. A collector of the transistor 111 is connected to the connection terminal 101. The emitter of transistor 112 is connected to ground, and the base of transistor 112 is connected to one end of resistor 114 and one end of 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 ground.

The PWM control circuit 11 includes 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 ground, and the base is connected to one end of a resistor 117 and one end of a resistor 118. The other end of resistor 117 is connected to terminal 105, and the other end of resistor 118 is connected to ground.

The detection circuit 12 includes 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 connected in a pull-up manner to the output of a stabilized power supply circuit supplied with power from the 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.

[Configuration of LED board 200]
The LED board 200 includes an LED 211 as a light source, a resistor 210, a momentary switch 213, a temperature-sensitive resistor 214, a switching circuit 20, and connection terminals 201 to 203.

Connection terminal 201 is connected to one end of resistor 210. Further, the connection terminal 201 is connected to one end of a resistor 216 via a power supply line 218 serving as a power supply means.
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.
The connection terminal 203 is connected to one end of a momentary switch 213 and one end of a temperature sensitive resistor 214. The other end of the momentary switch 213 is connected to ground, and the other end of the temperature sensitive resistor 214 is connected to the collector of a transistor 215.

The switching circuit 20 as a switching means includes a transistor 215, a resistor 216, and a resistor 217.
The emitter of transistor 215 is connected to ground, and the base is connected to the other end of resistor 216 and one end of resistor 217. The other end of resistor 217 is connected to ground.

The connection terminals 201 to 203 are connected to the connection terminals 101 to 103 of the control unit board 100 via a harness 150, respectively.

(Operation of light source control device 1)
The control unit 110 is composed of, for example, a microcomputer, and has input/output terminals. The terminal 106 as an input terminal included in the control unit 110 is an analog input terminal, and although not shown, the voltage input to the terminal is converted into analog-to-digital, and the input voltage value is taken into the control unit 110. . A switch signal corresponding to the operating state of the momentary switch 213 mounted on the LED board 200 is input to the terminal 106 .

FIG. 3 shows voltage values input to the terminal 106 when the momentary switch 213 is in an on state and an off state. When the momentary switch 213 is operated, the switch is turned on and the terminal 106 is short-circuited to ground. When the momentary switch 213 is not operated, the switch is in an off state, and a voltage of 5V is input to the terminal 106. Further, when the LED power supply circuit 10 described later is in the on state, a voltage obtained by dividing 5V is inputted by the temperature-sensitive resistor 214 and the resistor 119. Therefore, in FIG. 3, 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 changes depending on the temperature.

FIG. 4 shows the temperature near the temperature-sensitive resistor 214 and the voltage value input to the terminal 106. In this embodiment, the temperature-sensitive resistor 214 is configured using a thermistor. A thermistor having negative temperature characteristics is used as the temperature-sensitive resistor 214, and the resistance value decreases as the temperature increases. Therefore, as the temperature increases, the input voltage value at terminal 106 decreases. The control unit 110 can detect the temperature near the LED 211 from the voltage input to the terminal 106. At this time, in order to detect the temperature, it is necessary that the LED power supply circuit 10, which will be described later, is turned on.

The LED power supply circuit 10 is controlled to be turned on or off by an output signal from the terminal 104 of the control section 110. When the control section 110 detects that the momentary switch 213 has been operated based on the signal input to the terminal 106, it outputs a high-level control signal from the terminal 104 to turn on the LED power supply circuit. When the LED power supply circuit 10 is turned on, voltage is supplied to the connection terminal 201 of the LED board 200 via the connection terminal 101 and the harness 150. The voltage supplied to the connection terminal 201 is supplied to the switching circuit 20 via the power supply line 218, and the transistor 215 is turned on.

The PWM control circuit 11 controls the current flowing through the LED 211 by outputting a PWM control signal from the terminal 105 of the control unit 110 . The current flowing through the LED 211 changes the duty ratio of the PWM control signal based on the temperature detection result near the LED 211 described above. When the PWM control circuit 11 is turned on by the PWM control signal at the terminal 105, current flows through the resistor 210 and the LED 211, and the LED lights up.

FIG. 5 shows the relationship between the temperature near the LED 211 and the duty ratio of the PWM control signal in this embodiment. When the temperature calculated from the voltage value input to the terminal 106 is 85° C. or lower, the PWM control signal output from the terminal 105 is output at 100% duty. When the temperature exceeds 85°C, it is outputted at 50% duty, and when it exceeds 90°C, it is outputted at 5% duty. This control is performed in the process of increasing the temperature, but the duty ratio is changed with hysteresis in the process of decreasing the temperature. When the temperature falls below 85°C, the duty ratio is changed from 5% to 50%, and when the temperature falls below 80°C, the duty ratio is changed from 50% to 100%. The control unit 110 monitors the temperature near the LED 211, controls the duty ratio of the PWM control circuit 11, and controls the brightness (heat amount) of the LED 211 according to the temperature.

(effect)
The light source control device 1 according to the present embodiment includes a control unit board 100, an LED board 200, and a harness 150, as shown in FIG.
The control unit board 100 includes a control unit 110, an LED power supply circuit 10, a PWM control circuit 11, and a detection circuit 12.
The LED board 200 includes an LED 211, a momentary switch 213, and a temperature-sensitive resistor 214.

The control unit 110 of the light source control device 1 configured as described above controls lighting and extinguishing of the LED 211 when the momentary switch 213 is operated, and further controls the brightness of the LED 211 using the PWM control circuit 11 based on the temperature detection result. Control. Further, since the operation detection of the momentary switch 213 and the temperature detection by the temperature sensitive resistor 214 can be detected with one terminal 106, the number of terminals used in the control section can be reduced, and the cost can be reduced.

Further, the LED board 200 as the second board on which the LED 211, the momentary switch 213, and the temperature-sensitive resistor 214 are mounted, and the control unit board 100 as the first board are arranged at separate positions. Even in the configuration, it is possible to detect the operation of the momentary switch 213 and the temperature detection by the temperature-sensitive resistor 214 with one terminal 106, so the number of harnesses 150 can be reduced, and costs can be reduced. I can do it. Furthermore, since the number of harness connections can be reduced, the number of harness wires and the like can be reduced, and the weight of the light source control device 1 can also be reduced.

Furthermore, a switching circuit 20 is further incorporated into the LED board 200. By providing the switching circuit 20 that switches the current flowing through the temperature-sensitive resistor 214, the switching circuit 20 is controlled so that no current flows through the temperature-sensitive resistor 214 when temperature detection by the temperature-sensitive resistor 214 is unnecessary. Therefore, according to this configuration, it is possible to reduce the power consumption of the light source control device 1. Furthermore, by controlling the switching circuit 20 using the voltage supplied from the LED power supply circuit 10 via the power supply line 218, there is no need to provide a control terminal in the control unit 110, and costs can be reduced. Furthermore, since the number of harness connections can be reduced, the number of harness wires and the like can be reduced, and the weight of the light source control device 1 can also be reduced.

[Other embodiments]
The present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the scope of the invention.
Although an example has been described in which the on/off control of the LED power supply circuit 10 of the present invention is linked to the operation of the momentary switch 213, it may also be controlled in conjunction with the on/off of the accessory power supply of the vehicle V.

DESCRIPTION OF SYMBOLS 1... Light source control device, 10... LED power supply circuit, 11... PWM control circuit, 12... Detection circuit, 150... Harness, 100... Control unit board, 101, 102, 103, 201, 202, 203... Connection terminal, 104, 105, 106...terminal, 110...control unit, 20...switching circuit, 200...LED board, 211...LED, 213...momentary switch, 214...temperature sensitive resistor, 218...power supply line, V...vehicle

Claims (4)

a light source and
One end is connected to the power supply via a pull-up resistor, the other end is connected to ground, and conduction occurs between the one end and the other end when it is operated, and the one end and the other end when it is not operated. a momentary switch that cuts off the
It has an input terminal that is connected to the one end of the momentary switch and receives a switch signal according to the operation state of the momentary switch, and when it is detected from the switch signal that the momentary switch has been operated, the light source is turned off. a control unit that controls power supply to the light source so as to switch to a lit state or a non-lit state;
A light source control device comprising:
a temperature-sensitive 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 whose resistance value changes depending on the temperature;
The switch signal of the momentary switch or a divided voltage signal obtained by dividing the voltage of the power source by the pull-up resistor and the temperature-sensitive resistor is input to the input terminal of the control unit,
A light source control device, wherein the control unit controls the brightness of the light source based on the partial pressure signal. a light source and
One end is connected to the power supply via a pull-up resistor, the other end is connected to ground, and conduction occurs between the one end and the other end when it is operated, and the one end and the other end when it is not operated. a momentary switch that cuts off the
It has an input terminal that is connected to the one end of the momentary switch and receives a switch signal according to the operation state of the momentary switch, and when it is detected from the switch signal that the momentary switch has been operated, the light source is turned off. a control unit that controls power supply to the light source so as to switch to a lit state or a non-lit state;
a temperature-sensitive 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 whose resistance value changes depending on the temperature;
A light source control device comprising a first substrate and a second substrate spaced apart from each other at different positions,
The first substrate is provided with the control section,
The second substrate is provided with the light source, the momentary switch, and the temperature-sensitive resistor,
The switch signal of the momentary switch or a divided voltage signal obtained by dividing the voltage of the power source by the pull-up resistor and the temperature-sensitive resistor is input to the input terminal of the control unit,
A light source control device, wherein the control unit controls the brightness of the light source based on the partial pressure signal. 2. The temperature sensitive resistor further comprises a switching means provided between the other end of the temperature sensitive resistor and the ground to switch the temperature sensitive resistor between a state in which a current flows and a state in which a current does not flow. The light source control device according to claim 2. 4. The light source control device according to claim 3, further comprising power supply means for supplying power to said switching means in conjunction with power supply to said light source.

Images