JP2016201173A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem of a lighting device which is configured to be divided into a power supply unit and a light emission unit and needs to apply a voltage of a forward drop voltage (VF) or more to both the ends of LED at the light emission time, the problem being as follows: when the voltage is set to zero under lights-out, a divided voltage when a lighting switch is turned on cannot be input to a comparator, and thus a voltage of not more than VF is applied; however, the voltage is not less than VF under lighting of LED whereas the voltage is not more than VF under lights-out, so that a comparison voltage input to the comparator greatly varies between the lighting and lights-out state of LED and thus turn-on/off of the switch cannot be detected.SOLUTION: A voltage to be applied to LED is used as voltage from which a reference voltage to be input to a reference voltage input unit is generated.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a lighting device that is divided into a power supply unit and a light emitting unit, and that incorporates an LED as a light source in the light emitting unit.

  In a lighting fixture in which a power supply unit and a light emitting unit are separately separated, it is more convenient to provide a switch for controlling on / off of light emission in the light emitting unit in the light emitting unit. On the other hand, since it is necessary to change the output of the power supply unit by turning the switch on and off, it is necessary to detect the on / off state of the switch on the power supply unit side.

  In such a case, a circuit using a comparator is generally employed. A reference voltage is input to a reference voltage input unit provided in the comparator, and a voltage that changes depending on the on / off state of the switch is input to the comparison voltage input unit. In the comparator, when the voltage of the comparison voltage input unit becomes higher than the voltage input to the reference voltage input unit, it is determined that the switch is turned on.

  As described above, since it is desired that the reference voltage input to the reference voltage input unit does not change depending on the environment, the reference voltage is generated by a voltage dividing resistor based on a fixed voltage (see, for example, Patent Document 1).

JP-A-6-105482 (FIG. 1)

  In order to cause the LED to emit light, it is necessary to apply a voltage equal to or higher than the forward voltage drop (hereinafter referred to as VF) across the LED. On the other hand, when the LED is turned off, the voltage may be reduced to a voltage lower than VF. However, if the voltage is reduced to zero, the partial pressure when the lighting switch is turned on cannot be input to the comparator. For this reason, it is necessary to apply a voltage lower than VF instead of setting the voltage applied to the LED to zero when the LED is turned off.

  However, the voltage that is the basis for generating the partial pressure in this way is a voltage that is equal to or higher than VF when the LED is turned on, and is lower than VF when the LED is turned off. For this reason, the comparison voltage input to the comparator changes greatly between when the LED is turned on and when the LED is turned off, and it becomes impossible to detect the on / off state of the switch.

  In view of the above problems, an object of the present invention is to provide an illuminating device that can reliably detect on / off of a switch even when an LED is on or off.

  In order to solve the above problems, the lighting device according to the present invention has a light emitting unit connected to the power supply unit by a total of three wires of one common line and two individual lines, and in this light emitting unit, An LED connected between the common line and one individual line, a resistor connected between the common line and the other individual line, and a switch for short-circuiting the resistor are provided. In the device, a resistor is provided on the other individual line on the power supply unit side, and a voltage dividing point between the light-emitting unit resistance and the power supply unit resistance is connected to the comparison voltage input unit of the comparator, A voltage dividing resistor for generating a reference voltage input to the reference voltage input unit is connected to the common line, and the reference voltage is generated based on the voltage of the common line.

  In general, the reference voltage input to the comparator is generated by dividing the voltage based on a voltage that does not vary. In the present invention, the voltage that is the basis for generating the reference voltage changes in accordance with the variation in the voltage that is the basis for generating the comparison voltage. I did it.

  As is clear from the above description, the present invention changes the voltage used as the basis for generating the reference voltage in accordance with the fluctuation of the voltage used as the basis for generating the comparison voltage. It is possible to reliably detect on / off of the switch with time.

The figure which shows the structure of the illumination device of this invention The circuit diagram which shows the connection state of the secondary side of a power supply part, and a light emission part

  Referring to FIG. 1, reference numeral 1 denotes a power supply unit that is a part of a lighting device according to the present invention. Since the power supply unit 1 is relatively large, it is installed in the hanging cabinet HC so as to be hidden from the outside. On the other hand, the light-emitting part 2 which is a component part of an illuminating device is attached to the bottom plate lower surface of this hanging cupboard HC. The light emitting unit 2 is provided with a switch 21 for turning on / off. By turning on / off the switch 21, the LED in the light emitting unit 2 is turned on / off.

  A power line 11 for supplying power from an external commercial power source is connected to the power source unit 1. Further, the power supply unit 1 and the light emitting unit 2 are connected to each other through three conducting wires 12.

  Referring to FIG. 2, one of the three conductors 12 is a common line 12a, and the other two are individual lines 12b and 12c, respectively. In the light emitting section 2, in addition to the switch 21, an LED unit 22 in which a plurality of LEDs are connected in series and a voltage dividing resistor 23 connected in parallel to the switch 21 are provided. In addition, 3 is a harness which connects the power supply part 1 and the light emission part 2. FIG.

  The switch 21 and the voltage dividing resistor 23 are connected between the common line 12a and the individual line 12b. The individual line 12b is connected to two voltage dividing resistors 61 and 62 in the power supply unit 1. The voltage dividing resistor 23 is turned on and off by the switch 21 by the switch 21 on and off. It varies depending on whether or not it is short-circuited.

  On the other hand, the reference voltage input unit 41 of the comparator 4 is supplied with the divided voltage generated by the two voltage dividing resistors 51 and 52, but the voltage that is the basis of the voltage dividing by both the voltage dividing resistors 51 and 52 is common. The voltage of the line 12a was used.

  The feature of the present invention is that the reference voltage of the comparator 4 for detecting the on / off of the switch 21 depends on the voltage of the common line 12a. In the other comparator 7, the reference voltage is generated based on the power supply “A” whose voltage value is fixed. doing.

  The comparator 7 switches the control voltage value of the shunt regulator portion composed of the two Zener diodes 71 and 72 between high and low by turning on the transistor 73. The two types of high and low voltages are set such that one voltage is higher than VF and the other is lower than VF across the VF.

  Therefore, when the switch 21 is turned on, the LED unit 22 is caused to emit light by setting the voltage of the common line 12a higher than VF, and when the switch 21 is turned off, the voltage of the common line 12a is set lower than VF. Turn off the LED unit.

  Even if the voltage of the common line 12a is lower than VF and the LED unit 22 is turned off, the voltage is applied to the common line 12a. Two types of voltages are switched and input, and it is possible to detect the on / off state of the switch 21 even when the LED unit 22 is turned off.

  In addition, this invention is not limited to an above-described form, You may add a various change in the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Power supply part 2 Light emission part 4 Comparator 7 Comparator 12a Common line 12b Individual line 12c Individual line 21 Switch 22 LED unit 23 Voltage dividing resistor 41 Reference voltage input part 42 Comparison voltage input part 71 Zener diode 72 Zener diode

Claims (1)

  It has a light emitting part connected to the power supply part by a total of three wires of one common line and two individual lines, and is connected between the common line and one individual line in the light emitting part. Provided with a resistor connected between the common line and the other individual line, and further provided with a switch for short-circuiting the resistor, the other individual line is provided on the power supply unit side. A resistor is connected to the comparison voltage input section of the comparator to generate a reference voltage to be input to the reference voltage input section of the comparator by connecting a voltage dividing point between the light emitting section resistance and the power supply section resistance. An illuminating apparatus comprising: connecting a piezoresistor to the common line, and generating a reference voltage based on a voltage of the common line.

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