JP5945819B2 - LED lighting device, vehicle lighting device and lighting fixture using the same - Google Patents

Description

  The present invention relates to an LED lighting device for lighting an LED, a vehicle lighting device using the same, and a lighting fixture.

  Light emitting diodes (hereinafter referred to as LEDs) are capable of emitting light with low power and high luminance, and are used as light sources for various electric devices such as displays and lighting equipment. In recent years, LEDs have been used as light sources for in-vehicle lighting devices that replace discharge lamps. In such an in-vehicle lighting device, generally, the brightness of irradiation light is increased by using a plurality of LEDs.

  However, LEDs have individual differences in light emission characteristics due to manufacturing variations and the like, and the amount of light may vary. Therefore, in an illuminating device using an LED as a light source, even if the current supplied to the LED is controlled to a constant value using an LED lighting device that converts a power supply voltage, the same light output cannot be obtained for each device. Sometimes. In particular, in an in-vehicle lighting device using a plurality of LEDs, there is a possibility that individual differences among the LEDs are combined and the light output of each device varies.

  Therefore, as shown in FIG. 7, a DC power supply circuit 105 including a DC-DC converter that supplies current to the LED 103 and a current control unit 106 that controls the supply current Io from the DC power supply circuit 105 to the LED 103 are provided. LED lighting device 101 is provided. The current control unit 106 includes an output current setting unit 161 that controls the supply current Io by turning on and off the switching element Q0 of the DC-DC converter in accordance with a predetermined input voltage value Vc, and 2 arranged in series from the reference voltage Vref. And a resistance voltage dividing circuit 162 including two resistors R1 and R2. Here, the input voltage value Vc for the output current setting unit 161 is set by the resistance voltage dividing value of the reference voltage Vref.

  In addition, the control circuit that controls the supply current from the power supply circuit to the LED has a circuit that adjusts the supply current in a corrective manner, and the LED for which the light amount with respect to a predetermined current value deviates from the reference value matches the reference value There is known an LED driving circuit to be operated (see, for example, Patent Document 1).

JP 2007-305920 A

  However, in the LED lighting device 101 shown in FIG. 7, it is necessary to incorporate a resistance voltage dividing circuit having a resistance R <b> 1 or a resistance R <b> 2 whose resistance value is set according to the variation in the amount of light of the LED into the power supply control unit. Therefore, there are many types of circuits to be prepared at the time of manufacture, and there is a possibility that the production efficiency of the LED lighting device is deteriorated. Further, in the LED drive circuit described in Patent Document 1, the value of the current flowing through the resistor arranged in the circuit for correcting the supply current to the LED is larger than the output value of the control signal for controlling the supply current to the LED. Affect. Therefore, when external noise is applied between the control circuit and the resistor, the output value of the control signal varies due to the influence of the noise, and the light output of the LED may also vary.

  The present invention solves the above-described problem, and an LED lighting device capable of correcting variations in the amount of light of an LED with a simple configuration and suppressing fluctuations in the light output of the LED due to the influence of noise, and the same An object of the present invention is to provide a vehicular lighting device and a lighting fixture using the above.

In order to solve the above problems, the present invention is an LED lighting device comprising: a DC power supply circuit that supplies current to an LED; and a current control unit that controls supply current from the DC power supply circuit to the LED, The current control unit controls a supply current to the LED according to a predetermined input voltage value, and a resistance voltage dividing circuit including two resistors arranged in series from a reference voltage, and a variation in light quantity of the LED. And a correction resistor that corrects the input voltage value that is set in accordance with the input voltage value, the input voltage value is set by a resistance voltage-dividing value of the reference voltage, and the correction resistor is connected to the resistance voltage dividing circuit. It is arranged in parallel with one of the two resistors and is located away from the circuit group constituting the current control unit, and is connected to the current control unit by a wire harness or a board wiring. Characterized by

  In the LED lighting device, the correction resistor is preferably a temperature sensitive resistor or a thermistor.

  In the LED lighting device, it is preferable that the correction resistor is located away from a circuit group constituting the current control unit and connected to the current control unit by a wire harness or a substrate wiring.

  The LED lighting device is preferably used for an in-vehicle lighting device.

  It is preferable that the said LED lighting device is used for a lighting fixture.

  According to the present invention, since the input voltage value of the current control unit that controls the supply current to the LED is corrected by the correction resistor set according to the variation in the light amount of the LED, the variation in the light amount of the LED can be simplified. It can be corrected. For example, if the correction amount by the correction resistor in the input voltage value is reduced, even if noise is applied between the correction resistor and the current control unit, this noise has little effect on the input voltage value. The fluctuation of the light output can be suppressed.

The perspective view which shows schematic structure of the vehicle-mounted illuminating device using the LED lighting device which concerns on the 1st Embodiment of this invention. The block block diagram of the LED lighting device. The figure which shows the setting method of the input voltage value in the LED lighting device. The block block diagram of the LED lighting device which concerns on the 2nd Embodiment of this invention. The figure which shows the setting method of the input voltage value in the LED lighting device. (A) is a side view of the lighting fixture using the LED lighting device, (b) is a front view. The block block diagram of the conventional LED lighting device.

  An LED lighting device and an in-vehicle lighting device using the LED lighting device according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the LED lighting device 1 according to the present embodiment is used for an in-vehicle lighting device 2. The in-vehicle illumination device 2 includes a lamp 4 that uses a light emitting diode (hereinafter, LED 3) as a light source, a battery (DC power supply DC) that supplies current to the LED 3, and a switch SW that turns on and off the supply current to the LED 3. . The LED lighting device 1 controls the supply current from the DC power source DC to the LED 3 according to an on / off operation in the switch SW. In the illustrated example, the LED lighting device 1 is arranged in each of the pair of left and right lamps 4 (headlights). However, one LED lighting device 1 controls the supply current of the LEDs 3 in the plurality of lamps 4. It may be configured.

  As shown in FIG. 2, the LED lighting device 1 is arranged between the DC power supply DC and the lamp 4, and supplies a DC power supply circuit 5 that supplies current to the LED 3 and a supply current Io from the DC power supply circuit 5 to the LED 3. A current control unit 6 to be controlled. LED3 is a generic term for an LED group in which a plurality of light emitting diode elements D1, D2,... Dn are arranged in series.

  The LED 3 is an LED that can emit illumination light of a desired light color. For example, a GaN-based blue LED chip is coated with a YAG-based yellow phosphor, and white light is emitted by mixing blue light and yellow light. LEDs are used. In addition, not only white LEDs but also a plurality of LEDs having different emission colors of red, green, and green may be used in combination as appropriate, or an OLED using an organic light emitting material for the light emitting part may be used. Good.

  The DC power supply circuit 5 includes a DC-DC converter 51 that converts a DC output voltage of a supply current Io from the DC power supply DC to the LED 3 into a predetermined voltage. The DC-DC converter 51 includes a switching element Q0 that switches the DC output voltage of the DC power supply DC, and a transformer (not shown) that stores and discharges excitation energy by switching of the switching element Q0. The DC-DC converter 51 includes a diode and a smoothing capacitor for rectifying and smoothing the output current from the transformer, and a resistor (not shown) arranged to detect the current voltage of the switching element Q0.

  The supply current Io from the DC power supply circuit 5 to the LED 3 is obtained by comparing the voltage value of a detection resistor (not shown) arranged between them with a reference voltage Vref in a comparison circuit (not shown). By being output to the current control unit 6, feedback control is performed. In this manner, the current control unit 6 performs constant current control of the supply current Io to the LED 3 by controlling the switching frequency and duty of the switching element Q0 in response to the detection voltage in the detection resistor.

  The current control unit 6 includes an output current setting unit 61 formed of a general-purpose microcomputer or the like, and controls the switching frequency and duty of the switching element Q0 according to a predetermined input voltage value Vc input to the output current setting unit 61. As a result, the supply current Io to the LED 3 is controlled. In the present embodiment, the current control unit 6 includes a resistance voltage dividing circuit 62 including a first resistor R1 and a second resistor R2 arranged in series from the reference voltage Vref, and the input voltage value Vc is the reference voltage Vref. It is set by the resistance partial pressure value. The resistance values of the first resistor R1 and the second resistor R2 of the resistance voltage dividing circuit 62 are statistically calculated from the range in which the light quantity of the LED 3 varies and the average value thereof, and are set based on the average value.

  Further, in the LED lighting device 1, the correction resistor Rc set according to the light amount variation of the LED 3 is one of the first resistor R1 and the second resistor R2 of the resistor voltage dividing circuit 62, in this example. It is arranged in parallel with the second resistor R2. According to this configuration, the ratio of the resistance value of the combined resistor Z1 occupying the sum of the respective resistance values of the first resistor R1 and the combined resistor Z1 of the second resistor R2 and the correcting resistor Rc is the voltage dividing ratio. A resistance voltage division value obtained by multiplying the reference voltage Vref by the voltage division ratio is input to the output current setting unit 61 as the input voltage value Vc. In other words, the resistance voltage division value of the reference voltage Vref is corrected by the correction resistor Rc, and the corrected resistance voltage division value becomes the input voltage value Vc.

  The correction resistor Rc is located away from the circuit group constituting the current control unit 6 and is connected to the output current setting unit 61 of the current control unit 6 by a wire harness or a substrate wiring 64. In this way, when the LED lighting device 1 is incorporated in the in-vehicle lighting device 2, the correction resistor Rc having a resistance value suitable for the LED 3 is selected while checking the light quantity of the LED 3, and this is simply set. Can be attached to the LED lighting device 1.

  Further, the correction resistor Rc may be a variable resistor such as a temperature sensitive resistor or a thermistor. In this case, the LED lighting device 1 uses a separate variable resistance control circuit for controlling the resistance value of the correction resistor Rc. The variable resistance control circuit includes, for example, an illuminance sensor that detects the illuminance of the emitted light from the lamp 4, a temperature sensor that measures the ambient temperature of the LED lighting device 1, and a correction resistor Rc according to these detection values. A microcomputer and a comparator for outputting a control signal are incorporated. For example, even if the same amount of light is obtained at the same temperature and the same current, the LED 3 has a light emission characteristic that changes when the ambient temperature changes, and the same amount of light cannot be obtained at the same current. On the other hand, if the correction resistor Rc is a variable resistor and the resistance value is appropriately changed, the resistance value of the correction resistor Rc can be set according to the ambient temperature change or the like. The light output of the LED 3 can be controlled according to the use environment.

  FIG. 3 shows the relationship between the light quantity of the LED 3 (light emitting diode elements D1, D2,... Dn), the supply current Io, the correction resistor Rc, and the input voltage value Vc to the output current setting unit 61 under various conditions. As used herein, the “condition” refers to a plurality of light-emitting diode elements D1, D2,... That have the same type of element, but have individual differences in light-emitting characteristics due to differences in manufacturing time, method, and the like. A combination of Dn. In the following description, when the LED lighting device 1 lights the LED 3, the light amount of each element D1, D2,... Dn is C1, and the target value of the light output of the LED 3 is C1 × n (n is a light emitting diode). Number of elements). Further, the resistance values of the first resistor R1 and the second resistor R2 of the resistance voltage dividing circuit 62 are set as specified values R1 and R2, respectively. Further, the output current setting unit 61 performs current control so that the current value of the supply current Io increases as the input voltage value Vc increases.

  Under a certain condition (1), when the resistance value of the correction resistor Rc is Rc1, the input voltage value Vc1 (resistance voltage division value) is obtained by the following formulas 1 and 2. In Equations 1 and 2, Z1 is a combined resistance of the second resistor R2 and the correction resistor Rc1.

[Equation 1]
Vc = Vref · Z1 / (R1 + Z1) = Vc1 (Formula 1)
Z1 = R2 / Rc1 / (R2 + Rc1) (Formula 2)

  When the input voltage value Vc1 is input, the output current setting unit 61 outputs a control signal for controlling the switching element Q0 of the DC-DC converter 51 in accordance with the input voltage value Vc1, and the LED3 is output from the DC-DC converter 51. A supply current Io1 is output. At this time, if the light amounts of the light emitting diode elements D1, D2,... Dn are C1, respectively, the light output of the LED 3 becomes C1 × n which is a target value.

  However, in another condition (2), the light amounts of the light emitting diode elements D1, D2,... Dn when the supply current Io1 is output may be C2 (for example, C2> C1) due to individual differences. . Further, under still another condition (3), the light amounts of the light emitting diode elements D1, D2,... Dn may be C3 (for example, C1> C3) when the supply current Io1 is output.

  Therefore, in the case of the condition (2), the correction resistor Rc is supplied so that the supply current Io2 smaller than the supply current Io1 is supplied to the light emitting diode elements D1, D2,. Let Rc2 (Rc1> Rc2). In FIG. 3, the input voltage value Vc and the like when the resistance value of the correction resistor Rc is Rc2 are shown as the condition (4). Under this condition (4), when the resistance value of the correction resistor Rc is Rc2, the input voltage value Vc2 (resistance voltage division value) is obtained by the following equations 3 and 4. In Equations 3 and 4, Z2 is a combined resistance of the second resistor R2 and the correction resistor Rc2.

[Equation 2]
Vc = Vref · Z2 / (R1 + Z2) = Vc2 (Formula 3)
Z2 = R2 / Rc2 / (R2 + Rc2) (Formula 4)

  Further, even in the condition (3), the light emitting diode elements D1, D2,... Dn are used for correction so that the supply current Io3 larger than the supply current Io1 is supplied to each light quantity C1. The resistance value of the resistor Rc is Rc3 (Rc3> Rc1). In FIG. 3, the input voltage value Vc and the like when the resistance value of the correction resistor Rc is Rc3 are shown as the condition (5). Under this condition (5), when the resistance value of the correction resistor Rc is Rc3, the input voltage value Vc3 (resistance divided value) is obtained by the following equations 5 and 6. In Equations 5 and 6, Z3 is a combined resistance of the second resistor R2 and the correction resistor Rc3.

[Equation 3]
Vc = Vref · Z3 / (R1 + Z3) = Vc3 (Formula 5)
Z3 = R2 / Rc3 / (R2 + Rc3) (Formula 6)

  That is, when the LED 3 is turned on under the condition (1), the resistance value of the correction resistor Rc is Rc1, and when the LED 3 is turned on under the conditions (2) and (3), the conditions (4) and (5) in FIG. As shown, the resistance values of the correction resistor Rc are Rc2 and Rc3, respectively. In this way, by setting the resistance value of the correction resistor Rc according to the variation in the light amount of the LED 3, even if the LED 3 that does not output the same light amount even if the same current is applied is used for the lamp 4, the light amount of the LED 3 Variations can be easily corrected.

  According to the above configuration, the resistance value of the correction resistor Rc is set according to the variation in the amount of light of the LED 3, but the resistance values of the first resistor R1 and the second resistor R2 are set to predetermined values. Thus, a common resistance voltage dividing circuit 62 can be used for any LED lighting device 1. Therefore, the types of circuits to be prepared in the manufacturing stage are reduced, and the manufacturing efficiency of the LED lighting device 1 can be improved.

  Further, the resistance values of the first resistor R1 and the second resistor R2 of the resistance voltage dividing circuit 62 are set based on the average value of the light amount of the LED 3, respectively. It does not fluctuate significantly and falls within a certain range. Therefore, the input voltage value Vc to the output current setting unit 61 is mainly determined by the resistance values of the first resistor R1 and the second resistor R2, and the correction amount of the correction resistor Rc at the input voltage value Vc can be reduced. . In the above configuration, since the correction resistor Rc is connected to the current control unit 6 by the wire harness or the substrate wiring 64, noise may be applied between the correction resistor Rc and the current control unit 6. . However, as described above, if the correction amount of the correction resistor Rc at the input voltage value Vc is reduced, the influence of noise on the input voltage value Vc is also reduced, so that fluctuation in the light output of the LED 3 due to noise is suppressed. Can do.

  In the present embodiment, the configuration in which the correction resistor Rc is arranged in parallel to the second resistor R2 of the resistance voltage dividing circuit 62 has been described. However, the correction resistor Rc is arranged in parallel to the first resistor R1. May be. However, if the correction resistor Rc is arranged in parallel with the second resistor R2, the contribution ratio of the resistance value of the correction resistor Rc in the voltage division ratio multiplied by the reference voltage Vref increases, so that the input voltage can be efficiently input. The value Vc can be corrected.

  Next, an LED lighting device according to a second embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 4, in the LED lighting device 1 according to the present embodiment, the current control unit 6 includes a constant current circuit 63 and a predetermined resistor R3 through which the current Ir from the constant current circuit 63 flows. The input voltage value Vc for the current control unit 6 is set by the voltage value generated in the predetermined resistor R3. The correction resistor Rc is arranged in parallel with the predetermined resistor R3. Therefore, the voltage value generated in the predetermined resistor Rc is corrected by the correcting resistor Rc, and the corrected voltage value becomes the input voltage value Vc. Other configurations are the same as in the above embodiment.

  FIG. 5 shows the relationship between the light amount of the LED 3 (light emitting diode elements D1, D2,... Dn), the supply current Io, the correction resistor Rc, and the input voltage value Vc to the output current setting unit 61 under various conditions.

  Under a certain condition (1), when the output voltage of the constant current circuit 63 is Vs and the resistance value of the correction resistor Rc is Rc1, the input voltage value Vc1 is obtained by the following equation (7).

[Equation 4]
Vc = Vs · (R3 · Rc1) / (R3 + Rc1) = Vc1 (Expression 7)

  When the input voltage value Vc1 is input, the output current setting unit 61 outputs a control signal for controlling the switching element Q0 of the DC-DC converter 51 according to the input voltage value Vc. A supply current Io1 is output. At this time, if the light-emitting diode elements D1, D2,... Dn have a light amount C1, respectively, the light output of the LED 3 is C1 × n which is a target value.

  However, in another condition (2), the light amounts of the light emitting diode elements D1, D2,... Dn when the supply current Io1 is output may be C2 (for example, C2> C1) due to individual differences. . In this case, the resistance value of the correction resistor Rc is set to Rc2 (Rc1> Rc2) so that the light-emitting diode elements D1, D2,. ). In FIG. 5, the input voltage value Vc and the like when the resistance value of the correction resistor Rc is Rc2 are shown as the condition (4). In this condition (4), when the resistance value of the correction resistor Rc is Rc2, the input voltage value Vc2 is obtained by the following equation (8).

[Equation 5]
Vc = Vs · (R3 · Rc2) / (R3 + Rc2) = Vc2 (Equation 8)

  Further, in yet another condition (3), the light emitting diode elements D1, D2,... Dn may each have a light amount C3 (for example, C1> C3) when the supply current Io1 is output. In this case, the resistance value of the correction resistor Rc is set to Rc3 (Rc3> Rc1) so that the light-emitting diode elements D1, D2,. To do. In FIG. 5, the input voltage value Vc and the like when the resistance value of the correction resistor Rc is Rc2 are shown as the condition (5). In this condition (5), when the resistance value of the correction resistor Rc is Rc3, the input voltage value Vc3 is obtained by the following equation 9.

[Equation 6]
Vc = Vs · (R3 · Rc3) / (R3 + Rc2) = Vc3 (Equation 9)

  According to this configuration, the LED 3 that does not output the same light amount even when the same current is applied to the lamp 4 by setting the resistance value of the correction resistor Rc according to the light amount variation of the LED 3, as in the above embodiment. Even if it is used, it is possible to easily correct variations in the amount of light of the LED 3. In addition, the circuit configuration of the current control unit 6 can be simplified.

  The LED lighting device 1 according to the embodiment described above can be applied not only to an in-vehicle lighting device but also to a lighting fixture using an LED as a light source. Here, as shown in FIGS. 6A and 6B, a downlight type lighting fixture 7 embedded in a ceiling or the like is taken as an example. The luminaire 7 includes a light source unit 71 in which a plurality of diode elements D1, D2,. And comprising. In addition, the lighting fixture 7 is a terminal block to which a frame body portion 73 that is fitted in an opening formed in a ceiling or the like and holds the light source portion 71 and the like, and a power supply line for receiving power supply from a commercial power supply AC are connected. 74 and an attachment spring 75 for fixing the frame body portion 73 to the ceiling or the like. In addition, when used for such a lighting fixture 7, it replaces with or adds to the direct-current power supply DC and DC-DC converter 51 which were mentioned above, and the AC-DC converter which converts the alternating current supplied from commercial power supply AC into a direct current (Not shown) is mounted.

  The present invention is not limited to the above embodiment, and various modifications can be made. For example, in the above embodiment, the correction resistor Rc is displayed as a single unit, but the correction resistor Rc may be composed of a plurality of resistors arranged in series or in parallel. Further, as long as the resistance value can be set as appropriate, the resistance value is not limited to a predetermined resistance having a predetermined resistance value or a variable resistance such as the thermistor described above, and for example, a resistance element such as an LED may be used.

DESCRIPTION OF SYMBOLS 1 LED lighting device 2 In-vehicle lighting device 3 Light emitting diode (LED)
5 DC power supply circuit 6 Current control unit 62 Resistance voltage dividing circuit 63 Constant current circuit 64 Wire harness or substrate wiring 7 Lighting fixture R1 First resistance (resistance)
R2 Second resistance (resistance)
R3 Default resistance Rc Correction resistance (temperature-sensitive resistance or thermistor)
Vc Input voltage value Vref Reference voltage

Claims (5)

An LED lighting device comprising: a DC power supply circuit that supplies current to the LED; and a current control unit that controls supply current from the DC power supply circuit to the LED,
The current control unit controls a supply current to the LED according to a predetermined input voltage value, and a resistance voltage dividing circuit including two resistors arranged in series from a reference voltage, and a variation in light quantity of the LED. A correction resistor that corrects the input voltage value that is set according to the input voltage value, and the input voltage value is set by a resistance voltage-dividing value of the reference voltage
The correction resistor is arranged in parallel with one of the two resistors of the resistance voltage dividing circuit and is away from a circuit group constituting the current control unit, and is a wire harness or a board An LED lighting device, wherein the LED lighting device is connected to the current control unit by wiring . The LED lighting device according to claim 1, wherein the correction resistor is a temperature sensitive resistor or a thermistor. The current control unit includes a constant current circuit and a predetermined resistance through which a current from the constant current circuit flows, and the input voltage value is set by a voltage value generated in the predetermined resistance,
The correction resistor, LED lighting device according to claim 1 or claim 2, characterized in that are arranged in parallel with the predetermined resistance. The vehicle-mounted illuminating device using the LED lighting device as described in any one of Claims 1 thru | or 3. The lighting fixture using the LED lighting device as described in any one of Claims 1 thru | or 3.

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