JP6089266B2 - Lighting device and lamp, lighting system and vehicle using the same - Google Patents

Lighting device and lamp, lighting system and vehicle using the same Download PDF

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JP6089266B2
JP6089266B2 JP2011094918A JP2011094918A JP6089266B2 JP 6089266 B2 JP6089266 B2 JP 6089266B2 JP 2011094918 A JP2011094918 A JP 2011094918A JP 2011094918 A JP2011094918 A JP 2011094918A JP 6089266 B2 JP6089266 B2 JP 6089266B2
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lighting
light source
unit
current
circuit unit
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JP2012227045A (en
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神原 隆
隆 神原
濱名 哲也
哲也 濱名
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パナソニックIpマネジメント株式会社
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Description

  The present invention relates to a lighting device, a lamp using the lighting device, a lighting system, and a vehicle.

  Conventionally, a vehicular lamp using an LED (light emitting diode) as a light source has been provided (see, for example, Patent Document 1). The lamp includes an LED module including a plurality of LED elements, an optical unit including a lens and a reflector, and a power supply device that supplies lighting power to the LED module. The power supply device is provided with an abnormality notification circuit that outputs an abnormality signal when an abnormality occurs in the output from the power supply device, and this abnormality signal is transmitted to the vehicle-side unit through the abnormality notification signal line.

JP 2009-284721 A (paragraph [0107] -paragraph [0110] and FIGS. 9-10)

  In the vehicular lamp shown in Patent Document 1 described above, when an abnormality occurs in the output of the power supply device, the output to the LED module is stopped. For example, when this lamp is used as a headlight of a vehicle, it is nighttime. There was a possibility that the safety of could not be ensured. In addition, a dedicated signal line for notifying the abnormality of the power supply device is necessary, which increases the cost.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to continuously turn on the light source even if an abnormality occurs in the light source, and to suppress the cost increase. An object of the present invention is to provide a lighting device capable of notifying the outside of the abnormality, a lamp using the same, a lighting system, and a vehicle.

A lighting device according to the present invention includes a lighting circuit unit that receives power supply from a DC power source and outputs lighting power to a light source configured by a plurality of LED modules connected in series, and a control unit that controls the output of the lighting circuit unit And a state detection unit that detects the state of the light source, the control unit has an input current detection unit that detects an input current to the lighting circuit unit, and the control unit includes a lighting circuit unit during normal operation. A first threshold value that is a value equal to or less than half of the input current is set in advance, and the control unit short-circuits at least one LED module among the plurality of LED modules that constitute the light source as a light source abnormality. Upon detection of, while continuing the supply of power to the light source from the lighting circuit unit, the detection current according to the input current detection section and controlling the lighting circuit unit to be equal to or less than the first threshold value.
Moreover, the lighting device of the present invention controls the output of the lighting circuit unit that receives the power supply from the DC power source and outputs the lighting power to the light source composed of a plurality of LED modules connected in series. A control unit, and a state detection unit that detects the state of the light source. The control unit includes a second output current value to the light source when the input current to the lighting circuit unit is less than half of that during normal operation. When the state detection unit detects a short circuit of at least one LED module among the plurality of LED modules constituting the light source as an abnormality of the light source , the control unit detects power from the lighting circuit unit to the light source. while continuing the supply, the output current to the light source and controls the lighting circuit unit to be equal to or less than the second threshold value.

  The lamp of the present invention includes the above lighting device and a light source.

  The lighting system of the present invention includes the above-described lighting device or the above-described lamp, and monitors the current supplied from the DC power source to the lighting circuit unit, and when the current falls below a preset third threshold, Is provided on the DC power supply side.

  A vehicle according to the present invention includes the lighting system described above.

  Even if an abnormality occurs in the light source, it is possible to provide a lighting device, a lamp, a lighting system, and a vehicle that can continuously light the light source and can notify the outside of the light source while suppressing an increase in cost. effective.

It is a schematic block diagram of the lighting device of Embodiment 1. It is a circuit diagram of the control part which comprises the same as the above. It is a circuit diagram of the state detection part which comprises the same as the above. It is a schematic block diagram of the lighting device of Embodiment 2. It is a circuit diagram of the control part which comprises the same as the above. It is a schematic block diagram of the lighting device of Embodiment 3. It is a circuit diagram of the control part which comprises the same as the above. It is a circuit diagram of the control part which comprises the lighting device of Embodiment 4. It is a circuit diagram of the state detection part which comprises the same as the above. It is sectional drawing of the lamp of Embodiment 5. It is a schematic block diagram of the lighting system of Embodiment 6. FIG. 10 is an external perspective view of a vehicle according to a seventh embodiment.

  Hereinafter, embodiments of a lighting device, a lamp using the lighting device, a lighting system, and a vehicle will be described based on the drawings.

(Embodiment 1)
FIG. 1 is a schematic configuration diagram of a lighting device 2 according to the first embodiment. The lighting device 2 receives a power supply from a DC power source (for example, a battery mounted on a vehicle) 1 and outputs lighting power to a light source 3. A circuit unit 21, a control unit 22 that controls the output of the lighting circuit unit 21, and a state detection unit 23 that detects the state of the light source 3 are provided.

  As shown in FIG. 1, the lighting circuit unit 21 includes a transformer T1 for power conversion, a smoothing capacitor C1 provided on the primary side of the transformer T1, and a rectifier provided on the secondary side of the transformer T1. The flyback type DC-DC converter is composed of the diode D1, the smoothing capacitor C2, and the switching element Q1. This lighting circuit unit 21 is input from the DC power source 1 by switching operation of the switching element Q1 at a high frequency (a frequency defined by an after-mentioned oscillator 22g, for example, several hundred kHz) by the drive signal S1 from the control unit 22. The voltage is converted into a DC voltage having a desired voltage value and stored in the capacitor C2. The DC voltage stored in the capacitor C2 is output to the output terminals O1 and O2 via the resistor R1 and supplied to the light source 3. At this time, since a load current flows through the resistor R1, a voltage corresponding to the load current is generated as a negative potential and is input to the control unit 22 as a voltage signal S2.

  FIG. 2 is a circuit diagram of the control unit 22. The control unit 22 includes a first inverting amplifier circuit including an operational amplifier 22b, a capacitor C12, and resistors R14 and R15, and a first error calculation amplifier circuit including an operational amplifier 22a, a capacitor C11, and resistors R12 and R13. Prepare. Further, the control unit 22 compares the output of the first error operational amplifier circuit with the high frequency reference oscillation signal of the male oscillator (high frequency oscillation circuit) 22g, so that the output value from the first inverting amplification circuit becomes the reference voltage Vref1. Comparing the comparator 22e which determines the duty of the drive signal S1 of the switching element Q1 to be equal, and the voltage obtained by dividing the output voltage of the lighting circuit unit 21 by the resistors R16 and R17 with the reference voltage Vref2, thereby comparing the lighting circuit unit 21. And a comparator 22f for detecting a voltage abnormality occurring in the circuit. Further, the control unit 22 includes a second inverting amplifier circuit including an operational amplifier 22d, a capacitor C14, and resistors R20 and R21, and a second error calculation amplifier circuit including an operational amplifier 22c, a capacitor C13, and resistors R18 and R19. With. The output of the comparator 22e and the output of the comparator 22f are input to the AND circuit 22h, and the output of the AND circuit 22h is output to the lighting circuit unit 21 as the drive signal S1 for the switching element Q1.

  FIG. 3 is a circuit diagram of the state detection unit 23. The state detection unit 23 includes a comparator 23a that detects a decrease in the output voltage by comparing a voltage obtained by dividing the output voltage of the lighting circuit unit 21 with the resistors R22 and R23 with a reference voltage Vref4. For example, when the voltage is higher than the reference voltage Vref4, the detection signal S5 output from the comparator 23a is Lo, and when the voltage is lower than the reference voltage Vref4, the detection signal S5 is Hi. The detection signal S5 is input to the control unit 22 as shown in FIG. 1, and the switch SW1 is turned on / off according to the detection signal S5. Specifically, SW1 is turned off when the detection signal S5 is Lo, and SW1 is turned on when the detection signal S5 is Hi, that is, when a decrease in the output voltage of the lighting circuit unit 21 is detected.

  The light source 3 includes, for example, a plurality of (three in FIG. 1) LED modules 31 to 33 connected in series, and each LED module 31 to 33 has four LEDs (light emitting diodes) connected in series. doing.

  Next, the operation of the lighting device 2 will be described. The DC power supplied from the DC power source 1 is converted into a DC voltage having a desired voltage value by the lighting circuit unit 21 and supplied to the light source 3. At this time, the voltage signal S2 is controlled according to the load current flowing through the resistor R1. Input to the unit 22. In the control unit 22, after the voltage signal S2 is inverted and amplified by the first inverting amplifier circuit, an error from the reference voltage Vref1 is calculated by the first error calculation amplifier circuit, and the result is output to the comparator 22e via the resistor R11. Input to non-inverting input. The comparator 22e determines the duty of the drive signal S1 of the switching element Q1 by comparing the above calculation result with the high frequency reference oscillation signal of the oscillator 22g.

  At this time, the output voltage of the lighting circuit unit 21 is input to the control unit 22 as the voltage signal S3. In the control unit 22, the voltage signal S3 is divided by the resistors R16 and R17 and input to the inverting input of the comparator 22f. The comparator 22f compares the voltage with the reference voltage Vref2, and outputs a Hi signal or a Lo signal according to the comparison result. For example, when the above voltage is smaller than the reference voltage Vref2, the Hi signal is output from the comparator 22f. Therefore, the output signal of the comparator 22e is output from the AND circuit 22h, and is applied to the switching element Q1 as the drive signal S1. The That is, in this case, the switching element Q1 is PWM-controlled by the drive signal S1 output from the AND circuit 22h. Here, by setting the reference voltage Vref1 according to the type of the light source 3, so-called constant current control can be performed. At this time, since no abnormality has occurred in the light source 3, the switch SW1 is in an OFF state, and the output of the second error calculation amplifier circuit is not input to the comparator 22e.

  On the other hand, when the output voltage of the lighting circuit unit 21 exceeds a predetermined reference value, the voltage becomes higher than the reference voltage Vref2, and thus a Lo signal is output from the comparator 22f. When the Lo signal is input to the AND circuit 22h, the drive signal S1 output from the AND circuit 22h becomes Lo, and the switching operation of the switching element Q1 is stopped. In this way, the output voltage of the lighting circuit unit 21 is monitored, and once the output voltage exceeds a predetermined reference value, the switching operation of the switching element Q1 is once stopped so that the output voltage does not increase any more. Can do. As a result, it is possible to prevent the output voltage from excessively rising and damaging the apparatus, for example, in a no-load state where the light source 3 is not connected.

  The output voltage of the lighting circuit unit 21 is input to the state detection unit 23 as the voltage signal S4. The state detection unit 23 divides the voltage signal S4 by the resistors R22 and R23 and inputs the voltage signal S4 to the inverting input of the comparator 23a. The comparator 23a compares the voltage with the reference voltage Vref4 and outputs a Hi signal or a Lo signal according to the comparison result. For example, when the output voltage of the lighting circuit unit 21 decreases and the voltage becomes lower than the reference voltage Vref4, a Hi signal is output from the comparator 23a and input to the control unit 22 as the detection signal S5. In the control unit 22, the switch SW1 is turned on by the detection signal S5. When the output voltage of the lighting circuit unit 21 is in the normal range, the Lo signal is output from the comparator 23a, and thus the switch SW1 of the control unit 22 is turned off.

  Here, it is preferable to set the reference voltage Vref4 to a voltage corresponding to the lower limit value of the voltage range that the light source 3 can take during normal lighting. In this case, when the light source 3 is normal, the Lo detection signal is output from the comparator 23a. When S5 is output and a part of the light source 3 is short-circuited, the voltage across the light source 3 is lower than that at normal time, so the Hi detection signal S5 is output from the comparator 23a.

  In the lighting device 2 of the present embodiment, the input current to the lighting circuit unit 21 is detected as a voltage (negative potential) corresponding to the input current by the resistor R2, and this detected voltage is the voltage signal S6. 2 is input to the inverting amplifier circuit. The voltage signal S6 inverted and amplified by the second inverting amplifier circuit is input to the second error calculation amplifier circuit, and the second error calculation amplifier circuit calculates an error between the voltage signal S6 and the reference voltage Vref3, and the result. Is input to the non-inverting input of the comparator 22e via the switch SW1 and the diode D11.

  For example, when the voltage corresponding to the input current to the lighting circuit unit 21 tries to exceed the reference voltage Vref3, the output voltage of the operational amplifier 22c decreases, and the potential of the non-inverting input of the comparator 22e is limited by the output of the operational amplifier 22c. The As a result, the lighting device 2 operates such that the input current to the lighting circuit unit 21 is not more than a predetermined value corresponding to the reference voltage Vref3. The reference voltage Vref3 of the operational amplifier 22c is preferably set to a value such that the input current to the lighting circuit unit 21 is not more than half of the input current during normal operation. Here, in the present embodiment, the input current detection unit is configured by the resistor R2, and the reference voltage Vref3 is the first threshold value.

  Next, a method for determining whether or not the light source 3 is abnormal will be described. First, the conventional method will be described. Assuming that the range of voltages generated in the LED modules 31 to 33 is 11.5 V to 15.5 V (standard value 13.5 V), when the light source 3 is normal, the range of voltages that the light source 3 can take is as follows. 34.5V to 46.5V (standard value 40.5V). If the output current from the lighting circuit unit 21 is 500 mA, the output power range is 17.25 W to 23.25 W (standard value 20.25 W). Here, the input power to the lighting circuit unit 21 is obtained from the output power and the power conversion efficiency. When the power conversion efficiency is 85%, the range of the input power to the lighting circuit unit 21 is about 20.3 W to about 27. .4W (standard value about 23.8W). When the input voltage to the lighting circuit unit 21 is 13.5 V, the range of the input current to the lighting circuit unit 21 is 1.50 A to 2.03 A (standard value 1.76 A).

  On the other hand, when one of the LED modules 31 to 33 has a short circuit failure, the voltage range that the light source 3 can take is 23V to 31V (standard value 27V). If the output current from the lighting circuit unit 21 is 500 mA, the output power range is 11.5 W to 15.5 W (standard value 13.5 W). Furthermore, the range of input power to the lighting circuit unit 21 is about 13.5 W to about 18.2 W (standard value about 15.9 W) because the power conversion efficiency is 85%, and the input power to the lighting circuit unit 21 is The current range is 1.00 A to 1.35 A (standard value 1.18 A).

  When comparing the lower limit value 1.50A of the input current when the light source 3 is normal and the upper limit value 1.35A of the input current when one of the LED modules 31 to 33 is short-circuited, the difference is It is about 10%, and it is difficult to determine an abnormality occurring in the light source 3 by monitoring the input current. In the above example, the input voltage to the lighting circuit unit 21 is constant at 13.5 V. However, when the voltage fluctuation of the DC power supply 1 is taken into consideration, the input current to the lighting circuit unit 21 is normal and abnormal. Since crossing is also conceivable, it is difficult to determine the abnormality of the light source 3 from the difference in input current.

  By the way, in this embodiment, when abnormality of the light source 3 is detected by the state detection unit 23 as described above, the input current to the lighting circuit unit 21 is set to half or less of the input current during normal operation. The difference in input current between the normal time and the abnormal time becomes large, and it becomes easy to determine whether the light source 3 is abnormal. Specifically, since the input current when the light source 3 is normal is 1.50 A to 2.03 A, it may be set to about 0.8 A when the light source 3 is abnormal.

  Thus, according to the present embodiment, since the light source 3 is continuously turned on even when an abnormality occurs in the light source 3, for example, when the lighting device 2 is used for a vehicle headlamp, the driver at night Can be secured. In addition, when an abnormality occurs in the light source 3, the input current to the lighting circuit unit 21 is reduced to half or less than that in the normal operation, so that the difference in input current between the normal time and the abnormal time becomes large. By detecting it, the abnormality of the light source 3 can be reliably detected. Furthermore, since the input current to the lighting circuit unit 21 can be detected outside the lighting device 2, it is not necessary to provide an abnormality notification signal line as in the conventional example, and the cost increase can be suppressed accordingly.

(Embodiment 2)
A second embodiment of the lighting device 2 will be described with reference to FIGS. 4 and 5. In the following description, the same components as those in the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  As illustrated in FIG. 4, the lighting device 2 of the present embodiment includes a lighting circuit unit 21, a control unit 22, and a state detection unit 23.

  As shown in FIG. 5, the control unit 22 includes the first inverting amplifier circuit, the first error calculation amplifier circuit, and the comparator 22f described in the first embodiment, and includes an operational amplifier 22j and resistors R24 and R25. A non-inverting amplifier circuit, a comparator 22k, and an RS flip-flop 22q are provided. The control unit 22 also receives a one-shot pulse circuit 22m that outputs a pulse signal to the reset input of the RS flip-flop 22q in response to the rise of the output of the comparator 22k, and a pulse signal with a preset duty (for example, several hundred kHz). The generated oscillator 22p includes a one-shot pulse circuit 22n that receives a rising edge of the pulse signal from the oscillator 22p and outputs a pulse signal to the set input of the RS flip-flop 22q. The non-inverting amplifier circuit receives a voltage signal S7 corresponding to the current flowing through the switching element Q1 of the lighting circuit unit 21, and is amplified by the non-inverting amplifier circuit. In this embodiment, the reference voltage Vref5 is connected to the non-inverting input of the comparator 22k via the diode D12. This reference voltage Vref5 is used when the detection signal S5 from the state detection unit 23 is Lo. It is set to a high value (a value that does not affect the output of the operational amplifier 22a during normal operation). In addition, the reference voltage Vref5 is set to a low value (a value at which the input current to the lighting circuit unit 21 is less than or equal to half that in normal operation) when the detection signal S5 is Hi. Here, in the present embodiment, the reference voltage Vref5 is the second threshold value.

  Next, the operation of the lighting device 2 will be described. When a pulse signal generated by the oscillator 22p is input to the one-shot pulse circuit 22n, the one-shot pulse circuit 22n receives the rising edge of the pulse signal and outputs a pulse signal to the set input of the RS flip-flop 22q and the AND circuit 22h. . At this time, since the output voltage of the lighting circuit unit 21 is equal to or lower than a predetermined reference value, a Hi signal is output from the comparator 22f. When a pulse signal is input from the one-shot pulse circuit 22n, the RS flip-flop 22q outputs a Hi signal. As a result, a Hi drive signal S1 is output from the AND circuit 22h, and the switching element Q1 of the lighting circuit unit 21 is activated. Turn on (turn on).

  On the other hand, the current flowing through the switching element Q1 of the lighting circuit unit 21 is detected by the resistor R3 and input to the non-inverting amplifier circuit as the voltage signal S7. In the non-inverting amplifier circuit, the voltage signal S7 is amplified and input to the comparator 22k. Further, the output current of the lighting circuit unit 21 is detected by the resistor R1, and is input to the first inverting amplifier circuit as the voltage signal S2. The voltage signal S2 inverted and amplified by the first inverting amplifier circuit is input to the first error calculation amplifier circuit, and an error from the reference voltage Vref1 is calculated. When the calculation result is input to the comparator 22k, the comparator 22k compares the calculation result with the voltage signal S7 from the non-inverting amplifier circuit and outputs a pulse signal. The one-shot pulse circuit 22m outputs the pulse signal to the reset input of the RS flip-flop 22q in response to the rise of the pulse signal of the comparator 22k, and the RS flip-flop 22q outputs the Lo signal by this reset input. As a result, the Lo drive signal S1 is output from the AND circuit 22h, and the switching element Q1 is turned off (turned off). Then, by repeating the above on / off operation, feedback control in a so-called current mode is performed.

  Here, when an abnormality occurs in the light source 3, a Hi detection signal S5 is output from the state detection unit 23, and the control unit 22 sets the reference voltage Vref5 to the low value by the detection signal S5. Then, the switching operation of the switching element Q1 is controlled so that the output current of the lighting circuit unit 21 is equal to or less than a predetermined current corresponding to the reference voltage Vref5.

For example, when the lighting circuit unit 21 is operated in a current discontinuous mode (a mode in which the current flowing in the primary side and the current flowing in the secondary side of the transformer T1 is discontinuous), the primary of the lighting circuit unit 21 A sawtooth switching current is generated on the side, and if the peak value of the current at this time is Ip, the power W1 converted by the transformer T1 is
W1 = (L1 × Ip × Ip) / 2
It becomes. Note that L1 is the inductance of the primary coil of the transformer T1. From the above equation, the input power can be set to a desired value or less by limiting the current Ip.

  Thus, according to the present embodiment, since the light source 3 is continuously turned on even when an abnormality occurs in the light source 3, for example, when the lighting device 2 is used for a vehicle headlamp, the driver at night Can be secured. In addition, when an abnormality occurs in the light source 3, the input current to the lighting circuit unit 21 is reduced to half or less than that in the normal operation, so that the difference in input current between the normal time and the abnormal time becomes large. By detecting it, the abnormality of the light source 3 can be reliably detected. Furthermore, since the input current to the lighting circuit unit 21 can be detected outside the lighting device 2, it is not necessary to provide an abnormality notification signal line as in the conventional example, and the cost increase can be suppressed accordingly. Further, when feedback control is performed in the current mode as in the present embodiment, it is not necessary to provide a circuit for detecting the input current as in the first embodiment, and the circuit configuration can be simplified. .

(Embodiment 3)
A third embodiment of the lighting device 2 will be described with reference to FIGS. The lighting device 2 of the present embodiment is a circuit for detecting an input current to the lighting circuit unit 21 (resistor R2, second inverting amplifier circuit, second error calculation amplifier circuit, switch SW1 and diode D11). Is different from the first embodiment in that the reference voltage Vref1 of the operational amplifier 22a is variable, and the other configuration is the same as that of the first embodiment. A description thereof will be omitted.

  As illustrated in FIG. 6, the lighting device 2 of the present embodiment includes a lighting circuit unit 21, a control unit 22, and a state detection unit 23. As shown in FIG. 7, the control unit 22 deletes the above circuit from the control unit 22 of the first embodiment, and makes the reference voltage Vref1 of the operational amplifier 22a variable according to the detection signal S5 from the state detection unit 23. Yes.

  Here, from Embodiment 1, the range of the input current to the lighting circuit unit 21 when the light source 3 is normal is 1.50 A to 2.03 A, and one of the LEDs 31 to 33 constituting the light source 3 is The range of the input current to the lighting circuit unit 21 in the case of a short circuit failure is 1.00 A to 1.35 A. The difference between the lower limit value at normal time and the upper limit value at abnormal time is only about 10%, and it is difficult to detect the abnormality of the light source 3 from these input currents.

  Therefore, in this embodiment, when an abnormality of the light source 3 is detected, the output current to the light source 3 is reduced from 500 mA to 300 mA. In this case, since the voltage range that the light source 3 can take is 23 V to 31 V (standard value 27 V), the output power range is 6.9 W to 9.3 W (standard value 8.1 W). Furthermore, the range of input power to the lighting circuit unit 21 is about 8.1 W to about 10.9 W (standard value about 9.5 W) because the power conversion efficiency is 85%, and the input power to the lighting circuit unit 21 is The current range is 0.60 A to 0.81 A (standard value 0.70 A).

  That is, according to the present embodiment, when an abnormality in the light source 3 is detected, the output current to the light source 3 is reduced from 500 mA to 300 mA, so that the input current to the lighting circuit unit 21 is less than half that in normal operation. By detecting the input current to the lighting circuit unit 21, it is possible to determine whether the light source 3 is abnormal. In addition, since the circuit for detecting the input current is not provided as in the first embodiment, the same effect can be obtained with a simpler configuration.

(Embodiment 4)
Embodiment 4 of the lighting device 2 will be described with reference to FIGS. 8 and 9. In addition, since the whole structure of the lighting device 2 is the same as that of Embodiment 3, refer to FIG. 6 when needed. Moreover, about the structure similar to Embodiment 1, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As illustrated in FIG. 6, the lighting device 2 of the present embodiment includes a lighting circuit unit 21, a control unit 22, and a state detection unit 23.

  As shown in FIG. 8, the control unit 22 includes the first inverting amplification circuit, the first error calculation amplification circuit, the comparator 22f, the male oscillator 22g, the comparator 22e, and the AND circuit 22h described in the first embodiment. An output voltage excessive abnormality detection circuit configured by 22r and a timer 22t, an output voltage excessive abnormality detection circuit configured by a comparator 22s and a timer 22u, and a NOR circuit 22v to which outputs of these circuits are input.

  The state detection unit 23 includes the comparator 23a described in the first embodiment and a timer 23b.

  Next, the operation of the lighting device 2 will be described. Note that the normal operation is the same as that of the first embodiment, and therefore the description thereof is omitted here. The operation when an abnormality occurs in the lighting device 2 will be described.

  When the output terminals O1 and O2 of the lighting device 2 are open or unloaded, the voltage of the non-inverted input of the comparator 22r becomes larger than the reference voltage Vref6, so that the signal output from the comparator 22r is Lo. The timer 22t changes the output from Lo to Hi when this signal is Hi for a predetermined time. As a result, since the Lo signal is output from the NOR circuit 22v, the output of the AND circuit 22h becomes Lo, and the switching operation of the switching element Q1 of the lighting circuit unit 21 is stopped.

  Further, when the output terminals O1 and O2 of the lighting device 2 are short-circuited, the voltage at the inverting input of the comparator 22s becomes smaller than the reference voltage Vref7, so the signal output from the comparator 22s changes from Lo to Hi, The timer 22u changes the output from Lo to Hi when this signal is Hi for a predetermined time. As a result, since the Lo signal is output from the NOR circuit 22v, the output of the AND circuit 22h becomes Lo, and the switching operation of the switching element Q1 of the lighting circuit unit 21 is stopped.

  Further, when one of the LED modules 31 to 33 constituting the light source 3 is short-circuited, the voltage of the inverting input of the comparator 23a of the state detection unit 23 is smaller than the reference voltage Vref4. The output changes from Lo to Hi, and the timer 23b changes the output from Lo to Hi and outputs the Hi signal to the control unit 22 when the signal is Hi for a predetermined time.

  Thus, according to the present embodiment, by providing the timers 22t, 22u, and 23b, it is possible to reliably detect an abnormality occurring in the lighting device 2 and the light source 3 without being affected by noise. Further, similarly to the first embodiment, it is possible to provide the lighting device 2 that can ensure safety and suppress an increase in cost while notifying the abnormality of the light source 3 to the outside.

(Embodiment 5)
FIG. 10 is a cross-sectional view of the vehicle headlight (lamp) 4 according to this embodiment. The headlight 4 includes a light source 3, a lens and a reflector, the optical unit 5 disposed in front of the light source 3 (left side in FIG. 10), and the above-described embodiment for supplying lighting power to the light source 3. The lighting device 2 described in 1 to 4 is provided.

  The lighting device 2 and the light source 3 are electrically connected by an output line L2, and lighting power is supplied to the light source 3 through the output line L2. A heat radiating plate 6 is attached to the light source 3, and heat generated by the light source 3 is radiated to the outside by the heat radiating plate 6. Further, the optical unit 5 is for controlling the light distribution of the light emitted from the light source 3. The lighting device 2 is supplied with power via a power line L1 from a battery (not shown) provided on the vehicle side.

  Thus, according to the present embodiment, by using the lighting device 2 described in the first to fourth embodiments, the light source 3 can be continuously lit even if an abnormality occurs in the light source 3, In particular, when the vehicle headlight 4 is used, the field of view can be ensured and the oncoming vehicle can be recognized by the oncoming vehicle or the like, and the safety of the driver at night can be ensured. Further, since the abnormality of the light source 3 can be determined by detecting the input current to the lighting device 2 on the vehicle side, it is not necessary to provide a separate signal line for notifying the abnormality from the lighting device 2 side to the vehicle side. You can suppress the up.

(Embodiment 6)
FIG. 11 is a schematic configuration diagram of the lighting system of the present embodiment. This lighting system monitors the light source 3, the lighting device 2 that supplies lighting power to the light source 3, and the output current of the DC power source 1 (that is, the current supplied to the lighting circuit unit 21 of the lighting device 2), and an abnormality occurs. A power supply current monitoring unit 7 that sometimes outputs an abnormal signal to the outside is provided. A power supply harness 8 is connected between the power supply current monitoring unit 7 and the lighting device 2.

  The power supply current monitoring unit 7 includes a comparator 71, and a voltage corresponding to the output current of the DC power supply 1 is input to the inverting input of the comparator 71 and compared with the reference voltage Vref8. When the above voltage is lower than the reference voltage Vref8, that is, when the output current of the DC power supply 1 decreases, the output of the comparator 71 changes from Lo to Hi, and the outside is informed that an abnormality has occurred due to this Hi signal. be able to. For example, when this lighting system is mounted on a vehicle, the driver can be notified that an abnormality has occurred by transmitting this Hi signal to the vehicle-side unit and displaying a warning light or the like. Here, in the present embodiment, the reference voltage Vref8 is the third threshold value.

  Here, the lighting system of the present embodiment includes the lighting device 2 described in the first to fourth embodiments. When the light source 3 is abnormal (for example, a short circuit failure), the input current to the lighting device 2 is normally operated. Since the power current monitoring unit 7 detects the input current, the abnormality of the light source 3 can be detected and notified to the outside. Further, it is not necessary to separately provide a signal line for notifying abnormality from the lighting device 2 side to the vehicle side, so that an increase in cost can be suppressed.

  The power supply voltage monitoring unit 7 described above is an example, and any other device may be used as long as it can detect that the input current to the lighting device 2 has decreased when the light source 3 is abnormal. The reference voltage Vref8 of the comparator 71 may be variable according to the supply voltage, and may be set as appropriate according to the specifications of the light source and the lighting device.

(Embodiment 7)
FIG. 12 is an external perspective view of the vehicle 9 according to the present embodiment. The vehicle 9 is mounted with the lighting device 2, the pair of headlights 4 and 4, and the lighting system. Therefore, according to the present embodiment, it is possible to provide the vehicle 9 that can ensure safety and can notify the abnormality of the light source 3 to the outside while suppressing an increase in cost. Further, it is not necessary to separately provide a signal line for notifying abnormality from the lighting device 2 side to the vehicle 9 side, so that the weight is reduced and the vehicle 9 is economical (high energy efficiency such as fuel efficiency). Can do.

  In the first to seventh embodiments described above, a flyback type DC-DC converter has been described as an example of the lighting circuit unit 21, but a converter of another type (eg, SEPIC, Cuk, or forward) may be used. . Moreover, in the above-mentioned Embodiments 1-7, although the light source 3 is comprised by the three LED modules 31-33, the structure of a light source is not limited to said embodiment. Further, in the above-described first to seventh embodiments, the proportional-integral control by the error calculation circuit is used as the constant current control technique, but the constant current control technique is not limited to the above technique as long as the constant current control is possible.

DESCRIPTION OF SYMBOLS 1 DC power supply 2 Lighting device 3 Light source 21 Lighting circuit part 22 Control part 23 State detection part

Claims (6)

  1. A lighting circuit unit that receives power supply from a DC power source and outputs lighting power to a light source composed of a plurality of LED modules connected in series;
    A control unit for controlling the output of the lighting circuit unit;
    A state detection unit for detecting the state of the light source,
    The control unit has an input current detection unit that detects an input current to the lighting circuit unit,
    In the control unit, a first threshold value that is a value that is half or less of an input current to the lighting circuit unit during normal operation is preset,
    When the state detection unit detects a short circuit of at least one LED module among the plurality of LED modules constituting the light source as an abnormality of the light source , the control unit supplies power from the lighting circuit unit to the light source. while continuing the lighting device the detected current due to the entering force current detecting unit and controls the lighting circuit unit to be equal to or less than the first threshold value.
  2. A lighting circuit unit that receives power supply from a DC power source and outputs lighting power to a light source composed of a plurality of LED modules connected in series;
    A control unit for controlling the output of the lighting circuit unit;
    A state detection unit for detecting the state of the light source,
    In the control unit, a second threshold value is set in advance as the value of the output current to the light source when the input current to the lighting circuit unit is less than half of that during normal operation,
    When the state detection unit detects a short circuit of at least one LED module among the plurality of LED modules constituting the light source as an abnormality of the light source, the control unit supplies power from the lighting circuit unit to the light source. while continuing the lighting device output current to the previous SL light source and controls the lighting circuit unit to be equal to or less than the second threshold value.
  3.   A lamp comprising the lighting device according to claim 1 and the light source.
  4. A lighting device according to claim 1 or 2,
    A power source current monitoring unit is provided on the DC power source side for monitoring the current supplied from the DC power source to the lighting circuit unit and notifying the outside when the current falls below a preset third threshold value. A lighting system characterized by
  5. A lamp according to claim 3 ,
    A power source current monitoring unit is provided on the DC power source side for monitoring the current supplied from the DC power source to the lighting circuit unit and notifying the outside when the current falls below a preset third threshold value. A lighting system characterized by
  6.   A vehicle comprising the lighting system according to claim 4.
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JP6089273B2 (en) * 2013-01-09 2017-03-08 パナソニックIpマネジメント株式会社 Lighting device, lighting fixture using the same, and lighting fixture for vehicle
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