JP2011204628A - Failure discrimination device and illumination apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a failure discrimination device for discriminating an illumination load involved in a short fault without reduction in the optical output causing darkness during discrimination of failure.SOLUTION: The failure discrimination device 3 includes a plurality of organic EL elements EL1-EL3 connected in series to one another, switches SW1-SW3 connected in parallel to the organic EL elements EL1-EL3, respectively, a constant current power supply 4 for supplying a constant current to the organic EL elements, a voltage detecting circuit 7 for detecting voltage applied to both ends of the organic EL elements, and a discriminating circuit 8 for discriminating the organic EL element EL2 being in failure. The current flowing in the organic EL elements EL1-EL3 is bypassed via the switches SW1-SW3. During the operation of failure discrimination, the organic EL element involved in short fault and the organic EL element connected with the switch in an ON-state are lit off and the other organic EL element is lit on, and so the organic EL element involved in a short fault can be discriminated. Thus, the optical output is hardly reduced during discrimination of failure.

Description

  The present invention relates to a failure determination device that determines a failure of a lighting load and a lighting fixture using the failure determination device.

  A failure determination device that determines that a lighting load such as a light-emitting diode element (LED element) has failed is known (for example, see Patent Document 1). This failure determination apparatus includes a plurality of lighting loads connected in series and a switch connected in parallel to each lighting load. When this switch is turned on, it bypasses the drive current flowing to the lighting load connected to the switch. The failure of the lighting load is determined by lighting the lighting loads one by one in order and detecting the voltage across each lighting load. At this time, control is performed to turn off the switch connected to the lighting load to be turned on and turn on the switch connected to the lighting load to be turned off.

  Since the failure determination device determines the failure by sequentially lighting the illumination loads one by one, the light output during the failure determination is lowered and darkened. Further, if it is attempted to obtain a high light output with one illumination load during failure determination, the illumination load to which a high voltage is applied may be destroyed due to a great deal of stress.

JP 2005-310998 A

  The present invention has been made in order to solve the above-described problem, and a failure determination device capable of determining a lighting load having a short-circuit failure without reducing the light output and darkening during failure determination, and the same It aims at providing the used lighting fixture.

  The failure determination device of the present invention is a failure determination device for determining a failure of a lighting load, wherein a plurality of lighting loads connected in series, a switch connected in parallel to each of the lighting loads, and the lighting load A constant current power source that supplies a constant current to the lighting load, a voltage detection circuit that detects a voltage applied to both ends of the lighting load, and a detection value by the voltage detection circuit is outside a predetermined range, And a determination circuit that sequentially switches the switch-on state and compares the voltage value of the voltage detection circuit in each state to determine the malfunctioning illumination load.

  The luminaire of the present invention includes a power source and the failure determination device.

  According to the present invention, the current flowing through the lighting load is bypassed via the switch connected in parallel to the lighting load during the failure determination operation. The lighting load connected to the state switch is turned off, and the other lighting loads are turned on. From this, it is possible to determine the illumination load in which the short circuit has failed. As a result, the light output hardly decreases during the failure determination, so that it can be prevented from becoming dark.

The electric circuit diagram of the lighting fixture provided with the failure determination apparatus which concerns on one Embodiment of this invention. The electrical circuit diagram of the discrimination circuit and voltage detection circuit of the failure discrimination device. (A) is a diagram showing an output signal from the SW1 drive circuit of the failure determination device, (b) is a diagram showing an output signal from the SW2 drive circuit, (c) is a diagram showing an output signal from the SW3 drive circuit, (D) is a figure which shows the detection voltage waveform Vdet of the voltage detection part, and the reference voltage Vbc. (A) is a diagram showing an output signal from the SW1 drive circuit of the failure determination device, (b) is a diagram showing an output signal from the SW2 drive circuit, (c) is a diagram showing an output signal from the SW3 drive circuit, (D) is a figure which shows the detection voltage waveform Vdet of the voltage detection part, and the reference voltage Vab.

  A lighting apparatus using a failure determination device according to an embodiment of the present invention will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the luminaire 1 includes a load module 2 and a constant current power source 4 that supplies a constant current to the load module 2, and a failure determination that detects and determines a failure of a lighting load in the load module 2. The device 3 is incorporated. The constant current power source 4 is supplied with power from the power source Vin.

  The load module 2 includes a plurality of lighting loads connected in series, ie, organic EL (electroluminescence) elements EL1, EL2, and EL3, and switches SW1 that are electrically connected in parallel to the respective organic EL elements EL1 to EL3. SW2 and SW3 and a connection part 5 for electrical connection with the constant current power source 4 are provided. The organic EL elements EL <b> 1 to EL <b> 3 are supplied with a constant current from the constant current power source 4. When the switches SW1 to SW3 are turned on, they bypass the drive current that flows through the organic EL elements EL1 to EL3 connected to the switches SW1 to SW3. When the failure determination device 3 detects a failure of the organic EL element, the failure determination device 3 starts to determine the failed organic EL element.

  The constant current power source 4 includes a main circuit 6, a voltage detection circuit 7, a determination circuit 8, a control circuit 9, a SW1 drive circuit 10 a, a SW2 drive circuit 10 b, a SW3 drive circuit 10 c, and a connection unit 11. The main circuit 6 controls the current supplied to the load module 2 based on the power from the power source Vin. Supply of current to the load module 2 is performed via a connection portion 11 that is electrically connected to the connection portion 5 of the load module 2.

  The load module 2 includes a capacitance component Cp that is electrically connected in parallel with each of the organic EL elements EL1 to EL3. In the present embodiment, the load module 2 includes three organic EL elements EL1 to EL3, switches SW1 to SW3, and three capacitance components Cp, but the number is arbitrary. Further, the illumination load is not composed of an organic EL element, but may be composed of a light emitting diode element (LED element) or the like.

  The main circuit 6 includes an electrolytic capacitor C1, a switching element Q1 composed of an FET or the like, a drive circuit 6a that drives the switching element Q1, a current detection resistor Rd, and a feedback unit that controls the detection value of the resistor Rd to be constant. 6b. A regenerative diode D1 for flowing a regenerative current generated when the element is off is connected in series to the switching element Q1, and a series circuit of an inductor L1 and an electrolytic capacitor C1 is connected in parallel to the diode D1. Yes. The connection part 11 is arrange | positioned in parallel with the electrolytic capacitor C1. The resistor Rd is inserted between the ground side terminal of the connecting portion 11 and the electrolytic capacitor C1.

  In the main circuit 6, when the switching element Q1 is on, a current flows from the power source Vin through the path of the switching element Q1, the inductor L1, and the electrolytic capacitor C1, and power is stored in the electrolytic capacitor C1. The load module 2 is lit by the electric power stored in the electrolytic capacitor C1. Further, when the switching element Q1 is off, current is regenerated through the path of the inductor L1, the electrolytic capacitor C1, and the regenerative diode D1.

  The feedback unit 6b includes an operational amplifier OP1 that outputs a signal due to a voltage difference between the two input terminals to the drive circuit 6a, and makes the current flowing through the organic EL elements EL1 to EL3 constant. In the operational amplifier OP1, the current detection voltage from the resistor Rd is applied to the negative input terminal via the resistor R1. The output terminal and the negative input terminal of the operational amplifier OP1 are connected by a gain adjusting resistor R2. The operational amplifier OP1 is connected to the grounded power supply voltage Vd at its plus input terminal.

  The voltage detection circuit 7 includes lighting voltage detection resistors R3 and R4 connected in series between the input terminal of the connection unit 11 and the ground, and both ends of the input terminal of the organic EL element EL1 and the output terminal of the organic EL element EL3. In order to detect the voltage applied to the resistor R3, the voltage at the connection point of the resistors R3 and R4 is output to the discrimination circuit 8 and the control circuit 9.

  The determination circuit 8 detects a failure of the organic EL element from the voltage at the connection point between the resistor R3 and the resistor R4, and determines the failed organic EL element. The control circuit 9 outputs a drive signal to the electrically connected drive circuit 6a, and outputs a drive signal to each of the electrically connected SW drive circuits 10a to 10c. The drive circuit 6a controls the on / off operation of the switching element Q1 according to the drive signal from the control circuit 9. The SW drive circuits 10a to 10c control the on / off operations of the corresponding switches SW1 to SW3 according to the drive signal from the control circuit 9, respectively.

  As shown in FIG. 2, the determination circuit 8 includes a comparator COMP1, a comparator COMP2, an open detection control unit 8a, a short circuit detection control unit 8b, a resistance connected in series between the control power source Vcc and the ground. Ra, Rb, Rc, and changeover switch SW0 are provided. The points A, B, and C in the figure correspond to the same symbols in FIG.

  In the comparator COMP1, the negative input terminal is electrically connected to the connection point of the resistors Ra and Rb, the positive input terminal is electrically connected to the connection point of the resistors R3 and R4, and the output terminal is an open detection control unit. 8a is electrically connected. The comparator COMP2 has a positive input terminal electrically connected to a connection point between the resistors Rb and Rc, a negative input terminal connected electrically to a connection point between the resistors R3 and R4, and an output terminal short-circuit detection control unit. 8b is electrically connected. The changeover switch SW0 has a contact (x) connected to the output side of the open detection control unit 8a, an open contact (y), and a contact (z) connected to the output side of the short circuit detection control unit 8b.

  A detection voltage Vdet is generated at a connection point between the resistors R3 and R4, a reference voltage Vab is generated at a connection point between the resistors Ra and Rb, and a reference voltage Vbc is generated at a connection point between the resistors Rb and Rc. When the organic EL elements EL1 to EL3 are in a steady state, Vdet satisfies Vbc ≦ Vdet ≦ Vab, which is within a predetermined range. When at least one organic EL element is in an open failure state, Vdet is Vdet> Vab, which is outside a predetermined range, and a high signal is output from COMP1. Further, when at least one organic EL element is in a short-circuit fault state, Vdet becomes Vdet <Vbc, which is outside a predetermined range, and a “high” signal is output from COMP2. Thereby, the determination circuit 8 can detect an open failure and a short-circuit failure of the organic EL element by comparing Vdet with Vab and Vbc.

  The change-over switch SW0 is connected to the contact (y) in the steady state, and is switched to the contact (x) by the open detection control unit 8a that has received the “high” signal from the COMP1 in the open failure state. In this case, the short-circuit detection control unit 8b that has received the “high” signal from COMP2 switches to the contact (z). When the changeover switch SW0 is switched from the contact (y) to the contact (x), the open detection control unit 8a is configured to detect the organic EL element that has failed due to the open circuit via the control circuit 9 or the like. Control. When the change-over switch SW0 is switched from the contact (y) to the contact (z), the short-circuit detection control unit 8b uses the switches SW1 to SW3 via the control circuit 9 or the like to determine the organic EL element that has short-circuited. Control.

  Here, the operation of the failure determination device 3 when a short-circuit failure is detected will be described with reference to FIG. 3A shows an output signal from the SW1 drive circuit 10a, FIG. 3B shows an output signal from the SW2 drive circuit 10b, and FIG. 3C shows an output signal from the SW3 drive circuit 10c. . FIG. 3D shows the detection voltage waveform Vdet (solid line portion) of the voltage detection circuit 7 and the reference voltage Vbc (one-dot chain line portion) superimposed on each other.

  In the period of t1, the determination circuit 8 detects the occurrence of a short circuit failure of the organic EL element when the detection voltage Vdet decreases and falls below the reference voltage Vbc. When a short circuit failure is detected, the changeover switch SW0 is switched from the contact point (y) to the contact point (z), and a short circuit failure determination mode for determining which organic EL element has a short circuit failure is set. During the short-circuit fault determination mode, the organic EL element in which the short-circuit fault has occurred and the organic EL element in which the fault is being determined are turned off, and the other organic EL elements are turned on.

  During the period from t2 to t4, the short-circuit detection control unit 8b performs control so that all the switches SW1 to SW3 are turned on one by one through the control circuit 9 and the SW drive circuits 10a to 10c. Specifically, the short circuit detection control unit 8b turns on only the switch SW1 during the period t2, turns on only the switch SW2 during the period t3, and turns on only the switch SW3 during the period t4. Each period from t2 to t4 is set at the same time. Each period from t2 to t4 may be set at a different time.

  Since the value of Vdet increases only during the period t3, the short-circuit detection control unit 8b determines the organic EL element EL2 that has a short-circuit failure. After the failure determination, control is performed by the control circuit 9 so that only the switch SW2 connected to the failed organic EL element EL2 is kept on, the short-circuit failure determination mode is terminated, and the changeover switch SW0 is connected to the contact (z ) To contact (y). Since the failure determination device 3 bypasses the current flowing through the short-circuited organic EL element EL2 with the switch SW2, the organic EL element EL2 is turned off and the other organic EL elements EL1 and EL3 are turned on. Accordingly, the organic EL light emitting element EL2 does not repeat the short circuit state and the steady state, thereby preventing flickering. In addition, when determining the failed organic EL element, the switches SW1 to SW3 are turned on in the order in which the organic EL elements EL1 to EL3 are arranged. The switches SW1 to SW3 may be turned on in order. Further, the voltage applied to the load module 2 may be lowered by the amount corresponding to the failed organic EL element EL2, and the reference voltages Vab and Vbc may also be changed.

  Next, the operation of the failure determination device 3 when an open failure is detected will be described with reference to FIG. 4A shows an output signal from the SW1 drive circuit 10a, FIG. 4B shows an output signal from the SW2 drive circuit 10b, and FIG. 4C shows an output signal from the SW3 drive circuit 10c. . FIG. 4D shows the detection voltage waveform Vdet (solid line portion) of the voltage detection circuit 7 and the reference voltage Vab (one-dot chain line portion) superimposed.

  In the period t1, the determination circuit 8 detects the occurrence of an open failure of the organic EL element by increasing the detected voltage Vdet and exceeding the reference voltage Vab. When an open failure is detected, the change-over switch SW0 is switched from the contact (y) to the contact (x), and an open failure determination mode for determining which organic EL element has an open failure is set. During the open failure determination mode, since the current path is lost due to the open failure of the organic EL elements, all the organic EL elements EL1 to EL3 are turned off.

  In the period from t2 to t4, the open detection control unit 8a controls the switches SW1 to SW3 to be turned on one by one through the control circuit 9 and the SW drive circuits 10a to 10c. Specifically, the opening detection control unit 8a turns on only the switch SW1 during the period t2, turns on only the switch SW2 during the period t3, and turns on only the switch SW3 during the period t4. Each period from t2 to t4 is set at the same time.

  The open detection control unit 8a determines the organic EL element EL2 that has failed due to a decrease in the value of Vdet only during the period t3. After the failure determination, control is performed by the control circuit 9 so that only the switch SW2 connected to the failed organic EL element EL2 is turned on, the open failure determination mode is terminated, and SW0 is connected from the contact (x). Switch to contact (y). The failure determination device 3 bypasses the current flowing through the open-circuit failure organic EL element EL2 by the switch SW2, so that the remaining organic EL elements EL1 and EL3 are lit again.

  In the failure determination device 3 configured as described above, the current flowing through the organic EL elements EL1 to EL3 is bypassed via the switches SW1 to SW3 connected in parallel to the organic EL elements EL1 to EL3. A short-circuited organic EL element connected to an on-state switch is turned off, and another organic EL element is turned on, so that the short-circuited organic EL element can be identified. As a result, the light output hardly decreases during the failure determination, so that it can be prevented from becoming dark. Further, it is possible to determine an organic EL element that has failed open.

  In addition, this invention is not restricted to the structure of said embodiment, A various deformation | transformation is possible in the range which does not change the summary of invention. For example, in order to determine a faulty organic EL element, only one switch is sequentially switched on, but a plurality of switches may be switched on sequentially.

DESCRIPTION OF SYMBOLS 1 Lighting fixture 2 Failure discrimination device 4 Constant current power supply 7 Voltage detection circuit 8 Discrimination circuit EL1, EL2, EL3 Organic EL element (lighting load)
SW1, SW2, SW3 Switch Vin Power supply

Claims (2)

A failure determination device for determining a failure of a lighting load,
A plurality of lighting loads connected in series;
A switch connected in parallel to each of the lighting loads;
A constant current power source for supplying a constant current to the lighting load;
A voltage detection circuit for detecting a voltage applied to both ends of the lighting load;
When the detection value by the voltage detection circuit is outside a predetermined range, the switch is turned on sequentially, and the voltage value by the voltage detection circuit in each state is compared to cause a failure. A failure determination device comprising: a determination circuit for determining an illumination load.   A lighting apparatus comprising a power source and the failure determination device according to claim 1.

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