JP5639391B2 - LED lighting circuit and lighting apparatus using the same - Google Patents

Description

  The present invention relates to an LED lighting circuit suitable for a power distribution system that performs LED lighting and a lighting apparatus using the LED lighting circuit, and more particularly to measures against disconnection when a plurality of LEDs provided in parallel are subjected to constant current control collectively.

  FIG. 2 is a conventional example of a power distribution system that performs LED illumination (Patent Document 1). The DC power output from the power converter 5 is temporarily supplied to the DC system unit (LED controller 6a) via the conductive bar 8 serving as a DC power supply path, and the power is supplied from the DC system unit to the LED module 11. Therefore, it is possible to supply power to the plurality of LED modules 11 from one power conversion unit 5 via one or a plurality of DC system units, thereby realizing a power distribution system that can easily cope with the plurality of LED modules 11. it can. In addition, the power conversion efficiency is improved as compared with the case where one power source device is associated with one lighting load. In addition, the DC system unit can be used for various lighting control of the LED module 11 by interposing the DC system unit. This is possible through the unit (LED controller 6a).

  When using a large number of LEDs to obtain the required light output, such as when using LEDs (light-emitting diodes) in lighting fixtures, low-current LEDs are highly efficient, and the chip is subdivided to obtain the same light output. In this case, an LED module in which a plurality of LED load circuits composed of a plurality of series LEDs are arranged in parallel with each other is used for the light emitting portion. For such an LED module, the DC power supply is driven to light at a constant current so as to have a predetermined luminance.

  FIG. 4 (a) shows a typical prior art LED lighting circuit having such a configuration. This prior art is disclosed in Patent Document 2. In this LED lighting circuit, an LED module 11 is configured by connecting three LED load circuits 12 in which a large number of LEDs 13 are connected in series in parallel. The LED module 11 detects the total energization current value to each LED load circuit 12 by converting the voltage with a resistor 17a, and the comparator 17b compares the voltage with a reference voltage so that the result becomes a constant value. The PWM control circuit 17c is configured to control the DC-DC converter 16. The DC-DC converter 16 switches the rectified voltage from the DC power supply by the switching element 16b and applies it to the primary side of the transformer 16a, and the DC voltage obtained by rectifying and smoothing the secondary side output by the rectifying and smoothing circuit 16c. By providing each LED load circuit 12, a one-stone flyback converter is provided that insulates the power supply side from the load side. In this LED lighting circuit, each LED load circuit 12 is provided with a constant current circuit 14 as shown in FIG. 4 (b) in series, and the current between the LED load circuits 12, that is, the luminance is evenly distributed. It is comprised so that it may become.

JP 2008-043001 A JP 2004-319583 A

  In the prior art as described above, when a disconnection occurs in any of the LEDs 13 in each LED load circuit 12 connected in parallel to each other, the current to flow through the LED load circuit flows into the remaining LED load circuit, There is a problem that the remaining LED load circuit is lit in an overload state, and the failure spreads in a chain. For example, as shown in FIG. 4A, when a disconnection occurs in any of the three LED load circuits 12, and the DC-DC converter 16 performs constant current control as it is, the remaining LED load circuits include: A current that is 3/2 times flows.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an LED lighting circuit capable of preventing an increase in failure at the time of disconnection of an LED and a lighting fixture using the same when a DC power source collectively drives an LED load circuit composed of a plurality of LEDs at a constant current. Is to provide.

In order to solve the above-described problem, the LED lighting circuit according to claim 1 is provided with respect to an LED module 11 in which a plurality of LED load circuits 12 including a plurality of series-connected LEDs 13 are connected in parallel as shown in FIG. In the LED lighting circuit in which the DC power supply 10 is driven to light at a constant current , each of the LED load circuits 12 has a thermistor (PTC thermistor 1) that is a semiconductor device having a positive resistance temperature characteristic. They are connected in series .

According to a second aspect of the invention, the LED lighting circuit according to claim 1, wherein said DC power source, as shown in FIG. 3, an LED controller 6a with a built-in DC-DC converter 23, the power flowing to the LED module 11 A power detection means 24 for detecting the amount; a set value input means 26 for the amount of power flowing through the LED module 11; and a comparator 25 for comparing a detection result from the power detection means 24 with a set value, It is characterized by comprising a control means 21 that receives an abnormal output from the comparator 25 and outputs an abnormal display or sound, or a notification to the host controller.

Invention of Claim 3 is provided with the LED lighting circuit in any one of Claim 1 or 2 , It is a lighting fixture characterized by the above-mentioned.

According to the first to third aspects of the invention, when any one of the LEDs is disconnected, the remaining LED load circuit flows, in the worst case, the absolute maximum rated current of the LED, causing the LED to break down. It is possible to easily prevent the light from being turned off.
Further, according to the invention of claim 2 , there is an advantage that an abnormal state can be notified and an early response can be achieved by performing an abnormal display or outputting a sound or notifying the host control unit.

It is a circuit diagram of the LED lighting circuit of Embodiment 1 of this invention. It is a block circuit diagram which shows the structural example of the power distribution system using the LED lighting circuit of Embodiment 2 of this invention. It is a block circuit diagram which shows the structural example of the LED controller in the power distribution system using the LED lighting circuit of Embodiment 2 of this invention. It is the circuit diagram of the prior art example disclosed by patent document 2, (a) is a circuit diagram which shows the whole structure of the conventional LED lighting circuit, (b) is a circuit diagram which shows the principal part structure.

(Embodiment 1)
FIG. 1 is a circuit diagram of Embodiment 1 of the present invention. This LED lighting circuit is an LED lighting circuit in which a DC power source 10 is driven to be lit at a constant current with respect to an LED module 11 in which a plurality of LED load circuits 12 including a plurality of series-connected LEDs 13 are arranged in parallel. .

  In the circuit of FIG. 1, a PTC thermistor 1, which is a semiconductor device having a temperature characteristic with a positive resistance value, is inserted in each LED load circuit 12 in series. The PTC thermistor is a positive temperature coefficient thermistor and is a circuit element having a positive temperature characteristic of a resistance value. In other words, the resistance value increases as the ambient temperature increases.

  The constant current power supply 10 supplies a constant current to the LED module 11 using the DC voltage of the capacitor C as an input power supply. ZNR is an overvoltage prevention element, D1 is a diode, and FUSE is a current fuse. The constant current power supply 10 may have the same configuration as that shown in FIG. 4, or may be replaced with an LED controller 6a shown in FIG.

  According to the circuit of FIG. 1, when the DC power source 10 drives and drives an LED module 11 formed by connecting a plurality of LED load circuits 12 in parallel with a constant current, any one of the LEDs 13 or the LED load circuit 12 is disconnected. When an excessive current flows into the remaining LED load circuit 12, the PTC thermistor 1 has a high resistance and a level different from that before the disconnection, but satisfies the absolute maximum current of the LED 13 or less. Therefore, it is possible to prevent excessive current from flowing into the remaining LED load circuit 12 to light up in an overload state, and failure from spreading in a chain. That is, when an open abnormality occurs in any of the LEDs 13 or the LED load circuit 12, when the current exceeding the rated current flows through the remaining LED load circuit 12 and the temperature rises, the resistance value of the PTC thermistor 1 increases. However, a current that is lower than the rated current or that is higher than the rated current and lower than the absolute maximum rated current is allowed to flow. Thereby, the problem that a failure spreads in a chain manner in the remaining LED load circuit 12 does not occur.

  In the conventional example of FIG. 4A, the constant current circuit 14 as shown in FIG. 4B is inserted in series with the LED load circuit 12. In the constant current circuit 14, the transistor Q1 is turned on by the base bias current flowing through the transistor Q1 through the resistor R1, and the emitter current flows through the resistor R2, thereby generating a bias voltage in the capacitor C1. When the bias voltage generated in the capacitor C1 increases, the base current flowing between the base and emitter of the transistor Q2 increases, and the resistance between the collector and emitter of the transistor Q2 decreases, so that the base bias current of the transistor Q1 decreases. The collector current of the transistor Q1 is reduced. However, since the circuit 14 as shown in FIG. 4B is connected in series with each LED load circuit 12, the circuit configuration is complicated as a whole and the mounting area increases.

  On the other hand, according to the configuration of FIG. 1 of the present invention, it is only necessary to insert the PTC thermistor 1 in series. Therefore, the circuit configuration is not complicated, and an increase in mounting area can be suppressed, and the size and weight can be reduced. LED module 11 can be realized.

  In the circuit of FIG. 1, the configuration in which one LED module 11 is driven with constant current by one constant current power supply 10 is shown. However, as described in the second embodiment, the plurality of LED modules 11 are collectively driven with constant current. It is good also as composition to do.

(Embodiment 2)
FIG. 2 is a block circuit diagram of Embodiment 2 of the present invention, in which the configuration of the LED lighting circuit of the present invention is applied to the LED module 11 of a power distribution system that performs LED illumination.

  The circuit configuration of the power conversion unit 5, which is the main configuration of the power distribution system of the present invention, the LED controller 6a configuring the DC system unit, the LED module 11 as the LED lighting terminal, and the battery unit B will be described with reference to FIG. To do.

  First, the power conversion unit 5 rectifies and smoothes a single-phase three-wire 200V commercial AC power supply and converts the DC voltage obtained by the rectifier circuit 5A into a predetermined DC voltage. The DC / DC converter 5B for converting the direct current voltage into a direct current voltage is supplied from the DC / DC converter 5B to the direct current system unit (LED controller 6a) via the conductive bars 8 and 8. .

  In addition, the power converter 5 connects a resistor R to the electric circuit between the rectifier circuit 5A and the DC / DC converter 5B, and detects a power failure of the commercial AC power source from the voltage across the resistor R. A current sensor 5D that detects a current output from the rectifier circuit 5A, and a current monitoring unit 5E that monitors an input current of the power conversion unit 5 from a current detected by the current sensor 5D, and a voltage detection unit 5C. Function as a power failure detection unit that transmits a control signal to the battery unit B through the communication unit 5F and transmits a power failure detection signal to the DC system unit (LED controller 6a) when the voltage detected by the When the current monitoring unit 5E detects that the monitored input current exceeds the threshold value, a control signal is transmitted to the battery unit B through the communication unit 5F in the same manner as when a power failure is detected. Ability, and a control unit 5G having the function of controlling the operation of the DC / DC converter 5B.

  On the other hand, the battery unit B turns on / off the storage battery module 9A composed of the secondary battery group and connecting the storage battery module 9A to the electric circuit between the rectifier circuit 5A in the power converter 5 and the DC / DC converter 5B. A switch circuit 9B and a battery control unit 9D that performs control to turn on the switch circuit 9B while the control signal from the power conversion unit 5 is received via the communication unit 9C are provided, and the switch circuit 9B is turned on. Then, the DC voltage of the storage battery module 9A is input to the DC / DC converter 5B, and the DC of the storage battery module 9A is input from the DC / DC converter 5B to the DC system unit (LED controller 6a) via the conductive bars 8 and 8. Power is supplied. In addition, while direct current is output from the rectifier circuit 5A of the power conversion unit 5, a charging current flows through the diode D through the storage battery module 5A in the battery unit B due to the output. The switch circuit 9B turns on / off the connection of the positive electrode of the storage battery module 9A and passes through the negative electrode for charging.

  As shown in FIG. 3, the LED controller 6 a turns on and off the LED module 11, and adjusts the light intensity of the switch circuit 18 inserted between the conductive bars 8 and 8 and the power supply line 15 that connects the LED module 11. A signal from the operation unit 19 that is an information input operation terminal that gives an instruction to perform is taken in via the interface, and the switch circuit 18 is turned on / off according to the content of the signal, and a power failure detection from the power conversion unit 5 When the signal is received by the communication unit 22, the control unit 21 that controls the switch circuit 18 according to the preset operation content at the time of a power failure and the DC power supply voltage input through the conductive bars 8 and 8 are controlled by the control unit 21. Including a DC / DC converter 23 for converting into an operating voltage of a circuit unit in the LED controller 6a.

  Further, the LED controller 6 a incorporating the DC-DC converter 23 includes a power detection unit 24 that detects the amount of power flowing through the LED module 11, and a power amount setting function as a setting value input unit for the amount of power flowing through the LED module 11. Means 26 and a comparator 25 for comparing a detection result from the power detection means 24 with a set value, and the control unit 21 receives an abnormal output from the comparator 25 and receives an abnormality from the abnormality display unit 27. A function of displaying or outputting sound by the audio output unit 28 or notifying the host control unit by the communication unit 22 is added.

  As shown in FIG. 1, the LED module 11 of the present embodiment is configured by connecting a plurality of LED load circuits 12 each having a plurality of LEDs 13 connected in series, and the amount of lighting power supplied to the parallel circuit. Thus, the light output of each LED 13 is determined, and the DC voltage applied to the power supply line 15 is pulse-controlled (duty ratio control) by turning on / off the switch circuit 18 of the LED controller 6a, so that the amount of lighting power is reduced. The lighting of the LED 13 is dimmed and controlled.

  In the power distribution system of FIG. 2, during normal times when commercial AC power is converted into DC power by the power converter 5 and supplied to the LED controller 6 a through the conductive bars 8, 8, the LED controller 6 a The operation of controlling the lighting of the LED module 11 can be performed according to the used operation instruction.

  In other words, when there is a full lighting instruction by operating the operation unit 19 while the light is turned off or dimming, the LED controller 6a continuously turns on the switch circuit 18 and supplies the maximum amount of lighting power to the LED module 11. Then, all the LEDs are turned on. On the contrary, if there is an instruction to turn off during lighting, the switch circuit 18 is turned off, power supply to the LED module 11 is stopped, and the LED is turned off.

  On the other hand, if there is an up or down dimming instruction from the operation unit 19 during lighting, the on-duty of the switch circuit 18 is gradually decreased or increased according to the dimming instruction operating period, and supplied to the LED module 11. The amount of electric power is changed, and the lighting of the LED is dimmed and controlled.

  When the commercial AC power supply fails, the detection voltage of the voltage detection unit 5C of the power conversion unit 5 becomes equal to or lower than a predetermined value, whereby the control unit 5G sends a control signal to the battery unit B via the communication unit 5F and sends a power failure detection signal. Send to LED controller 6a.

  The control unit 9D of the battery unit B that has received the control signal through the communication unit 9C turns on the switch circuit 9B. By this turning on, the DC voltage of the storage battery module 9A is input to the DC / DC converter 5B. At this time, the operation power supply of each part of the power converter 5 is supplied from the storage battery module 9A and maintains the operation. The voltage detector 5C detects the DC voltage of the storage battery module 9A. However, since no current flows from the rectifier circuit 5A, no current is detected by the current sensor 5D, and the input current monitored by the current monitor 5E is Since the control unit 5G disappears, the control unit 5G maintains the operation of transmitting the above-described control signal to the battery unit B and continues the ON state of the switch circuit 9B.

  As a result, the DC power of the battery unit B is supplied from the DC / DC converter 5B to the LED controller 6a through the conductive bars 8 and 8. On the other hand, since the control unit 21 of the LED controller 6a receives the power failure detection signal, the control circuit 21 controls the switch circuit 18 based on the preset operation content at the time of the power failure. That is, in order to reduce power consumption, the switch circuit 18 is controlled to achieve a predetermined dimming level.

  Alternatively, when a plurality of LED controllers 6a are connected to the power distribution system, the LED controller 6a whose operation content is set to turn off the connected LED modules 11 and the LED modules 11 are turned on. Thus, the LED controller 6a for which the operation content is set is determined in advance, and the operation is thinned out during a power failure.

  By dimming or thinning the lighting of the LED module 11 at the time of a power failure, it is possible to lengthen the time during which the illumination can be secured by the backup power supply by the battery unit B.

  Further, when a power failure is recovered during backup by the battery unit B, a current flows from the rectifier circuit 5A. Therefore, when a current detection signal is input from the current monitoring unit 5E to the control unit 5G, the control unit 5G returns to the normal operation. That is, the supply of DC power by commercial AC power is started from the DC / DC converter 5B. Moreover, since the power failure detection signal is not sent to the LED controller 6a, the operation is returned to the normal state.

  When the detection voltage of the voltage detection unit 5C indicates that the voltage of the storage battery module 9A of the battery unit B has dropped to a certain level due to discharge, the control unit 5G operates the DC / DC converter 5B so as not to overdischarge. While stopping, transmission of a control signal is stopped and the switch circuit 9B of the battery unit B is turned off.

  By the way, the lighting control of the LED module 11 by the LED controller 6a at the time of a power failure is mainly intended to reduce the power consumption. However, in order to notify the user that a power failure has occurred, The controller 21 of the LED controller 6a may control the switch circuit 18 so as to light up at a level. When a plurality of LED controllers 6a are connected to the power distribution system, the LED module 11 under the specific LED controller 6a may be lit at a predetermined dimming level to improve the discrimination. Further, the switch circuit 18 may be controlled so as to blink so as to improve the discrimination.

  The above-mentioned LED controller 6a controls the lighting power amount of the LED module 11 by performing on / off control of the DC voltage for supplying DC power to the LED module 11 by the switch circuit 18 so as to perform dimming. However, the LED controller 6a is provided with a constant current source capable of changing the current value and flowing the constant current of the current value to the LED module 11 as a control signal, and the dimming level designated by the operation of the operation unit 19 Or you may make it let the constant current of the electric current value corresponding to the light control level at the time of a power failure detection flow through the LED controller 6a.

  As described above, in the power distribution system of FIG. 2, the lighting of the LED of the LED module 11 can be dimmed and controlled only by controlling the DC power supplied from the DC system unit (LED controller 6a). No means for dimming control is required on the 11 side.

  Similarly to the first embodiment shown in FIG. 1, if any of the LEDs 13 of the LED load circuit 12 in the LED module 11 is disconnected, the resistance value of the PTC thermistor 1 is increased, so that the remaining LED load is increased. There is no problem that the fault spreads in the circuit 12 in a chain manner. Furthermore, the power detection means 24 in the LED controller 6a detects the amount of power supplied to the load side, and the reference power amount set by the power amount setting means 26 is compared with the comparator 25, so that an abnormality on the load side is detected. When detected, the control unit 21 notifies the abnormal state by performing an abnormal display by the abnormal display unit 27, an output of sound by the audio output unit 27, or a notification to the upper control unit by the communication unit 22, and an early response is made. It has an advantage that can be achieved.

1 PTC thermistor 11 LED module 12 LED load circuit 13 LED

Claims (3)

In an LED lighting circuit in which a DC power source is driven to light at a constant current for an LED module in which a plurality of LED load circuits composed of LEDs in a plurality of stages are connected in parallel, all the LED load circuits include: An LED lighting circuit , wherein a thermistor, which is a semiconductor device having a positive temperature characteristic, is connected in series . The direct current power source is an LED controller incorporating a DC-DC converter, and includes a power detection means for detecting the amount of power flowing through the LED module, a set value input means for the amount of power flowing through the LED module, and the power detection means. Comprising a comparator for comparing the detection result from the set value and a control means for receiving an abnormal output from the comparator and outputting an abnormality display or sound or notification to the host controller. LED lighting circuit according to claim 1, characterized in that it is. A lighting fixture comprising the LED lighting circuit according to claim 1 .

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