JP2008130989A - Led lighting circuit, and luminaire using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent spread of damage upon disconnection of an LED when a module configured by many LEDs is driven with a constant current in a lump, in an LED lighting circuit to be used for a luminaire and the like. <P>SOLUTION: Currents flowing from a DC-DC converter 35 to an LED module 32 are detected by a resistor R2 and compared with a reference voltage Vref from a reference voltage source 38 by a comparison circuit 37. Based on the results, a control circuit 36 controls the DC-DC converter 35, and the currents flowing to the LED module 32 are controlled to be constant currents at the same time, in a lighting circuit 31. Furthermore, between terminals of an LEDD1 of each of LED load circuits U1-U3 configuring the LED module 32, a flow dividing circuit A through which a predetermined current is made to pass by detouring at disconnection is provided in parallel. Thereby, for example, when disconnection is caused in the LEDD10 of the LED load circuit U1, the current which should flow flows at the same level as before disconnection by detouring, so that it is prevented that excess current flows in the left LED load circuits U2 and U3 to light in an overload state, and that damage spreads continuously. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an LED lighting circuit and a luminaire using the same, and more particularly to measures against disconnection when a plurality of LEDs provided in parallel are subjected to constant current control.

  When using a large number of LEDs to obtain the required light output, such as when using the LEDs (light emitting diodes) in the luminaire, a low current LED is more efficient and can be used to obtain the same light output. When subdividing, an LED module in which a plurality of LED load circuits composed of one or a plurality of series-connected 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. 5 is a block diagram showing a typical prior art LED lighting circuit 11 having such a configuration. This prior art is disclosed in Patent Document 1. In this LED lighting circuit 11, the LED module 2 is configured by connecting three LED load circuits u 1 to u 3 in which a large number of LED loads are connected in series in parallel. The LED module 2 detects the total energization current value to the LED load circuits u1 to u3 by converting the voltage with the resistor r2, and the comparator 17 compares the voltage with the reference voltage Vref to a constant value. Thus, the PWM control circuit 16 is configured to control the DC-DC converter 15. The DC-DC converter 15 switches the voltage Vdc from the DC power supply 13 by the switching element q0 and applies it to the primary side of the transformer t. The DC voltage VDC obtained by rectifying and smoothing the secondary output by the rectifying and smoothing circuit 14 is provided. Is provided to each of the LED load circuits u1 to u3, thereby constituting a one-stone flyback converter that insulates the power supply side from the load side. In the LED lighting circuit 11, constant current circuits d1 to d3 are provided in series with the LED load circuits u1 to u3, respectively, so that the current between the LED load circuits u1 to u3, that is, the luminance is equalized. It is configured.
JP 2004-319583 A

  In the conventional technology as described above, when a disconnection occurs in any of the LEDs in the LED load circuits u1 to u3 that are parallel to each other, the current that should flow to the LED load circuit flows to the remaining LED load circuit, and the remaining There is a problem that the LED load circuit is lit in an overload state, and the failure spreads in a chain. For example, as shown in FIG. 5, if any one of the three LED load circuits u1 to u3 is disconnected and the DC-DC converter 15 performs constant current control as it is, the remaining LED load circuits include 3 / 2 times the current flows.

  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 luminaire using the same when a DC power source collectively drives an LED module composed of a plurality of LEDs at a constant current. It is to be.

  The LED lighting circuit of the present invention is an LED lighting in which a DC power source is driven to light at a constant current with respect to an LED module in which a plurality of LED load circuits composed of one or a plurality of series LED's are arranged in parallel with each other. The circuit includes a shunt circuit that is interposed in parallel between the terminals of one or a plurality of series-connected LEDs, and bypasses a predetermined level of current through the LED when the corresponding LED is disconnected. It is characterized by that.

  According to the above configuration, in an LED lighting circuit used for a lighting fixture or the like, a direct current power source is defined for an LED module in which a plurality of LED load circuits including one or a plurality of series-connected LEDs are arranged in parallel with each other. In the lighting drive with electric current, a shunt circuit is provided in parallel between the terminals for any number of LEDs such as each LED or each of a plurality of series LED load circuits, and the shunt circuit corresponds to the corresponding LED. Is disconnected, the current of the level defined in advance for the LED is passed instead of the LED.

  Therefore, the DC power supply is lit and driven with a constant current all at once, and even if any LED breaks, the current that should flow to that LED bypasses the broken point and before the break. Therefore, it is possible to prevent excessive current from flowing into the remaining LED load circuit to light up in an overload state, and failure from spreading in a chain.

  In the LED lighting circuit of the present invention, the shunt circuit includes a Zener diode.

  According to the above configuration, by connecting a Zener diode or a series circuit of a Zener diode and a resistor in parallel with the LED, it is particularly suitable as a shunt circuit provided for each of one or several small LEDs, and always has a loss. No current can be bypassed from disconnection detection.

  Furthermore, in the LED lighting circuit of the present invention, the shunt circuit includes a series circuit of an impedance element and a switch element provided in parallel to the one or a plurality of series LED, and the one or a plurality of series LED. It is configured to include a disconnection detection circuit that detects the presence or absence of disconnection, opens the switch element in a normal state, and closes the switch element when the disconnection is detected.

  According to said structure, it is especially suitable as a shunt circuit provided for every LED load circuit which consists of LED of several steps | paragraphs in series, always has a small loss, and can bypass an electric current from disconnection detection.

  Further, in the LED lighting circuit of the present invention, a control element is provided in series in each LED load circuit, and these control elements constitute a current mirror circuit to link the energization current value between the LED load circuits. Among these control elements, the one corresponding to the LED load circuit having the highest voltage drop due to the LED current including the sum of the LED ON voltages in the corresponding LED load circuit is the reference current circuit of the current mirror. Thus, it is diode-connected.

  According to said structure, the control element which comprises a current mirror circuit is provided in series with each said LED load circuit which carries out package constant current energization from DC power supply, In those control elements, LED of each LED load circuit is provided. With reference to the circuit with the highest voltage drop due to the LED current, including the sum of the ON voltage Vf, the control element corresponding to the LED load circuit has a diode structure, and the energization current of the control elements of the remaining circuit via the control terminal By linking the values, a balance is obtained between the LED load circuits. Specifically, when the control element is a transistor, the base that is the control terminal and the collector are short-circuited and the bases are connected in common. When the control element is a MOS transistor, the gate and drain which are control terminals are short-circuited and the gates are connected in common.

  Therefore, the current balance between the LED load circuits is uniformly controlled by the current mirror circuit, so that the light output from a large number of LEDs can be made uniform. In addition, since the LED load circuit having the highest sum of the ON voltages Vf is used as the circuit for generating the reference current of the current mirror circuit, a circuit for generating only the reference current is unnecessary, and the circuit loss corresponding to that is eliminated. It can be lost.

  Furthermore, in the LED lighting circuit of the present invention, the DC power source is a DC-DC converter, and current detection means for detecting a total current value flowing through each LED load circuit, and a detection result from the current detection means. A reference voltage source and a comparator for comparison, and control means for feedback-controlling the DC power supply so that a sum of energization current values to the LED module becomes a predetermined value in accordance with an output from the comparator It is characterized by comprising.

  According to the above configuration, the current value flowing from the DC power source to each LED load circuit is detected, and the DC current is fed back by feedback so that the sum of the current values becomes a predetermined value based on the detection result. Since the power source is controlled at a constant current, the loss at the control element is small compared to the constant voltage control, and the loss can be reduced.

  Moreover, the lighting fixture of this invention uses the said LED lighting circuit, It is characterized by the above-mentioned.

  According to the above configuration, it is possible to realize a luminaire that can prevent an increase in failure at the time of LED disconnection when the DC power source collectively drives constant current LED modules composed of a plurality of LEDs.

  As described above, the LED lighting circuit of the present invention is an LED lighting circuit used for lighting fixtures, etc., for an LED module in which a plurality of LED load circuits composed of one or a plurality of series LED's are arranged in parallel with each other. Thus, when the DC power source is driven to light at a constant current, a shunt circuit is provided in parallel between the terminals for any number of LEDs such as each LED or each of a plurality of series LED load circuits. When the corresponding LED is disconnected, the circuit passes a current of a level defined in advance for the LED instead of the LED.

  Therefore, the direct current power supply drives LED modules consisting of a plurality of LEDs at a constant current in a lump, and even if any LED is disconnected, the current that should flow to that LED bypasses the disconnection location and is disconnected. Since the current flows at the same level as before, it is possible to prevent excessive current from flowing into the remaining LED load circuit and light up in an overload state, and failure from spreading in a chain.

  As described above, the LED lighting circuit of the present invention realizes the shunt circuit by connecting a Zener diode or a series circuit of a Zener diode and a resistor in parallel with the LED.

  Therefore, it is particularly suitable as a shunt circuit provided for each one or several small number of LEDs, there is no loss at all times, and current can be bypassed from disconnection detection.

  Furthermore, as described above, the LED lighting circuit of the present invention includes a series circuit of an impedance element and a switch element provided in parallel to the one or a plurality of series LEDs, and the one or a plurality of series LEDs. The shunt circuit is realized by detecting whether or not there is a disconnection, and opening the switch element in a normal state and disconnecting the switch element when the disconnection is detected.

  Therefore, it is particularly suitable as a shunt circuit provided for each LED load circuit composed of LEDs in a plurality of stages in series, the loss is always small, and current can be bypassed from disconnection detection.

  Further, as described above, the LED lighting circuit of the present invention is provided with a control element constituting a current mirror circuit in series with each LED load circuit that performs energization with a constant current from a DC power supply, and in those control elements, The control element corresponding to the LED load circuit has a diode structure on the basis of the circuit having the highest voltage drop due to the LED current, including the total of the LED ON voltage Vf in each LED load circuit, and the remainder via the control terminal The LED load circuits are balanced by interlocking the energization current values of the control elements of the circuit.

  Therefore, the current balance between the LED load circuits is uniformly controlled by the current mirror circuit, so that the light output from a large number of LEDs can be made uniform. In addition, since the LED load circuit having the highest sum of the ON voltages Vf is used as the circuit for generating the reference current of the current mirror circuit, a circuit for generating only the reference current is unnecessary, and the circuit loss corresponding to that is eliminated. It can be lost.

  Furthermore, as described above, the LED lighting circuit of the present invention is a DC-DC converter for the DC power source, and a current detection unit that detects a total current value flowing through the LED load circuits, and the current detection unit. A reference voltage source and a comparator for comparing the detection results from the output, and the DC power supply is fed back so that the sum of energization current values to the LED module becomes a predetermined value according to the output from the comparator And control means for controlling.

  Therefore, a current value from the DC power source to each LED load circuit is detected, and based on the detection result, the DC power source is controlled by feedback so that the sum of the current values becomes a predetermined value. Since the control is performed, the loss in the control element is small compared to the constant voltage control, and the loss can be reduced.

  Moreover, the lighting fixture of this invention uses the said LED lighting circuit as mentioned above.

  Therefore, when the direct current power source collectively drives the LED modules composed of a plurality of LEDs, it is possible to realize a lighting fixture that can prevent an increase in failure when the LEDs are disconnected.

[Embodiment 1]
FIG. 1 is a block diagram showing a configuration of an LED lighting circuit 31 according to an embodiment of the present invention. In the LED lighting circuit 31, an LED module 32 is configured by connecting three LED load circuits U <b> 1 to U <b> 3 in which a large number of LEDs D <b> 1 are connected in series in parallel. The number of series LED loads in each of the LED load circuits U1 to U3 is arbitrary, and may be composed of a single LED.

  Each of the LED load circuits U1 to U3 is configured such that the LEDD1 is mounted on a common heat sink and bonded, and a wavelength conversion phosphor, a light diffusion lens, and the like are attached. The LED module 32 and the LED lighting circuit 31 are used as a lighting fixture. The LED load emits blue or ultraviolet light, and the light from the LED load is wavelength-converted by the phosphor and emitted as white light. . The number of parallel circuits of the LED load circuits U1 to U3 is also arbitrary, and a method for obtaining white light, for example, combining light emitted by the three primary colors of RGB is also arbitrary.

  The LED module 32 is supplied with the DC voltage VDC obtained by converting the voltage Vac from the commercial power source 33 into a direct current from the noise-cutting capacitor C <b> 1 by the rectifier bridge 34 and converting the voltage through the DC-DC converter 35. The DC-DC converter 35 rectifies the output current from the choke coil L, the switching element Q0 that switches the DC output voltage of the rectifier bridge 34, the choke coil L that stores and discharges the excitation energy by the switching, and the like. It comprises a smoothing diode D and a smoothing capacitor C2, a resistor R1 for detecting the current flowing through the switching element Q0 by converting it into a voltage, and a control circuit 36 for controlling the switching of the switching element Q0. A boost chopper circuit.

  The current flowing from the DC-DC converter 35, which is a DC power supply, to the LED module 32 is converted into a voltage value by the current detection resistor R2, and compared with the reference voltage Vref from the reference voltage source 38 in the comparison circuit 37. The comparison result is fed back to the control circuit 36. The control circuit 36 controls the switching frequency and duty of the switching element Q0 in response to the detection results of the resistors R1 and R2. Thus, the constant voltage control of the voltage VDC and the collective constant current control of the current flowing to the LED module 32 are performed.

  Each of the LED load circuits U1 to U3 is provided with control elements Q1 to Q3 constituting a current mirror circuit in series in order to make the energization current values flowing through them equal to each other. Of Q3, including the sum of the LED ON voltages Vf in the corresponding LED load circuits U1 to U3, the circuit having the highest voltage drop due to the LED current (U1 in the example of FIG. 1) is used as a reference in the circuit. The control element (Q1 in the example of FIG. 1) has a diode structure, and the energization current value of the control elements (Q2, Q3 in the example of FIG. 1) of the remaining circuits (U2, U3 in the example of FIG. 1) via the control terminal The LED load circuits U1 to U3 are balanced with each other.

  Specifically, when the control elements Q1 to Q3 are transistors as shown in FIG. 1, the base that is the control terminal and the collector are short-circuited and the bases are connected in common. When the control element is a MOS transistor, the gate and drain which are control terminals are short-circuited and the gates are connected in common.

  It should be noted that in the present embodiment, a shunt circuit A is provided in parallel with each LED D1, and the shunt circuit A is defined in advance for that LED D1 when the corresponding LED (D1 in the example of FIG. 1) is disconnected. In FIG. 1, the current of the level is bypassed as indicated by reference numeral F1.

  Specifically, the shunt circuit A includes a constant current such as a single Zener diode ZD as shown in FIG. 2A and a series circuit of a Zener diode ZD and a resistor R as shown in FIG. The passing current value is a value preset in each of the LED load circuits U1 to U3. As the Zener diode ZD provided in parallel with each LEDD1, a Zener diode provided for countermeasures against static electricity can be used in combination.

  With this configuration, control is performed so that the sum of energization current values from the DC-DC converter 35 to the LED load circuits U1 to U3 is constant by collective constant current control based on the detection result of the resistor R2. Since the current balance between the LED load circuits U1 to U3 is uniformly controlled by the current mirror circuit, the light output from the multiple LEDs D1 can be made uniform. Further, since the LED load circuit (U1 in the example of FIG. 1) having the highest sum of the ON voltages Vf of the LEDs D1 is used as a circuit for generating the reference current of the current mirror circuit, a circuit for generating only the reference current Is unnecessary, and the circuit loss corresponding to that can be eliminated. Furthermore, since one of the control elements Q1 to Q3 such as a transistor has a diode structure and is only configured as a mirror circuit, current equalization can be realized with an inexpensive configuration.

  For example, when the number of LED load circuits is three of U1 to U3, each of the LED load circuits U1 to U3 is constituted by five stages of LEDs D1, and the variation of the ON voltage Vf is ± 5%, the resistance In the case of only the collective constant current control based on the detection result of R2, that is, when the control elements Q1 to Q3 are not provided, the current variation between the LED load circuits U1 to U3 is 17.5 to 22.7 mA (described above). The current value of the batch constant current control is 60 mA), whereas the control elements Q1 to Q3 are provided, and the control element Q1 corresponding to the LED load circuit U1 having the highest sum of the ON voltages Vf as described above is used as a reference. As described above, by causing the other control elements Q2 and Q3 to perform the mirror operation, the current variation can be suppressed to 20.0 to 20.1 mA. Similarly, when the variation of the ON voltage Vf is ± 10%, 15.2 to 25.8 mA is obtained only by collective constant current control, and 20.0 to 20.1 mA is obtained by performing the mirror operation. be able to.

  Although the DC power source of the LED lighting circuit 31 is the DC-DC converter 35 having the choke coil L, it may be an insulating DC-DC converter having the transformer t shown in FIG. The DC power supply is optional. However, when performing the constant current control by the current mirror operation using the control elements Q1 to Q3, it is preferable to use the constant current control for the DC power supply in the constant voltage control and the constant current control.

  In the above description, the emitter area ratios of the control elements (transistors) Q1 to Q3, that is, the rated currents of the LEDs D1 in the LED load circuits U1 to U3 are equal to each other, but may be configured to be different from each other. In this case, the control elements Q1 to Q3 perform control so as to maintain the different set current ratios. Moreover, organic EL (organic LED) is applicable to LEDD1 in this invention.

  Further, by configuring as in the present embodiment, the DC-DC converter 35 collectively drives the LED modules 32 composed of a plurality of LEDs D1 with a constant current, and even if a disconnection occurs in any LED D10, Since the current that should flow through the LEDD10 bypasses the disconnection point by the shunt circuit A and flows at the same level as before the disconnection, excessive current flows into the remaining LED load circuits U2 and U3, and the LED lights in an overload state. Can be prevented from spreading in a chain.

  The shunt circuit A is composed of a Zener diode ZD provided in parallel with the LED D1 or a series circuit of a Zener diode ZD and a resistor R, and is particularly suitable as a shunt circuit provided for each of one or several small LEDs. There is no loss and current can be bypassed from disconnection detection.

[Embodiment 2]
FIG. 3 is a block diagram showing a configuration of an LED lighting circuit 51 according to another embodiment of the present invention. The LED lighting circuit 51 is similar to the LED lighting circuit 31 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that in this LED lighting circuit 51, the shunt circuits A1 to A3 are provided for each of the LED load circuits U1 to U3 including the LEDD1 of a plurality of stages in series.

  Therefore, the shunt circuits A1 to A3 include impedance elements Z1 to Z3 and switch elements SW1 to SW3 provided in parallel to the LED load circuits U1 to U3, and the LED load circuits U1 to U3. It is configured to detect the presence or absence of disconnection of the LEDD1, and open the switch elements SW1 to SW3 in a normal state, and when the disconnection is detected, the disconnection detection circuits S1 to S3 are configured to close the switch elements SW1 to SW3. Is done.

  The disconnection detection circuits S1 to S3 include current-voltage conversion resistors R11 to R31 provided in series with the LED load circuits U1 to U3, and a reference voltage Vref1 that predetermines voltages between the terminals of the current-voltage conversion resistors R11 to R31. Comparators CP1 to CP3 and reference voltage sources E1 to E3 to be compared, and base resistors R12 to R32 connecting the bases of the switch elements SW1 to SW3 made of transistors and the output terminals of the comparators CP1 to CP3 It is prepared for.

  Therefore, when the LEDD1 in each of the LED load circuits U1 to U3 is not disconnected, a terminal voltage of a predetermined level is output from the current-voltage conversion resistors R11 to R31 and becomes higher than the reference voltage Vref1, and comparators CP1 to CP3. Outputs a low level, whereby the switch elements SW1 to SW3 are turned OFF, and the impedance elements Z1 to Z3 are disconnected from the LED load circuits U1 to U3. On the other hand, when the disconnection occurs, the terminal voltages of the current-voltage conversion resistors R11 to R31 become the ground level, which becomes lower than the reference voltage Vref1, and the comparators CP1 to CP3 output a high level, thereby the switch element SW1. SW3 is turned on, and the impedance elements Z1 to Z3 are connected between the output terminals of the DC-DC converter 35 in series with the control elements Q1 to Q3, instead of the LED load circuits U1 to U3.

  By configuring in this way, it is particularly suitable to be provided for each of the LED load circuits U1 to U3 including the LEDD1 of a plurality of stages in series. The shunt circuit A1 can always perform a bypass of the current from the disconnection detection with a small loss. A3 can be realized.

[Embodiment 3]
FIG. 4 is a block diagram showing a configuration of an LED lighting circuit 61 according to still another embodiment of the present invention. The LED lighting circuit 61 is similar to the LED lighting circuit 51 described above, and corresponding portions are denoted by the same reference numerals, and description thereof is omitted. It should be noted that in this LED lighting circuit 61, only the current-voltage conversion resistor R11 is provided in the LED load circuit U1 for creating the reference current of the current mirror circuit, the shunt circuit A1 is not provided, and the remaining In the shunt circuits A2 ′ and A3 ′ of the LED load circuits U2 and U3, the comparators CP2 and CP3 of the disconnection detection circuits S2 ′ and S3 ′ are connected to the voltage across the current-voltage conversion resistor R11 and the current-voltage conversion resistor R21, It is to compare with the voltage between terminals of R31.

  As described above, the LED load circuit U1 that creates the reference current of the current mirror circuit is the circuit having the highest sum of the ON voltages Vf of the LEDs D1. Therefore, in the state where no disconnection occurs in any LED, the ground side The terminal voltage of the current-voltage conversion resistor R11 inserted in is lower than the terminal voltages of the remaining current-voltage conversion resistors R21, R31, and the switch elements SW2, SW3 are OFF. On the other hand, when a disconnection occurs in the LED load circuits U2 and U3, the terminal voltages of the current-voltage conversion resistors R21 and R31 become lower than the terminal voltage of the current-voltage conversion resistor R11. Turn on. Thus, the reference voltage sources E2 and E3 for creating the reference voltage Vref1 can be eliminated, and complicated adjustment of the reference voltage Vref1 can be eliminated. When a short circuit occurs in the LED load circuit U1 that generates the reference current of the current mirror circuit, all the lights are turned off for safety.

It is a block diagram which shows the structure of the LED lighting circuit which concerns on one Embodiment of this invention. FIG. 2 is a diagram illustrating a configuration example of a shunt circuit in the LED lighting circuit illustrated in FIG. 1. It is a block diagram which shows the structure of the LED lighting circuit which concerns on the other form of implementation of this invention. It is a block diagram which shows the structure of the LED lighting circuit which concerns on other form of implementation of this invention. It is a block diagram which shows the structure of a typical prior art LED lighting circuit.

Explanation of symbols

31, 51, 61 LED lighting circuit 32 LED module 33 Commercial power supply 34 Rectifier bridge 35 DC-DC converter 36 Control circuit 37 Comparison circuit 38 Reference voltage source A; A1, A2, A3; A2 ', A3' Shunt circuit C2 Smoothing capacitor CP1, CP2, CP3 Comparator D Diode D1, D10 LED
E1, E2, E3 Reference voltage source L Choke coil Q0 Switching element Q1, Q2, Q3 Control element R, R1, R2 Resistance R11, R21, R31 Current-voltage conversion resistance R12, R22, R32 Base resistance S1-S3; S2 ′, S3 'disconnection detection circuit SW1, SW2, SW3 switch element U1, U2, U3 LED load circuit Z1, Z2, Z3 impedance element ZD Zener diode

Claims (6)

In an LED lighting circuit in which a DC power source is driven to be lit at a constant current for an LED module in which a plurality of LED load circuits composed of one or a plurality of series LEDs are arranged in parallel with each other,
It includes a shunt circuit that is interposed in parallel between the terminals of one or a plurality of series LEDs, and allows a predetermined level of current to be diverted through the LED when the corresponding LED is disconnected. LED lighting circuit.   The LED lighting circuit according to claim 1, wherein the shunt circuit includes a Zener diode.   The shunt circuit detects the presence or absence of disconnection of the one or more series of LEDs and the series circuit of the impedance element and the switch element provided in parallel with the one or more series of LEDs, and normally the switch The LED lighting circuit according to claim 1, further comprising: a disconnection detection circuit that opens the element and closes the switch element when the disconnection is detected.   Each LED load circuit is provided with a control element in series, and these control elements constitute a current mirror circuit to link the current value between the LED load circuits and correspond to the control elements. The LED load circuit including the sum of the ON voltages of the LEDs in the LED load circuit, which corresponds to the LED load circuit with the highest voltage drop due to the LED current, is diode-connected so as to be the reference current circuit of the current mirror. The LED lighting circuit according to any one of claims 1 to 3. The DC power supply is a DC-DC converter,
Current detection means for detecting a total current value flowing through each LED load circuit;
A reference voltage source and a comparator for comparing the detection results from the current detection means;
And a control unit that feedback-controls the DC power supply so that a total sum of energization current values to the LED module becomes a predetermined value in accordance with an output from the comparator. Item 5. The LED lighting circuit according to any one of Items 1 to 4.   A lighting fixture using the LED lighting circuit according to any one of claims 1 to 5.

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