JP4744966B2 - DC power supply device for light emitting diode and lighting apparatus using the same - Google Patents

Description

  The present invention relates to a power supply device for lighting a light emitting diode used particularly for lighting and a lighting fixture using the same, and more particularly to an existing phase control dimming when replacing an incandescent lamp lighting fixture with a light emitting diode lighting fixture. The present invention relates to a configuration for realizing dimming control using an instrument.

  In recent years, lighting fixtures using light-emitting diodes have become widespread with the improvement in luminance. The basic lighting fixture 101 is configured as shown in FIG. 13, for example. This luminaire 101 includes a light-emitting diode lighting power supply device 102 and one or a plurality of light-emitting diodes 11 to ln connected in series and parallel (n in FIG. 13 are in series). The power supply apparatus 102 rectifies and smoothes commercial alternating current from the commercial power supply 103 into direct current by the diode bridge 104 and the smoothing capacitor c1, and then switches the commercial alternating current from the insulating transformer t by using the switching element q. Output to the light emitting diodes 11 to ln via the diode d1 and the smoothing capacitor c2.

  The current value of the current flowing through the light emitting diodes l1 to ln is detected by a voltage value by a current detection resistor r connected in series to the light emitting diodes l1 to ln, and through the feedback means such as a photocoupler (not shown), This is fed back to the PWM control circuit 105 that controls the switching of the switching element q. In the transformer t, the PWM control circuit 105 uses a capacitor c3 to generate a voltage induced in a tertiary winding t3 provided together with the primary winding t1 on the commercial AC side and the secondary winding t2 on the light emitting diodes 11 to ln side. The power source is smoothed and the current value flowing through the light emitting diodes 11 to ln is controlled to be constant by changing the ON duty of the switching element q according to the fed back current values of the light emitting diodes 11 to ln.

  In the lighting fixture 101 configured as described above, when dimming is performed, as illustrated by the lighting fixture 111 in FIG. 14 or the lighting fixture 121 in FIG. 15, a dedicated dimming for changing a circuit constant for the dimming operation. It is necessary to connect the optical device 112 to the power supply device 102 and change the target value of constant current control of the light emitting diodes 11 to ln.

  Specifically, in the luminaire 111 of FIG. 14, the dimmer 112 is connected in series with a capacitor c3 serving as a power source of the PWM control circuit 105, and the dimming amount by the dimmer 112, that is, the resistance value is The larger the voltage is, the smaller the charging voltage of the capacitor c3 is. As a result, the ON duty of the switching element q by the PWM control circuit 105 is decreased. In the luminaire 121 of FIG. 15, the dimmer 112 is used as the current detection resistor r, and flows through the light emitting diodes 11 to ln as the dimming amount by the dimmer 112, that is, the resistance value increases. This indicates that the current value is apparently large, and the PWM control circuit 105 thereby reduces the ON duty of the switching element q. Thus, the current value flowing through the light emitting diodes 11 to ln becomes a constant light control amount determined by the light controller 112.

  However, in the configuration of dimming control as described above, the power supply device 102 installed on the ceiling or the like is directly connected to the commercial AC power line 106 passing through the wall or behind the ceiling, and is provided on the wall surface or the like. 112 is connected by a dedicated signal line 113.

  On the other hand, as shown in FIG. 16, in the conventionally used lighting fixture 131 of the incandescent lamp 133, a phase control dimmer 132 is inserted into the power line 106 from the commercial power supply 103 to the lighting fixture 131. In many cases, dimming is performed by directly applying a controlled AC voltage to the incandescent lamp 133. In such a configuration, if the lighting fixture 131 of the incandescent lamp 133 is replaced with the lighting fixtures 111 and 121 of the light emitting diodes 11 to ln, it is necessary to replace the phase control dimmer 132 on the wall surface with the dimmer 112. At the same time, large-scale wiring changes are required.

In order to solve such a problem, Patent Document 1 has been proposed. The structure of the lighting fixture 141 by the prior art is shown in FIG. In the configuration, the same components as those shown in FIGS. 13 to 16 are denoted by the same reference numerals, and the description thereof is omitted. It should be noted that in this lighting fixture 141, in the power supply device 142 for dimming the light emitting diodes 11 to ln, a diode d 2 is interposed between the diode bridge 104 and the smoothing capacitor c 1. The obtained pulsating flow is divided by the voltage dividing resistors r 1 and r 2 and taken into the effective value conversion circuit 143. According to the detected effective value, the effective value conversion circuit 143 performs dimming by changing the target current value in the PWM control circuit 145, so that the phase control for the lighting fixture 131 of the existing incandescent lamp 133 is performed. Dimming control of the light emitting diodes 11 to ln is possible without diverting the wiring by using the dimmer 132.
JP 2004-325152 A

  In the above-described prior art, when the commercial AC voltage fluctuates, the effective value also fluctuates, so that there is a problem that the operational feeling of light control and the brightness of the light emitting diodes 11 to ln change.

  An object of the present invention is to perform dimming control using a phase control dimmer for an incandescent lamp, and always with a desired dimming amount (current value) even for voltage fluctuations of commercial AC. It is an object to provide a direct current power supply device for a light emitting diode that can be lit and a lighting fixture using the same.

  The direct current power supply for a light emitting diode according to the present invention is the direct current power supply for a light emitting diode, wherein commercial AC is input to the switching power supply, and the control means performs PWM control of the switching power supply to light the light emitting diode at a predetermined current value. Conduction width detecting means for detecting a conduction width when the commercial alternating current is phase-controlled, and the control means is configured so that a current flowing through the light emitting diode has a current value corresponding to a detection result of the conduction width detection means. The switching power supply is controlled.

  According to the above configuration, in the constant current control type light-emitting diode DC power supply device in which the commercial AC is input and the control means performs PWM control of the switching power supply so that the light-emitting diode is lit at a predetermined current value. If a width detecting means is provided and the input commercial alternating current is phase-controlled, the conduction width detecting means detects the conduction width and gives it to the control means. The control means increases the level of the direct current output to the light emitting diode as the conduction width increases, corresponding to the conduction width detected by the conduction width detection means.

  Therefore, when the lighting fixture is replaced with a light-emitting diode lighting fixture from the configuration in which the phase control dimmer is interposed in the commercial AC line using the lighting fixture of the incandescent lamp, The dimming control can be performed using the existing phase control dimmer without laying a wiring for control. In addition, by determining the dimming amount from the conduction width of the phase control dimmer, it is possible to always turn on the light with the desired dimming amount (current value) even for commercial AC voltage fluctuations. It is possible to perform control that does not cause fluctuations in the operational feeling and brightness.

  In the DC power supply for a light emitting diode according to the present invention, the switching power supply includes a rectifying and smoothing circuit that converts input commercial alternating current into direct current voltage, a switching element that switches the converted direct current voltage, and the switching element. A transformer to which a switched voltage is applied to the primary side, an output smoothing circuit that is provided on the secondary side of the transformer, converts the induced pulse voltage into a DC voltage and applies the voltage to the light emitting diode, and the light emitting diode And a current detection circuit for detecting a flowing current and feeding back to the control means.

  According to said structure, the switching power supply which gives a direct current | flow constant current to a light emitting diode by feedback control is concretely realizable.

  Furthermore, in the DC power supply for a light emitting diode according to the present invention, the conduction width detecting means is a rectangular wave whose phase value is controlled and the peak value is constant with the same conduction width as that of the commercial alternating current that is full-wave rectified by the rectifying and smoothing circuit. And a smoothing circuit that converts the rectangular wave into a DC voltage corresponding to a conduction width thereof, and the control means is configured such that the value of the current flowing through the light emitting diode is the smoothing circuit. The switching power supply is controlled so as to have a value corresponding to the DC voltage output by

  According to the above configuration, when detecting the conduction width, the peak is controlled with the same conduction width as the commercial AC in the rectangular wave conversion circuit from the commercial AC that is phase-controlled and full-wave rectified by the rectifying and smoothing circuit. By converting to a rectangular wave with a constant value, it is possible to obtain a rectangular wave having the same conduction width without being affected by the voltage fluctuation of commercial AC, and the smoothing circuit converts the rectangular wave into a direct current corresponding to the conduction width. By converting to voltage, the control means can recognize the conduction width. In this way, the conduction width detecting means capable of accurately detecting the conduction width even with the commercial AC voltage fluctuation as described above can be specifically configured.

  In the DC power supply for a light emitting diode according to the present invention, the conduction width detecting means is a phase-controlled rectangular wave having the same conduction width as the commercial alternating current that is full-wave rectified by the rectifying and smoothing circuit and having a constant peak value. A rectangular wave conversion circuit for converting, and a conduction width calculation circuit for detecting the conduction width from the Hi / Lo switching timing of the rectangular wave, and the control means is configured to detect a current value flowing through the light emitting diode. The switching power supply is controlled to have a value corresponding to a detection result of the conduction width arithmetic circuit.

  According to the above configuration, when detecting the conduction width, the peak is controlled with the same conduction width as the commercial AC in the rectangular wave conversion circuit from the commercial AC that is phase-controlled and full-wave rectified by the rectifying and smoothing circuit. By converting the value into a rectangular wave having a constant value, a rectangular wave having the same conduction width can be obtained without being affected by voltage fluctuations of commercial alternating current, and the conduction width arithmetic circuit switches the Hi / Lo of the rectangular wave. The control means can recognize the conduction width by directly detecting the conduction width from the timing and inputting the detection result to the control means. In this way, the conduction width detecting means capable of accurately detecting the conduction width even with the commercial AC voltage fluctuation as described above can be specifically configured.

  Furthermore, the direct-current power supply for a light emitting diode according to the present invention further comprises a peak value detection circuit for detecting the peak value of the commercial alternating current, and the control means includes the conduction width detection means, a current detection circuit, and a peak value detection circuit. In response to the detection result, the variation of the conduction width accompanying the fluctuation of the peak value of the commercial alternating current is compensated so that the value of the current flowing through the light emitting diode becomes a value corresponding to the detection result of the conduction width detection means. The switching element is controlled.

  According to the above configuration, the switching power supply and the control unit control the current value flowing through the light emitting diode by PWM duty control, and when performing the PWM duty control, the control unit includes the light emitting diode by the current detection circuit. Is fed back. Further, the detection result from the peak value detection circuit is input, so that the fluctuation of the conduction width detected by the conduction width detection means accompanying the peak value fluctuation of commercial AC is compensated.

  Therefore, it is possible to accurately control the current value flowing through the light emitting diode so as to be a value corresponding to the detection result of the conduction width detecting means by compensating for the fluctuation of the conduction width accompanying the peak value fluctuation of commercial AC. In addition, it is possible to perform control that does not cause fluctuations in the operational feeling of dimming and brightness with respect to peak value fluctuations in commercial alternating current.

  The light-emitting diode direct-current power supply device according to the present invention is responsive to the peak value detection circuit for detecting the peak value of the commercial alternating current, the output from the conduction width detecting means and the peak value detection circuit, and accompanying the fluctuation of the peak value. A correction circuit that compensates for variation in conduction width and that performs non-linear correction in the current-luminance characteristics of the light-emitting diode, wherein the control means responds to detection results of the correction circuit and the current detection circuit, and And the switching element is controlled so that the current value flowing through the light emitting diode becomes a value corresponding to the detection result of the conduction width detecting means.

  According to the above configuration, the switching power supply and the control unit control the current value flowing through the light emitting diode by PWM duty control, and when performing the PWM duty control, the control unit includes the light emitting diode by the current detection circuit. Is fed back. Further, the signal input from the correction circuit compensates for the variation in the conduction width detected by the conduction width detection means due to the fluctuation in the peak value of the commercial alternating current, and has non-linearity in the current-luminance characteristics of the light emitting diode. It has been corrected.

  Therefore, it is possible to accurately control the current value flowing through the light emitting diode to be a value corresponding to the detection result of the conduction width detecting means by compensating for the fluctuation of the conduction width accompanying the peak value fluctuation of commercial AC. In addition, it is possible to perform control that does not cause fluctuations in the operational feeling of light control and brightness with respect to peak value fluctuations in commercial alternating current.

  Furthermore, the light-emitting diode DC power supply device of the present invention further includes an amplifier circuit for amplifying the output of the current detection circuit, and the amplification factor of the amplifier circuit is changed according to the detection result of the conduction width detection means. It is characterized by that.

  According to the above configuration, the conduction width detecting unit is configured by using the configuration of the existing control unit that makes the current value flowing through the light emitting diode constant by controlling the duty of the switching element from the difference of the feedback value with respect to the control target value. Is a simple configuration that only changes the amplification factor of the amplification circuit interposed in the feedback loop, and performs dimming control using an existing phase control dimmer that used an incandescent lamp lighting fixture. Can do.

  In the DC power supply for a light emitting diode according to the present invention, the current detection circuit changes the gain of the amplifier circuit and also changes the control target value of the light emitting diode current in the control means. To do.

  According to said structure, the change of the control target value of a control means can give a various change to the electric current value of a light emitting diode with respect to the change of a conduction width.

  Furthermore, the lighting fixture of the present invention is characterized in that a light emitting diode is integrated with the light emitting diode DC power supply device.

  According to the above configuration, the dimming control can be performed by diverting the existing phase control dimmer using the incandescent lamp lighting fixture as it is without laying a new control wiring. In addition, it is possible to realize a luminaire using a light emitting diode that can always be lit with a desired dimming amount (current value) even with a commercial AC voltage fluctuation.

  As described above, the direct current power supply device for light emitting diodes of the present invention is a constant current control type in which the commercial alternating current is input and the control means performs PWM control of the switching power supply so that the light emitting diodes are turned on at a predetermined current value. In the direct current power supply device for light emitting diodes, when a conduction width detecting means is provided and the input commercial alternating current is phase-controlled, the conduction width detecting means detects the conduction width, and the control means outputs to the light emitting diode. The level of the direct current to be increased is increased as the conduction width increases, corresponding to the conduction width detected by the conduction width detection means.

  Therefore, when the lighting fixture is replaced with a light emitting diode lighting fixture from the configuration in which the phase control dimmer is interposed in the commercial AC line using the lighting fixture of the incandescent lamp, Dimming control can be performed using an existing phase control dimmer without laying new wiring for control. In addition, by determining the dimming amount from the conduction width of the phase control dimmer, it is possible to always turn on the light with the desired dimming amount (current value) even for commercial AC voltage fluctuations. It is possible to perform control that does not cause fluctuations in the operational feeling and brightness.

  Moreover, the lighting fixture of this invention integrates a light emitting diode with the said DC power supply device for light emitting diodes as mentioned above.

  Therefore, dimming control can be performed by diverting the existing phase control dimmer that used the incandescent lamp lighting fixture as it is without laying new control wiring, etc. It is possible to realize a lighting fixture using a light emitting diode that can always be lit with a desired light control amount (current value) even with a commercial AC voltage fluctuation.

[Embodiment 1]
FIG. 1 is a block diagram showing an electrical configuration of a lighting fixture 1 according to the first embodiment of the present invention. This lighting fixture 1 uses a light emitting diode as a light source, and includes a power supply device 2 and one or a plurality of light emitting diodes L1 to Ln connected in series and parallel (n in FIG. 1 are in series). The light emitting diodes L1 to Ln are dimmed and controlled by using the existing phase control dimmer 132 for the incandescent lamp shown in FIG. 15 and FIG.

  The power supply device 2 rectifies and smoothes commercial alternating current from the commercial power source 3 into direct current by the diode bridge 4 and the smoothing capacitor C1, and then performs switching by the switching element Q so that the power supply device 2 performs rectification from the transformer T for insulation. The light is output to the light emitting diodes L1 to Ln via the diode D1 and the smoothing capacitor C2. The above configuration constitutes a switching power supply, the diode bridge 4 and the smoothing capacitor C1 constitute a rectifying / smoothing circuit for converting the commercial AC input to a DC voltage, and the diode D1 and the smoothing capacitor C2 are induced pulse voltages. An output smoothing circuit that converts the signal into a DC voltage and applies the converted voltage to the light emitting diodes L1 to Ln is configured. In the configuration of FIG. 1, an insulating configuration via the transformer T is illustrated, and the circuit system is illustrated as a flyback system, but the insulation and circuit system are not particularly limited.

  The current value of the current flowing through the light emitting diodes L1 to Ln is detected as a voltage value by a current detection resistor R connected in series to the light emitting diodes L1 to Ln, and is fed through feedback means such as a photocoupler (not shown). It is fed back as an LED current detection signal to the PWM control circuit 5 that controls the switching of the switching element Q. In the transformer T, the PWM control circuit 5 uses a capacitor C3 to generate a voltage induced in the tertiary winding T3 provided together with the primary winding T1 on the commercial AC side and the secondary winding T2 on the light emitting diodes L1 to Ln side. The power source is smoothed and the current value flowing through the light emitting diodes L1 to Ln is controlled to be constant by changing the ON duty of the switching element Q according to the fed back current values of the light emitting diodes L1 to Ln.

  The above configuration is the same as the configuration shown in FIG. 12, FIG. 13, FIG. 14, and FIG. It should be noted that in the present invention, the conduction width of the commercial AC is detected in response to the phase control dimmer 132 being inserted into the power line 6 from the commercial power source 3 to the lighting fixture 1. A conduction width detection circuit 7 is provided, and the PWM control circuit 5 is configured so that a current value flowing through the light emitting diodes L1 to Ln becomes a value corresponding to a detection result of the conduction width detection circuit 7. The dimming control is performed by controlling the ON duty. Specifically, the control target value of the direct current to be supplied to the light emitting diodes L1 to Ln is increased as the conduction width is increased.

  For this reason, in the power supply device 2, the diode D2 is interposed between the diode bridge 4 and the smoothing capacitor C1, and the pulsating flow obtained by the diode bridge 4 is divided by the voltage dividing resistors R1 and R2, The conduction width detection circuit 7 is used.

  FIG. 2 is a block diagram showing a conduction width detection circuit 7a which is a specific configuration example of the conduction width detection circuit 7. As shown in FIG. The voltage of the pulsating current divided by the voltage dividing resistors R1 and R2 is input to the comparator CP11, and is subjected to level discrimination with a predetermined reference voltage from the reference voltage source E11. When it is high, a low-level logic pulse is inverted. The rectangular wave pulse is applied to the base of the transistor TR, the emitter of the transistor TR is grounded, and the collector is connected to the power supply of the high level Vcc via the pull-up resistor R11. As a result, the logic of the rectangular wave is inverted again and converted to a pulse having a level Vcc sufficiently lower than the effective value level of the commercial alternating current. The pulse from the collector of the transistor TR is smoothed to a DC voltage by the diode D11 and the capacitor C11 and input to the PWM control circuit 5 as a conduction width detection signal.

  Therefore, the phase-controlled commercial alternating current as shown in FIG. 3A from the phase control dimmer 132 is first converted into a rectangular wave conversion circuit comprising the comparator CP11, the reference voltage source E1, the transistor TR, and the pull-up resistor R11. In FIG. 3B, the pulse is converted into a pulse having the same conduction width at a level Vcc sufficiently lower than the effective value level of the commercial alternating current as shown in FIG. Square waves with equal can be obtained. Also, the PWM control circuit 5 converts the conduction voltage from the input voltage level to the DC voltage corresponding to the conduction width as shown in FIG. 3C by the smoothing circuit including the diode D11 and the capacitor C11. The width can be recognized. In this way, the conduction width detection circuit 7 capable of accurately detecting the conduction width even with commercial AC voltage fluctuations can be specifically configured.

  With such a configuration, as shown in FIG. 16, the lighting device 131 of the incandescent lamp 133 is used to adjust the light by the phase control dimmer 132 being interposed in the commercial AC line. When the lighting fixture is replaced with the lighting fixture 1 of the light emitting diodes L1 to Ln, the dimming control is performed using the existing phase control dimmer 132 without laying a new control wiring or the like. It is possible to easily replace the luminaire. Further, by determining the dimming amount from the conduction width of the phase control dimmer 132, it is possible to always turn on the light with the desired dimming amount (current value) even for commercial AC voltage fluctuations. It is possible to perform control that does not cause fluctuations in the operational feeling and brightness of light.

  FIG. 4 is a block diagram showing a conduction width detection circuit 7b which is another specific configuration example of the conduction width detection circuit 7. In FIG. The voltage of the pulsating current rectified in the full wave by the diode bridge 4 is divided by the voltage dividing resistors R1 and R2 and inputted to the comparator CP11, and the level is discriminated by a predetermined reference voltage from the reference voltage source E11. Is the same as the above-described conduction width detection circuit 7a. In this conduction width detection circuit 7b, the pulse from the comparator CP11 is input to the conduction time calculation circuit 18, and this conduction time calculation circuit 18 realized by a timer or the like is based on the Hi / Lo switching timing of the pulse. , Directly detecting the conduction width. Similarly to the smoothing circuit comprising the diode D11 and the capacitor C11, the conduction time arithmetic circuit 18 may output a DC voltage corresponding to the detection result. When the PWM control circuit 5 comprises a microcomputer or the like, The conduction width data may be output as it is.

  Even with this configuration, the conduction width can be accurately detected even with respect to voltage fluctuations of commercial AC as described above.

[Embodiment 2]
FIG. 5 is a block diagram showing an electrical configuration of the lighting fixture 21 according to the second embodiment of the present invention. The power supply device 22 of the lighting fixture 21 is similar to the power supply device 2 described above, and corresponding portions are denoted by the same reference numerals and description thereof is omitted. It should be noted that the power supply device 22 is provided with a peak detection circuit 28 that detects the peak of the AC voltage together with the conduction width detection circuit 7, and the PWM control circuit 25 receives the output from the conduction width detection circuit 7. The control target value is set by subtracting the output from the peak detection circuit 28.

  Here, in the configuration using the thyristor element as the phase control dimmer 132, when the commercial AC input voltage fluctuates, the conduction width itself slightly changes (the conduction width increases as the AC voltage increases). Further, even if the comparator CP11 of the conduction width detecting circuit 7 discriminates the conduction width by discriminating with a constant level of reference voltage from the reference voltage source E11, there is a possibility that the discrimination timing is shifted and the conduction width fluctuates. is there.

  Therefore, by providing the peak detection circuit 28 and compensating for the control target value for constant current control of the light emitting diodes L1 to Ln, it is possible to keep the operational feeling and brightness of the light control from changing.

[Embodiment 3]
FIG. 6 is a block diagram showing an electrical configuration of a lighting fixture 31 according to the third embodiment of the present invention. The power supply device 32 of the luminaire 31 is similar to the power supply device 22 described above, and corresponding portions are denoted by the same reference numerals, and description thereof is omitted. It should be noted that in the power supply device 32, together with the conduction width detection circuit 7 and the peak detection circuit 28, in response to the outputs from them, the fluctuation of the conduction width due to the peak value fluctuation is compensated, and the light emitting diodes L1 to L1 That is, a correction circuit 33 that performs nonlinear correction in the current-luminance characteristic of Ln is provided.

  FIG. 7 is a graph for explaining the operation of the correction circuit 33, and shows a change in how the brightness is perceived with respect to a change in the lamp current. In the case of an incandescent lamp, it is felt that the brightness changes in proportion to the lamp current, as indicated by reference numeral α1. On the other hand, in the case of a light emitting diode, when the luminous flux is small, and when looking at the lamp for dimming control, the brightness changes even if the lamp current is decreased, as indicated by reference numeral α2. I can hardly feel it. Therefore, the correction circuit 33 performs control as indicated by the reference symbol α3 on the feedback LED current detection signal, thereby compensating for the nonlinearity indicated by the reference symbol α2, and the incandescence indicated by the reference symbol α1. You can get close to the characteristics of electric lights.

  With this configuration, the signal input from the correction circuit 33 to the PWM control circuit 35 includes non-linearity in the conduction width variation caused by the commercial AC peak value variation and the current-luminance characteristics of the light emitting diodes L1 to Ln. The current value flowing through the light emitting diodes L1 to Ln can be accurately controlled so as to be a value corresponding to the detection result of the conduction width detection circuit 7. In this way, it is possible to perform a control that does not cause a dimming operation feeling or brightness fluctuation with respect to fluctuations in the peak value of commercial alternating current.

[Embodiment 4]
FIG. 8 is a block diagram showing an electrical configuration of a lighting fixture 41 according to the fourth embodiment of the present invention. The power supply device 42 of the lighting fixture 41 is similar to the power supply device 2 described above, and corresponding portions are denoted by the same reference numerals, and the description thereof is omitted. It should be noted that in this power supply device 42, the PWM control circuit 45 has a simple configuration such as a CR oscillator, and controls the duty of the switching element Q from the difference of the feedback value with respect to the control target value. The configuration of an existing PWM control circuit that uses a constant current value flowing through Ln is used.

  Therefore, for the amplifier circuit 43 that amplifies the LED current detection signal fed back from the current detection resistor R and outputs the amplified signal to the PWM control circuit 45, the conduction width detection circuit 7 corresponds to the detection result. A conduction width detection signal is applied to change the amplification factor. When the conduction width is increased, the amplification factor of the amplifier circuit 43 is decreased, the current value fed back is apparently decreased, the ON duty is increased, and the current value flowing through the light emitting diodes L1 to Ln is increased.

  With this configuration, the PWM control circuit 45 performs constant current control at a constant control target value with a simple configuration that only changes the amplification factor of the amplifier circuit 43 interposed in the feedback loop. However, the current value that actually flows through the light emitting diodes L1 to Ln can be changed, and dimming control can be performed.

[Embodiment 5]
FIG. 9 is a block diagram showing an electrical configuration of a lighting fixture 51 according to the fifth embodiment of the present invention. The power supply device 52 of the lighting fixture 51 is similar to the power supply device 42 described above. It should be noted that in this power supply device 42, the PWM control circuit 55 is realized by a microcomputer or the like, and performs feedback control in response to the LED current detection signal via the amplifier circuit 43, and the conduction width detection circuit 7 In response to the conduction width detection signal from, the control target value of the current flowing through the light emitting diodes L1 to Ln also changes.

  With this configuration, it is possible to finely control the non-linear characteristics as indicated by the reference symbol α3 in FIG. 7, and various current values flowing through the light emitting diodes L1 to Ln with respect to changes in the conduction width. Can be changed.

[Embodiment 6]
FIG. 10 is a block diagram showing an electrical configuration of a lighting fixture 61 according to the sixth embodiment of the present invention. The power supply device 62 of the lighting fixture 61 is similar to the power supply device 52 described above. It should be noted that in this power supply device 62, the changeover switch 63 is interposed in the feedback loop of the LED current detection signal to the PWM control circuit 45.

  The changeover switch 63 is controlled to be switched by the conduction width detection circuit 7. When the conduction width is reduced, the changeover switch 63 is switched to the amplification circuit 43 side, and the LED current detection signal is fed back to the PWM control circuit 45 with a large gain. The value of the current flowing through the light emitting diodes L1 to Ln has increased, and the ON duty of the switching element Q is reduced. On the other hand, when the conduction width is increased, the changeover switch 63 is switched to the through side, and the LED current detection signal is not amplified (gain 1) but directly fed back and apparently flows through the light emitting diodes L1 to Ln. This means that the current value has decreased, and the ON duty of the switching element Q increases.

  With this configuration, when the fine dimming characteristic indicated by the reference symbol α3 in FIG. 7 is not required, the dimming characteristic as shown in FIG. Can be realized.

  As shown in FIG. 12, the power supply devices 2, 22, 32, 42, 52, 62 configured as described above are integrated with the light emitting diodes L <b> 1 to Ln to configure the lighting fixture 71, thereby controlling the phase. It is possible to realize a lighting fixture using light emitting diodes L1 to Ln which has the same wiring configuration as the lighting fixture 131 using the dimmer 132 and can be easily replaced with each other.

It is a block diagram which shows the electric constitution of the lighting fixture which concerns on the 1st Embodiment of this invention. It is a block diagram which shows one specific structural example of the conduction | electrical_connection width detection circuit in the lighting fixture shown in FIG. It is a wave form diagram for demonstrating operation | movement of the said conduction | electrical_connection width detection circuit. It is a block diagram which shows the other specific example of a structure of a conduction | electrical_connection width detection circuit. It is a block diagram which shows the electric constitution of the lighting fixture which concerns on the 2nd Embodiment of this invention. It is a block diagram which shows the electric constitution of the lighting fixture which concerns on the 3rd Embodiment of this invention. It is a graph for demonstrating operation | movement of the correction circuit in the lighting fixture shown in FIG. It is a block diagram which shows the electric constitution of the lighting fixture which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the electric constitution of the lighting fixture which concerns on the 5th Embodiment of this invention. It is a block diagram which shows the electric constitution of the lighting fixture which concerns on the 6th Embodiment of this invention. It is a graph for demonstrating operation | movement of the power supply device in the lighting fixture shown in FIG. It is a block diagram of the lighting fixture of other form of implementation of this invention. It is a block diagram which shows the electric constitution of the basic lighting fixture using a light emitting diode. It is a block diagram which shows the electric constitution of the lighting fixture of the prior art in which light control is possible using a light emitting diode. It is a block diagram which shows the electric constitution of the other conventional lighting fixture which can carry out light control using a light emitting diode. It is a block diagram which shows the electric constitution of the lighting fixture which can carry out light control using an incandescent lamp. It is a block diagram which shows the electric constitution of the typical prior art lighting fixture which can control light control using a light emitting diode.

Explanation of symbols

1, 21, 31, 41, 51, 61, 71 Lighting equipment 2, 22, 32, 42, 52, 62 Power supply device 3 Commercial power supply 4 Diode bridge 5, 25, 35, 45, 55 PWM control circuit 6 Power supply line 7 , 7a, 7b Conduction width detection circuit 18 Conduction time arithmetic circuit 28 Peak detection circuit 33 Correction circuit 43 Amplification circuit 63 Changeover switch 132 Phase control dimmer C1, C2 Smoothing capacitor C3, C11 Capacitor CP11 Comparator D1, D2, D11 Diode E11 Reference voltage sources L1 to Ln Light emitting diode Q Switching element R Current detection resistor R1, R2 Voltage dividing resistor R11 Pull-up resistor T Insulation transformer TR transistor

Claims (7)

In a direct current power supply for a light emitting diode, a commercial alternating current is input to a switching power supply, and the control means performs PWM control on the switching power supply to light the light emitting diode with a predetermined current value.
Conduction width detecting means for detecting a conduction width when the commercial alternating current is phase-controlled ;
A peak value detection circuit for detecting the peak value of the commercial alternating current ,
The switching power supply is
A rectifying / smoothing circuit that converts input commercial AC to DC voltage;
A switching element for switching the converted DC voltage;
A transformer to which a voltage switched by the switching element is applied to the primary side;
An output smoothing circuit which is provided on the secondary side of the transformer and converts the induced pulse voltage into a DC voltage to be applied to the light emitting diode;
A current detection circuit configured to detect a current flowing through the light emitting diode and feed back to the control unit ;
The control means responds to the detection results of the conduction width detection means, the current detection circuit, and the peak value detection circuit, compensates for fluctuations in the conduction width accompanying the peak value fluctuations of the commercial AC, and flows through the light emitting diode. Wherein the switching element is controlled so as to have a current value corresponding to a detection result of the conduction width detecting means. The conduction width detecting means includes
A rectangular wave conversion circuit that is phase-controlled and converts into a rectangular wave having a constant peak value with the same conduction width as that of the commercial alternating current that is full-wave rectified by the rectifying and smoothing circuit;
A smoothing circuit that converts the rectangular wave into a DC voltage corresponding to the conduction width thereof, and
Wherein, the current value flowing through the light emitting diode, a direct current for the smoothing circuit emitting diode according to claim 1, wherein the controller controls the switching element to a value corresponding to the DC voltage output by the Power supply. The conduction width detecting means includes
A rectangular wave conversion circuit that is phase-controlled and converts into a rectangular wave having a constant peak value with the same conduction width as that of the commercial alternating current that is full-wave rectified by the rectifying and smoothing circuit;
A conduction width arithmetic circuit that detects the conduction width from the Hi / Lo switching timing of the rectangular wave,
Wherein, the current value flowing through the light emitting diodes, the conducting width computing circuit of the detection result to control the switching element to a value which corresponds to said direct current for claim 1, wherein the light emitting diode Power supply. It is interposed between the conduction width detection means and the peak value detection circuit and the control means, and responds to the outputs from the conduction width detection means and the peak value detection circuit to compensate for fluctuations in the conduction width due to peak value fluctuations. with light emitting diode current - light-emitting diode DC power supply device according to any one of claims 1 to 3, wherein the obtaining further Bei correction circuits for performing nonlinear correction in the luminance characteristics. An amplifier circuit for amplifying the output of the current detection circuit;
The direct current power supply device for a light emitting diode according to any one of claims 1 to 4, wherein an amplification factor of the amplifier circuit is changed according to a detection result of the conduction width detecting means. The current detection circuit, the amplification factor of the amplifier circuit with changing a, the control unit of the light-emitting diode current claim 5 Symbol mounting the light emitting diode for a DC power supply and said varying along the control target value of . A lighting apparatus comprising a light emitting diode integrated with the light emitting diode DC power supply device according to any one of claims 1 to 6 .

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