JP5538078B2 - LED power supply - Google Patents

Description

  The present invention relates to an LED power supply device and an LED lighting fixture.

There is a need for highly efficient LED lighting to reduce CO ₂ . Furthermore, there is a demand for LED illumination that can change the light color according to the usage environment.

  In conventional LED lighting, a plurality of LED groups having different light colors are mounted on a single lighting fixture, and a constant current circuit individually connected to each LED group is controlled one by one to increase the brightness for each LED group. By changing it, the light color was made variable (for example, refer to Patent Document 1).

JP 2009-302008 A

  Conventional LED lighting fixtures are expensive because a constant current circuit is individually connected to each LED group, and there is a problem that the loss of the constant current circuit increases when the LED current increases.

  An object of the present invention is, for example, to obtain highly efficient light color variable LED illumination at low cost.

An LED power supply apparatus according to one aspect of the present invention is provided.
A constant current power supply circuit for supplying a constant current;
Each of the plurality of light emitting units, each of which includes at least one LED, emits light by turning on the at least one LED with a constant current from the constant current power supply circuit, and is connected to each other in series. At least one switch element connected in parallel, turned on when conducting, and turned off when shut off,
A control circuit that causes the light emitting unit connected to the at least one switch element to blink at the period by switching on / off the at least one switch element at a predetermined period ;
The control circuit inputs a dimming signal for instructing the dimming degree of the plurality of light emitting units as a whole, controls a constant current to be supplied to the constant current power supply circuit in accordance with the input dimming signal, and controls the at least one One of the features that you change the size of the constant current to be supplied to the constant current source circuit at the same timing as the timing of switching on / off of the switching element.

  According to one aspect of the present invention, the LED power supply device does not need to be provided with a constant current power supply circuit for each light emitting unit, so that highly efficient light color variable LED illumination can be obtained at low cost.

1 is a circuit diagram of a lighting device according to Embodiment 1. FIG. It is a figure which shows the external appearance of the surface of the LED module with which the illuminating device which concerns on Embodiment 1 is provided, and the connection between an LED module and a color temperature control circuit. (A) The figure which shows the example of the waveform of a PWM signal, (b) The graph which shows the relationship between the duty ratio of a light control signal, and brightness, (c) The graph which shows the relationship between the duty ratio of a color temperature signal, and color temperature. . 3 is a timing chart illustrating an operation example of the lighting apparatus according to Embodiment 1. 3 is a timing chart illustrating an operation example of the lighting apparatus according to Embodiment 1. 3 is a timing chart illustrating an operation example of the lighting apparatus according to Embodiment 1. FIG. 6 is a circuit diagram of a lighting apparatus according to Embodiment 2. It is a figure which shows the external appearance of the surface of the LED module with which the illuminating device which concerns on Embodiment 2 is provided, and the connection between an LED module and a color temperature control circuit. FIG. 6 is a circuit diagram of a lighting device according to Embodiment 3. FIG. 6 is a circuit diagram of a lighting device according to Embodiment 4. FIG. 10 is a circuit diagram of a lighting device according to Embodiment 5. FIG. 10 is a circuit diagram of a lighting device according to Embodiment 6. FIG. 10 is a circuit diagram of a lighting device according to Embodiment 7. FIG. 10 is a circuit diagram of a lighting device according to Embodiment 8.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of a lighting device 10 (LED lighting fixture) according to the present embodiment. FIG. 2 is a diagram illustrating the appearance of the surface of the LED module 11 included in the lighting device 10 and the connection between the LED module 11 and the color temperature control circuit 50.

  The lighting device 10 includes a power supply device 20 (LED power supply device) to which a commercial AC power supply AC is supplied, and an LED module 11 that is lit by inputting a direct current output from the power supply device 20.

  The LED module 11 includes, as a plurality of light emitting units, an LED array 1a (also referred to as “LED1”) (first light emitting unit) and an LED array 2a (also referred to as “LED2”) (second light emitting unit). The LED module 11 includes a substrate 12 (for example, a printed circuit board) on which the LED array 1a and the LED array 2a are mounted. Each of the LED array 1a and the LED array 2a includes at least one LED, and emits light by turning on the at least one LED by a constant current from an output constant current circuit 40 (constant current power supply circuit) described later. Specifically, the LED array 1a includes a plurality of first light color LEDs having a color temperature of, for example, 3000K (Kelvin), and emits light having a color temperature of 3000K (first color light) as a whole. The LED array 2a includes a plurality of second light color LEDs having a color temperature of, for example, 5000K, and emits light having a color temperature of 5000K as a whole (second color light different from the first color). The LED array 1a and the LED array 2a are connected in series with each other, and the first light color LED and the second light color LED constituting the LED array 1a and the LED array 2a are mounted on the substrate 12 so as to be alternately arranged. The Thus, by alternately arranging the first light color LEDs constituting the LED array 1a and the second light color LEDs constituting the LED array 2a, the emission color of the first light color LED and the second light color LED are changed. It becomes easy to mix with luminescent color.

  The power supply device 20 includes a rectifying / smoothing circuit 30, an output constant current circuit 40, a color temperature control circuit 50, and a control circuit 60 (for example, a microcomputer). The rectifying / smoothing circuit 30 performs full-wave rectification on the commercial AC power supply AC by the diode bridge 31 and smoothes it by the smoothing capacitor 32 to obtain a DC voltage. The output constant current circuit 40 supplies a constant current. Specifically, the output constant current circuit 40 receives the DC voltage of the rectifying / smoothing circuit 30 and outputs a constant DC current. The color temperature control circuit 50 receives the direct current output from the output constant current circuit 40 and controls the current flowing through the connected LED module 11. The control circuit 60 receives a dimming signal and a color temperature signal from the outside (such as a dimmer) and outputs an output control signal for controlling the output constant current circuit 40 based on the input dimming signal and color temperature signal. And a color temperature control signal for controlling the color temperature control circuit 50 is generated.

  The dimming signal input to the power supply device 20 (control circuit 60) is a signal indicating brightness information according to a PWM (pulse width modulation) duty ratio (a dimming signal for instructing the dimming degree of the plurality of light emitting units as a whole). It is. The color temperature signal input to the power supply device 20 (control circuit 60) is a signal indicating the color temperature information based on the PWM duty ratio (a toning signal for instructing the emission color of the entire plurality of light emitting units).

  The output constant current circuit 40 includes a constant current control FET 41, a resistor 42, a choke coil 43, a transistor 44, a diode 45, a current detection resistor 46, a constant current control circuit 47, and an electrolytic capacitor 48. The drain terminal of the constant current control FET 41 is connected to the high potential side of the rectifying and smoothing circuit 30. The resistor 42 is connected in parallel to the drain terminal and the gate terminal of the FET 41. One end of the choke coil 43 is connected to the source terminal of the FET 41. The transistor 44 has a collector terminal connected to the gate terminal of the FET 41 and an emitter terminal connected to the low potential side of the rectifying and smoothing circuit 30. The diode 45 has a cathode terminal connected to the source terminal of the FET and an anode terminal connected to the low potential side of the rectifying and smoothing circuit 30. One end of the current detection resistor 46 is connected to the low potential side of the rectifying and smoothing circuit 30, and the other end is connected to the color temperature control circuit 50 in the subsequent stage. The constant current control circuit 47 is connected to the other end of the current detection resistor 46, the base terminal of the transistor 44, and the control circuit 60. The electrolytic capacitor 48 has a positive electrode connected to the source terminal of the FET 41 via the choke coil 43 and a negative electrode connected to the low potential side of the rectifying and smoothing circuit 30.

  The control circuit 60 generates an output control signal for controlling the current output from the output constant current circuit 40 according to the duty ratio of the dimming signal input from the outside. The constant current control circuit 47 of the output constant current circuit 40 receives the output control signal from the control circuit 60, controls the switching of the transistor 44 based on the input output control signal, and the FET 41 is switched by the switching of the transistor 44. Is turned on / off to obtain a predetermined constant current. In accordance with this current, the brightness of light emitted from the entire LED module 11 changes.

  Only a direct current flows through the wiring between the output constant current circuit 40 and the substrate 12 of the LED module 11.

  The color temperature control circuit 50 includes, as a plurality of switch elements, an FET 1 (first switch element) that is a switch element connected in parallel to the LED array 1a and an FET 2 (second switch element) that is a switch element connected in parallel to the LED array 2a. Switch element). The color temperature control circuit 50 also includes an FET drive circuit 51 that controls ON / OFF of the FET1 and FET2. Each of FET1 and FET2 is turned on to be in a conductive state, and turned off to be in a cut-off state. A connection point of FET1 and FET2 and a connection point of LED array 1a and LED array 2a are connected, and FET1 is connected in parallel with LED array 1a and FET2 is connected in parallel with LED array 2a. Therefore, the LED array 1a is short-circuited when the FET 1 is turned on, and the LED array 2a is short-circuited when the FET 2 is turned on.

  The control circuit 60 controls the FET drive circuit 51 to switch on / off of the FET 1 at a predetermined cycle, thereby causing the LED array 1a connected to the FET 1 to blink at that cycle. Further, the FET drive circuit 51 controls the FET drive circuit 51 to switch on / off of the FET 2 at a predetermined cycle, thereby causing the LED array 2a connected to the FET 2 to blink at that cycle. Specifically, the control circuit 60 outputs a color temperature control signal for controlling the cycle in which the color temperature control circuit 50 turns on and off the FET 1 and FET 2 in accordance with the duty ratio of the color temperature signal input from the outside. Generate. The FET drive circuit 51 of the color temperature control circuit 50 receives the color temperature control signal from the control circuit 60 and controls on / off of the FET 1 and FET 2 based on the input color temperature control signal. The color temperature of the light emitted from the entire LED module 11 changes according to the on / off cycle.

  Next, the operation of the lighting device 10 (lighting control method) will be described.

  FIG. 3A is a diagram illustrating an example of a waveform of a PWM signal. FIG. 3B is a graph showing the relationship between the duty ratio of the dimming signal and the brightness, and FIG. 3C is a graph showing the relationship between the duty ratio of the color temperature signal and the color temperature.

  As shown in FIG. 3A, the duty ratio (Duty) is determined from the rising edge of the PWM signal to the falling edge with respect to the time T (time of one cycle) from the rising edge of the PWM signal to the next rising edge. It is the ratio of time t. As described above, the dimming signal and the color temperature signal input from the outside are both PWM signals, and the operation (the dimming control process and the color temperature control process) is performed with the duty ratio (that is, the ratio of the on time). This is a signal for instructing the control circuit 60.

  As shown in FIG. 3B, if the duty ratio of the input dimming signal is 0%, the control circuit 60 adjusts the brightness (dimming degree) of the light source to 100% and the input dimming signal. If the duty ratio of the optical signal is 100%, the brightness of the light source is adjusted to 0% (turned off). The control circuit 60 darkens the brightness of the light emitted from the LED array 1a and the LED array 2a when the ON time of the dimming signal becomes longer. That is, the control circuit 60 performs control so that the light source is lit darker as the duty ratio of the input dimming signal is larger.

  As shown in FIG. 3C, if the duty ratio of the input color temperature signal is 0%, the control circuit 60 adjusts the color temperature of the light source to 5000K, and the duty ratio of the input color temperature signal. Is 100%, the color temperature of the light source is adjusted to 3000K. When the ON time of the color temperature signal becomes longer, the control circuit 60 lengthens the time that the LED array 1a that emits light having a color temperature of 3000K is turned on and the time that the LED array 2a that emits light having a color temperature of 5000K is turned on. shorten. Therefore, when the ON time of the color temperature signal becomes longer, the color temperature of the light emitted from the LED array 1a and the LED array 2a is relatively close to 3000K, which is the color temperature emitted by the LED array 1a. That is, the control circuit 60 performs control so that the color temperature of the light source decreases as the duty ratio of the input color temperature signal increases.

  FIGS. 4A to 4C, FIGS. 5A to 5D, and FIG. 6 are timing charts illustrating an operation example of the illumination device 10.

  As described above, the power supply device 20 of the lighting device 10 has a dimming signal for inputting brightness information as a signal by a PWM duty ratio and a color temperature signal for inputting color temperature information by a PWM duty ratio. Applied. These two signals are received by the control circuit 60.

  The control circuit 60 controls the switching of the constant current control FET 41 of the output constant current circuit 40 based on the dimming signal, and the output current is controlled by the DC / DC converter including the choke coil 43, the electrolytic capacitor 48, and the diode 45. Adjust the brightness by controlling the value of. At this time, the control circuit 60 inputs to the output constant current circuit 40 an output control signal that indicates a constant current value for obtaining the dimming degree indicated by the duty ratio of the dimming signal. Note that the control circuit 60 may input the dimming signal as it is to the output constant current circuit 40 as an output control signal. The output constant current circuit 40 detects the output current, that is, the current flowing through the LED by the current detection resistor 46, and supplies the constant current according to the current value indicated by the output control signal to the LED by the constant current control circuit 47. .

  The control circuit 60 controls the switching of the FET1 and FET2 of the color temperature control circuit 50 on the basis of the color temperature signal. When the FET1 is on, the LED array 1a is short-circuited to stop the light emission, and the FET2 is on. During the period, the LED array 2a is short-circuited to stop its light emission. At this time, the control circuit 60 inputs to the color temperature control circuit 50 a color temperature control signal instructing a switching operation for obtaining a color temperature indicated by the duty ratio of the color temperature signal. The control circuit 60 may input the color temperature signal as it is to the color temperature control circuit 50 as the color temperature control signal. The color temperature control circuit 50 performs a switching operation instructed by the color temperature control signal by the FET drive circuit 51.

  As described above, for example, if the LED array 1a has an emission color of 3000K and the LED array 2a has an emission color of 5000K, the output constant current circuit 40 is the same as the LED array 1a → the LED array 2a while the FET1 and FET2 are off. When a current is passed, the combined emission color can be set to 4500K. On the other hand, during the period when the FET 1 is on, the current flows through the path of the FET 1 → the LED array 2a, and only the LED array 2a emits light, so that the emission color is 5000K. On the contrary, when the FET 2 is on, the emission color of the LED array 1a, that is, 3000K. Therefore, the light color between 3000K and 5000K can be freely created by controlling the FET1 and FET2 on / off at a predetermined period. At this time, the combined luminous flux decreases during a period in which current flows only in one LED. When changing the light color with constant brightness, if the LED array 1a and the LED array 2a emit light of substantially the same luminous flux when supplied with the same current, only one of the FET1 and FET2 is turned on. During the period, the brightness can be controlled to be constant by doubling the output current of the output constant current circuit 40. Note that even if the LED array 1a and the LED array 2a emit light of different luminous fluxes even if the same current is supplied to each other, only one of the FET1 and FET2 is turned on during the period of the output constant current circuit 40. The brightness can be controlled to be constant by adjusting the output current according to the luminous flux ratio of the LED array 1a and the LED array 2a (the luminous flux ratio when the same current is passed).

  Further, when it is desired to change only the combined brightness with a constant light color, it can be realized by changing the output of the output constant current circuit 40 while keeping the on / off control states of the FET1 and FET2 constant. It is desirable that the on / off period of the FET1 and FET2 is equal to or higher than a frequency (generally 200 Hz or higher) that human eyes cannot recognize as flicker.

  Hereinafter, the examples of FIGS. 4A to 4C, FIGS. 5A to 5D, and FIG. 6 will be described in detail. Here, the first light color LED (color temperature is 3000K) constituting the LED array 1a and the second light color LED (color temperature is 5000K) constituting the LED array 2a are both currents of 0.4A as an example. Is input at 100% light output, and the light output is proportional to the current value. In addition, the characteristic of 1st light color LED and 2nd light color LED is not restricted to this.

  In the example of FIG. 4A, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 to set its output current to 0.4A. Further, the control circuit 60 controls the color temperature control circuit 50 to always turn off the FET1 and FET2. Since the FET 1 is always off, the LED array 1a (LED 1) is always lit with a light output of 100% (50% of the entire illumination device 10). Similarly, since the FET 2 is always off, the LED array 2a (LED 2) is always lit with a light output of 100% (50% of the entire lighting device 10). As a result, the brightness (appearance) of the light emitted from the illumination device 100 is 100%, and the (appearance) color temperature is 4000K. In this example, it is assumed that a PWM signal having a duty ratio of 0% (a signal for instructing a dimming degree of 100%) is input to the control circuit 60 as a dimming signal. Further, it is assumed that a PWM signal having a duty ratio of 50% (a signal for instructing a color temperature of 4000K) is input to the control circuit 60 as the color temperature signal.

  In the example of FIG. 4B, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 to set its output current to 0.4A. In addition, the control circuit 60 controls the color temperature control circuit 50 to turn on the FET 1 for 25% of one cycle and always turn off the FET 2. Since the FET 1 is on for 25% in one cycle, the LED array 1a is turned on with 100% light output for only 75% in one cycle, and is turned off for 25% in one cycle. On the other hand, since the FET 2 is always off, the LED array 2a is always lit with a light output of 100%. Thereby, the brightness of the light emitted from the lighting device 100 is 87.5% (= 100 × 0.75 + 50 × 0.25), and the color temperature of (visible) is 4250 K (= 4000 × 0.75 + 5000 ×). 0.25). In this example, it is assumed that a PWM signal having a duty ratio of 12.5% (a signal for instructing a dimming degree of 87.5%) is input to the control circuit 60 as the dimming signal. Further, it is assumed that a PWM signal having a duty ratio of 46.875% (a signal for instructing the color temperature 4250K) is input to the control circuit 60 as the color temperature signal.

  In the example of FIG. 4C, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 so that its output current is 0.4A. Further, the control circuit 60 controls the color temperature control circuit 50 to always turn off the FET 1 and turn on the FET 2 by 75% of one cycle. Since the FET 1 is always off, the LED array 1a is always lit with a light output of 100%. On the other hand, since the FET 2 is on for 75% in one cycle, the LED array 2a is turned on only at 25% in one cycle with a light output of 100%, and 75% in one cycle is turned off. As a result, the (appearance) brightness of the light emitted from the illumination device 100 is 62.5% (= 100 × 0.25 + 50 × 0.75), and the (appearance) color temperature is 3250K (= 4000 × 0.25 + 3000 ×). 0.75). In this example, it is assumed that a PWM signal having a duty ratio of 37.5% (a signal for instructing a dimming degree of 62.5%) is input to the control circuit 60 as the dimming signal. Further, it is assumed that a PWM signal (a signal for instructing the color temperature 3250K) having a duty ratio of 59.375% is input to the control circuit 60 as the color temperature signal.

  In the example of FIG. 5A, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 to set its output current to 0.4A. The control circuit 60 controls the color temperature control circuit 50 to always turn on the FET 1 and always turn off the FET 2. Since the FET 1 is always on, the LED array 1a is always extinguished. On the other hand, since the FET 2 is always off, the LED array 2a is always lit with a light output of 100%. Thereby, the (appearance) brightness of the light emitted from the lighting device 100 is 50%, and the (appearance) color temperature is 5000K. In this example, it is assumed that a PWM signal having a duty ratio of 50% (a signal for instructing a dimming degree of 50%) is input to the control circuit 60 as the dimming signal. Further, it is assumed that a PWM signal having a duty ratio of 0% (a signal for instructing a color temperature of 5000K) is input to the control circuit 60 as the color temperature signal.

  In the example of FIG. 5B, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 to set its output current to 0.4A. Then, after a certain point in time, the control circuit 60 controls the output constant current circuit 40 to increase its output current to 0.5A. The control circuit 60 controls the color temperature control circuit 50 to always turn on the FET 1 and always turn off the FET 2. Since the FET 1 is always on, the LED array 1a is always extinguished. On the other hand, since the FET 2 is always off, the LED array 2a is lit with a light output of 100% until the time point, and is lit with a light output of 125% (= 0.5 / 0.4 × 100) after the time point. To do. As a result, the brightness (appearance) of the light emitted from the illumination device 100 is 50% and the (appearance) color temperature is 5000K until the above time point. From the above time point, the (appearance) brightness of the light emitted from the illumination device 100 is 62.5% (= 50 × 1.25), but the (appearance) color temperature is maintained at 5000K. In this example, as the dimming signal, a PWM signal having a duty ratio of 50% (a signal for instructing a dimming degree of 50%) is input to the control circuit 60 until the time point, and the duty ratio is 37. It is assumed that a 5% PWM signal (a signal for instructing a dimming degree of 62.5%) is input to the control circuit 60. Further, it is assumed that a PWM signal having a duty ratio of 0% (a signal for instructing a color temperature of 5000K) is input to the control circuit 60 as the color temperature signal.

  In this example, since the control circuit 60 controls the constant current supplied to the output constant current circuit 40 in accordance with the input dimming signal, the brightness of the light emitted from the lighting device 100 can be easily changed.

  In the example of FIG. 5C, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 to set its output current to 0.4A. Thereafter, the control circuit 60 controls the output constant current circuit 40 to gradually reduce the output current to 0 A with time. In addition, the control circuit 60 controls the color temperature control circuit 50 to turn on the FET 1 for 25% of one cycle and always turn off the FET 2. Since FET1 is on for 25% of one cycle, the LED array 1a is turned on only for 75% of one cycle and is turned off for 25% of one cycle. The light output when the LED array 1a is turned on gradually decreases from 100% to 0%. On the other hand, since the FET 2 is always off, the LED array 2a is always lit. The light output of the LED array 2a gradually decreases from 100% to 0%. Thereby, although the light emitted from the illumination device 100 gradually becomes dark, the color temperature (appearance) is maintained at 3500 K (= 3000 × 0.75 + 5000 × 0.25) until the light is extinguished. In this example, a PWM signal having a duty ratio of about 0% (a signal for instructing a dimming degree of about 100%) is input to the control circuit 60 as the dimming signal, and then the duty ratio of the input PWM signal is It rises over time and will eventually reach 100%. Further, it is assumed that a PWM signal having a duty ratio of 56.25% (a signal for instructing a color temperature of 3500K) is input to the control circuit 60 as the color temperature signal.

  In the example of FIG. 5D, the control circuit 60 of the power supply device 20 controls the output constant current circuit 40 so that the output current is 0.4A. Further, the control circuit 60 controls the color temperature control circuit 50 to turn on the FET 1 by 50% for one cycle and turn on the FET 2 by 25% for one cycle. Since the FET 1 is ON for 50% in one cycle, the LED array 1a is turned on with 100% light output only for 50% in one cycle, and is turned off for 50% in one cycle. On the other hand, since the FET 2 is on for 25% in one cycle, the LED array 2a is turned on with only 100% light output for 75% in one cycle, and is turned off for 25% in one cycle. Thus, the (appearance) brightness of the light emitted from the lighting device 100 is 62.5% (= 100 × 0.25 + 50 × 0.25 + 50 × 0.5), and the (appearance) color temperature is 4250K (= 4000 ×). 0.25 + 3000 × 0.25 + 5000 × 0.5). In this example, it is assumed that a PWM signal having a duty ratio of 37.5% (a signal for instructing a dimming degree of 62.5%) is input to the control circuit 60 as the dimming signal. Further, it is assumed that a PWM signal having a duty ratio of 46.875% (a signal for instructing the color temperature 4250K) is input to the control circuit 60 as the color temperature signal.

  In the example of FIG. 6, the control circuit 60 of the power supply device 20 controls the color temperature control circuit 50 to turn on the FET 1 for 25% of one cycle and always turn off the FET 2. Further, the control circuit 60 controls the output constant current circuit 40 so that the output current is 0.4 A when the FET 1 is on and 0.2 A (= 0.4 / 2) when the FET 1 is off. To do. That is, the control circuit 60 adjusts the output current of the output constant current circuit 40 in accordance with the switching operation of the FET 1. Since FET1 is on for 25% in one cycle, the LED array 1a is turned on with a light output of 50% for only 75% in one cycle, and is turned off for 25% in one cycle. On the other hand, since the FET 2 is always off, the LED array 2a is always lit. The light output of the LED array 2a is 100% when the FET 1 is on and 50% when the FET 1 is off. Thereby, the brightness of the light emitted from the lighting device 100 is 50%, and the color temperature is 4250 K (= 4000 × 0.75 + 5000 × 0.25). In this example, it is assumed that a PWM signal having a duty ratio of 50% (a signal for instructing a dimming degree of 50%) is input to the control circuit 60 as the dimming signal. Further, it is assumed that a PWM signal having a duty ratio of 46.875% (a signal for instructing the color temperature 4250K) is input to the control circuit 60 as the color temperature signal.

  In this example, the control circuit 60 changes the magnitude of the constant current supplied to the output constant current circuit 40 at the same timing as when the FET 1 is turned on / off. The brightness of the light emitted from the device 100 can be kept constant. When this example is modified so that the FET 2 also performs the switching operation, the control circuit 60 supplies the output constant current circuit 40 with the same timing as the ON / OFF switching timing of either the FET 1 or the FET 2. The same effect can be obtained by changing the magnitude of the constant current.

  As described above, in the present embodiment, the control circuit 60 switches on / off at least one of the plurality of switch elements at a predetermined cycle, thereby causing at least one of the plurality of light emitting units to blink at the cycle. . At this time, the control circuit 60 controls the cycle according to the input color temperature signal. When a dimming signal is also input as in the above examples, the period is controlled in consideration of the input dimming signal. For example, in the example of FIG. 4B and the example of FIG. 5D, the color temperature commanded by the color temperature signal is the same as 4250K, but the light control level commanded by the light control signal is 87.degree. 5%, the other is 62.5%. Therefore, the control circuit 60 controls the light emitting units to blink at different periods in the example of FIG. 4B and the example of FIG.

  As described above, in the present embodiment, since the power supply device 20 has one output constant current circuit 40, not only can the power supply device 20 be configured at low cost, but also the switch elements (FET1 and FET1) that bypass the LED current. Since the loss of the FET 2) is very small, the efficiency of the entire lighting device 10 can be increased. Furthermore, the entire illumination device 10 can be made inexpensive because of a simple configuration in which the switch element is simply turned on / off.

  The light emission colors of the LED array 1a and the LED array 2a may be other than 3000K and 5000K, respectively. For example, a combination of 4200 to 6500K white or daylight white and 2700 to 3000K light bulb color can be used for practically variable colors. LED lighting can be obtained. Further, the LED array 1a and the LED array 2a do not have to be composed of LEDs of the same light color, and may be selected according to the combined light color (color temperature) when the FET1 and FET2 are turned off. For example, if all four LED arrays 1a are composed of LEDs with a color temperature of 3000K, and the LED array 2a is configured to have two LEDs of 5000K and two LEDs of 3000K, when all the LEDs emit light The color temperature of the obtained luminescent color can be 3500K. In the present embodiment, the LED array 1a and the LED array 2a are each composed of four LEDs, but may be composed of three or less LEDs or five or more LEDs. Alternatively, each of the LED array 1a and the LED array 2a may be replaced with one LED. Further, the LED array 1a and the LED array 2a may be configured by different numbers of LEDs.

  In the present embodiment, the LED module 11 is configured by two light emitting units (LED array 1a, LED array 2a), but the LED module 11 may be configured by three or more light emitting units. In the present embodiment, one switching element (FET1, FET2) is connected in parallel to each of the two light emitting units (LED array 1a, LED array 2a), but some light emitting units (LED A switch element (FET1 or FET2) may be connected in parallel only to the array 1a or the LED array 2a). The same applies to the case where there are three or more light emitting units. That is, the power supply device 20 only needs to include at least one switch element.

  In the present embodiment, the LED array 11 is configured by mounting the LED array 1a and the LED array 2a on one substrate 12, but the LED array 1a and the LED array 2a are separately mounted on the two substrates, respectively. The LED module 11 may be configured. In the present embodiment, the first light color LED and the second light color LED constituting the LED array 1a and the LED array 2a are alternately mounted on the substrate 12, but the substrate 12 is not mounted alternately. The first light color LED may be mounted on one side and the second light color LED may be mounted on the other side. Further, in the present embodiment, the first light color LEDs and the second light color LEDs are alternately arranged in a straight line on the substrate 12, but other arrangement methods may be adopted. For example, the first light color LED and the second light color LED may be arranged in a staggered pattern on the substrate 12, may be alternately arranged in a ring shape, or the first light color LED and the first light color LED The two light color LEDs may be arranged randomly so as not to be adjacent to each other. In this way, by preventing two or more LEDs having the same color temperature from being arranged in succession, the color mixing property of the emission color is improved. In the present embodiment, the shape of the substrate 12 constituting the LED module 11 is substantially rectangular. However, the shape of the substrate 12 constituting the LED module 11 may be a square, a circle, a horseshoe shape, or the like. You may form according to the shape of the lighting equipment used.

  In the present embodiment, the LED module 11 and the power supply device 20 may be housed in the same housing or in separate housings. When the LED module 11 and the power supply device 20 are housed in separate housings, only the color temperature control circuit 50 of the power supply device 20 may be housed in the same housing as the LED module 11. At this time, the FET 1 and FET 2 that are switch elements of the color temperature control circuit 50 and the FET drive circuit 51 may be arranged on the same substrate 12 as the LED array 1a and LED array 2a. In this case, when the FET1 and FET2 are turned on / off, the pulsed current flowing through the FET1 and FET2 is only in the substrate 12 of the LED module 11, and the main current between the output constant current circuit 40 and the LED module 11 is Since only a direct current is used, noise generation can be suppressed.

  In the present embodiment, the control circuit 60 of the power supply device 20 performs control so that the light source is lit darker as the duty ratio of the dimming signal is larger. However, the light source is brighter as the duty ratio of the dimming signal is larger. You may control to do. In this embodiment, the control circuit 60 performs control so that the color temperature of the light source decreases as the duty ratio of the color temperature signal increases. However, the color temperature of the light source increases as the duty ratio of the color temperature signal increases. May be controlled to be higher.

Embodiment 2. FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 7 is a circuit diagram of lighting device 10 (only a part) according to the present embodiment. FIG. 8 is a diagram illustrating the appearance of the surface of the LED module 11 included in the lighting device 10 and the connection between the LED module 11 and the color temperature control circuit 50.

  In the present embodiment, two LED modules 11 similar to those in the first embodiment are connected to the power supply device 20. About another structure, it is the same as that of the illuminating device 10 which concerns on Embodiment 1 shown in FIG.

  The LED array 1a and the LED array 1b (first light emitting unit) include a plurality of LEDs having substantially the same color temperature, and the voltage drops of the LED array 1a and the LED array 1b are substantially equal. The LED array 1a and the LED array 1b are connected in parallel. As described above, in the present embodiment, the voltage drop between the LED array 1a and the LED array 1b is made substantially equal, so that the LED array 1b connected in parallel to the LED array 1a has a current substantially equal to that of the LED array 1a. Can flow.

  Similarly, the LED array 2a and the LED array 2b (second light emitting unit) include a plurality of LEDs having substantially the same color temperature, and the voltage drops of the LED array 2a and the LED array 2b are substantially equal. The LED array 2a and the LED array 2b are connected in parallel. As described above, in the present embodiment, the voltage drop between the LED array 2a and the LED array 2b is made substantially equal. Therefore, the LED array 2b connected in parallel to the LED array 2a has a current substantially equal to the LED array 2a. Can flow.

  As described above, in the present embodiment, since the number of LED modules 11 is increased as compared with the first embodiment, the luminous flux can be increased.

Embodiment 3 FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 9 is a circuit diagram of lighting device 10 (only a part) according to the present embodiment.

  In the present embodiment, the connection positions of the LEDs connected in series and the FETs 1 and 2 that are switch elements connected in parallel to the LEDs are changed. About another structure, it is the same as that of the illuminating device 10 which concerns on Embodiment 1 shown in FIG.

  In the first embodiment, one switch element (FET1 and FET2) is connected in parallel to each of two light emitting units (LED array 1a and LED array 2a) that emit light of different colors. The control circuit 60 switches on / off of at least one of the two switch elements (FET1 or / and FET2) at a predetermined cycle, thereby at least one of the two light emitting units (LED array 1a or / and The LED array 2a) is blinked at this cycle. In contrast, in the present embodiment, two of the four light emitting units (one LED on the high potential side of the LED array 1a, two LEDs in the middle, one LED on the low potential side, and the LED array 2a) One switch element (FET1 and FET2) is connected in parallel to each of the light emitting units (two LEDs in the middle of the LED array 1a and the LED array 2a). The control circuit 60 switches on / off of at least one of the two switch elements (FET1 and / or FET2) at a predetermined cycle, thereby at least one of the two light emitting units (in the middle of the LED array 1a). The two LEDs or / and the LED array 2a) are blinked in this cycle.

  The LED array 1a has four LEDs connected in series. The FET 1 is connected in parallel to, for example, two intermediate LEDs among the four LEDs constituting the LED array 1a.

  When the FET 1 is turned off, it is possible to control the color temperature of the light emitted from the lighting device 100 to be the same color temperature as in the first embodiment. For example, when the FET 2 is turned on, the color temperature of the light emitted from the lighting device 100 becomes the color temperature of the LED array 1a (for example, 3000K). When FET1 and FET2 are turned off, the color temperature of the light emitted from the illumination device 100 becomes an intermediate color temperature (for example, 4000K) in which the color temperatures of the LED array 1a and the LED array 2a are mixed.

  When the FET 1 is turned on, two LEDs out of the four LEDs constituting the LED array 1a are turned off. Therefore, when the FET 2 is turned off in this state, the LED array 2a is turned on. However, unlike the first embodiment, the color temperature of the light emitted from the illumination device 100 is different from that of the LED array 2a (for example, 5000K). Don't be. That is, since a part of the LED array 1a is lit, the color temperature of the light emitted from the illumination device 100 is a color temperature in which the color temperatures of the LED array 1a and the LED array 2a are mixed. Since the LED array 1a is partially lit, the mixed color temperature at this time is not intermediate between the color temperatures of the LED array 1a and the LED array 2a, but approaches the color temperature of the LED array 2a. It becomes. For example, when the color temperature of the LED array 1a is 3000K and the color temperature of the LED array 2a is 5000K, the color temperature when mixed is 4500K.

  As described above, in the present embodiment, of the four LEDs constituting the LED array 1a, two LEDs can be turned on and off by the FET 1, and the color temperature of light as a lighting fixture is implemented. It may be different from the first mode.

  In addition, since the current is supplied to the LED array 1a and the LED array 2a by the output constant current circuit 40, even if the lighting state of the LEDs constituting the LED array 1a is controlled, the current flowing through each LED is substantially constant. Can be.

Embodiment 4 FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 10 is a circuit diagram of lighting device 10 (only a part) according to the present embodiment.

  In the present embodiment, three LED arrays similar to those in the first embodiment are connected in series, and three switch elements corresponding to each LED array are also connected in series. About another structure, it is the same as that of the illuminating device 10 which concerns on Embodiment 1 shown in FIG.

  The LED array 1a (first light emitting unit), LED array 2a (second light emitting unit), and LED array 3a (third light emitting unit) connected in series are connected to the power supply device 20 (color temperature control circuit 50). . The color temperature control circuit 50 includes three switch elements (FET1, FET2, FET3) connected in parallel to the LED array 1a, the LED array 2a, and the LED array 3a.

  The LED array 1a and the LED array 2a include, for example, three LEDs each having the same color temperature (for example, 5000K). The LED array 3a includes, for example, two red LEDs.

  The power supply device 20 (color temperature control circuit 50) controls the lighting of the LED array 1a, the LED array 2a, and the LED array 3a by individually turning on / off the FET1, FET2, and FET3, and mixes the respective emission colors. And accurately produce the color of the bulb. For example, the amount of light emitted from the LED array 3a is changed by changing the on-time ratio of the FET 3, and the combined light of the LED array 1a, LED array 2a, and LED array 3a is light within the range of the bulb color on the chromaticity diagram. To be.

  Current white LEDs have variations in light color (color temperature) and light flux, and if the LEDs are combined without sorting, the target light color or light flux cannot be obtained. However, in the present embodiment, the target light color can be obtained by adjusting the chromaticity by controlling on / off of the FET1, FET2, and FET3. Further, the target light flux can be obtained by adjusting the output current of the output constant current circuit 40.

  Thus, in the present embodiment, by controlling the number of LED arrays that are individually turned on / off, it becomes possible to control the color temperature and brightness more finely than in the first embodiment.

Embodiment 5 FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 11 is a circuit diagram of lighting apparatus 10 according to the present embodiment.

  In the present embodiment, there is no FET 1 of the first embodiment. About another structure, it is the same as that of the illuminating device 10 which concerns on Embodiment 1 shown in FIG.

  In the first embodiment, one switch element (FET1 and FET2) is connected in parallel to each of two light emitting units (LED array 1a and LED array 2a) that emit light of different colors. In contrast, in the present embodiment, the first light emitting unit (LED array 1a) that emits the first color light (light having a color temperature of 3000K) and the second color light (color temperature is different from the first color). The switch element (FET2) is connected in parallel only to one (LED array 2a) with the second light emitting unit (LED array 2a) emitting 5000K light).

  Switch elements are not connected in parallel to the LED array 1a, and FETs 2 are connected in parallel only to the LED array 2a. Therefore, the control circuit 60 only controls the FET 2 based on the color temperature signal. For example, when the FET 2 is off, light with a high luminous flux with a color temperature of 4500 K is obtained as light emitted from the lighting device 100. When the FET 2 is on, light emitted only from the LED array 1a as light emitted from the lighting device 100, that is, light having a light flux of about ½ at a color temperature of 3000K is obtained. Power can be saved while maintaining a good visual environment. Note that when the FET 2 is on, the control circuit 60 controls the output current to be twice, so that it is possible to obtain light of the same luminous flux as the light emitted from the lighting device 100 when the FET 2 is off. In the present embodiment, the FET drive circuit 51 can be simplified by connecting the FET 2 in parallel with the LED connected to the common potential.

Embodiment 6 FIG.
In the present embodiment, differences from the fifth embodiment will be mainly described.

  FIG. 12 is a circuit diagram of lighting apparatus 10 according to the present embodiment.

  In the present embodiment, the power supply device 20 includes a rectifying / smoothing circuit 30, an output constant current circuit 40, a color temperature control circuit 50, a control circuit 60, a light flux adjusting resistor 63 connected to the control circuit 60, and a control circuit. 60 and a chromaticity adjusting resistor 64 connected to 60.

  The light flux adjusting resistor 63 is for adjusting the current supplied to the LED module 11 by the output constant current circuit 40. The chromaticity adjustment resistor 64 changes the timing (period) for turning on / off the FET 2 of the color temperature control circuit 50, and adjusts the color temperature (chromaticity) emitted by the LED module 11.

  In the present embodiment, the LED array 1a of the LED module 11 includes six LEDs having a color temperature of 5000K. The LED array 2a includes two red LEDs.

  The power supply device 20 (color temperature control circuit 50) controls the lighting of the LED array 2a by turning on / off the FET 2, and mixes the light emission colors of the LED array 1a and the LED array 2a to produce a light bulb color with high accuracy. . For example, the light emission amount of the LED array 2a is changed by changing the ratio of the ON time of the FET 2, so that the combined light of the LED array 1a and the LED array 2a becomes light within the range of the light bulb color on the chromaticity diagram. To do.

  Current white LEDs have variations in light color (color temperature) and light flux, and if the LEDs are combined without sorting, the target light color or light flux cannot be obtained. However, in the present embodiment, the target light color can be obtained by adjusting the chromaticity (adjusting the chromaticity adjustment resistor 64) by controlling on / off of the FET2. Further, the target light flux can be obtained by adjusting the output current of the output constant current circuit 40 (adjusting the light flux adjusting resistor 63). Further, when the white LED is composed of a combination of a blue LED element and a yellow phosphor (Blue-YAG), the red spectrum tends to be weak, but it can be interpolated by turning on the red LED.

  As described above, in the present embodiment, the power supply device 20 includes the light flux adjustment resistor 63 and the chromaticity adjustment resistor 64, so that the light flux adjustment and the chromaticity adjustment can be easily performed at the time of factory shipment or after installation on the ceiling or the like. Yes.

Embodiment 7 FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 13 is a circuit diagram of lighting apparatus 10 according to the present embodiment.

  In the present embodiment, the LED module 11 and the color temperature control circuit 50 of the power supply device 20 are accommodated in one casing 13, and at least the output constant current circuit 40 of the power supply apparatus 20 is accommodated in another casing 14. .

  The power supply device 20 includes a first control circuit 61 and a second control circuit 62 instead of the control circuit 60 of the first embodiment. The first control circuit 61 receives a dimming signal from the outside, and controls the output current output from the output constant current circuit 40 based on the dimming signal. The second control circuit 62 receives an external color temperature signal and outputs a color temperature control signal for changing the color temperature to the FET drive circuit 51 based on the color temperature signal.

  Although the control circuit 60 of the first embodiment is divided into a first control circuit 61 and a second control circuit 62 in the present embodiment, details of operations of the power supply device 20 and the LED module 11 are described in the first embodiment. The explanation is omitted because it is the same as.

  As described above, in the present embodiment, the color temperature control circuit 50 (FET drive circuit 51, FET1, FET2) of the power supply device 20 and the second control circuit 62 are provided in the same housing 13 as the LED module 11. That is, the LED module 11 and the color temperature control circuit 50 are disposed in the same housing 13, and the output constant current circuit 40 is disposed in a housing 14 different from the housing 13. For this reason, when the distance between the housing 13 (LED module 11) and the housing 14 (output constant current circuit 40) is increased, the electric wire connecting the housing 13 and the housing 14 extends. The leakage current to the outside can be reduced, or the response deterioration due to the floating capacity caused by the electric wire can be prevented. The LED module 11 and the color temperature control circuit 50 may be arranged on the same board, and the output constant current circuit 40 may be arranged on a board different from this board. A substantially similar effect can be obtained.

Embodiment 8 FIG.
In the present embodiment, differences from the first embodiment will be mainly described.

  FIG. 14 is a circuit diagram of lighting apparatus 10 according to the present embodiment.

  In the present embodiment, the power supply device 20 further includes a voltage detection circuit 70 and a protection circuit 80. The voltage detection circuit 70 divides the output voltage of the output constant current circuit 40 by the voltage detection resistor 71 and the voltage detection resistor 72 and applies the divided voltage to the protection circuit 80. The protection circuit 80 compares the output voltage with the reference voltage 82 by the comparator 81. The protection circuit 80 detects an open failure of the LED in either the LED array 1a or the LED array 2a by detecting the increase in the output voltage. The protection circuit 80 outputs an abnormality detection signal (predetermined signal) when detecting an open failure of the LED in either the LED array 1a or the LED array 2a. When an abnormality detection signal is output from the protection circuit 80, the control circuit 60 inputs this abnormality detection signal. Based on the input abnormality detection signal, the protection circuit 80 detects the LED open failure. The FET (FET1 or FET2) connected to the array is controlled to be turned on.

  In the example of FIG. 4B, regardless of whether the FET 1 is on or off, if any LED of the LED array 2a is open while the FET 2 is off, the LED array 1a and the LED array 2a connected in series have Since no current flows, the LED array 1a and the LED array 2a are turned off.

  At this time, the output constant current circuit 40 increases its output voltage in order to flow a constant current to the LED. The voltage detection circuit 70 divides the output voltage by the voltage detection resistor 71 and the voltage detection resistor 72 and applies it to the comparator 81 of the protection circuit 80. The reference voltage 82 of the comparator 81 is set higher than the voltage across the LEDs connected in series in advance and lower than the output voltage of the output constant current circuit 40 when no load is applied. Therefore, the comparator 81 inverts the output voltage (from Low to Hi) and applies it to the control circuit 60 as an abnormality detection signal.

  In the control circuit 60, since the protection circuit 80 performed the protection operation (the abnormality detection signal was output) while the FET1 was turned on / off and the FET2 was kept off, the LED array 2a caused an open failure. Estimated. Then, the control circuit 60 changes the control so that the FET 2 is always on from the off state, and controls the FET 1 so that it is always off. Thereby, the LED array 1a can continue lighting.

  Thus, the control circuit 60 estimates that an open failure of the LED has occurred in the LED array 2a when an abnormality detection signal is output from the protection circuit 80 with at least the FET 2 always turned off. Then, the control circuit 60 controls the color temperature control circuit 50 so that the FET 1 is always turned off and the FET 2 is always turned on. Since the FET 1 is always off and the FET 2 is always on, the LED array 1a is always lit with a light output of 100% even if the LED array 2a includes an LED with an open failure. Thereby, the (appearance) brightness of the light emitted from the lighting device 100 is 50%, and the (appearance) color temperature is 3000K.

  Here, even if the LED open failure has occurred in the LED array 2a, and the LED open failure has occurred in the LED array 1a, the protection circuit 80 operates in the same manner as described above and outputs an abnormality detection signal. Output. Therefore, the control circuit 60 once controls the FET 1 to be always off and the FET 2 to be always on, and then determines whether or not the output of the abnormality detection signal from the protection circuit 80 is continuously output. When it is determined that the abnormality detection signal is not continuously output, the control circuit 60 determines that the estimation that an LED open failure has occurred in the LED array 2a is correct. On the other hand, when the control circuit 60 determines that the abnormality detection signal is continuously output, an LED open failure has not occurred in the LED array 2a, but an LED open failure has occurred in the LED array 1a. Judge that Then, the control circuit 60 controls the color temperature control circuit 50 so that the FET 1 is always turned on and the FET 2 is always turned off. Since the FET 1 is always on and the FET 2 is always off, the LED array 2a is always lit with a light output of 100% even if the LED array 1a includes an LED with an open failure. Thereby, the (appearance) brightness of the light emitted from the lighting device 100 is 50%, and the (appearance) color temperature is 5000K.

  In this example, since the LED array 1a and the LED array 2a are set to have different emission colors as described above, it is possible to visually check which one of the LED array 1a and the LED array 2a has failed and repair the failure in a short time. Can be implemented.

  Contrary to the example of FIG. 4B, when one of the LEDs in the LED array 1a has an open failure while the control circuit 60 is controlling the FET 1 to be off and the FET 2 is on / off, the same as above. With this operation, the control circuit 60 changes the control so that the FET 1 is always on from the off state, and controls the FET 2 so that it is always off. Thereby, the LED array 2a can continue lighting.

  Here, an example is shown in which one of FET1 and FET2 performs a switching operation and the other is always off, and an open failure occurs in the LED. However, both FET1 and FET2 are in a switching operation. Even in the case where an open failure occurs in the LED when one of the FET1 and FET2 is always on, the same operation can be used. In any case, since the protection circuit 80 outputs an abnormality detection signal, the control circuit 60 estimates that an LED open failure has occurred in the LED array 1a or the LED array 2a based on the abnormality detection signal. The operation described above may be performed. At this time, if either one of FET1 and FET2 is always on, it can be determined from the beginning that an LED open failure has occurred in an LED array connected to a different FET from that FET.

  As described above, according to the present embodiment, when one of the LEDs connected to the common output constant current circuit 40 has an open failure, the other LEDs can be protected. In such a case, a certain brightness can be ensured by turning on the other LEDs. That is, it is possible to prevent all LEDs from turning off and becoming completely dark when an open failure occurs in LEDs connected in series. In addition, since the light from the illumination changes (for example, the brightness is reduced by half or the color temperature changes), it is possible to visually check which LED (light emitting unit) has failed, and repair the failure. Can be implemented in a short time.

  As mentioned above, although embodiment of this invention was described, you may implement combining 2 or more embodiment among these. Alternatively, one of these embodiments may be partially implemented. Or you may implement combining two or more embodiment among these partially.

  1 FET, 1a, 1b LED array, 2 FET, 2a, 2b LED array, 3 FET, 3a LED array, 10 lighting device, 11 LED module, 12 substrate, 13, 14 housing, 20 power supply device, 30 rectifying and smoothing circuit , 31 Diode bridge, 32 Smoothing capacitor, 40 Output constant current circuit, 41 FET, 42 Resistance, 43 Choke coil, 44 Transistor, 45 Diode, 46 Current detection resistance, 47 Constant current control circuit, 48 Electrolytic capacitor, 50 Color temperature control Circuit, 51 FET drive circuit, 60 control circuit, 61 first control circuit, 62 second control circuit, 63 luminous flux adjustment resistor, 64 chromaticity adjustment resistor, 70 voltage detection circuit, 71 voltage detection resistor, 72 voltage detection resistor, 80 Protection circuit, 81 Comparator, 82 Reference voltage, AC Commercial AC power supply.

Claims (5)

A constant current power supply circuit for supplying a constant current;
Each of the plurality of light emitting units, each of which includes at least one LED, emits light by turning on the at least one LED with a constant current from the constant current power supply circuit, and is connected to each other in series. At least one switch element connected in parallel, turned on when conducting, and turned off when shut off,
A control circuit that causes the light emitting unit connected to the at least one switch element to blink at the period by switching on / off the at least one switch element at a predetermined period ;
The control circuit inputs a dimming signal for instructing the dimming degree of the plurality of light emitting units as a whole, controls a constant current to be supplied to the constant current power supply circuit in accordance with the input dimming signal, and controls the at least one One of the LED power device characterized that you change the size of the constant current to be supplied to the constant current source circuit at the same timing as the timing of switching on / off of the switching element. The at least one switch element is a plurality of switch elements connected in parallel to each of the plurality of light emitting units,
2. The control circuit according to claim 1, wherein at least one of the plurality of light emitting units blinks in the cycle by switching at least one of the plurality of switch elements on / off in the cycle. LED power supply. The plurality of light emitting units include a first light emitting unit that emits light of a first color, and a second light emitting unit that emits light of a second color different from the first color,
The at least one switch element is connected in parallel to one of the first light emitting unit and the second light emitting unit,
3. The control circuit according to claim 1, wherein the control circuit inputs a toning signal for instructing emission colors of the plurality of light emitting units as a whole, and controls the cycle according to the input toning signal. LED power supply. The plurality of light emitting units emit different colors of light,
3. The LED power supply according to claim 2, wherein the control circuit inputs a toning signal for instructing an emission color of the whole of the plurality of light emitting units, and controls the cycle according to the input toning signal. apparatus.   5. The control circuit according to claim 1, wherein the control circuit inputs a dimming signal that instructs the dimming degree of the plurality of light emitting units as a whole, and controls the cycle according to the input dimming signal. LED power supply.

Images