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Light-emitting diode drive device and light-emitting diode illumination control method

A technology for light-emitting diodes and driving devices, applied in the field of light-emitting diode driving devices and lighting control of light-emitting diodes, can solve the problems of performance degradation, easy noise generation, residual unconsumed power, etc.

Active Publication Date: 2012-07-25
NICHIA CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In addition, general electrolytic capacitors have the problem of short life when the ambient temperature is high
In addition, the coils used in switching power supplies also have the problems of large size and performance degradation at high temperatures.
On the other hand, in switching power supply circuits, noise is likely to be generated due to high-speed switching and high-current, so noise countermeasures are also required
In this way, there are problems in the conventional drive circuit: it is necessary to ensure the layout space of the elements in the drive circuit that should be suitable for miniaturized LEDs, a structure for reducing the influence of temperature is required, and noise countermeasures are required.
[0012] Therefore, if the Vf of each LED block deviates from the desired value, if the Vf value becomes higher than the switching voltage value, no current will flow immediately after switching, and the LED cannot be turned on, resulting in noise and a drop in power factor.
On the contrary, when the Vf of the LED becomes lower than the switching voltage value, its corresponding power is unnecessarily consumed by the constant current circuit
Therefore, it is difficult to realize the desired operation according to the deviation of the LED element, and as a result, a delay in lighting switching and a decrease in efficiency will occur, and it is difficult to realize LED lighting quality and reliability in reality.
[0013] Furthermore, in the above-mentioned method, although the LEDs can be turned ON with a plurality of square waves by switching the LED blocks, if Figure 15 As shown by the slash of the , there is still unconsumed power, so there is a disadvantage that the efficiency is still not good
[0014] Especially in the area with the highest voltage, there is a problem that the area where the LED can emit the brightest light cannot be effectively used.

Method used

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  • Light-emitting diode drive device and light-emitting diode illumination control method
  • Light-emitting diode drive device and light-emitting diode illumination control method
  • Light-emitting diode drive device and light-emitting diode illumination control method

Examples

Experimental program
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Embodiment 1

[0061] Next, as Example 1, in figure 2 is shown using semiconductor components to achieve figure 1 A specific circuit configuration example of the structure. In the light emitting diode driving device 200 shown in the figure, a diode bridge is used as the rectification circuit 2 connected to the AC power supply AP. Furthermore, a protection resistor 17 is provided between the AC power supply AP and the rectification circuit 2 . Furthermore, a bypass capacitor 19 is connected to the output side of the rectifier circuit 2 .

[0062] (AC Power AP)

[0063] AC power supply AP can properly use 100V commercial power supply. 100V of this commercial power supply is an effective value, and the maximum voltage of the rectified waveform after full-wave rectification is about 141V.

[0064] (LED block)

[0065] Each LED block is connected in series with each other, and is divided into a plurality of blocks, and a terminal is drawn from the boundary between blocks, and is connected...

Embodiment 2

[0099] The above operation is control in consideration of the power factor. especially in figure 2 In the circuit example of , since the LED block group 1 is connected in series with one line, by performing constant current control on each LED block with a different current value, as image 3 Make the current waveform into a step shape as shown in the curve of . On the other hand, as Example 2, Figure 4 The voltage waveform is indicated using the figure 2 An example of a circuit that places more emphasis on utilization efficiency than power factor. In this control example, with image 3 Compared with the example of the above example, the resistance value and the like are set so that the constant current control of each LED block is close to each other, and the output is increased by increasing the overall current amount, and brighter illumination light is obtained. as Figure 4 In the LED current waveform shown, the measured values ​​of the circuit constants are power...

Embodiment 3

[0101] In the above example, the LED current detection resistor is made common to each LED block or the like. That is, each current detection control unit performs control based on the current amount of the common current detection unit, and the circuit configuration can be simplified. However, it is also possible to employ a configuration in which LED current detection resistors are individually provided for each LED block or the like. As Example 3, in Figure 5 An example of this is shown in the circuit diagram. In the light emitting diode driving device 300 shown in the figure, the basic structure and operation are substantially the same as those of the first embodiment, and LED current detection resistors are provided for each of the three LED blocks. Specifically, the current detection of the second LED block 12 is performed by the first LED current detection resistor 4B, the current detection of the third LED block 13 is performed by the second LED current detection re...

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Abstract

Disclosed is a light-emitting diode drive device that improves the utilization efficiency and power factor of LEDs while maintaining power supply efficiency. Said light-emitting diode drive device is provided with: a rectification circuit (2) that can be connected to an AC power supply and rectifies the AC voltage from said AC power supply into a pulsed voltage; a first LED block (11) comprising a plurality of light-emitting diodes, a second LED block (12) comprising a plurality of light-emitting diodes, and a third LED block (13) comprising a plurality of light-emitting diodes, connected sequentially in series to the output side of the rectification circuit (2); a first switching means that turns a first bypass path (BP1), which bypasses the second LED block (12), on or off on the basis of the amount of power supplied to the first LED block (11); and a second switching means that turns a second bypass path (BP2), which bypasses the third LED block (13), on or off on the basis of the amount of power supplied to the first LED block (11) and the second LED block (12).

Description

technical field [0001] The present invention relates to a driving circuit for driving light-emitting diodes and a lighting control method for light-emitting diodes, in particular to a light-emitting diode driving device driven by an AC power source and a lighting control method for light-emitting diodes. Background technique [0002] In recent years, light-emitting diodes (hereinafter also referred to as "LEDs") that can be driven with lower power consumption than incandescent bulbs or fluorescent lamps have attracted attention as light sources for lighting. The advantages of LEDs are: small size and strong impact resistance, so there is no need to worry about the lamp body breaking. [0003] As a power source for such lighting equipment, it is desirable to use an AC power source such as a household power source. LEDs, on the other hand, are DC-driven components that emit light only with forward current. In addition, the forward voltage Vf of LEDs currently mostly used for...

Claims

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Application Information

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IPC IPC(8): H05B37/02H01L33/00
CPCH05B33/083H05B45/48H05B45/46H05B47/155
Inventor 六车修二小椋涉渡边照雄
Owner NICHIA CORP
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