Driving method and system for improving luminous efficacy of light-emitting diode
A technology of a light emitting diode and a driving method, which is applied in the field of driving and system for improving the luminous efficacy of the light emitting diode, can solve the problem of low luminous efficacy of the light emitting diode, and achieve the effect of improving the luminous efficiency and improving the luminous efficacy.
Inactive Publication Date: 2011-08-17
THE HONG KONG POLYTECHNIC UNIV
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[0007] The technical problem to be solved by the present invention is to provide a driving method and a driving system for improving the luminous efficiency of light-emitting diodes in view of the defect of low luminous efficacy of light-emitting diodes driven by the existing PWM driving technology
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[0039] The "high level" and "low level" current mentioned below refer to the "first current level" and "second current level" mentioned above, respectively. The use of "high level" and "low level" here is to facilitate the description of the negative impact of the increase in current level on the LED light efficiency.
[0040] Both the stability of chromaticity and the good functionality of dimming mentioned in the present invention can be realized in the PWM driving mode, however, the high level of current used by the PWM driving also leads to a decrease in light efficiency. Therefore, in order to improve this problem, the present invention reduces the high-level current of the PWM, and at the same time increases the low-level current from zero and adjusts the duty cycle of the high-level current to be the same as the average current of the conventional PWM, so that the continuous execution In the above steps, the gap between the high-level and low-level currents will gradual...
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The invention relates to a driving method and a driving system for improving the luminous efficacy of a light-emitting diode. The method comprises the steps of periodically switching direct current supplied to the LED (light-emitting diode) between a first current level 1H and a second current level 1L, keeping the set average current to be a preset current value 1f by reducing the difference value between the first current level 1H and the second current level 1L and correspondingly adjusting the duty ratio of the first current level 1H, and simultaneously improving the luminous efficacy of the light-emitting diode, wherein the first current level 1H is higher than the second current level 1L, and the second current level 1L is zero or higher than zero to produce direct current bias. The driving method and the system can effectively improve the luminous efficacy of the light-emitting diode.
Description
technical field [0001] The invention relates to a driving method and a driving system for improving luminous efficiency of a light emitting diode (LED). Background technique [0002] Due to the tremendous progress made in solid-state lighting technology in recent years, the light-emitting performance of light-emitting diodes is now close to that of traditional light sources. They outperform traditional light bulbs and fluorescent tubes in terms of lifespan, lumen maintenance, color rendering, reliability and operational safety. Because LEDs operate at very low voltages, lamp drivers are relatively easy to design and more reliable because of the lower voltage applied to the driver components compared to fluorescent tubes. However, fluorescent tubes require a high starting voltage and precise control of the heating current on the filament during the start-up period and the dimming process. The use of LEDs is therefore becoming more and more popular and rapidly replacing inca...
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IPC IPC(8): H05B37/02
CPCY02B20/42Y02B20/40
Inventor 卢家航伦伟强黎沃铭陈秀聪谢智刚
Owner THE HONG KONG POLYTECHNIC UNIV