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A dimming method of indoor white light LED

A white light and dimming technology, applied in the field of LED communication, can solve the problems of LED flicker, low energy utilization rate, and communication rate drop, and achieve the effect of reducing consumption, saving energy, and high bandwidth utilization rate.

Active Publication Date: 2017-09-01
南通固威机械科技有限公司
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  • Claims
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AI Technical Summary

Problems solved by technology

If the traditional OOK and PPM modes are used, at the cost of sacrificing the symbol bandwidth, the bandwidth occupied by the signal is reduced, and the impact of the signal on the lighting is reduced. However, the energy utilization rate of this encoding method is low, and when the transmission rate is low, There will be LED flickering phenomenon
In summary, these methods all have a drawback, the communication rate will decrease significantly with the increase or decrease of the light level

Method used

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  • A dimming method of indoor white light LED
  • A dimming method of indoor white light LED
  • A dimming method of indoor white light LED

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Embodiment Construction

[0051] Below in conjunction with accompanying drawing, technical scheme of the present invention is described in further detail:

[0052] The M-PAM encoding method is aimed at distinguishing multi-ary signal symbols by marking different pulse amplitudes in the linear area of ​​the LED. It can be seen that the higher the binary level M is, the more effective bits are carried by each symbol, and the bandwidth utilization rate increases. However, too high M will also bring problems: ①Due to the limitation of the LED linear region, the difference in electrical signal waveforms is small, resulting in a higher precision for the A / D converter; ②The receiving end needs a larger SNR when reading the signal, The bit error rate increases and the sensitivity decreases; ③The tiny voltage difference is easily lost in the background noise. Therefore, choosing an appropriate M has an important impact on the performance of PAM encoding.

[0053] The M-PAM of the present invention has M volta...

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Abstract

The invention discloses a dimming method of an indoor white light LED, which adjusts the light intensity by changing the probability of occurrence of signal symbols combined with amplitude dimming: the variable η is used as the proportional factor of DC compensation Dshift in analog dimming, and DC Compensation Dshift=A|1‑2ε|; ε is the dimming level, and A is the rated value of light intensity in the LED linear area; when the dimming level is below 50%, by increasing the occurrence of signal symbols with low light intensity amplitude Probability, reduce the probability of occurrence of signal symbols with high light intensity amplitude to adjust the light intensity; when the dimming level is 50%, there is no DC compensation Dshift; adjust the light intensity by changing the probability of high and low amplitude symbols; When the dimming level is higher than 50%, adjust the light intensity by reducing the probability of occurrence of signal symbols with low light intensity amplitude, increasing the probability of occurrence of signal symbols with high light intensity amplitude, and reducing Dshift compensation . Compared with the traditional digital dimming method, the present invention has higher bandwidth utilization rate, and ensures that the communication rate will not decrease following the change of the dimming level.

Description

technical field [0001] The invention relates to the technical field of LED communication, in particular to a dimming method of an indoor white LED. Background technique [0002] White light LED communication systems mostly use baseband modulation. Currently, the modulation methods suitable for white light LED communication are: on-off keying (OOK); pulse position modulation (PPM); multi-pulse position modulation (VPPM); pulse width modulation (PWM); Pulse Interval Modulation (DPIM); Dual Head Pulse Interval Modulation (DH-PIM) and Color Keying (CSK). The purpose of these modulation methods is to obtain higher power utilization ratio and lower bit error rate under relatively narrow bandwidth. In addition, the indoor white light LED communication system also needs to take into account the dual needs of lighting and communication. In order to save energy, it is necessary to adjust the brightness of the light source at any time according to different background light intensitie...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H05B33/08H04B10/116H05B44/00
CPCH04B10/116H05B45/10
Inventor 洪文昕钱晨朱晓叶王希琪李绍瑜
Owner 南通固威机械科技有限公司