Selection of driving power supply for LED light bar dimming application
Time:2022-04-04
Views:2158
LED is more and more widely used in lighting and lighting, which is superior to traditional lighting. Apart from improving the quality of life, improving the efficiency of light source and prolonging the life of lamps and lanterns, it uses its unique dimmable function to change the color temperature and brightness of lamps, and fully achieves the biggest advantage of energy saving application.
The dimming efficiency of LED lighting fixtures depends on the matched LED light source and driving power supply.
Generally speaking, LED light sources can be simply divided into two categories: single LED diode light source or LED diode light source with resistance. In application, sometimes led light sources will be designed as a module containing DC-DC converter, and such complex modules are not within the scope of this article. If the LED light source or module is a separate LED diode itself, the common dimming method is to adjust the amplitude of the LED input current, so the selection of LED driving power supply should refer to this characteristic. The HLG / ELG family of Mingwei company is characterized by adjustable current and can be adjusted by external 1-10vdc * or 10vpwm pulse width, or even control the adjustment of output current only through an external simple variable resistor. Another LED diode light source with resistor (commonly known as LED strip or ledtrip). LED strip is widely used. It has a resistance in series with LED diodes, so the voltage is relatively stable. Therefore, users can use any commercially available constant voltage power supply to drive LED strip. The common LED light bar is generally driven by 12VDC or 24VDC, but it may be a little difficult in the dimming application of LED light bar. This paper describes the application of current amplitude dimming driver in LED light bar, and discusses some common dimming problems. At the same time, it introduces the dimmable LED power driver with output pulse width (PWM) modulation. The PWM family series launched by Mingwei company and affirmed by the national technological innovation product award is the most appropriate and simplest LED light bar dimming scheme on the market.
Common poor LED dimming conditions:
Dimming sounds like a simple thing. In fact, many factors need to be considered to have a good and smooth dimming performance. There are many common cases of poor LED dimming, as shown in table (I):
Table 1: common dimming problems
Deadtravel is a common problem when using LED power driver with adjustable output current to dimming LED lamps. Although the LED drive power supply can operate well when it is in the full load state (as shown in Fig. 1-A), it is obvious that the dimming is not smooth when the LED drive is not in the full load state
Figure: (G-100) the light length of LED driver is different from that of full load (hla-1); (b) 70% load - shows imperfect dimming effect; (c) 30% load - shows poor dimming results because the dimmable range is too narrow.
Output pulse width modulation (PWM) solution
If the LED driving power supply is used for LED light bar dimming application under full load, there is no deadtravel problem. The above argument is true, but it is not very practical. In fact, led strips are often used in various applications (decorative lighting / auxiliary lighting / advertising lighting) because the length cannot be accurately estimated. Therefore, the simplest and best application solution is to correctly select the LED driving power supply with output pulse width PWM dimming function to realize the dimming demand of LED strips. The output brightness reduces the dimming change of brightness by virtue of the load cycle of dimming signal. The important parameters for selecting the driving power supply are dimming analysis and the frequency of output pulse width modulation PWM. The minimum dimming ability should be as low as 0.1%, so as to achieve the dimming resolution of 8bit to meet all LED light bar dimming applications. The frequency of output pulse width modulation PWM should be increased as much as possible, In order to prevent the light flicker problem mentioned in table (I), according to the relevant technical research literature, the frequency is recommended to be at least higher than 1.25khz to reduce the ghost flicker visible to human eyes.
conclusion
The best LED light bar dimming scheme is to use the output pulse width modulation PWM dimming function to solve the common deadtravel dimming problem. The PWM models provided by Mingwei company cover four series such as 40 / 60 / 90 / 120W. They are very suitable for LED driving power supply for various LED light bar dimming applications.
|
Disclaimer: This article is transferred from other platforms and does not represent the views and positions of this site. If there is infringement or objection, please contact us to delete. thank you! |
Business consulting
13823761625
Mail me