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| Digital controlled linear current source IC simple to use? |
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| smile:
Hello, I'm looking for digital controlled (arduino) linear current source IC easy to use like LM317 (few external components). I need at least 5W of power, more better. This is for RGBW led. Do not offer specialized LED controllers as these are not linear but square wave 180KHz etc. I would use LM338, but the resistor to control current must be power potentiometer of very low resistance and these are not cheap, besides I was told there is no way to digitally control LM338 etc. |
| spec:
--- Quote from: smile on October 22, 2018, 10:22:38 am --- I need at least 5W of power, more better. This is for RGBW led. --- End quote --- + smile (1) What is the total maximum and minimum constant current required for the RGBW LED? (2) What is the maximum voltage drop across the RGBW LED at the maximum current? (3) Can you identify the RGBW LED? (4) What degree of control of the constant current do you require? For example, 8 digital data lines would give 255 steps so, if the maximum current were 5A, each step would be 19.6 mA. --- Quote from: smile on October 22, 2018, 10:22:38 am ---I was told there is no way to digitally control LM338 etc. --- End quote --- It is possible to use LM338s etc as constant current generators, and control the constant current digitally but, so far, I cannot see an easy way using non-specialist chips. |
| spec:
--- Quote from: smile on October 22, 2018, 10:22:38 am --- I would use LM338, but the resistor to control current must be power potentiometer of very low resistance and these are not cheap --- End quote --- +2 smile Would you be happy with a circuit where the constant current could be controlled by a normal potentiometer. If so, there is a simple circuit that would do the job :D |
| smile:
--- Quote from: spec on October 22, 2018, 10:59:04 pm --- --- Quote from: smile on October 22, 2018, 10:22:38 am --- I would use LM338, but the resistor to control current must be power potentiometer of very low resistance and these are not cheap --- End quote --- +2 smile Would you be happy with a circuit where the constant current could be controlled by a normal potentiometer. If so, there is a simple circuit that would do the job :D --- End quote --- No POT will not work, I already made LM338 current circuit with 2.2Ohm resistor for 1.90Eur instead of paying 80Eur or 100Eur. Are you guys find it also crazy that in US and Europe the wireqound POTS are crazy expensive? Why? Nichrome wire is nonexistent in these parts of the world or is made from gold? |
| smile:
I wanted to drive something like this https://www.aliexpress.com/item/CREE-XML-MC-E-10W-RGBW-diodes-High-Power-led-RGBW-Color-led-red-green-blue/1809369010.html?spm=2114.01010208.3.206.eNIfRV&ws_ab_test=searchweb0_0,searchweb201602_2_10065_10068_10000009_10084_10083_10080_10082_10081_10060_10062_10056_503_10055_10054_10059_9911_10099_10078_501_10079_426_10103_10073_10102_10096_10052_10053_10050_10107_10051_10106-9911,searchweb201603_9,afswitch_5&btsid=5510bf64-5f8d-4909-8d15-4864ae161cc8 Perhaps there are better LEDS. My requirement are : RGBW LED with 4000K for white. 5W minimum 10W MAX I prefer it sold soldered to a star board https://www.cree.com/led-components/media/documents/XLampMCE.pdf The only problem is that this LED has 85CRI, and I need like 95 or better CRI. |
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