Since the driver is rated for output V up to 60V, driving a 6V LED should not be a problem, but the up to 16 3.2V leds bugs me. There is something I am not getting with the driver specs: why 3.2V? 16*3.2 = 51.2V, which is below the 60V max spec... That makes me wonder if there is a spec that imposes a max V drop per led, and a 6V led would not be suitable for this driver?
White/blue LEDs could have a higher Vf than 3.2volt, and slightly higher when cold.
And the chip needs some overhead voltage to do it's thing.
The chip seems to be a common switching CC LED driver, but with inductor etc. built-in. Drivers like this are designed to drive strings of LEDs (in series).
Better said: "The chip can drive a string of LEDs up to about 55volt."
Your 6volt LED (strange) would need a 9volt supply minimum.
Higher than 12volt will see efficiency go down (chip gets hotter).
Post a weblink to the LED (what is the required current).
Leo..
Using your LED with this driver will be fine. The driver cannot tell the difference between two 3 V LEDs or one 6V LED.
Per the table below (from their spec) you would need somewhere between 7 or 8 volts and 20 volts. I'm assuming the input voltage has to be some what above the output voltage but I could not find any minimum input to output delta in their specification.
Device operation:
The driver controls the current to the LEDs. Essentially adjusting the output voltage until the target current is attained. Except for power dissipation the driver doesn't care what the voltage needs to be for the LEDs it only knows it has to change the output voltage to keep the required current.
This is great for LEDs which output light as a function of current, not voltage. So as the LED heats up and the voltage requirement changes this driver will keep the current constant.
NOTE the LEDs are NOT connected to common (aka ground). Keep this in mind when you heatsink the LEDs.
The first one is 150mA and has two LEDs in series.
The second one is a single 100mA LED.
Not worth getting a CC driver for, unless you have a high voltage and a long string.
For those relative small currents a simple resistor will do.
What is your project.
Leo..
Indeed, very strange. I don't know of any leds with this forward voltage unless they're two leds in a single package.
I'd start by getting the specs of these leds very clear before proceeding.
Sure you can, but I never really liked it. What happens if one string fails? The CCS driver doesn't know and will just try to pump the same amount of current through the remaining half. How bad that is for your project depends, but I never preferred this option.
Nothing wrong with that. These little buck drivers are nifty and often easy to implement. Just keep a close eye on the datasheet. Generally the application circuit mentioned there can be copied virtually 1:1 to your project.
I find the Texas Instruments datasheets are generally the best in terms of guiding you through the calculations of stuff like the required inductor etc. Datasheets from Chinese brands generally just stick with "take this value and you're good" or leave it to the engineer to take a guess at it. With the possible exception of Monolithic Power Systems perhaps; their datasheets are pretty good too.
