Hi all.
I want to use my Arduino to control a 10W RGB LED using PT4115 driver. I have to connect each color to separate drivers (obviously 3 PT4115 drivers is needed). I use 3 PWM pin of the Arduino to control the LED.
Since each driver has a 2 pins for each LED there is 6 pins total. My question is if I have a common anode LED is there any way I can control that? Is it possible to connect all positives together?
How much current do you need for each color?
I think you might need a part like this for common anode RGB LEDs. It can do 500mA/channel.
ahmadx87:
My question is if I have a common anode LED is there any way I can control that? Is it possible to connect all positives together?
No. You have to use a 6-pin RGB LED.
RS (current sense resistor on the diagram) has to measure LED current for each separate colour.
Does your 10watt (cob) LED have a bar that connects the three anodes.
Then you can simply cut that bar into three anodes.
Leo..
CrossRoads:
How much current do you need for each color?
I think you might need a part like this for common anode RGB LEDs. It can do 500mA/channel.
AL1793AFE-13 Diodes Incorporated | Integrated Circuits (ICs) | DigiKey
I need maximum of 350mA per channel. This chip seems very interesting. I took a look at the datasheet but i couldn't find out if it is a buck or linear converter. I think if it was a buck converter some external parts like instructors and diodes would be necessary. If it is linear it will be very inefficient.
Wawa:
No. You have to use a 6-pin RGB LED.
RS (current sense resistor on the diagram) has to measure LED current for each separate colour.Does your 10watt (cob) LED have a bar that connects the three anodes.
Then you can simply cut that bar into three anodes.
Leo..
Yes I can cut the bar. But the reason I want to use common anode driver is that some PCBs for high power LEDs are already common anode, and I wanted to avoid wiring complexity.
ahmadx87:
I took a look at the datasheet but i couldn't find out if it is a buck or linear converter.Yes I can cut the bar. But the reason I want to use common anode driver is that some PCBs for high power LEDs are already common anode, and I wanted to avoid wiring complexity.
Anything with an inductor is switching (not linear), but it can be buck or boost.
The PT4115E is buck (lowering). 1-3 LEDs in series on a 12volt supply, or 3-6 LEDs in series on a 24volt supply.
You can always solder a single wire across the three pins again.
Leo..
Wawa:
Anything with an inductor is switching (not linear), but it can be buck or boost.
The PT4115E is buck (lowering). 1-3 LEDs in series on a 12volt supply, or 3-6 LEDs in series on a 24volt supply.You can always solder a single wire across the three pins again.
PicoBuck LED Driver - COM-13705 - SparkFun Electronics
Leo..
Thank you for your reply. Solder a single wire across which 3 pins? In Sparkfun PicoBuck LED Driver each LED has separate + and - pins.
Q: "Yes I can cut the bar."
A: "You can always solder a single wire across the three pins again." (if you want to make the LED original)
Another solution is a LED driver shield.
Leo..
That 0.33R resistor measures the current through the LED. So you have to have access to both anade and cathode for circuits like this to work.