Powering an LED Project from a PSU

[cjmadrigal]

Hi friends! Long time listener, first time caller. I need some bearings before I dive face-first into my (first!) LED project.

I'm working out how I'm going to power my project from within my PC. My GPU is connected to the PSU with an 8-pin PCIe connector. There's another header spliced on the same lines (presumably for dual GPU setups). The output is 12V, which I understand is at the upper limit of what the Vin pin on my Arduino UNO can accept.

However, 12V is perfect! I took my LED strip from some stand lighting fixture that broke, and it accepts 12V. The driver IC is an SM16703P, whose data sheet also suggests a circuit for 12V. My plan is to power the Arduino and LED strip from the same line powering my GPU.

I drew up a schematic. You'll see the PSU-GPU power rail, a simplified LED strip circuit (without resistors/capacitors for ease-of-reading), and my precious thinking box.

Ultimately, as fun as it sounds, I don't want to destroy any equipment. Has anyone attempted a similar power setup? Are there potential current draw concerns? Should I put a diode between the power supply and the LEDs? Am I crazy for powering this setup off my own PSU?! I'd love to get some insights.

[Grumpy_Mike]

Have you read this link about driving this ?

Problem with IC SM16703P

I see there is a resistor on the red output on the data sheet circuit.
Otherwise looks OK apart from the total lack of decoupling capacitors anywhere in the circuit.

[johnwasser]

The datasheet shows typical circuits: https://www.gree-leds.com/web/userfiles/download/SM16703ICdatasheet.pdf

For multiple LEDs in series, they put a resistor (RL) on the RED output.

Note also the "RSER" resistor on the data output pin and "RIN" resistor between the 12V supply and Vdd.

[cjmadrigal]

Hi! Yes, sorry about that, I left those out to minimize the clutter on the diagram. However I see the LED strip is equipped with a pair for each driver.