# how to drive 500W of leds

I am currently developing a project that needs 9 led stripes, each led stripe has 5 meters, 300 leds, it consumes 60W per stripe in a total of 540W...

This are the led stripes - 5M 12W/M 24V SMD 2835

This led stripes use a 24V power supply.

The thing is I want to drive them with an arduino and PWM. What would I need to do it. I was looking for something like CAT4101 but I never dealt with so much power before and I would like your advice.

Thanks

The led strips will have their own current limiting / drivers. A couple of quick calculations:

• 24V at 12W is (I=P/V) 12/24 = 0.5A per meter
• 5 meters = 0.5*5 = 2.5A

So each strip takes 2.5A. The CAT4101 is a 1A max driver, but since it is a constant current driver it's not suitable for a strip that has its own current control built in.

I suspect each meter consists of 10 chains of 6 LEDs with a current limiting resistor or two. Out of interest, calculations:

• 6 LEDs at (say) 3V forward voltage would be 18V.
• 24 - 18 = 6 volts to drop
• 500mA divided by 10 chains = 50mA
• R=V/I = 6 / 0.05 = 120Ω current limiting resistors.
• P=I²R = 0.05²×6 = 300mW dissipated from the resistors.

Instead all you need is an N-channel MOSFET as a low-side switch that can operate with that much current and not dissipate too much heat while switching. The more you derate the MOSFET the less heatsinking it would need.

A quick look on Digikey gave a possible match of PSMN022-30PL - 30V, 30A, 27mΩ (typ) at 4.5V gate voltage.

simulate this circuit – Schematic created using CircuitLab

• And I would need one of those for each led stripe? What if I get a 600W power supply? I don't think that the leds have drivers at all? I was thinking on direct power supply connection.... I guess that would be mistake right? May 15, 2017 at 22:03
• Ideally, yes - spread the load nicely. However one, with proper heat sinking, should be able to do all of them together (22.5A) at a pinch. May 15, 2017 at 22:05
• sorry I edited the question: What if I get a 600W power supply? I don't think that the leds have drivers at all? I was thinking on direct power supply connection.... I guess that would be mistake right? May 15, 2017 at 22:07
• Do you have a link to the LED strips? May 15, 2017 at 22:07
• it's in portuguese, but google translate should handle it: May 15, 2017 at 22:09