# Leds in parallel

#### joseimaz1

Joined May 13, 2014
2
Hi I'm new to electronics. I have a question. I need to connect 512 "PIXEL LEDs" (in parallel) Specifications for LED PIXEL are: http://www.aliexpress.com/item/1000...0-3W-ws2801-rgb-led-pixel/1472325849.html?s=p.

According to my calculations, I need a source of 20 A (actually 15.36 A). These LEDs are wired in parallel with a 2mm cable. There would be a problem? Supports those drivers these amps?

Thanks and sorry for my English.

#### Papabravo

Joined Feb 24, 2006
14,872
You can adjust the required current to any value over a range. For example you could use 5 ma per LED or 15 ma per LED. the choice makes a huge difference in the required current. The problem is actually in the current carrying capacity of the cable, not the power supply. If you daisy chain the 5V you will experience IR drop on the 5V line and a similar drop on the ground return. If you split the power cables from the data cables so that there is a low impedance path to the supply and ground return you should be set to go.

512 * .005 = 2.56 A which is a great deal less than your calculations.

#### Wendy

Joined Mar 24, 2008
22,206

#### joseimaz1

Joined May 13, 2014
2
You can adjust the required current to any value over a range. For example you could use 5 ma per LED or 15 ma per LED. the choice makes a huge difference in the required current. The problem is actually in the current carrying capacity of the cable, not the power supply. If you daisy chain the 5V you will experience IR drop on the 5V line and a similar drop on the ground return. If you split the power cables from the data cables so that there is a low impedance path to the supply and ground return you should be set to go.

512 * .005 = 2.56 A which is a great deal less than your calculations.
Ok, thanks for your response. Assuming use 30mA per LED. What is the maximum number of LEDs in parallel from a single source output you recommend?

regards

#### Papabravo

Joined Feb 24, 2006
14,872
Ok, thanks for your response. Assuming use 30mA per LED. What is the maximum number of LEDs in parallel from a single source output you recommend?

regards
Remember that each PIXEL consists of 1 RED, 1 GREEN, and 1 BLUE LED. That means each PIXEL could consume 3*30 mA 90 mA

512 * 90 mA = 46.08 A

You cannot send 46 A down a 2mm cable. You have to take the +5V and GND cables out of the daisy chain and run separate wires back to the power supply.