Need help Using SX output pin to power LED Bank...

Steel

I believe the SX pins only sink/source 45mA.

I have a display of 16 leds in parallel.· I want to use a SX to control the on/off of these LEDs.

Knowing that the LEDs use about 15mA Each, that means that the whole display will be pulling approximately 240mA...way over the threshold of the SX Pin.

Unfortunately, I am not too hot with transistors (other than basic switching) and somebody mentioned using a darlington to pull the power from the main power source into the leds.

I drew out the circuit, but I was wondering if somebody could tell me if a)This is the best way to go, or b) There is an easier way to do it.

Unfortunately, this project is going to be a very small project and I will need to hand-solder Surface-mount components...So the fewer components necessary(or better packaged), the better.

Please let me know what you think.· I have attached the schematic.

Shaun

Sparks-R-Fun

Although not a full answer to your question, you do need to have a current limiting resistor in-line with your LEDs.

Just a quick observation.

- Sparks

T&E Engineer

For this much current you will need something like a P-Channel MOSFET or power transistor.

metron9

You need a resistor for each led, you cant put led's in parallel as the forward voltage on each of them is a little different. Some will pass more current than others it may be one will pass all the current and blow up then another one and you will blow them all up.

see this link
http://led.linear1.org/led.wiz

Then use a N channel mosfet like this. the pushbutton can be a microcontroller pin that goes high and low.

http://brunningsoftware.co.uk/FET.htm

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