Switching LED Strips from 3.3v on battery source

Other Hardware General Electronics
1

Hi All

Working on a project for a friend that involves remotely illuminating three small LED strips (I'd guess about 80mA each, but final lights have not been chosen). The whole controller and power source needs to be battery powered and carried on a person (i.e. in a pocket). The LEDs will be used very infrequently for short periods of time, so battery size and life shouldn't be an issue

I chose the Moteino (very small, low power with built in wireless) and I've got the comms and the software working. I've read a great deal about swtiching high power loads and seen lots of Darlngton arrays, TIP120, etc. but nearly all examples are with 5v and hardwired source. I read someone was having issues when using the TP120 with a 3.3v battery powerwed source because of a 1.7v voltage drop (were very few details).

So, I'm lookign for a suitable to switch the LED's. The idea is that I'll have a 6v/12v battery source (or whatever is required for the LEDs). Drop that to 3.3v for the moteino and drive the LEDs being switched on digital ouptut pins. Anyone got any suggestions?

Regards

Mark

2

BC337?

3

TPIC6B595, you may increase number of leds up to 8

4

Magician:
TPIC6B595, you may increase number of leds up to 8

But not run it on 3.3V, its a 5V only chip.

5

It's confusion, he says

The idea is that I'll have a 6v/12v battery source (or whatever is required for the LEDs).

So, I thought there 'd be +5 and problem only with high saturation voltage, where mosfet looks preferable. But why to worry about saturation 0.8V if led's strip AFAIK 12V?
ULN2003 is the best option - don't need +5V regulator, resistors, just plug and run!