Switching 7.4V 3A LED Driver

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cbnathanael

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Hi, all!

I'm trying to find the best way to switch a SparkFun PicoBuck on and off. When the circuit is first powered, the picobuck turns on at full power on all 3 channels until the Teensy finishes it's setup routine, at which point the Teensy drops the PWM to 0. This results in a momentary flash from the LEDs the PicoBuck is driving, which is an unwanted effect.

From what I've been reading, a Darlington pair or a MOSFET would be the way to go. Unfortunately, I'm still trying to get my transistor knowledge up to snuff. It appears that a MOSFET is better suited for what I need (higher current, no need for PWM on this channel), but I'm not sure I completely understand what to look for on the datasheets. Or am I barking up the wrong tree?
 
Looking at the PicoBuck documentation the inputs have pullups on them, you might try a 1k resistors to ground on the input pins to prevent the startup flash.
 
cartere said:
Looking at the PicoBuck documentation the inputs have pullups on them, you might try a 1k resistors to ground on the input pins to prevent the startup flash.
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Ugh. I just noticed that, myself, but wasn't sure if it was the right approach. I will definitely give that a try. Thanks for the quick response!
 
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