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Topic: right transistor for tlc5940 multiplex (Read 604 times) previous topic - next topic

ocmyface

Apr 13, 2012, 02:56 am Last Edit: Apr 13, 2012, 03:26 am by ocmyface Reason: 1
Hi all,

I'm working on a project trying to multiplex a 9x9 grid of RGB LED's. I'm currently using these components:

arduino uno
9.6V 3Ah battery supply for Vled
TLC5940 driver
CD74HCT42E decoder


I'm also using the Vishay IRF9510 NPN transistor to source (9x3x20mA) .54A

The issue is that in order to turn the transistor OFF, my gate voltage has to equal my source voltage (9.6V). I would prefer to use my arduino's 5V/3.3V supply as the supply (gate) for my mux(transistors) rather than my LED power supply.

What are some good transistors ppl commonly use for this kind of application? (Or at least a better mux that can take a 9.6V supply and is active low)

Source = 9.6V
gate = ground or 3.3/5V
drain = LED->TLC5940 current sink

I've done LOTS of research but aren't sure what would work best for this application. I really appreciate any input. Thanks!

Grumpy_Mike

It is no wonder why you have not found the right transistor as they do not work like you want.
If you connect the source to 9.6V it has to be a p-channel type, and while connecting the gate to ground will turn it on you have to take it much higher than 5V to turn it off.

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