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Topic: Tip122 or MOSFET (Read 243 times) previous topic - next topic

Sulee

So I want to control LED strip using arduino 5V digital output. I was planing to use Tip122 transistor but after I've read few topics I got little woried about heating problem. Should I stick to it or use some kind of logical MOSFET (if yes which one)?

About LED strip:
Input voltage: 12V
Power: 72W/5 meters
Current: 1.2A/meter
I'm using only 2 meters!!!

larryd

It's easy enough to try it out and see how things work.

Most would recommend you to use a logic MOSFET with a low rdson when saturated.


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No technical PMs.
The last thing you did is where you should start looking.

Sulee

Thanks for reply. Would something like this work? http://www.farnell.com/datasheets/2304248.pdf

larryd

Looks reasonable, but the rdsON is ~100 mΩ

AOD510/AOI510 is about 4mΩ at 4.5V


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No technical PMs.
The last thing you did is where you should start looking.

Sulee

Oh yes I see it now. AOD510/AOI510 looks great. Thanks for your help!!!

MarkT

So I want to control LED strip using arduino 5V digital output. I was planing to use Tip122 transistor but after I've read few topics I got little woried about heating problem. Should I stick to it or use some kind of logical MOSFET (if yes which one)?

About LED strip:
Input voltage: 12V
Power: 72W/5 meters
Current: 1.2A/meter
I'm using only 2 meters!!!
So 2.4A, so about 5W dissipation with the TIP120/1/2 darlington devices which have about 2V saturation
voltage at 3A.  So that would require a largish heatsink and your LED strip would only get 10V, not 12V,
from a 12V supply.

A logic-level MOSFET with an on resistance of 0.1 ohm or less (0.01 isn't rare) would be much better
all round.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

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