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TLC5940 to drive 16 arrays of 64 leds (3,3v 20mA each)

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cid.nep

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I'm building a sculpture in Buenos Aires and I'm using an atmega128, 7 gorgeous TLC5940 PWM led drivers to independently control my leds.

I know almost nothing of electronics :( and I'm in a hurry with this. I'm trying to figure out the best way to connect the led arrays (how many in series...) because I don't have time to build up my own power source so I have to stick with a few Computer power source or something like that.

TLC output is negative so, as well as how to arrange the leds, I need to now what to use, mosfet or darlington? Wich ones are the best for my application?

Any help it's going to be everything to me.

Kind regards,
Victor
 

senthilkumar.b

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Hi,

you should first decide the operating voltage. then only you can fix the number of led in series.

There after you should consider the current requirement for driver selection(BJT?FET).

There is some operating voltage and current driving ranges are there for each and every device.

You should not void that.

Bye
 

cid.nep

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Senthilkumar.b,

I've choose to go with the high current path, so the longest array will hold 50 arrays (I=1A total) and use a transistor that can take 2A.

Is there a better way? I'll feed the emitter of the Transistor with something like 12V and use a resistor between the led array and the emitter (open collector is the name of this?).

Any advice is welcome!
Victor
 

senthilkumar.b

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From your statement you are going to select BJT.

Now you can use either PNP or NPN (power transistor).

According to this only you can choose where the higher potential and lower potential going to connect.


you can use Darlington also.

Take care of operating voltage, current and limiting resistor values.

Bye.
 

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