Dear Friends,

I have designed an LED board. The board has 3 nos of 3.2V LED's in series.

I want to connect 5 such boards in series ( 5 boards * 3 LEDs each = 15 LEDs )

Kindly tell me what input supply voltage / current I should use.?

Note: 120mA is the typical forward current for one LED.

Best Regards,
H.Krishnan.

 

Why do you wish to connect these boards in series and not parallel?

 

You need a current mode voltage booster that can be adjusted a little below 30V. Microchip has such ICs I think.

It's also possible when you use an inductor that just has the right dimensions, so it won't provide unlimited current. If voltage goes down just 1V if current increases too much, that would be sufficient.

 

In parallel you could use 12VDC, in series you will need 50VDC, minimum.

A LED tutorial, and a bit more...

LEDs, 555s, Flashers, and Light Chasers