LED driver proposal boost or other solution

[yassin.kraouch]

Please i need to driver 16 LEDs with Vf=2.5 V for each LED, the LEd are in series, and the input voltage is 13V, so i need a low cost solution, and i want to avoide inductor, please have you any suggestions?

 

[Tahmid]

To avoid inductor, you can use some kind of charge pump circuit. However, I think it's better you use an inductor and a boost converter.

There are many dedicated boost converters available with internal MOSFETs. They will make circuit construction very simple.

If you want to use cheap readily available components, you can design a boost converter using the UC3845 controller driving a Power MOSFET. Use feedback to keep the output regulated to 40V.

Hope this helps.
Tahmid.

 

[yassin.kraouch]

i found the datasheet of UC3845 from TI but the output voltage can not exceed 9V, how do i garentee 40 V ?

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http://www.ti.com/lit/ds/symlink/uc3845.pdf