Cheapest Way to Upconvert Various Voltages (4.0V - 7.6 V)DC to a constant 12V

[chiques]

I need to power a couple of 12V pc fans with various voltage sources. Is there an IC which could do this. I'm guessing something with a buck boost system built in but I haven't been able to find anything that works. Thanks.

 

[tpetar]

Are you using NiMh battery pack of 6 cells to power 12V fan ?

You can use MC34063 with input voltage variation of 20%.

Calculator can be found here:
**broken link removed**

For peak current 1,5A and higher use external switching transistor.




Best regards,
Peter

 

[GlazkovD]

MC33063 can give you about 100mA at output
LM2622 if you need more power output with integrated switch

 

[chiques]

This looks like a good start. I like the LM2622 and the current handling. Thanks!

 

[GlazkovD]

Sometime i use LM2576 as step down converter.
It's good working, i think, with step-up converter will not happen some problem.
Take care with diode rectifier. You should use shottky(50V at least) or
ultra fast diode.