Problem with using LT1172 to step up 3,6V battery to 12V

[algilsan]

I'm just using a LT1172 to step up 3,6v lition battery voltage to 12v, but i only can boost voltage to 9v, but linear datasheets sais that's possible, changing feedback resisors to 1.24k and 10.7k, but doing this my voltage is the same as input. I don't know what's the problem.

Any help would be appreciated,

thank you

 

[jankojarc]

I do not now what kind of applicatons notes you use.

My be your transformer ratio is not right.

 

[algilsan]

my application needs 12v, since i have 3.6v lition battery at ratio of 2.3AH, i need to boost 3.6v to 12v at no much of 300mA. i'll step up voltage at output sacrifing power of battery, because at this output current, battery will drain about 1A of current. But this isn't a problem for me.

thanks

 

[Eumel]

LT1172

Did you try to simulate the circuit? There is a free tool from Linear Technology called SwitcherCAD.

https://www.linear.com/software/

Try it, I think this will help you.