Hi,
I am going to build a circuit for cell phone charger but i have problem to convert these voltages and currents, when i convert voltages then current has been too much less .. .
any one who help me plz???
Any simple buck converter might do the job. Just take a look at National Semi Website. They got the WEBENCH tool that will do the design for you... I belive this current wont be a problem with 80% eff design.
Just make sure about the charging characteristics of the battery in question. Different technologies need to be handled different. To prevent an explosion a good practice is to always do heat sensing as well.