i have a project named 'desigining battery charger with better power efficiency'. I need some help as i am new and i have not a project on my own. can i get to know that what i should read and what should i do
My guess is that you're trying to charge a lead-acid battery. Correct me if I'm wrong.
For high efficiency charger, you need to use a switched mode power supply. Have you ever worked with switching power supplies?
Go through the book I mentioned in my earlier post.
Decide which topology you are going to use. Then decide on which components to use. This will have impact on efficiency. So choose wisely. The biggest hurdle for you may be the transformer, especially if you're going to wind it yourself. If not designed properly, the transformer can be a major source of inefficiency.
It's depends on transformer and the rectifier selected. I'm also recommend to use switched mode power supply. If you have any query about Battery chargers search on Google.
I see that you are going to charge a cell-phone battery. So, power requirement is quite low. You can use a flyback converter. You can use one of the available dedicated offline converter chips, such as TOP-Switch, TNY-Switch, VIPer, etc.