Hello Friends...! I want to make a SMPS Charger for 7Ah,12V battery using Buck Topology or Flyback topology. Help me out with some reference circuits or circuit diagrams.

Thanks in Advance

 

What is the value of your supply voltage?

 

Hello Colin55, Thank you for your reply. I want to charge from 230Vac supply.I need circuit without using transformer.

 

You will need a switching isolation transformer, such as with a flyback design.

You might try the TI Webench designer.

How much battery charging current do you want?

 

Do you want to kill yourself, or electrocute your younger sister?

 

Hello Crutschow, isolation transformer is OK.but don't want to use transformer for AC side step down.

 

I want to kill someone with a bullet, but I don't want to use a gun.

 

I need charging current of 700 milli amps.

 

Get a 240v to 12v transformer at 1 amp This will produce AC Put 4 x 1 amp diodes on the two output wires in the form of a bridge. On the positive and negative of the bridge put an 8 ohm 3 watt or 5 watt resistor. Connect it up to the battery and put your fingers on the resistor. Let me know if you can hold it.

 

I need charging current of 700 milli amps.

.... isolation transformer is OK.but don't want to use transformer for AC side step down.

Look at the flyback designs in the Webench Designer for a max input voltage of 250Vac and an output of 12V and 0.7A.
You want the designs with output regulation via optoisolator such as the one below.
You will then likely need to add current limiting in the output or change the output regulation to current-mode instead of voltage-mode when charging the battery.