Switching Mode Power Supply(SMPS)

hi to all
i need a circuit of "SMPS" that use of Switching ic for generating PWM
and have variable output voltage and high current.
and with calculating parameter such as Vout,Iout and other parameter
anybody can help me.
thanks.

The best place to start is with the datasheets and application notes from:
Linear Technology - Linear Home Page
**broken link removed**
Semiconductor and Integrated Circuit Devices

For magnetics you want to go to
Pulse Home Page - www.pulseeng.com
Bourns/J.W. Miller

Pay particular attention to the magnetics and the switch losses for a high current SMPS.