How can I drive 5v,2A from USB port

Please can any one tell me, how can I drive 5v,2A from USB port.
Actually I wont wants to use any external adaptors in my USB driven system.
Please if possible try to send me details & schematics as early as possible.
Thanks in anticipation.
Regards,
VINIT...
Actually I wont wants to use any external adaptors in my USB driven system.
Please if possible try to send me details & schematics as early as possible.
Thanks in anticipation.
Regards,
VINIT...