Thanks for your explanation and contributions
Yes, the 5v and 3.3v output should power up the micro-controller and other logical IC that they are so too sensitive to their input voltage.
in this statues if one regulator fails it's output can be more than 5 and 3.3 volt and it can burn my other devices?
if I use switching regulator and two linear regulator what linear regulator do you suggest that can withstand up to 12 volt (input(for Safety)) and output current 1A?(I can't see any low-drop linear regulator that can power up more than 800mA)