The persons who have worked on Micro-Controllers have the Idea that how much sensitive they are for Voltage.
They strongly need very regulated voltage to operate in safe mode.
for this purpose I have designed and fabricated and then implemented this this Power supply in projects.
It is not only designed on very limited area but it also provides the Over and Under Voltage protection as well as over current protection.
With this it also have the capability to suppress the voltage spikes till a very large extant. 
Moreover is it is designed by using discrete components so for a single piece it cost me very very low as compared to that if this single piece had made as IC.
However if for a large scale production it is fabricated in IC package than not only its Quality and efficiency can be improved but its cost can also be reduced effectively.