sorry audio guru but i was searching for more ideas
And by this act I have got a different ideas:
1> Transformer less design explained on microchip website and other sites too.
2> Using ready-to-use modules from https://www.rohm.com
So i was looking for different views and different ideas
as there are very less people who visit many forums some gurus are helping at one forum only.........
The supply is for a new switch which will be placed instead of regular on/off switch for appliance, switch consists of proximity sensor so when a finger or hand comes near the switch toggles this is how the switch work so you don't have to touch the switch to making things on and off.
Now you must be aware how small are these switches so in that space i have to provide sensor and control electronics and power supply.
A switching power supply uses a high frequency so its transformer or inductor can be small. They usually switch their pass transistor fully on and fully off to avoid wasting power as heat like a linear regulator does. Then the width of each pulse can be changed to regulate the output voltage by using Pulse-Width-Modulation.