How to increase or decrease the voltage of the power supply\Overclocking the power supply 

Thanks

Thanks bro!!

Right :)

I'd be more worried about the power supply for the TL494: the main output winding got doubled up, which means the TL494 is getting half the voltage it used to at 5V and twice at 20V, which also means about half the base/gate drive current at 5V and twice at 20V. I doubt the TL494 and switching devices will operate reliably across the whole range under load. Ideally, you'd have an independent fixed voltage rail operate the controller and gate drivers.

Big thanks:)