To both 2112 and RadekG

The idea is exactly the opposite - use simple diodes rectifier and transistor current limiter.
I am not a noob and know how the rectifiers work and in the calculations above 220 * 1.4 is simplified for  220 * sqrt(2).
Many people said that it won't work and that's why this (crazy / hobby) project - to prove it does!

I have a working design at 24V DC and the built-in current mirror in the chips is working and balancing (almost) perfectly the voltage. I have made extensive test with the chips previously and this project will be a miner around the 55nm Bitfury chips, not a standard miner design. The chip survives 1.5V with proper cooling and it's voltage drop depends mostly on the current passing through it.
So transistor current limiter should be more than enough and 1.5V per chip is 420V AC, which won't happen and at that voltage the current is over 3A, while i will limit it to 1.5A or 2A max. This equals to about 0.88V per chip, because it's internal resistance when hashing is 0.44 Ohms based on my tests.

There are two other problems concerning me - the SPI speed (my next post) and the ripple/capacitor size (the next next post)