To get the buck/Strengthen aspect, all that is needed is 2 independent switches so which the AC enter might be connected to among the two Key faucets, although the load is linked to the other, Hence using the major transformer's Most important windings being an autotransformer. Case in point #7 https://andreszskdv.tkzblog.com/33595378/5-easy-facts-about-uninterruptible-power-supply-ups-described