3.1 Basic DC to DC converters 3.1.1 Buck converter(Step-down converter) 3.1.2 Boost converter(Step-up converter) 3.1.3 Buck-Boost converter(Step-downstep-up converter)and Cuk converter 3.1.4 Sepic converter and Zeta converter 3.2 Composite DC/DC converters and connection of multiple DC/DC converters 3.2.1 A current-reversible chopper 3.2.2 Bridge chopper (H-bridge DC/DC converter) 3.2.3 Multi-phase multi-channel DC/DC converters