Every new electronic product, except those that are battery powered, requires converting off–line 115 Vac or 230 Vac power to some dc voltage for powering the electronics. The availability of design and application information and highly integrated semiconductor control ICs for switching power supplies allows the designer to complete this portion of the system design quickly and easily.Whether you are an experienced power supply designer, designing your first switching power supply or responsible for a make or buy decision for power supplies, the variety of information in the SWITCHMODE? Power Supplies Reference Manual and Design Guide should prove useful. ON Semiconductor has been a key supplier of semiconductor products for switching power supplies since we introduced bipolar power transistors and rectifiers designed specifically for switching power supplies in the mid–70’s. We identified these as SWITCHMODE? products. A switching power supply designed using ON Semiconductor components can rightfully be called a SWITCHMODE power supply or SMPS.This brochure contains useful background information on switching power supplies for those who want to have more meaningful discussions and are not necessarily experts on power supplies. It also provides real SMPS examples, and identifies several application notes and additional design resources available from ON Semiconductor, as well as helpful books available from various publishers and useful web sites for those who are experts and want to increase their expertise. An extensive list and brief description of analog ICs, power transistors, rectifiers and other discrete components available from ON Semiconductor for designing a SMPS are also provided. This includes our newest GREENLINE?, Easy Switcher and very high voltage ICs (VHVICs), as well as high efficiency HDTMOS and HVTMOS? power FETs, and a wide choice of discrete products in surface mount packages.