In Summary, a SEPIC converter is used in applications with a flexible input voltage range, which needs a stable output of a certain voltage. Such applications are battery operated devices, NiMH chargers and LED driver applications. Würth Elektronik is offering a full range of coupled inductors for such applications: WE-DD, WE-TDC and WE-DCT series. All products shown are available in stock at digikey.com. Additionally, Würth Elektronik offers an easy-to-use design software for magnetics design, which allows calculation of a coupled inductor for a SEPIC converter within seconds.