ABSTRACT
Direct DC/DC converters without isolation are used to convert electrical energy from a DC source to a DC load with a different DC level requirement. Most DC converters have a topology based on a single switch. Buck or boost converters can operate in discontinuous or continuous conduction mode, depending on the continuity of the current through the inductance. These converters and the operation limits are analysed in this chapter. Other topologies include the buck/boost converter, the Cuk converter for converters with a single switch or the H-bridge converter with bipolar operation. Synchronous converter operation is also used for efficiency improvement. Modern telecom applications feature high currents and impose the use of multiphase converters. Multiphase converters are buck or boost converters with multiple similar branches (parallel hardware) and an interleaved control achieved with dedicated integrated circuits. A special case is given with synchronous converters where the diode is replaced with another MOSFET transistor.
