| 摘要 |
PROBLEM TO BE SOLVED: To provide a converter that can take larger step-down ratio, that makes it possible to miniaturize components and to reduce the number of the components, and that is highly efficient and of low noise, compared with a conventional tap inductor step-down converter. SOLUTION: Unlike the conventional tap inductor step-down converter, a clamp capacitor Cc is inserted in series to the primary winding and a current of a tap inductor is commutated by a clamp switch. Consequently, switching surge by leak inductance is controlled. Furthermore, in contrast with a fact that operation of the conventional system is similar to that of a step-up and down converter, the operation of the converter in this invention is close to a step-down converter so that a lower output voltage can be generated and high control stability can be achieved. Moreover, elements of a low withstand voltage can be used for a main switch and the clamp switch, an imposing current of the inductor is less, and existing IC can be utilized for a drive circuit so that the circuit can be made compact with fewer number of components. COPYRIGHT: (C)2007,JPO&INPIT
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