| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a switching circuit that reduces the loss without increasing the size. <P>SOLUTION: Main/sub MOSFETs 1a, 3a are configured such that source terminals s are connected to each other, gate terminals g are connected to each other, and an external diode 5 is connected in parallel to a series circuit of the main/sub MOSFETs 1a, 3a with the same polarity as that of a body diode 2a. The main/sub MOSFETs 1a, 3a are simultaneously switching-controlled by a drive circuit 6a. A current flowing back to the body diode 2a is cut off by a sub-body diode 4a so as to allow both a reflux current and a recovery current to flow in the external diode 5, thereby reducing the total loss. A voltage-absorbing means is provided in the sub-MOSFET 3a. Therefore, it absorbs a surge voltage applied to the sub-MOSFET 3a immediately after the conduction of the external diode 5, and also, reduces a withstand voltage between a drain terminal d and the source terminal s of the sub-MOSFET 3a. Consequently, it is possible to reduce the loss of the sub-MOSFET 3a. <P>COPYRIGHT: (C)2010,JPO&INPIT |
