| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a step-up circuit in which the charging time of a backup capacitor is short and noise is not likely to be generated, when a transistor is turned on/off, and to provide a crew protection system comprising it. <P>SOLUTION: The step-up circuit 15 comprises a DC-DC converter 20, and a backup circuit 60 connected to the output side thereof and charged with a step-up voltage. The DC-DC converter comprises a step-up coil 26, a step-up switching transistor 55, and a diode 27. The step-up circuit 15 further comprises a current detecting circuit 30 for turning the transistor off when the transistor current has a predetermined level, and an off-time altering means 35, starting when the transistor is turned off and is capable of altering off-time lengths t2, t3 and t4. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
