| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve the high efficiency of a switching power-supply. <P>SOLUTION: A comparator 12 generates a comparison signal S2 asserted when a detection voltage V<SB POS="POST">DS</SB>is lower than a threshold voltage V<SB POS="POST">TH_DS</SB>. A pulse modulator 10 generates a pulse modulation signal S1 in which a duty cycle is adjusted so that an output of a switching power-supply 2 is stabilized. A driver 20 changes a drive pulse signal S3 to a third level corresponding to on of a switching transistor M1 when the pulse modulation signal S1 changes to a second level corresponding to on of the switching transistor M1. Further, the driver 20 changes the drive pulse signal S3 to a fourth level corresponding to off of the switching transistor M1 at the later timing between a timing when the pulse modulation signal S1 changes to a first level and a timing when the comparison signal S2 is asserted. <P>COPYRIGHT: (C)2013,JPO&INPIT |
