| 摘要 |
PROBLEM TO BE SOLVED: To suppress an output variation in the event of a sudden load change.SOLUTION: A switching power supply device A includes: an error amplifier 13 for generating an error voltage ERR corresponding to a difference of a reference voltage REF1 from a feedback voltage FB; a main comparator 14 for comparing the error voltage ERR with the feedback voltage FB and generating a comparison signal S1; an on time setting section 15 for generating an on time setting signal S2 of a fixed pulse width according to the comparison signal S1; a driver 17 for controlling on/off switch elements 11 and 12 according to the on time setting signal S2; an error voltage monitoring section 19 for comparing a reference voltage REF2 with the error voltage ERR and generating a lower limit detection signal DET; a selector 20 for selectively outputting either of REFa and REFb as the reference voltage REF1 according to the lower limit detection signal DET; and a selector 21 for selectively outputting either of REFc and REFd as the reference voltage REF2 according to the lower limit detection signal DET. |
