| 摘要 |
<P>PROBLEM TO BE SOLVED: To shorten a recovery time from a temporary variation of an output voltage caused by a load variation, and to quickly switch an operation mode between a step-down operation mode and a step-up operation mode. <P>SOLUTION: A first voltage comparator CMP_H, a second voltage comparator CMP_L, pull-up circuits I<SB>PU</SB>, SW<SB>PU</SB>, and pull-down circuits I<SB>PD</SB>, SW<SB>PD</SB>are connected to an error amplifier EA of a back-boost (step-down, boosting) DC-DC converter. When a feedback voltage V<SB>FB</SB>generated from the output voltage V<SB>OUT</SB>of an output terminal T<SB>2</SB>becomes higher than a first reference voltage V<SB>CNT</SB>+V<SB>α</SB>, or becomes lower than a second reference voltage V<SB>CNT</SB>-V<SB>β</SB>, a voltage V<SB>OE</SB>of an error amplifying output terminal of the error amplifier EA is pulled down or pulled up. In the other DC-DC converter, a noninverting input terminal, an inverting input terminal, and the output terminal of a first error amplifier are maintained at a voltage level of a first intermediate reference voltage by a first switch. <P>COPYRIGHT: (C)2009,JPO&INPIT |
