| 摘要 |
PROBLEM TO BE SOLVED: To provide a DC-DC converter which suppresses the occurrence of overshoot or undershoot even when an output voltage is changed. SOLUTION: The DC-DC converter includes: a switching transistor M1 whose one end is connected to a power input terminal and the other end is connected to one end of an inductor L1; and a synchronous commutation transistor M2 whose one end is connected to a connecting node between the switching transistor M1 and the inductor L1 and the other end is connected to a ground terminal.The DC-DC converter also includes: a comparator 11 which detects that a voltage Vim2 obtained by converting a current flowing to the synchronous commutation transistor M1 into a voltage becomes not less than Vr1; a comparator 12 which detects that the voltage Vim2 is larger than the Vr1 and becomes equal to or larger than Vr2; and a switch 15 which receives the output of the comparator 11 and that of the comparator 12 to output either of them according to a control signal. The synchronous commutation transistor M2 is on/off controlled according to the output of the comparator selected by the switch 15. COPYRIGHT: (C)2010,JPO&INPIT
|
