| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit for a DC-DC converter that can contribute to cost reduction and miniaturization of a circuit. SOLUTION: A voltage VLX at a connection point of a MOSFET 1 as a main switching element, and a MOSFET 2 as a sub-switching element, is compared with a second reference voltage Vref2 set to a value equal to or higher than the grounding potential and lower than a DC output voltage. By latching a comparison signal S4 obtained as its result by a clock signal S6 that rises during a blank period when both MOSFETs 1, 2 are put into an OFF state, the ON state of the MOSFET 2 is allowed only when the voltage VLX is lower than the reference voltage Vref2, and thus control in the normal mode of turning on and off the MOSFETs 1, 2 alternately is performed. COPYRIGHT: (C)2005,JPO&NCIPI
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