| 摘要 |
PROBLEM TO BE SOLVED: To provide an oscillation circuit which does not affect generation accuracy of an on-period Ton even when a switching frequency is changed, and a switching power supply using the same. SOLUTION: The oscillation circuit generates a trapezoidal wave, and since the cycle of the trapezoidal wave is made variable by changing a prescribed time of a second period when the trapezoidal wave holds the same value for a prescribed time by a control signal from the outside of the oscillation circuit, the inclinations of a rise and a fall of the trapezoidal wave in each cycle can be made constant. Accordingly, when the switching power supply device using the oscillation circuit generates the on-period Ton of a switching element from the trapezoidal wave and an error signal, the generation accuracy of the on-period Ton can be kept constant even when a switching frequency is changed. COPYRIGHT: (C)2011,JPO&INPIT |
