| 摘要 |
PROBLEM TO BE SOLVED: To provide the oscillation control method of a self-excitation switching power supply circuit which does not shift into an intermittent oscillation operation, causing no ripple voltage which is a cause of noises. SOLUTION: If a low load is connected to an output line, an output voltage exceeds a set voltage even after a flyback voltage disappears. So, an off adjusting period T<SB>ad</SB>is provided until the output voltage falls below the set voltage to delay next oscillation. Since the power consumption due to load is balanced with the power generated at a transformer (2) by self-excited oscillation in each oscillation cycle, shifting into intermittent oscillation does nor occur, and a ripple voltage caused by intermittent oscillation does not appear on the output voltage. COPYRIGHT: (C)2005,JPO&NCIPI
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