| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply capable of widening the input voltage range by suppressing unstable operation due to on-duty. SOLUTION: The switching power supply is provided with a control means for amplifying the error between the output voltage from a power supply circuit and a reference voltage, comparing an error amplified signal with the amplitude of a triangular waveform obtained from a filter circuit 21 formed in the power supply circuit and outputting it to a rectifying switch S1, and fixing the on timing of a rectification switch S1 with a clock signal, by delivering the error amplification signal thereto. The filter circuit 21 is provided with two or more capacitors C<SB>SAW1</SB>and C<SB>SAW2</SB>, an auxiliary switch S3 is connected with at least any one capacitor C<SB>SAW2</SB>and turned on at the on timing of a commutation switch S2 to short-circuit the capacitor C<SB>SAW2</SB>, connected in parallel with the auxiliary switch S3. COPYRIGHT: (C)2005,JPO&NCIPI
|
