| 摘要 |
PROBLEM TO BE SOLVED: To enable circuit protection to be conducted against short circuits in all lines of output voltages even if there are provided a plurality of insulating transformers in order to make a core thin or the like. SOLUTION: This switching power supply circuit is provided with the plurality of transformers, and also comprises a protection circuit for stopping switching operation in accordance with the vanishment of a level of a third output voltage level, when outputting a first output voltage (DC output voltage V1) fed as a main output and also as an inspection output for constant voltage control operation, a second output voltage (DC output voltage V2) fed as driving power to a control circuit for the constant voltage control operation, and the third output voltage (DC output voltage V3) other than the first and the second voltages. COPYRIGHT: (C)2006,JPO&NCIPI
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