| 摘要 |
PROBLEM TO BE SOLVED: To provide a control circuit of a DC-DC converter capable of detecting an unstable operation that causes the variation of an output voltage, and preventing the unstable operation from being continued, and to provide its control method. SOLUTION: The control circuit comprises an inverting input terminal to which a detection voltage V1 that is detected according to the output voltage is inputted, and a non-inverting input terminal to which a reference voltage e1 is inputted. The control circuit also comprises an error amplifier ERA1 for amplifying a differential voltage of the detection voltage with respect to the reference voltage e1, and a detection part 50 for detecting that an error output signal VOP of the error amplifier ERA1 is retained at a prescribed voltage level. The detection part 50 comprises a signal discrimination part for discriminating that the prescribed voltage level is out of a stationary operation range, and a continuous time counting part for detecting that a state that the prescribed voltage level is out of the stationary operation range and retained therein is continued for a prescribed time by using the signal discrimination part. COPYRIGHT: (C)2007,JPO&INPIT
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