| 摘要 |
PURPOSE:To optimize the dummy load of the switching power source of a variable output voltage setting and to decrease an electric power consumed for the dummy load by decreasing the output current of the switching power source from an optimum dummy current and controlling the dummy current of the switching power source by an arithmetic result. CONSTITUTION:When the output voltage of a switching power source 1 is set highly, a limit output current not to generate the intermittent oscillation is smaller than the case when the output voltage is low set, and an optimum dummy current converting part 3 obtains the optimum dummy current in accordance with the output voltage of the switching power source 1 corresponding to such a relation. Since the optimum dummy current is the minimum output current in which the switching power source 1 does not generate the intermittent oscillation at the time of the non-load, the current to supply to the load by an output current detecting part 2 is detected and when the current is smaller than the optimum dummy current, the difference is obtained by a subtracting part 4 and the current of the difference is controlled so as to flow at a current control part 5. Thus, the current of a necessary minimum limit flows, the intermittent oscillation of the switching power source 1 is prevented and the unification of the output voltage can be executed.
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