| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost switching power source apparatus which has a high efficiency in all range from a light load time to a heavy load time. SOLUTION: In the switching power source apparatus having a constitution as shown, a control means IC1 stops intermittent on and off operations of a switching element Q1 when a first voltage detecting means DET1 detects that the output voltage of a point A rises to a first threshold value, and starts the intermittent on and off operations of the element Q1 when a second voltage detecting means DET2 detects that the output voltage of the point A drops to a second threshold value. In this apparatus, a highest efficiency operation is conducted in the state that the element Q1 is intermittently turned on and off irrespective of the light load time and the heavy load time. Since the apparatus has a low loss in the state that the element Q1 is intermittently stopped on and off, the apparatus can operate in the high efficiency in all ranges from the light load time to the heavy load time. COPYRIGHT: (C)2004,JPO
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