| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching power supply device that keeps a holding time in a light load condition within a holding time in a heavy load condition.SOLUTION: The switching power supply device includes: a discharge path forming section 7 for forming a discharge path; a voltage monitoring section 5 for, in response to a stop of input of an AC input voltage, changing a condition of an output end from a first condition to a second condition at the timing when a first delay time elapses; and a load condition detection section 8 for, if the AC input voltage stops in a heavy load condition, outputting a first level signal until a second delay time set longer than the first delay time elapses and outputting a second level signal after the second delay time elapses, and if the AC input voltage stops in a light load condition, on the other hand, keeping on outputting the second level signal. The discharge path forming section 7 does not form the discharge path in the first condition or even in the second condition if the first level signal is input, and forms the discharge path in the second condition and if the second level signal is input. |
