| 摘要 |
PROBLEM TO BE SOLVED: To provide an overcurrent preventing power supply apparatus for turn on a lighting load by using a constant current unit to be driven by a voltage received from a constant voltage unit, which prevents the control operation of the constant voltage unit from being stopped due to an overcurrent when the constant current unit starts after the constant voltage unit starts supply voltage.SOLUTION: The power supply apparatus 1 includes: a constant voltage unit 2 for outputting a constant voltage; a constant current unit 3 and a timer 4 for measuring the time elapsed since the constant voltage unit 2 starts supplying voltage. The timer 4 measures the time until the start of the operation of each of the units 2 and 3, and transmits operation start signals Sb, Sa to the units 2, 3 respectively, when the elapsed time of each of the units reaches a predetermined time. The operation start signals Sb, Sa allow the constant current unit 3 to start operation before constant voltage control operation of the constant voltage unit 2. Thus, the control operation of the constant current unit 2 can be prevented from being stopped due to an overcurrent caused when the constant current unit 3 starts operation. |
