| 摘要 |
PROBLEM TO BE SOLVED: To provide a constant current power supply device for controlling constant currents even when a light load is applied. SOLUTION: The constant current power supply device 1 is provided with: a transformer T; a diode D1; a switch element Q1; and a control part 21. The control part 21 controls the switch Q1 according to currents flowing through a first primary coil T1 of the transformer T. In a period when the switch element Q1 is in an ON state, currents flow through light emission diodes LED1 to LEDn, the first primary coil T1 of the transformer T, a second primary coil T2 of the transformer T1, and the switch element Q1, and energy is accumulated in the first primary coil T1 of the transformer T. On the other hand, in a period when the switch element Q1 is in an OFF state, currents flow through the first primary coil T1 of the transformer T, the diode D1 and the light emission diodes LED1 to LEDn by using the energy accumulated in the first primary coil T1 of the transformer T in the period when the switch element Q1 is put in the ON state. COPYRIGHT: (C)2011,JPO&INPIT |
