POWER SUPPLY DEVICE AND LIGHTING APPARATUS HAVING POWER SUPPLY DEVICE

PROBLEM TO BE SOLVED: To provide a power supply device that can control lighting-off while restraining power consumption.SOLUTION: A power supply device 300 has: a transformer TR having a primary coil T1 and secondary coils T2, T4; a MOS-FETQ1 connected to the primary coil T1 and controlled by a lighting control circuit IC; a control power supply generation circuit 340 connected to the secondary coil T4 and generating a control power source Vcc2; an output voltage regulation circuit 380 for decreasing an impedance on an output side of the secondary coil T2 when the control voltage Vcc2 is less than a predetermined voltage, and increasing the impedance when it is not less than the predetermined voltage; and a light control signal conversion circuit 390 for stopping the MOS-FETQ1 when a dimmer 2000 outputs lighting-off signals. Therefore, power consumption can be restrained when a light source 140 is lit on, and lighting-off can be controlled even when the lighting-off signals are inputted from the dimmer 2000 connected to the power supply device 300.