| 摘要 |
PROBLEM TO BE SOLVED: To provide a power supply circuit and a lighting device, capable of stable operation.SOLUTION: An embodiment provides a power supply circuit having a power conversion part and a feedback circuit. The power conversion part controls on/off of an output element and current flowing in a DC load according to a voltage applied at a control terminal of a current control element. A feedback circuit provides a differential amplifier and an input/output isolation element. The differential amplifier outputs a feedback signal, corresponding to a difference between a detection voltage of a current flowing in the DC load and a reference voltage, from an output terminal. The input/output isolation element transfers a feedback signal to a control terminal at an electrically isolated condition between the control terminal and the output terminal. The power conversion part includes a voltage applying part. The voltage applying part turns off the current control element if a feedback signal is not transferred, and increases a voltage applied to the control terminal if the feedback signal is transferred. |
