| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric power supply and an illuminating device, capable of realizing protection from abnormal rise of temperature with a simple structure.SOLUTION: According to the embodiment, an electric power supply comprising a bridge circuit, a transformer, a rectifying and smoothing circuit, a driver, and a thermosensor is provided. The bridge circuit exchanges a DC voltage to an AC voltage by on and off of a switching element. The transformer includes a primary winding connected to the bridge circuit, and a secondary winding magnetically coupled with the primary winding. The rectifying and smoothing circuit converts the AC voltage outputted from the secondary winding to a DC output voltage, and supplies it to a DC load. The driver controls the output voltage by controlling the switching element with a switching frequency corresponding to a current flowing through a frequency setting terminal. The thermosensor is connected to the frequency setting terminal, and changes the current flowing through the frequency setting terminal corresponding to the rise of temperature.SELECTED DRAWING: Figure 1 |
