| 摘要 |
PROBLEM TO BE SOLVED: To prevent continuation of overcurrent state of an LED in an LED power supply by reducing the power supply output during a failure of constant current output control.SOLUTION: An LED power supply 1 includes a switching power supply circuit 200 for supplying an output current to an LED 20, an auxiliary power supply circuit 300 for generating a control voltage in response to driving of the switching power supply circuit 200, a control circuit 400 having a constant voltage control section 420 which is supplied with the control voltage and performs constant voltage control of the output voltage from the switching power supply circuit 200, and a voltage switching circuit 500 having an overcurrent detector 510 for detecting that the LED 20 is in an overcurrent state based on the output state of the LED 20 and a switching section 520 for operating the constant voltage control section 420 so as to lower the output voltage from the switching power supply circuit 200 to a low output voltage when the overcurrent state is detected. |
