| 摘要 |
PROBLEM TO BE SOLVED: To provide an LED lighting circuit and an LED light source device therewith which suppress an overcurrent to a light source section and an inrush current at the start of power supply.SOLUTION: The LED lighting circuit comprises: a supply voltage input section 1 for generating a first DC voltage; a step-up chopper circuit 3 for performing a step-up operation of generating a second DC voltage from the first DC voltage, and applying it to a light source section 7; a current regulation section 2 comprising a parallel circuit of an impedance element Z1 and a switching element SW1; a control section 4 for controlling an on-off action of the switching element SW1 and the step-up operation; and an anomaly detection section for detecting an anomalous state in which an overcurrent is supplied to the light source section 7. The control section 4 keeps the switching element SW1 off for a predetermined period from the start of supply of a supply voltage before turning it on, and if the anomalous state is detected, keeps the switching element SW1 off and stops the step-up operation. |
