Patent ID: 8575857

Claim:
An LED lighting device comprising: a lighting circuit to be connected to a lamp socket to which an LED lamp is to be connected, and configured to provide an output voltage in a form of a DC voltage to the lamp socket; a current detecting circuit configured to detect an output current which is caused by the output voltage and is supplied from the lighting circuit to the lamp socket; a voltage detecting circuit configured to detect the output voltage of the lighting circuit; and a control circuit configured to control the lighting circuit, wherein: the control circuit, including a memory, stores a maximum-load voltage and a no-load voltage higher than the maximum-load voltage in the memory, the no-load voltage being a voltage to be applied when the LED lamp is not connected to the lamp socket, and the control circuit is configured to: judge whether or not the output current detected by the current detecting circuit is not less than a predetermined threshold value which is less than a target value, perform constant-current control on the lighting circuit to regulate the output voltage such that the output current is equal to the target value while keeping the output voltage not higher than the maximum-load voltage, when the control circuit determines that the output current detected by the current detecting circuit is not less than the predetermined threshold value, and perform no-load control on the lighting circuit to regulate the output voltage such that the output voltage is kept equal to the no-load voltage, when the control circuit determines that the output current detected by the current detecting circuit is less than the predetermined threshold value.