Vehicle lamp and lighting circuit of light source

A lighting circuit configured to drive a light source including a plurality of light emitting elements connected in series, the lighting circuit comprising:

• a plurality of bypass switches respectively connected in parallel to the light emitting elements;
• a switching converter;
• a converter controller configured to (i) stabilize a lamp current generated by the switching converter to a first target amount in a lighting-on state where at least one of the plurality of light emitting elements is turned on, and to (ii) stabilize the lamp current to a second target amount smaller than the first target amount in a complete lighting-off state where all of the plurality of light emitting elements are turned off;
• and
• a determination circuit configured to compare a voltage across the light source with a threshold voltage and determine that the light source is at the complete lighting-off state if the voltage across the light source is lower than the threshold voltage,
• wherein the converter controller is configured to stabilize the lamp current to the second target amount smaller than the first target amount when the determination circuit determines that the light source is at the complete lighting-off state.