LIGHT SOURCE MODULE AND LIGHTING CIRCUIT

There is provided a rear sign lamp capable of enhancing safety. An LED string () includes four LEDs (_ to ) connected in series. An LED driver circuit () receives a battery voltage (V) and supplies a drive current (I) stabilized at a target current (I) to the LED string (). A bypass circuit () is provided in parallel with a bypassed portion () including two adjacent LEDs ( and _) of the LED string (), and sinks a bypass current (I) according to a battery voltage (V).