An input voltage stabilization circuit for a rear combination lamp includes: an optical output unit including a plurality of Organic Light Emitting Diodes (OLEDs); a voltage converter; and a feedback unit. The voltage converter is configured to supply an output voltage for driving the plurality of OLEDs by converting a first voltage supplied by a vehicle battery to the output voltage, the output voltage being different from the first voltage. The feedback unit is configured to provide, as feedback to the voltage converter, information regarding a maximum voltage value for the plurality of OLEDs. The voltage converter is further configured to adjust the output voltage based on the information provided as feedback by the feedback unit regarding the maximum.