The N light emitting element groups each include one or more light emitting elements. The power source circuit includes a control input terminal and supplies the power source voltage to the N light emitting element groups. The N current driving circuits, each including a feedback output terminal, generate N drive currents for driving the respective N light emitting element groups and generate main feedback voltages at the feedback output terminals based on the power source voltage. The main feedback circuit applies a main feedback signal to the control input terminal based on the N main feedback voltages. The auxiliary feedback circuit applies an auxiliary feedback signal to the control input terminal based on the power source voltage. The power source circuit adjusts the power source voltage based on at least one of the main feedback signal and the auxiliary feedback signal.