Dimmable LED reading light unit, arrangement of power supply and dimmable LED reading light unit, method of operating a dimmable LED reading light unit in a power supply system and method of replacing a dimmable light unit by a dimmable LED reading light unit

摘要

A dimmable LED reading light unit according to exemplary embodiments of the invention, in particular for a passenger transportation vehicle, such as an airplane, a ship, a bus, or a railcar, comprises an input connectable to a potentiometer being supplied with a constant supply voltage and outputting a direct voltage having a voltage intensity corresponding to a selected dimming rate; an electronic measuring and control unit connected to at least one LED and providing an operating current to the at least one LED, and method of operating same.

主权项

1. A dimmable LED reading light unit, in particular for a passenger transportation vehicle, comprising:
an input connected to a potentiometer being supplied with a constant supply voltage and outputting a direct voltage having a voltage intensity corresponding to a selected dimming rate; an electronic measuring and control unit connected to at least one LED and providing an operating current to the at least one LED; a resistor having a predetermined resistance value; and an output connected to a ground line; the electronic measuring and control unit and the resistor being connected in parallel; wherein the electronic measuring and control unit is configured to: measure a partial voltage applied to it and a partial load current flowing through it; determine a resistance value of the electronic measuring and control unit based on the measured partial voltage and based on the measured partial load current; determine a equivalent resistance value of the electronic measuring and control unit and of the resistor based on the predetermined resistance value of the resistor and based on the determined resistance value of the electronic measuring and control unit; determine a resistance value of the potentiometer based on the equivalent resistance value of the electronic measuring and control unit and of the resistor, based on the measured partial voltage and based on the constant voltage supplied to the potentiometer; determine a dimming rate of the potentiometer based on the determined resistance value of the potentiometer and based on the predetermined nominal resistance value of the potentiometer; and supply driving current to the at least one LED necessary to emit light with a luminous flux corresponding to the dimming rate of the potentiometer.