A RETROFIT LIGHT EMITTING DIODE, LED, TUBE FOR REPLACING A FLUORESCENT TUBE
FIG3 shows a simplified block diagram of a lighting system according to the present disclosure
FIG3 shows a simplified block diagram of a lighting system 21 according to the present disclosure. The block diagram depicted in FIG3 may be implemented using a hardware only approach or a hardware / software combination approach. Preferably, a hardware software combination approach is used as this is beneficial for the accuracy of the measurements and as this is beneficial for the size of each of the components.
simplified block diagram
28
LED array
24
matching circuit
22
ballast
29
load adaptor
3
horizontal axis
25
second matching circuit
31
current monitor
33
voltage monitor
27
power rectifier
26
bypass switch
21
lighting system
23
filament emulation circuit
32
network selector
['1. A retrofit Light Emitting Diode, LED, tube for replacing a fluorescent tube, wherein said retrofit LED tube is arranged to be connected to a ballast, said retrofit LED tube comprising: - an LED array (28) for emitting light; characterised in that  the retrofit LED tube further comprises - a configurable matching circuit (24, 25) for controlling input power from a connected ballast (22), when connected, towards said LED array (28); - a power rectifier (27) having an input connected to said matching circuit (24, 25) and an output connected to said LED array (28), wherein said power rectifier (27) is arranged to receive an AC supply voltage at its input, to convert said AC supply voltage to a DC voltage, and to provide said DC voltage, via its output, to said LED array (28); - a ballast determining unit (29, 30, 31, 32, 33) arranged for identifying a type of ballast connected to said retrofit LED tube by: - controlling an output voltage of said power rectifier (27) to a first voltage and measuring a first current provided by said power rectifier (27); - controlling said output voltage of said power rectifier (27) to a second voltage and measuring a second current provided by said power rectifier (27), wherein said second voltage differs from said first voltage; - determining said type of ballast based on said first and second output voltages and said measured first and second currents; wherein said ballast determining unit (29, 30, 31, 32, 33) is further arranged to configure said configurable matching circuit (24, 25) based on said determined type of ballast.', '3. A retrofit LED tube according to any of the previous claims, wherein said configurable matching circuit comprises two matching circuits: - a first matching circuit matched to a self-oscillating ballast, and - a second matching circuit matched to a Integrated Circuit, IC, controlled ballast, wherein said ballast determining unit is arranged to select one of said two matching circuits based on said determined type of ballast.', '15. A lighting system, comprising: - a retrofit LED lamp tube according to any of the claims 1 - 7, and - a ballast, wherein said ballast is connected to said retrofit LED tube.']