Patent ID: 11109470

Abstract:
A retrofit tubular lighting device (7), comprising first (p1, p2) and second connection pins (p3, p4), a first (12) and second filament emulation circuit (13) coupled to the first (p1, p2) and second connection pins (p3, p4) respectively, a lighting element (4), a driver (3) coupled to the first (12) and second filament emulation circuit (13), a battery (5) and the lighting element (4). The driver (3) provides a charge to the lighting element (4) and the battery (5). The battery (5) stores the charge provided by the driver (3) and provides charge to the lighting element (4). A communication device sends a first charging signal to another lighting device comprising a further battery and coupled to the electronic ballast, when the charge of the battery (5) is below a first threshold. The communication device receives a second charging signal from the other lighting device, wherein the second charging signal indicates that a further charge of the further battery is below a second threshold. At least one of the first and second filament emulation circuit provides power from the electronic ballast (2) to the driver (3) when the communication device receives the second charging signal.