Patent attributes
The present invention relates to a functional device (10) powered by a constant current driver (12). The device (10) comprises constant current driver (12), electrical energy storage unit (14), functional unit (16), and control unit (18). The device (10) is controlled by the control unit (18) such that the constant current driver (12) provides a constant current to the functional unit (16) and the storage unit (14) in dependence of a pulse width modulated voltage signal. Current is provided to the storage unit (14) for charging the storage unit (14) during at least part of off periods of the pulse width modulated voltage signal. During on periods of the pulse width modulated voltage signal, current is provided to the functional unit (16) and no current is provided to the storage unit (14). This allows providing the device with a constant current driver with less idle periods and lower current supply.
