ADAPTATION CIRCUIT FOR COUPLING LED TO BALLAST

摘要

Adaptation circuits (1) allow discharge lamps to be replaced by light circuits (45) with light emitting diodes, while keeping ballast circuits (8) designed for connection to the discharge lamps. The adaptation circuits (1) comprise conversion circuits (2) for converting input voltage and current signals coming from the ballast circuits (8) into output voltage and current signals destined for the light circuits (45). The conversion circuits (2) reduce amplitudes of the input voltage signals to values below predefined values during predefined time intervals after energy from the ballast circuits (8) has been transferred to the conversion circuits (2). The time intervals are synchronized with periods of the input voltage signals. Between first draining states for draining energy and second releasing states for releasing the energy, third states such as holding states for holding the energy have been introduced. The third states allow relevant values as experienced by the ballast circuits (8) to remain comparable to situations when the discharge lamps were powered.