LIGHTING SYSTEM ELECTRONIC BALLAST OR DRIVER WITH SHUNT CIRCUIT FOR LIGHTING CONTROL QUIESCENT CURRENT

摘要

Ballasts and LED drivers are presented for powering at least one light source, in which a shunt circuit provides a high impedance to allow operation of the light source when the AC input power exceeds a power threshold value, and provides a low impedance when the AC input power is below the power threshold value to prevent an output power stage from providing power to the light source.