MULTI-VOLTAGE BALLAST AND DIMMING CIRCUITS FOR A LAMP DRIVEN VOLTAGE TRANSFORMATION AND BALLASTING SYSTEM

摘要

A discharge lamp operating circuit is connected to a sourceof alternating current (AC) voltage, and has a discharge lamp anda semi-resonant circuit connected to the source of alternatingcurrent voltage and in series with the lamp. A starting circuitfor initiating operation of said discharge lamp is also connectedin the circuit. The lamp switching maintains the seriessemi-resonant circuit in oscillation and the series semi-resonantcircuit maintains the lamp in operation after operation has beeninitiated by the starting circuit. Highly efficient energytransfer between inductive and capacitive components of thesystem result in low loss and high power factor. A variablecapacitance circuit is provided to allow use of the dischargelamp operating circuit with different line voltages, and to allowdimming.