Switched capacitive ballasts for discharge lamps

摘要

Ballast and starting circuits for controlling current and voltage applied to an electrical dishcarge lamp. The ballast circuits use positive and negative capacitors which are alternately charged and discharged in an asychronous manner. The positively charged capacitors are charged during positive portions of alternating current and discharged during negative portions of the alternating current. The negatively charged capacitors are charged during negative portions of the alternating current and discharged during positive portions. Transistors or other appropriate switching means are used to switch the capacitors to the lamp during discharge thereof. Startup circuits are included for boosting the voltage applied to the lamp either manually or automatically upon startup. A startup regulator circuit is also shown for controlling current flow during periods of high current demand such as during startup.