| 摘要 |
<p>A control circuit utilizing the impedance transforming attributes of ballast/filter networks is disclosed for energizing high intensity gas discharge lamps, wherein the output amplitude and/or duty cycle of a power frequency waveform produced by a switching inverter is controlled using feedback techniques. A basic embodiment teaches the use of energy removal from the input inductor (26A) of a low pass ballast/filter (26) positioned between a switching inverter (22) operating at 30 kHz and a gas discharge lamp load (16) to serve as a feedback source, while an alternative embodiment teaches the use of this feedback source as a signal for controlling the duty cycle of the constant frequency square waves (5B) produced by the inverter (22'). These and other control circuits disclosed are particularly applicable for energizing high intensity discharge lamps of the types exhibiting very irregular characteristics, and for providing their desirable constant current controlling and protective features for the full range of lamp operating phases including lamp starting, constant power operation, and lamp restarting.</p> |
