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Arc Power

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Arc Power

Fig 12. Graph of lamp arc power against control voltage input

Fig 13. Ballast Waveforms at Minimum Brightness

Power Factor Correction Section

The power factor correction stage at the front end of the ballast is based on a standard critical

conduction mode circuit using an industry standard control IC. This stage has been designed to provide a

DC bus of 480 V and operates with the AC line input voltage from 90 Vrms up to 305 Vrms, which is the

maximum voltage that may occur on a 277 VAC line, allowing virtually world wide operation.

The value of LPFC given by the BDA software is 2.7 mH. In a dimming design with a wide voltage input

range it is necessary to select the optimum value for the PFC inductor.