Title: An electronic ballast circuit
Application Number: 00810476 Application Date: 2000.05.17
Publication Number: 1362002 Publication Date: 2002.07.31
Approval Pub. Date: Granted Pub. Date:
International Classifi-cation: H02M1/12;H05B41/282
Applicant(s) Name: Noontek Limited Address:
Inventor(s) Name: S. Noone;T. Durkan;M. Quinlan
Attorney & Agent: cheng tianzheng
Abstract:
    A driver waveform (30) for a gas discharge lamp is produced by a ballast circuit. The waveform (30) has a substantially vertical rising portion 831) forming an instantaneous, of time 10 mu secs or so between T0 and T1, transition between currents -l1 and l1 which are at a current value less than peak currents IP. Then in a transition rise at controlled slew rate the waveform (30) rises with a straight rising portion (32) to a steady peak current IP identified by the numeral (33). The peak current IP is maintained between T2 and T3 which accounts for between 40% and 80% of the cycle time. Then at T3 decline occurs with waveform having a declining slew rate portion (34) to time T4 when instantaneous transition between time T4 and T5 and currents l1 to -l1 occurs. The driver waveform reduces the formation of high frequency harmonies and increases arc stability.
Time: 13