Ballast for gas discharge lamp, has voltage tap circuit with frequency dependent transfer characteristic, which has input terminal connected to gas discharge lamp and output terminal connected to control circuit

摘要

The ballast (10) has an inverter (19) having an output terminal (18) for connecting a gas discharge lamp (11) and control input terminal (23,24) for connecting to output terminal (28) of a control circuit (25) having disable input terminal (30). The control circuit emits a drive signal with a mode of the gas discharge lamp, defining variable frequency at the output terminal (28). A voltage tap circuit (31) having frequency dependent transfer characteristic has input terminal (32) connected to the gas discharge lamp and output terminal (37) connected to the control circuit.