Method of ignition regulation of discharge lamp and the corresponding electronic ballast circuit

An electronic ballast circuit for regulating the ignition voltage of a discharge lamp, comprising:

• a half-bridge inverter circuit comprising two transistors for supplying AC voltage to said discharge lamp;
• a load circuit coupled between said discharge lamp and said half-bridge inverter circuit;
• a detector for detecting the current flowing through one of said two transistors;
• and
• a logic control circuit for comparing the current detected by said detector with a predetermined reference value, and terminating the driving period of said one transistor and starting the driving period of the other transistor of the two transistors if the detected current exceeds the predetermined reference value,
• wherein the logic control circuit further controls the started driving period of said other transistor so that it is the same as the terminated driving period of said one transistor.