Ballast for discharge lamp

A ballast for discharge lamp, the ballast for discharge lamp for utilizing high frequency voltage generated by alternatively switching two switching elements to light the discharge lamp, the ballast comprising:

• a primary winding of a switching transformer to which the high frequency voltage is applied;
• a secondary winding of a switching transformer for alternatively switching the two switching elements according to reverse electromotive voltage generated by application of high frequency voltage to the primary winding;
• and
• stabilizing means for stabilizing reverse electromotive voltage generating at the secondary winding, the stabilizing means comprises:
• a control winding where reverse electromotive voltage is generated according to high frequency voltage applied to the primary winding;
• a diode for half-rectifying the reverse electromotive voltage generated at the winding for control;
• charging/discharging circuit for receiving the reverse electromotive voltage half-rectified by the diode to charge and discharge according to charging/discharging time constant;
• and
• a transistor for switching according to a voltage value of the charge/discharge circuit to control reverse electromotive voltage generated at the secondary winding.