High pressure discharge lamp apparatus

A high pressure discharge lamp apparatus of the type comprising:

• a discharge tube and a current limiting device connected in series for connection across an A.C. power source, and
• a pulse generator connected by its output terminal in parallel to the discharge tube,
• the apparatus characterized in that:
• said pulse generator comprises:
• a positive reignition pulse controller for outputting a controlling pulse signal after a predetermined time period from said rise up in the negative direction of the output of said positive waveform shaper,
• a negative reignition pulse controller for outputting a controlling pulse signal after a predetermined time period from said rise up of the output of said negative waveform shaper,
• a first oscillation stopping means which stops oscillation by said positive reignition pulse oscillator upon receipt of said controlling pulse signal from said positive reignition pulse controller, and
• a second oscillation stopping means which stops oscillation by said negative reignition pulse oscillator upon receipt of said controlling pulse signal from said negative reignition pulse controller,
• said pulse generator impressing reignition pulses on said discharge tube at least during a period defined as from a zero-cross point of the source voltage of the power source to a phase defined by a peak of reignition voltage of lamp voltage waveform when no reignition pulse is impressed on the discharge tube, thereby retaining lamp current of the discharge tube without forming zero-current period.