Starting and operating circuit for gas discharge lamp

A circuit for starting and operating a gas discharge lamp comprising power supply means connected to the lamp and shiftable between a normal starting condition for applying a relatively high DV voltage to the lamp and a running condition for applying a relatively low DC voltage to the lamp;

• said power supply means including a constant-voltage transformer having primary winding means adapted for connection to an associated source of AC voltage and secondary winding means having first and second and third terminals, and rectifying means selectively connectable between said first and second terminals in said running condition or between said first and third terminals in said starting condition;
• control means coupled to said power supply means and to the lamp and operative for shifting said power supply means to the running condition thereof in response to starting of the lamp and for shifting said power supply means to the starting condition thereof in response to extinguishing of the lamp;
• and starting means coupled to said power supply means and to the lamp and responsive only to the relatively high DC voltage when said power supply means is in the starting condition thereof for producing a transient pulse of starting voltage and applying it to the lamp for starting thereof.

A circuit for starting and operating a gas discharge lamp comprising power supply means connected to the lamp and shiftable between a normal starting condition for applying a relatively high DC voltage to the lamp and a running condition for applying a relatively low DC voltage to the lamp, first control means coupled to said power supply means and operable in first and second conditions respectively for shifting said power supply means to the starting and running conditions thereof, second control means coupled to said first control means and connected in series with the lamp and responsive to the lamp current for shifting said first control means to the second condition thereof in response to starting of the lamp and for shifting said first control means to the first condition thereof in response to extinguishing of the lamp, and starting means coupled to said power supply means and to the lamp and responsive only to the relatively high DC voltage when said power supply means is in the starting condition thereof for producing a transient pulse of starting voltage and applying it to the lamp for starting thereof.

A circuit for starting and operating a gas discharge lamp comprising power supply means connected to the lamp and shiftable between a normal starting condition for applying a relatively high DC voltage to the lamp and a running condition for applying a relatively low DC voltage to the lamp, control means coupled to said power supply means and to the lamp and operative for shifting said power supply means to the running condition thereof in response to starting of the lamp and for shifting said power supply means to the starting condition thereof in response to extinguishing of the lamp, a starting circuit coupled to said power supply means and responsive only to the relatively high voltage when said power supply means is in the starting condition thereof for producing a transient pulse of starting voltage sufficiently high to ignite the lamp when it is warm, and spark gap means connected to said starting circuit and connected directly to the lamp for coupling said transient voltage pulse to the lamp to start same while preventing feedback of the DC voltage to said starting circuit.