Power supply

A power supply for driving a plurality of gas-discharge lamps, said power supply comprising:

• a DC voltage source;
• inverter means connected to said DC voltage source for providing a high frequency AC voltage at its output end;
• output transformer means having a primary winding coupled to the output end of said inverter means through tuning inductor means and a secondary winding with a plurality of gas discharge lamps connected across the secondary winding;
• a plurality of tuning capacitors connected across said secondary winding of said output transformer in parallel relation to said respective gas-discharge lamps and cooperative with said tuning inductor means to form resonant circuits which produce a resonance current for driving said gas-discharge lamps, said tuning capacitors being connected in circuit on the opposite side of said secondary winding from said gas-discharge lamps such that said tuning capacitor is open-circuited when any one of said corresponding gas-discharge lamps is disconnected from said secondary winding;
• and
• balancing choke coil means having a primary winding which is connected in series between one of two said adjacent tuning capacitors and corresponding one of said discharge lamps, and a secondary winding which is connected in series between the other of two said adjacent tuning capacitors and corresponding one of said discharge lamps, said primary and secondary windings of said balancing choke coil means having opposed polarity for equalizing the currents flowing through said adjacent two tuning capacitors.

A power supply comprising:

• a DC voltage source;
• inverter means connected to said DC voltage source for providing a high frequency AC voltage at its output end;
• output transformer means having a primary winding coupled to the output end of said inverter means through tuning inductor means and a secondary winding with a plurality of loads connected across the secondary winding;
• a plurality of tuning capacitors connected across said secondary winding of said output transformer in parallel relation to said respective loads and cooperative with said tuning inductor means to form resonant circuits which produce a resonance current for driving said loads,
• said tuning capacitors being connected in circuit on the opposite side of said secondary winding from said loads such that said tuning capacitor is open-circuited when the corresponding load is disconnected from said secondary winding.

A power supply for driving a plurality of discharge lamps comprising:

• a DC voltage source;
• inverter means connected to said DC voltage source for providing a high frequency AC voltage at its output end;
• output transformer means having a primary winding coupled to the output, end of said inverter means through tuning inductor means and a plurality of secondary windings, with a plurality of discharge lamps, each having two filaments, connected respectively across the secondary windings;
• a plurality of tuning capacitors connected across said secondary windings of said output transformer, respectively in parallel relation to corresponding one of said discharge lamps with each tuning capacitor connected across said two filaments of each discharge lamp, each of said tuning capacitors cooperative with said tuning inductor means to form a resonant circuit which produces a resonance current for driving the corresponding discharge lamp;
• and
• each of said tuning capacitors being connected across each of said secondary windings through the filaments of each lamp such that said tuning capacitor is open-circuited when the corresponding discharge lamp is disconnected from said secondary winding;
• each of said discharge lamps being connected in series with a current limiting element across each of said secondary windings.