Discharge lamp lighting system using series connected starters

• US 4,145,638 A
• Filed: 11/16/1977
• Issued: 03/20/1979
• Est. Priority Date: 05/20/1975
• Status: Expired due to Term

• Current Assignee: NEC Sylvania Corporation (NEC Corporation)
• Original Assignee: NEC Sylvania Corporation (NEC Corporation)
• Inventors: Kaneda, Isao
• Primary Examiner(s): LaRoche, Eugene R.
• Application Number:
  US05/851,943
• Time in Patent Office: 489 Days
• Field of Search: 315/95, 315/97, 315/99, 315/101, 315/103, 315/105, 315/187, 315/189, 315/244, 315/323, 315/324, 315/DIG. 5
• US Class Current: 315/323
• CPC Class Codes: H05B 41/044 for lamp provided with pre-heating electrodes
• CPC Class Codes: Y10S 315/05 Starting and operating circuit for fluorescent lamp

Abstract

The present discharge lamp system comprises two or more serially connected discharge lamps connected across a pair of power input supply terminals through a ballast circuit and two or more serially connected semiconductor starter circuits. The starters are connected in parallel with their respective discharge lamps and have inherent breakdown voltages, whereby the total value of the breakdown voltages for each starter is higher than the source voltage at the power supply terminals. The system further comprises voltage dividing circuit elements enabling the conduction of one of the starters before the conduction of the other starter or starters in response to the source voltage, whereby the starters operate sequentially. At least one of the starters employs a backswing booster including a series circuit of a nonlinear inductor and a switching semiconductor and a capacitor connected in parallel with the series circuit to provide a sufficient starting voltage for the associated discharge lamp.

Claims

1. A discharge lamp lighting system for first and second discharge lamp means including respective filament means, said system comprising power input supply terminals, means for connecting said first and second discharge lamp means in series to form a first series circuit, ballast means connected in series with said first series circuit, said ballast means and said first series circuit being connected serially between said power supply terminals, said ballast means comprising a substantially linear inductor, a second series circuit comprising first and second starting booster means, means connecting said first and second starting booster means in parallel with said first and second discharge lamp means respectively, said first starting booster means comprising a capacitor connected in parallel with said first discharge lamp means at the power supply side thereof, a third series circuit comprising a first nonlinear inductor connected in series with a first switching semiconductor having a given breakdown voltage, and means connecting said third series circuit in parallel with said first discharge lamp means opposite the power supply side thereof, said second starting booster means comprising a second capacitor connected in parallel with said second discharge lamp means at the power supply side thereof, a fourth series circuit comprising a second nonlinear inductor connected in series with a second switching semiconductor also having a given breakdown voltage, and means connecting said fourth series circuit in parallel with said second discharge lamp means opposite the power supply side thereof, and wherein the sum of the breakdown voltages of said first and second switching semiconductors is higher than the source voltage at said power supply terminals, said system further comprising voltage dividing means responsive to voltages at said power supply terminals for applying a breakdown voltage to the switching semiconductor of said first starting booster means before the operation of said second starting booster means, whereby said first and second starting booster means are sequentially operated for starting said discharge lamp means in a stable manner.

2. The discharge lamp lighting system of claim 1, wherein said voltage dividing means comprises a resistor connected in parallel with said second starting booster means.

3. The discharge lamp lighting system of claim 1, further comprising a bias coil connected in series with the capacitor which is connected in parallel with said second starting booster means, said bias coil being magnetically coupled to said second nonlinear inductor.

4. The discharge lamp lighting system of claim 1, wherein said voltage dividing means comprise said first mentioned capacitor and said second capacitor, the capacitance of said first and second capacitors being different from one another, whereby said first and second starters are sequentially operated.

5. The discharge lamp lighting system of claim 1, wherein said ballast means further comprise a phase advancing capacitor connected in series with said linear inductor.

6. The discharge lamp lighting system of claim 1, wherein said voltage dividing means comprise a resistor connected in parallel with the switching semiconductor of said second starter.

7. The discharge lamp lighting system of claim 1, wherein said voltage dividing means comprise a series circuit of a resistor and said nonlinear inductor of said second starter, said resistor being connected in parallel with the switching semiconductor of said second starter.

8. A discharge lamp lighting system comprising power input supply terminals, a first series circuit of first and second discharge lamp means, ballast means connected in series with said first series circuit, said ballast and said first series circuit being connected serially between said power supply terminals, said ballast means comprising a substantially linear inductor, and first and second backswing boosters connected in parallel with said first and second discharge lamps respectively, each backswing booster comprising a second series circuit of a switching semiconductor and a nonlinear inductor, said nonlinear inductors having distributed capacitances and a common core, said system further comprising igniting means enabling the switching semiconductor of said first backswing booster to breakdown before the breakdown of said switching semiconductor of said second backswing booster in response to voltages at said power supply terminals and a first capacitor connected in parallel with said first backswing booster, as well as a series circuit of a coil and a second capacitor connected in parallel with said second backswing booster, said coil being magnetically coupled to said core.

9. The discharge lamp lighting system of claim 8, wherein said igniting means comprise a resistor connected in parallel with the switching semiconductor of said second backswing booster.

10. The discharge lamp lighting system of claim 9, further comprising a capacitor connected in parallel with said first backswing booster.

11. The discharge lamp lighting system of claim 9, comprising a capacitor connected in parallel with said second backswing booster.

12. The discharge lamp lighting system of claim 8, wherein a first capacitor is connected in parallel with said first backswing booster, said igniting means comprising a second capacitor connected in parallel with said second backswing booster and having a capacitance that differs from the capacitance of said first capacitor.

13. The discharge lamp lighting system of claim 8, comprising capacitor means connected in parallel with said first and second backswing boosters, and wherein said ballast means further comprises a parallel connected resistor and capacitor connected in series with said linear inductor.

14. The discharge lamp lighting system of claim 13, wherein said igniting means comprise a resistor connected in parallel with the switching semiconductor of said second backswing booster.