Arrangement suitable for driving floating CCFL based backlight

• US 8,008,867 B2
• Filed: 02/02/2009
• Issued: 08/30/2011
• Est. Priority Date: 10/06/2003
• Status: Expired due to Fees

• Current Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Original Assignee: Microsemi Corporation (Microchip Technology Incorporated)
• Inventors: Jin, Xiaoping
• Primary Examiner(s): Tan; Vibol
• Application Number:
  US12/363,805
• Publication Number:
  US 20090195174A1
• Time in Patent Office: 939 Days
• Field of Search: 315/209.R, 315/209.CD, 315/244, 315/282, 315/297, 315/277, 315/177, 315/246, 315/276, 315/219, 315/121, 315/255, 315/130, 315/268, 315/312
• US Class Current: 315/277
• CPC Class Codes: H05B 41/2822 using specially adapted components in the load circuit, e.g. feed-back transformers, piezoelectric transformers; using specially adapted load circuit configurations

Abstract

A backlighting arrangement constituted of: a means for receiving an alternating current comprising a first lead and a second lead; at least one luminaire; and at least one first balancing transformer pair each associated with a particular one of the at least one luminaire, the primary of a first balancing transformer of the first balancing transformer pair serially coupled between the first lead of the means for receiving an alternating current and a first end of each of the at least one luminaire, and the primary of a second balancing transformer of the first balancing transformer pair serially coupled between the second lead of the means for receiving an alternating current and a second end of each of the at least one luminaire. The secondaries of all of the at least one first balancing transformer pair are serially connected in a closed in-phase loop.

Claims

1. A backlighting arrangement comprising:

a first lead and a second lead arranged to receive and return an alternating current;

at least one luminaire, each of said at least one luminaire comprising a pair of linear lamps each lamp of said pair exhibiting a far end removed from each of a first and a second end of said luminaire;

at least one first balancing transformer pair, each of said first balancing transformer pair associated with a particular one of said at least one luminaire, the primary winding of a first balancing transformer of each of said first balancing transformer pair serially coupled between said first lead and the first end of said associated at least one luminaire, and the primary winding of a second balancing transformer of each of said first balancing transformer pair serially coupled between said second lead and the second end of each of said associated at least one luminaire; and

at least one second balancing transformer pair, each of said second balancing transformer pair associated with a particular one of said at least one luminaire, the primary windings of said second balancing transformer pair being arranged in series with, and serially coupled between, said far ends of the associated pair of linear lamps of said particular luminaire,

wherein the secondary windings of all of said at least one first balancing transformer pair and said at least one second balancing transformer pair are serially connected in a closed in-phase loop.

2. A backlighting arrangement according to claim 1, further comprising a differential alternating current source arranged to supply power to said at least one luminaire via said first and second leads.

3. A backlighting arrangement according to claim 1, further comprising a sense resistor serially connected within said serially connected closed in-phase loop arranged to present a voltage drop representation of the current flowing through the closed in-phase loop.

5. A backlighting arrangement according to claim 1, wherein said at least one pair of linear lamps are arranged substantially in parallel to backlight a display, and wherein said serially connected closed in-phase loop exhibits a single twisted wire pair connecting a portion of the closed in-phase loop associated with a first end of the display to a portion of the closed in-phase loop associated with a second end of the display opposing said first end of the display.

6. A backlighting arrangement according to claim 1, wherein said at least one luminaire comprises a plurality of luminaires.

4. A backlighting arrangement comprising:

a first lead and a second lead arranged to receive and return an alternating current;

at least one luminaire, each of said at least one luminaire comprising a pair of linear lamps each exhibiting a far end removed from each of a first and a second of said luminaire;

at least one first balancing transformer pair, each of said first balancing transformer pair associated with a particular one of said at least one luminaire, the primary winding of a first balancing transformer of each of said first balancing transformer pair serially coupled between said first lead and a first end of said associated at least one luminaire, and the primary winding of a second balancing transformer of each of said first balancing transformer pair serially coupled between said second lead and a second end of each of said associated at least one luminaire; and

at least one second balancing transformer, each of said at least one second balancing transformer associated with a particular one of said pair of linear lamps, the primary winding of each of said second balancing transformer coupled between said far ends of said associated pair of linear lamps,

wherein the secondary windings of all of said at least one first balancing transformer pair and said at least one second balancing transformer are serially connected in a closed in-phase serial loop.

7. A method of driving at least one luminaire, comprising:

receiving an alternating current;

providing at least one luminaire, each of said provided at least one luminaire comprising a pair of linear lamps each exhibiting a far end removed from each of a first end and a second end of said provided luminaire;

providing at least one first balancing transformer pair, each of said provided first balancing transformer pair associated with a particular one of said provided at least one luminaire, the primary winding of a first transformer of the respective provided first balancing transformer pair associated with a first end of said associated luminaire, and the primary winding of a second transformer of the respective first balancing transformer pair associated with a second end of said associated luminaire;

providing at least one second balancing transformer pair, each balancing transformer of said pair associated with a particular one of said pair of linear lamps of a particular one of said provided at least one luminaire;

arranging the primary windings of said second balancing transformer pair in series and serially connecting the series arranged primary windings between said far ends of said associated pair of linear lamps;

coupling said received alternating current via said respective primary windings of said provided first balancing transformer pair to each end of said provided at least one luminaire; and

arranging the secondary windings of all of said provided at least one first balancing transformer pair and said provided at least one second balancing transformer pair in a serially connected closed in-phase loop.

8. A method according to claim 7, further comprising sensing a current flowing through the closed in-phase loop.

9. A method according to claim 7, further comprising sensing a current flowing through the closed in-phase loop.

10. A method of driving at least one luminaire, comprising:

receiving an alternating current;

providing at least one luminaire, each of said provided at least one luminaire comprising a pair of linear lamps each exhibiting a far end removed from each of a first and a second end of said luminaire;

providing at least one first balancing transformer pair, each of said provided at least one first balancing transformer pair associated with a particular one of said provided at least one luminaire, the primary winding of a first transformer of the respective provided first balancing transformer pair associated with a first end of said associated luminaire, and the primary winding of a second transformer of the respective first balancing transformer pair associated with a second end of said associated luminaire;

coupling said received alternating current via said respective primary windings of said provided first balancing transformer pair to each end of said provided at least one luminaire;

providing at least one second balancing transformer, each of said provided at least one second balancing transformer associated with a particular one of said provided at least one luminaire;

serially connecting the primary winding of one of said provided at least one second balancing transformer between said far ends of said respective associated pair of linear lamps of said particular associated luminaire; and

arranging the secondary windings of all of said provided at least one first balancing transformer pair and said provided at least one second balancing transformer in a serially connected closed in-phase loop.

11. A backlighting arrangement comprising:

a means for receiving an alternating current exhibiting a first lead and a second lead;

a plurality of luminaires; and

a plurality of first balancing transformer pairs, each of said first balancing transformer pairs associated with a particular one of said plurality of luminaires, the primary winding of a first balancing transformer of each first balancing transformer pair serially coupled between said first lead of said means for receiving an alternating current and a first end of the associated luminaire, and the primary winding of a second balancing transformer of each of said first balancing transformer pair serially coupled between said second lead of said means for receiving an alternating current and a second end of the associated luminaire; and

a plurality of second balancing transformer pairs each associated with a particular one of said plurality of luminaires and wherein each of said plurality of luminaires comprises a pair of linear lamps each exhibiting a far end removed from each of said first and second ends of said luminaire, the primary windings of said associated second balancing transformer pair being arranged in series and serially connected between said far ends of said pair of linear lamps;

wherein the secondary windings of all of said plurality of first balancing transformer pair and said plurality of second balancing transformer pairs are serially connected in a closed in-phase loop.