Primary side current balancing scheme for multiple CCF lamp operation
First Claim
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1. A backlight system comprising:
- M transformer groups in an electrically parallel configuration, wherein M is at least two and each transformer group comprises at least two lamp transformers with serially-coupled primary windings;
a plurality of lamp loads, wherein the lamp loads are coupled to respective secondary windings of the lamp transformers; and
at least M−
1 balancing transformers coupled between a common power source and the M transformer groups, wherein each balancing transformer comprises two balance windings and the serially-coupled primary windings of each transformer group are coupled in series with at least one balance winding to the common power source.
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Abstract
A backlight system drives multiple lamps using balanced groups of serially-connected lamp transformers. A plurality of lamp transformers is divided into multiple transformer groups. Primary windings of the lamp transformers are coupled in series in each transformer group. Lamps are coupled to secondary windings of the lamp transformers. The transformer groups are arranged in a parallel configuration. One or more balancing transformers couple the transformer groups to a common power source. The balancing transformers divide a common current from the common power source into multiple balanced currents for the respective transformer groups.
196 Citations
20 Claims
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1. A backlight system comprising:
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M transformer groups in an electrically parallel configuration, wherein M is at least two and each transformer group comprises at least two lamp transformers with serially-coupled primary windings; a plurality of lamp loads, wherein the lamp loads are coupled to respective secondary windings of the lamp transformers; and at least M−
1 balancing transformers coupled between a common power source and the M transformer groups, wherein each balancing transformer comprises two balance windings and the serially-coupled primary windings of each transformer group are coupled in series with at least one balance winding to the common power source. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method to balance currents among multiple lamps in a backlight system, the method comprising the acts of:
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arranging a plurality of lamp transformers into an electrically parallel configuration of M transformer groups, wherein each transformer group comprises at least two lamp transformers and primary windings of the lamp transformers in a common transformer group are coupled in series; coupling different lamp loads to respective secondary windings of the lamp transformers; and using at least M−
1 balancing transformers to interface the electrically parallel configuration of M transformer groups to a common power source, wherein each balancing transformer comprises two balance windings and each transformer group is coupled in series with at least one balance winding to the common power source. - View Dependent Claims (12, 13, 14, 15, 16)
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- 17. A backlight system comprising means for balancing currents among multiple lamps using one or more balancing transformers to divide a common current into multiple branches of balanced currents and groups of lamp transformers to conduct the respective balanced currents, wherein primary windings of the lamp transformers in each group are coupled in series and the lamps are coupled to secondary windings of the lamp transformers.
Specification