POWER SUPPLY FOR AN LCD DISPLAY
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Abstract
A power supply system is provided for a multiple lamp LCD panel. In one aspect, the power supply includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series to thereby reduce the stress on each transformer. For LCD panels that include longer CCFLs, a power supply is provided that includes a plurality of transformers for driving a plurality of respective CCFLs. The primary sides of each transformer are coupled in series and each lamp is coupled to two secondary sides of the transformers, thereby reducing the problems associated with longer CCFL tubes. In any of the embodiments, the power supply can be adapted to convert a high voltage DC signal to high voltage AC used to power the lamps.
101 Citations
39 Claims
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1-12. -12. (canceled)
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13. A DC/AC inverter circuit, comprising:
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a transformer comprising a primary winding for receiving an AC signal, and comprising a first secondary winding and a second secondary winding; a cold cathode florescent lamp (CCFL) coupled between a positive polarity terminal of said first secondary winding and a negative polarity terminal of said second secondary winding; and a capacitor divider feedback circuit electrically coupled to said CCFL for providing a voltage feedback signal to said inverter controller indicative of a voltage across said CCFL. - View Dependent Claims (14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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25. A display system, comprising:
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a display panel; an inverter controller coupled to a power train for converting a DC signal to an AC signal; a transformer coupled to said power train and comprising a first primary winding and a second primary winding coupled in series for receiving said AC signal, and comprising a first secondary winding and a second secondary winding; a cold cathode florescent lamp (CCFL) coupled to said first secondary winding and said second secondary winding in series and coupled between a positive polarity terminal of said first secondary winding and a negative polarity terminal of said second secondary winding for illuminating said display panel; a current feedback circuit coupled in series with said CCFL, said first secondary winding and second secondary winding, and for providing a current feedback signal to said inverter controller indicative of a current flowing through said CCFL; and a capacitor divider feedback circuit coupled to said CCFL for providing a voltage feedback signal to said inverter controller indicative of a voltage across said CCFL. - View Dependent Claims (26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A method for providing power to a cold cathode fluorescent lamp (CCFL) of a display system, said method comprising:
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receiving an AC signal by a primary winding of a transformer; generating a first output AC signal at a positive polarity terminal of a first secondary winding of said transformer; generating a second output AC signal at a negative polarity terminal of a second secondary winding of said transformer; powering said CCFL coupled between said positive polarity terminal and said negative polarity terminal; receiving a voltage feedback signal from a capacitor divider feedback circuit indicative of a voltage across said CCFL; and controlling power of said CCFL according to said voltage feedback signal. - View Dependent Claims (36, 37, 38, 39)
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Specification