Method and apparatus to drive LED arrays using time sharing technique
DC CAFCFirst Claim
1. A multi-load time sharing driver comprising:
- a current source configured to provide a regulated current;
a network of semiconductor switches coupled in series; and
a plurality of light sources in a backlight system, each light source associated with a semiconductor switch, wherein the semiconductor switch selectively opens to allow the associated light source to conduct the regulated current.
9 Assignments
Litigations
2 Petitions
Accused Products
Abstract
An efficient and flexible current-mode driver delivers power to one or more light sources in a backlight system. In one application, the current-mode driver is configured as an inverter with an input current regulator, a non-resonant polarity-switching network, and a closely-coupled output transformer. The input current regulator can output a regulated current source in a variety of programmable wave shapes. The current-mode driver may further include a rectifier circuit and a second polarity-switching network between the closely-coupled output transformer and a lamp load. In another application, the current-mode driver delivers power to a plurality of light sources in substantially one polarity by providing a regulated current to a network of time-sharing semiconductor switches coupled in series with different light sources coupled across each semiconductor switch.
267 Citations
13 Claims
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1. A multi-load time sharing driver comprising:
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a current source configured to provide a regulated current; a network of semiconductor switches coupled in series; and a plurality of light sources in a backlight system, each light source associated with a semiconductor switch, wherein the semiconductor switch selectively opens to allow the associated light source to conduct the regulated current. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method to selectively power one or more light sources in a backlight system using a single power source, the method comprising the acts of:
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generating a regulated current; coupling the regulated current to a plurality of semiconductor switches connected in series; coupling a different light source across each of the semiconductor switches; and selectively opening the semiconductor switches to provide power to the respective light sources. - View Dependent Claims (10, 11, 12)
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13. A multi-load time sharing driver comprising:
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means for generating a regulated current; and means for using a string of semiconductor switches to selectively provide the regulated current to different portions of an array of light emitting diodes in a backlight system, wherein the light emitting diodes are coupled in series, each semiconductor switch is coupled across a different group of series-connected light emitting diodes corresponding to a different row in the array, and the semiconductor switches are logically controlled to selectively short circuit the different groups of series-connected light emitting diodes for dimming.
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Specification