Control Methods and Backlight Controllers for Light Dimming
First Claim
1. A control method for light dimming, comprising:
- providing a dimming condition signal, wherein a first logic value of the dimming condition signal represents a light emitting device is expected to be emitting light, and a second logic value of the dimming condition signal represents the light emitting device is expected not to be emitting light, wherein the duration when the dimming condition signal is at the first logic value is a dimming-ON time;
providing, in the dimming-ON time, a close loop to make a power converter convert electric energy to the light emitting device such that the light emitting device is capable of emitting light, wherein a power-ON time is the duration when the power converter converts electric energy to the light emitting device; and
continuing, when the dimming condition signal is switched to be at the second logic value and the dimming-ON time is less than a minimum power-ON time, the power converter converting the electric energy to the light emitting device so as to keep the power-ON time not less than the minimum power-ON time.
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Abstract
A control method is disclosed for light dimming. A dimming condition signal is provided to represent whether a light emitting device is expected to be emitting light. The duration when the dimming condition signal is at a logic value indicating the light emitting device is emitting light is a dimming-ON time, in which a close loop is provided to make a power converter convert electric energy to the light emitting device such that the light emitting device is capable of emitting light. A power-ON time is the duration when the power converter converts electric energy to the light emitting device. When the dimming-ON time ends and is less than a minimum power-ON time, the power converter continues converting the electric energy to the light emitting device so as to keep the power-ON time not less than the minimum power-ON time.
22 Citations
17 Claims
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1. A control method for light dimming, comprising:
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providing a dimming condition signal, wherein a first logic value of the dimming condition signal represents a light emitting device is expected to be emitting light, and a second logic value of the dimming condition signal represents the light emitting device is expected not to be emitting light, wherein the duration when the dimming condition signal is at the first logic value is a dimming-ON time; providing, in the dimming-ON time, a close loop to make a power converter convert electric energy to the light emitting device such that the light emitting device is capable of emitting light, wherein a power-ON time is the duration when the power converter converts electric energy to the light emitting device; and continuing, when the dimming condition signal is switched to be at the second logic value and the dimming-ON time is less than a minimum power-ON time, the power converter converting the electric energy to the light emitting device so as to keep the power-ON time not less than the minimum power-ON time. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A back-light controller, comprising:
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a current control unit, receiving a digital dimming signal to generate a dimming condition signal and to control a driving current through a light emitting device, wherein, when the dimming condition signal is at a first logic value the driving current is about 0, and when the diming condition signal is at a second logic value different from the first logic value the driving current is about a constant more than 0, wherein the duration when the dimming condition signal is at the first logic value is a dimming-ON time; and a power controller for controlling a power converter to convert electric power to the light emitting device, wherein the duration when the power converter converts the electric energy to the light emitting device is a power-ON time; wherein, when the dimming condition signal is at the first logic value, the power controller provides a close loop and the power converter converts, based on the close loop, the electric energy to the light emitting device such that the light emitting device is capable of emitting light; and when the dimming condition signal is switched to be at the second logic value and the dimming-ON time is less than a minimum power-ON time, the power converter continues converting the electric energy to the light emitting device for elongating the power-ON time to be not less than the minimum power-ON time. - View Dependent Claims (15, 16, 17)
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Specification