Power supply and reference voltage circuit for TFT LCD source driver
First Claim
1. A power supply circuit, comprising:
- a drive power supply voltage generating circuit for generating a drive power supply voltage for a driver circuit for use in a display device; and
a reference voltage generating circuit for generating a reference voltage for use in generating a gray-scale voltage in said driver circuit, wherein feedback control is performed to maintain a specified relation between said drive power supply voltage and said reference voltage.
1 Assignment
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Accused Products
Abstract
A liquid crystal power supply is provided which generates a high-precision drive power supply voltage supplied to a driver circuit by using a low-precision reference voltage generating circuit. The power supply circuit includes a DC/DC converter which generates a voltage having a size based on an oscillation signal from a power supply voltage and outputs the generated voltage as a drive power supply voltage; a stabilized power supply circuit which generates a highest-level reference potential for generating a gray-scale voltage in a driver circuit; a comparison unit which outputs a difference voltage according to a difference between the drive power supply voltage and the highest-level reference potential; an internal reference voltage generating unit; an error amplifying unit which amplifies a difference between the reference voltage and the difference voltage; and a PWM conversion unit which outputs an oscillation signal in response to the amplified difference.
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Citations
20 Claims
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1. A power supply circuit, comprising:
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a drive power supply voltage generating circuit for generating a drive power supply voltage for a driver circuit for use in a display device; and
a reference voltage generating circuit for generating a reference voltage for use in generating a gray-scale voltage in said driver circuit, wherein feedback control is performed to maintain a specified relation between said drive power supply voltage and said reference voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A power supply circuit, comprising:
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a drive power supply voltage generating circuit for generating a drive power supply voltage for a driver circuit for use in a display device; and
a reference voltage generating circuit for generating a reference voltage for use in generating a gray-scale voltage in said driver circuit, wherein said drive power supply voltage generating circuit generates said drive power supply voltage with said reference voltage as a reference. - View Dependent Claims (11, 13, 14, 15, 17, 18, 19, 20)
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12. A driver circuit voltage generating method, comprising:
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a reference voltage generating step of generating a reference voltage for use in generating a gray-scale voltage in a driver circuit for use in a display device; and
a drive power supply voltage generating step of generating a drive power supply voltage of said driver circuit with said reference voltage as a reference.
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16. A display device, comprising:
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a display panel including a plurality of pixels arrayed in a matrix, said display panel being for displaying an image by said plurality of pixels;
a driver circuit for outputting a gray-scale voltage to said plurality of pixels based on a plurality of reference potentials; and
a power supply circuit for outputting a drive power supply voltage for said driver circuit and a reference voltage for deciding said plurality of reference potentials, wherein said power supply circuit performs feedback control to maintain a specified relation between said drive power supply voltage and said reference voltage.
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Specification