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US 2002/0158834 A1Published application
Switching circuit for column display driver
AssigneeWinbond Electronics Corp.
InventorsTim Blankenship, Stephen Bily
Life of this patent
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Abstract
According to the present invention, improved techniques for switching current flow in a display column driver circuit. Embodiments provide switching of analog outputs of digital to analog converters in order to drive columns of an LCD. Embodiments can provide a full range of voltage output to drive an LCD without necessitating a full range amplifier configuration. Further, many embodiments can be realized in smaller space on an IC chip than in conventional technologies.
Claims20
A column driver circuit, comprising:
- a voltage reference circuit for generating a plurality of reference voltages;
- at least one multiplexer, coupled to said voltage reference circuit, responsive to said reference voltages and an output signal from a decoder to provide at least one analog output;
- an analog selection circuit, coupled to said at least one multiplexer, responsive to said analog output from said at least one multiplexer;
- and
- a first amplifier stage, coupled to said analog selection circuit, responsive to an output from said analog selection circuit for providing at least one output.
2 more elements
A column driver circuit, comprising:
- a voltage divider for generating a plurality of reference voltage levels;
- a first data decoder coupled to said voltage divider for receiving a first subset of said plurality of reference voltage levels;
- a second data decoder coupled to said voltage divider for receiving a second subset of said plurality of reference voltage levels;
- a plurality of digital decoders coupled to said first and second data decoders, operable to select one of said plurality of reference voltage levels for each of said first and second data decoders each to provide at least one analog output;
- a plurality of amplifiers, each having a first stage that receives said analog output from one of said plurality of data decoders, and a second stage that receives as input an output of said first stage and provides a signal;
- and
- a plurality of switches, each coupled between said first stage and said second stage of each of said plurality of two stage amplifiers, wherein one of said switches couples one of said output from one of said first stage of one of said amplifiers to one of one of said second stage of one of said amplifiers.
4 more elements
A liquid crystal display, comprising:
- a plurality of columns of pixels;
- a plurality of rows of pixels;
- and
- a plurality of column driver circuits, each coupled to one of said plurality of pixels, each column driver circuit including,
- a voltage divider for generating a plurality of reference voltage levels,
- a first data decoder coupled to said voltage divider for receiving a first subset of said plurality of reference voltage levels,
- a second data decoder coupled to said voltage divider for receiving a second subset of said plurality of reference voltage levels,
- at least one digital decoder coupled to said first and second data decoders, operable to select one of said plurality of reference voltage levels for each of said first and second data decoders each to provide at least one analog output, and
- at least one switch, each of said at least one switch coupled between at least one of said data decoders and at least one amplifier,
- wherein said at least one switch provides a selection of one of said outputs from at least one of said first and second of data decoders to said at least one amplifier, wherein each of said at least one amplifier has a stage that receives as input said output from one of said first and second data decoders, and provides a signal.
7 more elements
A column driver circuit, comprising:
- means for generating reference voltages;
- means for decoding digital data coupled to said means for generating reference voltages;
- means for multiplexing said reference voltages and said decoded data coupled to said means for decoding digital data;
- means for selecting an output of said means for multiplexing coupled to said means for multiplexing;
- and
- means for amplifying said selected output coupled to said means for selecting an output.
3 more elements
A method for driving a liquid crystal display, comprising:
- providing a plurality of reference voltage levels;
- dividing said reference voltage levels into at least two subsets;
- multiplexing said reference voltage levels into a plurality of output voltages;
- selecting one of said plurality of output voltages;
- switching said selected output voltage to a plurality of amplifiers;
- and
- providing an output of said amplifiers to drive a column of said liquid crystal display.
4 more elements
Dependencies are inferred from the claim text.