US 7,116,300 B2Granted

Drive circuit and image display apparatus

AssigneeHitachi, Ltd.

InventorsHiroshi Kageyama, Yoshiro Mikami, Hajime Akimoto

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Abstract

Specified thin-film transistors 26 and 27 are caused to conduct by a gradation signal inputted in control circuits 24 and 25, and resistors with a conduction resistance of activated transistors are inserted between any of reference voltages V0, V2, and V4 and an output terminal T1 or between any of reference voltages V1 and V3 and an output terminal T2, and a pair of thin-film transistors 29 in a sampling circuit 23 are caused to conduct simultaneously in sync with the gradation signal. If a signal line SL1 is selected, reference voltages V0, V2, or V4 and V1 or V3 are applied to the signal line SL1, either as they are or as divided by the conduction resistance of the activated thin-film transistors, by using a junction point between the sampling circuit 23 and signal line SL1 as a voltage dividing point.

Claims34

Dependent claims

A drive circuit, comprising:

a plurality of digital-to-analog conversion circuits each of which selects one of difference reference voltages according to a digital gradation signal;
and
a sampling circuit which selectively connects each output terminal of two of the digital-to-analog conversion circuits to signal lines,
wherein each of the digital-to-analog conversion circuits includes a variable resistor circuit with a resistance value corresponding to a digital gradation;
and
wherein the sampling circuit comprises a plurality of pairs of switches, and a pair of switches is simultaneously activated and have an approximate same resistance value when the pair of switches is activated;
and
wherein a divided voltage for outputting to a signal line is generated by a first series resistance and a second series resistance, the first resistance comprises a variable resistance circuit included in one of the digital-to-analog conversion circuits and one of the pair of switches, the one of the digital-to-analog conversion circuits is connected to the sampling circuit and the second series resistance comprises a variable resistor circuit included in another of the digital-to-analog conversion circuits and another of the pair of switches.

5 more elements

A drive circuit, comprising:

a plurality of digital-to-analog conversion circuits each of which outputs an analog signal corresponding to a digital gradation signal;
a plurality of variable resistor circuits with a resistance value corresponding to a digital gradation signal;
and
a sampling circuit which selectively connects each output terminal of two of a plurality of variable resistor circuits to a corresponding one of signal lines,
wherein each output terminal of the digital-to-analog conversion circuit connects to a corresponding variable resistor circuit,
wherein the sampling circuit comprises a plurality of pairs of switches, and a pair of switches is simultaneously activated and have an approximate same resistance value when the pair of switches are activated;
and
wherein a divided voltage for outputting to a signal line is generated by a first series resistance and a second series resistance, the first resistance comprises one of variable resistance circuits and one of the switches, the one of variable resistance circuits is connected to the sampling circuit and the second series resistance comprises another of variable resistor circuits and another of the pair of switches.

5 more elements

A drive circuit, comprising:

a plurality of first digital-to-analog conversion circuits each of which selects one of difference positive reference voltages corresponding to a digital gradation signal;
a plurality of second digital-to-analog conversion circuits each of which selects one of difference negative reference voltages corresponding to a digital gradation signal;
and
a sampling circuit which selectively connects each output terminal of two of the first digital-to-analog conversion circuits to signal lines,
wherein each of the first digital-to-analog conversion circuits includes a variable resistor circuit with a resistance value corresponding to a digital gradation signal;
wherein each of the second digital-to-analog conversion circuits includes a variable resistor circuit with a resistance value corresponding to another digital gradation signal;
wherein the sampling circuit comprises a plurality of pairs of switches, a pair of switches is simultaneously activated and has an approximate same resistance value when the pair of switches is activated;
and
wherein a divided voltage for outputting a signal line is generated by a first series resistor and a second series resistor, the first resistor comprises a variable resistor circuit included in one of the first digital-to-analog conversion circuits and one of the pairs of switches, the one of the first digital-to-analog conversion circuits is connected to the sampling circuit and the second series resistor comprises a variable resistor circuit included in another of the first digital-to-analog conversion circuits and another of the pairs of switches;
wherein another divided voltage for outputting to another signal line is generated by a third series resistor and a fourth series resistor, the third series resistor comprises a variable resistor circuit included in one of the second digital-to-analog conversion circuit and one of the pair of switches, the one of the second digital-to-analog conversion is connected to the sampling circuit and the fourth series resistor comprises a variable resistor circuit included in one of the second digital-to-analog conversion circuit, the one of the second digital-to-analog conversion circuits is connected to the sampling circuit and the fourth series resistor comprises a variable resistor circuit included in another of the second digital-to-analog conversion circuits and another of the pairs of switches.

7 more elements

A drive circuit, comprising:

a plurality of first digital-to-analog conversion circuits each of which selects one of difference positive reference voltage corresponding to a digital gradation signal;
a plurality of second digital-to-analog conversion circuits each of which selects one of difference negative reference voltage corresponding to a digital gradation signal;
a plurality of first variable resistor circuits with a resistance value corresponding to a digital gradation signal;
a plurality of second variable resistor circuits with a resistance value corresponding to another digital gradation signal;
and
a sampling circuit which selectively connects each output terminal of two of the first variable resistor circuits and each terminal of two of the second variable resistor circuits to signal lines,
wherein each output terminal of the first digital-to-analog conversion circuits connects to a corresponding first variable resistor circuit;
wherein each output terminal of the second digital-to-analog conversion circuits connects to a corresponding second variable resistor circuit,
wherein the sampling circuit comprises a plurality of pairs of switches, a pair of switches is simultaneously activated and has an approximate same resistance value when the pair of switches is activated;
wherein a divided voltage for outputting to a signal line is generated by a first series resistor and a second series resistor, the first series resistor comprises one of the first variable resistor circuits and one of the pairs of switches, the one of the first variable resistor circuit is connected to the sampling circuit and the second series resistor circuit comprises another of the first variable resistor circuits and another of the pairs of switches;
and
wherein another divided voltage for outputting to another signal line is generated by a third series resistor and a fourth series resistor, the third series resistor comprises one of the second variable resistor circuits and one of the pairs of switches, the one of the second variable resistor is connected to the sampling circuit and the fourth series resistor comprises another of the second variable resistor circuits and another of pairs of switches.

9 more elements

A drive circuit, comprising:

a plurality of first digital-to-analog conversion circuits each of which outputs a positive analog voltage corresponding to a digital gradation signal;
a plurality of second digital-to-analog conversion circuits each of which outputs a negative analog voltage corresponding to a digital gradation signal;
a plurality of first variable resistor circuits with a resistance value corresponding to a digital gradation signal;
a plurality of second variable resistor circuits with a resistance value corresponding to another digital gradation signal;
and
a sampling circuit which selectively connects each output terminal of two of the first variable resistor circuits and each terminal of two of the second variable resistor circuits to signal lines,
wherein each output terminal of the first digital-to-analog conversion circuits connects to a corresponding first variable resistor circuit,
wherein each output terminal of the second digital-to-analog conversion circuits connects to a corresponding second variable resistor circuit,
wherein the sampling circuit comprises a plurality of pairs of switches, a pair of switches is simultaneously activated and has an approximate same resistance value when the pair of switches is activated;
wherein a divided voltage for outputting to a signal line is generated by a first series resistor and a second series resistor, the first series resistor comprises one of the first variable resistor circuits and one of the pairs of switches, the one of the first variable resistor circuit is connected to the sampling circuit and the second series resistor circuit comprises another of the first variable resistor circuits and another of the pairs of switches;
and
wherein another divided voltage for outputting to another signal line is generated by a third series resistor and a fourth series resistor, the third series resistor comprises one of the second variable resistor circuits and one of the pairs of switches, the one of the second variable resistor is connected to the sampling circuit and the fourth series resistor comprises another of the second variable resistor circuits and another of pairs of switches.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 09/938,614Filed 27 Aug 2001
Priority: JP 2001-04847223 Feb 2001
Published: US 2002/0180679 A15 Dec 2002
Granted: 3 Oct 2006
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

G09G 3/32
Using electroluminescent panels: semiconductive, e.g. using light-emitting diodes [LED]
G09G 2300/08
Aspects of the constitution of display devices: active matrix structure, i.e. with use of active elements, inclusive of non-linear two terminal…
G09G 2310/027
Details of driving circuits: details of drivers for data electrodes, the drivers handling digital grey scale data, e.g. use of D/A converters
G09G 2310/0275
Details of driving circuits: details of drivers for data electrodes, other than drivers for liquid crystal, plasma or OLED displays, not related…