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US 6,686,858 B2Granted
D/A conversion circuit and semiconductor device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorShou Nagao
Life of this patent
Estimating the term…
Abstract
A DAC whose area is held down and a semiconductor device using the DAC are fabricated. A D/A conversion circuit is disclosed, including n resistors A0, A1, . . . An−1, n resistors B0, B1, . . . , Bn−1, two power-supply voltage lines, a power-supply voltage line L and a power-supply voltage line H, maintained at potentials different from each other, n switches SWa0, SWa1, . . . , SWan−1, n switches SWb0, SWb1, . . . , SWbn−1, and an output line, wherein, by n-bit digital signals inputted from the outside, said n switches SWa0, SWa1, . . . , SWan−1 and said n switches SWb0, SWb1, . . . , SWbn−1 are controlled, and, from the output line, an analog gradation voltage signal is outputted.
Claims27
An active matrix device comprising:
- a pixel portion including a plurality of pixels, each of the plurality of pixels comprising at least a first thin film transistor formed over a substrate;
- a driver circuit for driving said pixel portion, said driver circuit comprising a D/A conversion circuit, said D/A conversion circuit comprising:
- a first power supply line;
- a second power supply line having a different potential from said first power supply line;
- an output line;
- a plurality of first resistors electrically connectable between said first power supply line and said output line in parallel through a plurality of first switching elements, respectively;
- a plurality of second resistors electrically connectable between said second power supply line and said output line in parallel through a plurality of second switching elements, respectively,
- wherein each of the plurality of first switching elements comprises at least a second thin film transistor provided over the substrate and each of the plurality of second switching elements comprises at least a third thin film transistor provided over the substrate.
5 more elements
An active matrix electroluminescence display device comprising:
- a pixel portion including a plurality of pixels, each of the plurality of pixels comprising at least a first thin film transistor formed over a substrate;
- an EL element electrically connected to said first thin film transistor;
- a driver circuit for driving said pixel portion, said driver circuit comprising a D/A conversion circuit, said D/A conversion circuit comprising:
- a first power supply line;
- a second power supply line having a different potential from said first power supply line;
- an output line;
- a plurality of first resistors electrically connectable between said first power supply line and said output line in parallel through a plurality of first switching elements, respectively;
- a plurality of second resistors electrically connectable between said second power supply line and said output line in parallel through a plurality of second switching elements, respectively,
- wherein each of the plurality of first switching elements comprises at least a second thin film transistor provided over the substrate and each of the plurality of second switching elements comprises at least a third thin film transistor provided over the substrate.
6 more elements
An active matrix liquid crystal device comprising:
- a pixel portion including a plurality of pixels, each of the plurality of pixels comprising at least a first thin film transistor formed over a substrate;
- a pixel electrode electrically connected to said first thin film transistor;
- a driver circuit for driving said pixel portion, said driver circuit comprising a D/A conversion circuit, said D/A conversion circuit comprising:
- a first power supply line;
- a second power supply line having a different potential from said first power supply line;
- an output line;
- a plurality of first resistors electrically connectable between said first power supply line and said output line in parallel through a plurality of first switching elements, respectively;
- a plurality of second resistors electrically connectable between said second power supply line and said output line in parallel through a plurality of second switching elements, respectively,
- wherein each of the plurality of first switching elements comprises at least a second thin film transistor provided over the substrate and each of the plurality of second switching elements comprises at least a third thin film transistor provided over the substrate.
6 more elements
An active matrix device comprising:
- a pixel portion including a plurality of pixels, each of the plurality of pixels comprising at least a first thin film transistor formed over a substrate;
- a driver circuit for driving said pixel portion, said driver circuit comprising a D/A conversion circuit, said D/A conversion circuit comprising:
- a first power supply line;
- a second power supply line having a different potential from said first power supply line;
- an output line;
- n first resistors electrically connectable between said first power supply line and said output line in parallel through n first switching elements, respectively (where n is a natural number greater than 1) wherein each one of said n first resistors has a different resistance from the other;
- n second resistors electrically connectable between said second power supply line and said output line in parallel through n second switching elements, respectively, wherein each one of said n second resistors has a different resistance from the other,
- wherein each of the n first switching elements comprises at least a second thin film transistor provided over the substrate and each of the n second switching elements comprises at least a third thin film transistor provided over the substrate.
5 more elements
An active matrix electroluminescence display device comprising:
- a pixel portion including a plurality of pixels, each of the plurality of pixels comprising at least a first thin film transistor formed over a substrate;
- an EL element electrically connected to said first thin film transistor;
- a driver circuit for driving said pixel portion, said driver circuit comprising a D/A conversion circuit, said D/A conversion circuit comprising:
- a first power supply line;
- a second power supply line having a different potential from said first power supply line;
- an output line;
- n first resistors electrically connectable between said first power supply line and said output line in parallel through n first switching elements, respectively (where n is a natural number greater than 1) wherein each one of said n first resistors has a different resistance from the other;
- n second resistors electrically connectable between said second power supply line and said output line in parallel through n second switching elements, respectively, wherein each one of said n second resistors has a different resistance from the other,
- wherein each of the n first switching elements comprises at least a second thin film transistor provided over the substrate and each of the n second switching elements comprises at least a third thin film transistor provided over the substrate.
6 more elements
An active matrix liquid crystal device comprising:
- a pixel portion including a plurality of pixels, each of the plurality of pixels comprising at least a first thin film transistor formed over a substrate;
- a pixel electrode electrically connected to the first thin film transistor;
- a driver circuit for driving said pixel portion, said driver circuit comprising a D/A conversion circuit, said D/A conversion circuit comprising:
- a first power supply line;
- a second power supply line having a different potential from said first power supply line;
- an output line;
- n first resistors electrically connectable between said first power supply line and said output line in parallel through n first switching elements, respectively (where n is a natural number greater than 1) wherein each one of said n first resistors has a different resistance from the other;
- n second resistors electrically connectable between said second power supply line and said output line in parallel through n second switching elements, respectively, wherein each one of said n second resistors has a different resistance from the other,
- wherein each of the n first switching elements comprises at least a second thin film transistor provided over the substrate and each of the n second switching elements comprises at least a third thin film transistor provided over the substrate.
6 more elements
Dependencies are inferred from the claim text.