Semiconductor device
First Claim
1. A semiconductor device comprising:
- a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
a third thin film transistor having a first impurity region electrically connected to the first power source;
a fourth thin film transistor having a first impurity region electrically connected to the second power source, wherein;
the first to fourth thin film transistors have a same conductivity type;
a second impurity region of the first thin film transistor and a second impurity region of the second thin film transistor are electrically connected to one terminal of a capacitance;
a second impurity region of the third thin film transistor, a second impurity region of the fourth thin film transistor, and a gate electrode of the first thin film transistor are electrically connected to the other terminal of the capacitance;
a gate electrode of the second thin film transistor and a gate electrode of the fourth thin film transistor are electrically connected to a first input signal line; and
a gate electrode of the third thin film transistor is electrically connected to a second input signal line.
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Accused Products
Abstract
There is provided a semiconductor device in which fabrication steps can be reduced by constructing a circuit using only TFTs of one conductivity type and in which a voltage amplitude of an output signal can be normally obtained. A capacitance (205) is provided between a gate and a source of a TFT (203) connected to an output node, and a circuit formed of TFTs (201) and (202) has a function to bring a node a into a floating state. When the node α is in the floating state, a potential of the node a is caused higher than VDD by using gate-source capacitance coupling of the TFT (203) through the capacitance (205), thus an output signal having an amplitude of VDD-GND can be normally obtained without causing amplitude attenuation due to the threshold value of the TFT.
391 Citations
23 Claims
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1. A semiconductor device comprising:
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a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
a third thin film transistor having a first impurity region electrically connected to the first power source;
a fourth thin film transistor having a first impurity region electrically connected to the second power source, wherein;
the first to fourth thin film transistors have a same conductivity type;
a second impurity region of the first thin film transistor and a second impurity region of the second thin film transistor are electrically connected to one terminal of a capacitance;
a second impurity region of the third thin film transistor, a second impurity region of the fourth thin film transistor, and a gate electrode of the first thin film transistor are electrically connected to the other terminal of the capacitance;
a gate electrode of the second thin film transistor and a gate electrode of the fourth thin film transistor are electrically connected to a first input signal line; and
a gate electrode of the third thin film transistor is electrically connected to a second input signal line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A display device having at least one driving circuit, the driving circuit comprising:
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a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
a third thin film transistor having a first impurity region electrically connected to the first power source;
a fourth thin film transistor having a first impurity region electrically connected to the second power source, wherein;
the first to fourth thin film transistors have a same conductivity type;
a second impurity region of the first thin film transistor and a second impurity region of the second thin film transistor are electrically connected to one terminal of a capacitance;
a second impurity region of the third thin film transistor, a second impurity region of the fourth thin film transistor, and a gate electrode of the first thin film transistor are electrically connected to the other terminal of the capacitance;
a gate electrode of the second thin film transistor and a gate electrode of the fourth thin film transistor are electrically connected to a first input signal line; and
a gate electrode of the third thin film transistor is electrically connected to a second input signal line.
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12. A semiconductor device comprising:
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a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
a third thin film transistor having a first impurity region electrically connected to the first power source;
a fourth thin film transistor having a first impurity region electrically connected to the second power source, wherein;
the first to fourth thin film transistors have a same conductivity type;
a second impurity region of the first thin film transistor and a second impurity region of the second thin film transistor are electrically connected to output signal line;
a second impurity region of the third thin film transistor and a second impurity region of the fourth thin film transistor are electrically connected to a gate electrode of the first thin film transistor;
a gate electrode of the second thin film transistor and a gate electrode of the fourth thin film transistor are electrically connected to a first input signal line; and
a gate electrode of the third thin film transistor is electrically connected to a second input signal line.
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13. A display device having at least one driving circuit, the driving circuit comprising:
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a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
a third thin film transistor having a first impurity region electrically connected to the first power source;
a fourth thin film transistor having a first impurity region electrically connected to the second power source, wherein;
the first to fourth thin film transistors have a same conductivity type;
a second impurity region of the first thin filxn transistor and a second impurity region of the second thin film transistor are electrically connected to output signal line;
a second impurity region of the third thin film transistor and a second impurity region of the fourth thin film transistor are electrically connected to a gate electrode of the first thin film transistor;
a gate electrode of the second thin film transistor and a gate electrode of the fourth thin film transistor are electrically connected to a first input signal line; and
a gate electrode of the third thin film transistor is electrically connected to a second input signal line.
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14. A semiconductor device comprising:
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a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
an output amplitude compensating circuit having an input terminal and an output terminal, wherein the output terminal is electrically connected to a gate electrode of the first thin film transistor, wherein;
channel forming regions of the first and second thin film transistors have a same conductivity type;
a second impurity region of the first thin film transistor and a second impurity region of the second thin film transistor are electrically connected to an output signal line;
a gate electrode of the second thin film transistor and the input terminal of the output amplitude compensating circuit are electrically connected to an input signal line. - View Dependent Claims (15, 16, 17, 18)
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19. A display device comprising:
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a first thin film transistor having a first impurity region electrically connected to a first power source;
a second thin film transistor having a first impurity region electrically connected to a second power source;
an output amplitude compensating circuit having an input terminal and an output terminal, wherein the output terminal is electrically connected to a gate electrode of the first thin film transistor, wherein;
channel forming regions of the first and second thin film transistors have a same conductivity type;
a second impurity region of the first thin film transistor and a second impurity region of the second thin film transistor are electrically connected to an output signal line;
a gate electrode of the second thin film transistor and the input terminal of the output amplitude compensating circuit are electrically connected to an input signal line. - View Dependent Claims (20, 21, 22, 23)
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Specification