Display device and electronic device
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsAtsushi Umezaki, Hiroyuki Miyake
Life of this patent
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Abstract
An object of the invention is to provide a circuit technique which enables reduction in power consumption and high definition of a display device. A switch controlled by a start signal is provided to a gate electrode of a transistor, which is connected to a gate electrode of a bootstrap transistor. When the start signal is input, a potential is supplied to the gate electrode of the transistor through the switch, and the transistor is turned off. The transistor is turned off, so that leakage of a charge from the gate electrode of the bootstrap transistor can be prevented. Accordingly, time for storing a charge in the gate electrode of the bootstrap transistor can be shortened, and high-speed operation can be performed.
Claims14
A semiconductor device comprising:
- a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, and a seventh transistor,
- wherein one of a source and a drain of the first transistor is electrically connected to one of a source and a drain of the second transistor and a first wiring,
- wherein one of a source and a drain of the third transistor is electrically connected to one of a source and a drain of the fourth transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a second wiring,
- wherein a gate of the first transistor is electrically connected to a gate of the fourth transistor, one of a source and a drain of the fifth transistor, and one of a source and a drain of the seventh transistor,
- wherein the other of the source and the drain of the second transistor is electrically connected to a third wiring,
- wherein a gate of the second transistor is electrically connected to one of a source and a drain of the sixth transistor,
- wherein the other of the source and the drain of the third transistor is electrically connected to a gate of the third transistor,
- wherein the other of the source and the drain of the fourth transistor is electrically to a fourth wiring which is different from the second wiring,
- wherein a gate of the fifth transistor is electrically connected to a gate of the sixth transistor,
- wherein the other of the source and the drain of the seventh transistor is electrically connected to a fifth wiring which is different from the second wiring and the fourth wiring,
- wherein a gate of the seventh transistor is electrically connected to a sixth wiring,
- wherein the other of the source and the drain of the second transistor is not electrically connected to the other of the source and the drain of the seventh transistor, and
- wherein the gate of the second transistor is not electrically connected to the gate of the seventh transistor.
A semiconductor device comprising:
- a first transistor, a second transistor, a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, and a seventh transistor,
- wherein one of a source and a drain of the first transistor is electrically connected to one of a source and a drain of the second transistor and a first wiring,
- wherein one of a source and a drain of the third transistor is electrically connected to one of a source and a drain of the fourth transistor,
- wherein the other of the source and the drain of the first transistor is electrically connected to a second wiring,
- wherein a gate of the first transistor is electrically connected to a gate of the fourth transistor, one of a source and a drain of the fifth transistor, and one of a source and a drain of the seventh transistor,
- wherein the other of the source and the drain of the second transistor is electrically connected to a third wiring,
- wherein a gate of the second transistor is electrically connected to one of a source and a drain of the sixth transistor,
- wherein the other of the source and the drain of the third transistor is electrically connected to a gate of the third transistor,
- wherein the other of the source and the drain of the fourth transistor is electrically to a fourth wiring which is different from the second wiring,
- wherein a gate of the fifth transistor is electrically connected to a gate of the sixth transistor,
- wherein the other of the source and the drain of the seventh transistor is electrically connected to a fifth wiring which is different from the second wiring and the fourth wiring,
- wherein a gate of the seventh transistor is electrically connected to a sixth wiring,
- wherein the other of the source and the drain of the second transistor is not electrically connected to the other of the source and the drain of the seventh transistor,
- wherein the gate of the second transistor is not electrically connected to the gate of the seventh transistor,
- wherein each of the first transistor, the second transistor, the third transistor, the fourth transistor, the fifth transistor, the sixth transistor, and the seventh transistor comprises an oxide semiconductor, and
- wherein the oxide semiconductor comprises indium.
Dependencies are inferred from the claim text.