Logic circuit and display device having the same
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorDaisuke KAWAE
Life of this patent
Estimating the term…
Abstract
It is an object to provide a logic circuit which can be operated even when unipolar transistors are used. A logic circuit includes a source follower circuit and a logic circuit an input portion of which is connected to an output portion of the source follower circuit and all transistors are unipolar transistors. A potential of a wiring for supplying a low potential connected to the source follower circuit is lower than a potential of a wiring for supplying a low potential connected to the logic circuit which includes unipolar transistors. In this manner, a logic circuit which can be operated even with unipolar depletion transistors can be provided.
Claims18
A semiconductor device comprising:
- a source follower circuit having an output portion;
- a logic circuit having an input portion electrically connected to the output portion, the logic circuit comprising a transistor;
- a first wiring electrically connected to the source follower circuit, the first wiring being adopted to be supplied with a first potential, and;
- a second wiring electrically connected to the logic circuit, the second wiring being adopted to be supplied with a second potential.
- wherein the first potential is lower than the second potential.
A semiconductor device comprising:
- a source follower circuit having an output portion;
- a logic circuit having an input portion electrically connected to the input portion, the logic circuit comprising a plurality of transistors;
- a first wiring electrically connected to the source follower circuit, the first wiring being adopted to be supplied with a first potential, and
- a second wiring electrically connected to the logic circuit, the second wiring being adopted to be supplied with a second potential
- wherein the plurality of transistors are unipolar transistors, and
- wherein the first potential is lower than the second potential.
A semiconductor device comprising:
- a logic circuit comprising;
- an input terminal, an output terminal, a first transistor, a second transistor, a third transistor and a fourth transistor;
- one of a source and a drain of the first transistor electrically connected to a first wiring, the first wiring being adopted to be supplied with a first potential;
- a gate of the first transistor electrically connected to the input terminal;
- one of a source and a drain of the second transistor electrically connected to the other of the source and the drain of the first transistor,
- the other of the source and the drain of the second transistor electrically connected to a second wiring, the second wiring being adopted to be supplied with a second potential;
- a gate of the second transistor electrically connected to a third wiring, the third wiring being adopted to be supplied with a first constant potential;
- one of a source and a drain of the third transistor electrically connected to the fourth wiring, the fourth wiring being adopted to be supplied with the first potential
- a gate of the third transistor electrically connected to the fifth wiring, the fifth wiring being adopted to be supplied with a second constant potential
- one of a source and a drain of the fourth transistor electrically connected to the other of the source and the drain of the third transistor;
- the other of the source and the drain of the fourth transistor electrically connected to a sixth wiring, the sixth wiring being adopted to be supplied with a third potential;
- a gate of the fourth transistor electrically connected between the first transistor and the second transistor,
- wherein the output terminal is electrically connected between the third transistor and the fourth transistor,
- wherein the second potential is lower than the third potential.
Dependencies are inferred from the claim text.