Semiconductor device, and display device and electronic device utilizing the same
A semiconductor device having a normal function means is provided, in which the amplitude of an output signal is prevented from being decreased even when a digital circuit using transistors having one conductivity is employed. By turning OFF a diode-connected transistor 101 , the gate terminal of a first transistor 102 is brought into a floating state. At this time, the first transistor 102 is ON and its gate-source voltage is stored in a capacitor. Then, when a potential at the source terminal of the first transistor 102 is increased, a potential at the gate terminal of the first transistor 102 is increased as well by bootstrap effect. As a result, the amplitude of an output signal is prevented from being decreased.
1. A semiconductor device comprising:
a first transistor;
a second transistor;
a third transistor; and
a fourth transistor,
wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are each an N-channel transistor, and
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;
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;
the one of the source and the drain of the third transistor is electrically connected to a gate of the first transistor;
the other of the source and the drain of the first transistor is 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 first transistor is electrically connected to a gate of the third transistor;
the other of the source and the drain of the second transistor is electrically connected to a first wiring;
the other of the source and the drain of the fourth transistor is electrically connected to the first wiring;
a gate of the second transistor is electrically connected to a gate of the fourth transistor;
the other of the source and the drain of the first transistor is electrically connected to a first input terminal;
the gate of the second transistor is electrically connected to a second input terminal; and
the one of the source and the drain of the first transistor is electrically connected to an output terminal.
2. The semiconductor device according to claim 1 ,
wherein the other of the source and the drain of the first transistor is configured to be input with a first signal,
wherein the gate of the second transistor is configured to be input with a second signal; and
wherein the one of the source and the drain of the first transistor is configured to output a third signal.
3. The semiconductor device according to claim 1 ,
wherein the first wiring is configured to be supplied with a first potential.
4. A semiconductor device comprising:
a first transistor;
a second transistor;
a third transistor; and
a fourth 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;
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;
the one of the source and the drain of the third transistor is electrically connected to a gate of the first transistor;
the other of the source and the drain of the first transistor is 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 first transistor is electrically connected to a gate of the third transistor;
the other of the source and the drain of the second transistor is electrically connected to the other of the source and the drain of the fourth transistor;
the other of the source and the drain of the first transistor is configured to be input with a first signal; and
a gate of the second transistor is configured to be input with a second signal.
5. The semiconductor device according to claim 4 ,
wherein the first transistor, the second transistor, the third transistor, and the fourth transistor have the same polarity.
6. The semiconductor device according to claim 4 ,
wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are each an N-channel transistor.
7. The semiconductor device according to claim 4 , comprising a gate line driver circuit comprising the first transistor, the second transistor, the third transistor, and the fourth transistor.
8. A display device comprising:
a pixel over a substrate; and
a gate line driver circuit over the substrate and configured to output a selection signal to the pixel,
wherein the gate line driver circuit comprises a first transistor, a second transistor, a third transistor and a fourth transistor, and
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;
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;
the one of the source and the drain of the third transistor is electrically connected to a gate of the first transistor;
the other of the source and the drain of the first transistor is 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 first transistor is electrically connected to a gate of the third transistor;
the other of the source and the drain of the second transistor is electrically connected to the other of the source and the drain of the fourth transistor;
the other of the source and the drain of the first transistor is configured to be input with a first signal; and
a gate of the second transistor is configured to be input with a second signal.
9. The display device according to claim 8 ,
wherein the first transistor, the second transistor, the third transistor, and the fourth transistor have the same polarity.
10. The display device according to claim 8 ,
wherein the first transistor, the second transistor, the third transistor, and the fourth transistor are each an N-channel transistor.