Semiconductor Device

Abstract

A semiconductor device which shifts a low-level signal is provided. In an example, a first transistor including a first terminal electrically connected to a first wiring and a second terminal electrically connected to a second wiring, a second transistor including a first terminal electrically connected to a third wiring and a second terminal electrically connected to the second wiring, a third transistor including a first terminal electrically connected to a fourth wiring and a second terminal electrically connected to a gate of the second transistor, a fourth transistor including a first terminal electrically connected to a fifth wiring, a second terminal electrically connected to a gate of the third transistor, and a gate electrically connected to a sixth wiring, and a first switch including a first terminal electrically connected to the third wiring and a second terminal electrically connected to a gate of the first transistor are included.

1 . (canceled) 
     
     
         2 . A semiconductor device comprising:
 a gate driver comprising first to sixth transistors,   wherein one of a source and a drain of the first transistor is electrically connected to a first power supply line,   wherein the other of the source and the drain of the first transistor is electrically connected to a first wiring,   wherein an output signal is output from the first wiring,   wherein one of a source and a drain of the second transistor is electrically connected to a second power supply line,   wherein the other of the source and the drain of the second transistor is electrically connected to the first wiring,   wherein one of a source and a drain of the third transistor is electrically connected to a gate of the second transistor,   wherein the other of the source and the drain of the third transistor is electrically connected to the second power supply line,   wherein a gate of the third transistor is electrically connected to a second wiring,   wherein a first signal is input to the second wiring,   wherein one of a source and a drain of the fourth transistor is electrically connected to a third wiring,   wherein a second signal is input to the third wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to the gate of the second transistor,   wherein a gate of the fourth transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring,   wherein a third signal is input to the fourth wiring,   wherein a gate of the fifth transistor is electrically connected to the second wiring, wherein one of a source and a drain of the sixth transistor is electrically connected to the second power supply line,   wherein the other of the source and the drain of the sixth transistor is electrically connected to a gate of the first transistor, and   wherein a gate of the sixth transistor is electrically connected to the gate of the fourth transistor.   
     
     
         3 . A semiconductor device according to  claim 2 , wherein the first to sixth transistors have a same polarity. 
     
     
         4 . A semiconductor device comprising:
 a gate driver comprising first to sixth transistors,   wherein one of a source and a drain of the first transistor is electrically connected to a first power supply line,   wherein the other of the source and the drain of the first transistor is electrically connected to a first wiring,   wherein an output signal is output from the first wiring,   wherein one of a source and a drain of the second transistor is electrically connected to a second power supply line,   wherein the other of the source and the drain of the second transistor is electrically connected to the first wiring,   wherein one of a source and a drain of the third transistor is electrically connected to a gate of the second transistor,   wherein the other of the source and the drain of the third transistor is electrically connected to the second power supply line,   wherein a gate of the third transistor is electrically connected to a second wiring,   wherein a first signal is input to the second wiring,   wherein one of a source and a drain of the fourth transistor is electrically connected to a third wiring,   wherein a second signal is input to the third wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to the gate of the second transistor,   wherein a gate of the fourth transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring,   wherein a third signal is input to the fourth wiring,   wherein a gate of the fifth transistor is electrically connected to the second wiring,   wherein one of a source and a drain of the sixth transistor is electrically connected to the second power supply line,   wherein the other of the source and the drain of the sixth transistor is electrically connected to a gate of the first transistor,   wherein a gate of the sixth transistor is electrically connected to the gate of the fourth transistor, and   wherein a ratio of a channel width to a channel length of the fourth transistor is larger than a ratio of a channel width to a channel length of the fifth transistor.   
     
     
         5 . A semiconductor device according to  claim 4 , wherein the first to sixth transistors have a same polarity. 
     
     
         6 . A semiconductor device comprising:
 a gate driver comprising first to sixth transistors; and   a pixel portion comprising seventh and eighth transistors and a light emitting element,   wherein the gate driver and the pixel portion are formed over a same substrate,   wherein one of a source and a drain of the first transistor is electrically connected to a first power supply line,   wherein the other of the source and the drain of the first transistor is electrically connected to a first wiring,   wherein an output signal is output from the first wiring,   wherein one of a source and a drain of the second transistor is electrically connected to a second power supply line,   wherein the other of the source and the drain of the second transistor is electrically connected to the first wiring,   wherein one of a source and a drain of the third transistor is electrically connected to a gate of the second transistor,   wherein the other of the source and the drain of the third transistor is electrically connected to the second power supply line,   wherein a gate of the third transistor is electrically connected to a second wiring, wherein a first signal is input to the second wiring,   wherein one of a source and a drain of the fourth transistor is electrically connected to a third wiring,   wherein a second signal is input to the third wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to the gate of the second transistor,   wherein a gate of the fourth transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring,   wherein a third signal is input to the fourth wiring,   wherein a gate of the fifth transistor is electrically connected to the second wiring,   wherein one of a source and a drain of the sixth transistor is electrically connected to the second power supply line,   wherein the other of the source and the drain of the sixth transistor is electrically connected to a gate of the first transistor,   wherein a gate of the sixth transistor is electrically connected to the gate of the fourth transistor,   wherein one of a source and a drain of the seventh transistor is electrically connected to a fifth wiring,   wherein a current is supplied to the light emitting element from the fifth wiring,   wherein the other of the source and the drain of the seventh transistor is electrically connected to one of a source and a drain of the eighth transistor,   wherein the other of the source and the drain of the eighth transistor is electrically connected to the light emitting element, and   wherein a gate of the eighth transistor is electrically connected to the first wiring.   
     
     
         7 . A semiconductor device according to  claim 6 , wherein the first to eighth transistors have a same polarity. 
     
     
         8 . A semiconductor device comprising:
 a gate driver comprising first to sixth transistors; and   a pixel portion comprising seventh and eighth transistors and a light emitting element,   wherein the gate driver and the pixel portion are formed over a same substrate,   wherein one of a source and a drain of the first transistor is electrically connected to a first power supply line,   wherein the other of the source and the drain of the first transistor is electrically connected to a first wiring,   wherein an output signal is output from the first wiring,   wherein one of a source and a drain of the second transistor is electrically connected to a second power supply line,   wherein the other of the source and the drain of the second transistor is electrically connected to the first wiring,   wherein one of a source and a drain of the third transistor is electrically connected to a gate of the second transistor,   wherein the other of the source and the drain of the third transistor is electrically connected to the second power supply line,   wherein a gate of the third transistor is electrically connected to a second wiring,   wherein a first signal is input to the second wiring,   wherein one of a source and a drain of the fourth transistor is electrically connected to a third wiring,   wherein a second signal is input to the third wiring,   wherein the other of the source and the drain of the fourth transistor is electrically connected to the gate of the second transistor,   wherein a gate of the fourth transistor is electrically connected to one of a source and a drain of the fifth transistor,   wherein the other of the source and the drain of the fifth transistor is electrically connected to a fourth wiring,   wherein a third signal is input to the fourth wiring,   wherein a gate of the fifth transistor is electrically connected to the second wiring,   wherein one of a source and a drain of the sixth transistor is electrically connected to the second power supply line,   wherein the other of the source and the drain of the sixth transistor is electrically connected to a gate of the first transistor,   wherein a gate of the sixth transistor is electrically connected to the gate of the fourth transistor,   wherein one of a source and a drain of the seventh transistor is electrically connected to a fifth wiring,   wherein a current is supplied to the light emitting element from the fifth wiring,   wherein the other of the source and the drain of the seventh transistor is electrically connected to one of a source and a drain of the eighth transistor,   wherein the other of the source and the drain of the eighth transistor is electrically connected to the light emitting element,   wherein a gate of the eighth transistor is electrically connected to the first wiring, and   wherein a ratio of a channel width to a channel length of the fourth transistor is larger than a ratio of a channel width to a channel length of the fifth transistor.   
     
     
         9 . A semiconductor device according to  claim 8 , wherein the first to eighth transistors have a same polarity.