Signal processing circuit and method for driving the same
View Patent ↗An object is to provide a signal processing circuit which can be manufactured without a complex manufacturing process and suppress power consumption. A storage element includes two logic elements (referred to as a first phase-inversion element and a second phase-inversion element) which invert a phase of an input signal and output the signal, a first selection transistor, and a second selection transistor. In the storage element, two pairs each having a transistor in which a channel is formed in an oxide semiconductor layer and a capacitor (a pair of a first transistor and a first capacitor, and a pair of a second transistor and a second capacitor) are provided. The storage element is used in a storage device such as a register or a cache memory included in a signal processing circuit.
1. A signal processing circuit comprising:
an arithmetic circuit; and
a storage device configured to store data from the arithmetic circuit, the storage device comprising a storage element,
the storage element comprising an input terminal, an output terminal, a first inverter, a second inverter, a first selection transistor, a second selection transistor, a first transistor, a second transistor, a first capacitor, and a second capacitor,
wherein each of the first transistor and the second transistor comprises an oxide semiconductor layer including a channel,
wherein an input terminal of the first inverter is electrically connected to the input terminal of the storage element via the first selection transistor and the second transistor,
wherein of an output terminal of the first inverter is electrically connected to the output terminal of the storage element via the second selection transistor,
wherein the output terminal of the first inverter is electrically connected to an input terminal of the second inverter via the first transistor,
wherein an output terminal of the second inverter is electrically connected to the input terminal of the first inverter via the second transistor,
wherein an electrode of the first capacitor is electrically connected to the input terminal of the second inverter, and
wherein an electrode of the second capacitor is electrically connected to the input terminal of the first inverter.
2. The signal processing circuit according to claim 1 , wherein the first inverter and the second inverter are an inverter or a clocked inverter.
3. The signal processing circuit according to claim 1 , wherein the oxide semiconductor layer comprises an In—Ga—Zn—O-based oxide semiconductor.
4. The signal processing circuit according to claim 2 , wherein the oxide semiconductor layer comprises an In—Ga—Zn—O-based oxide semiconductor.
5. A method for driving a signal processing circuit comprising a storage element, the storage element comprising a first inverter, a second inverter, a first selection transistor, a second selection transistor, a first transistor, a second transistor, a first capacitor, and a second capacitor, wherein each of the first transistor and the second transistor comprises an oxide semiconductor layer including a channel, wherein an input terminal of the first inverter is electrically connected to the input terminal of the storage element via the first selection transistor and the second transistor, wherein an output terminal of the first inverter is electrically connected to the output terminal of the storage element via the second selection transistor, wherein the output terminal of the first inverter is electrically connected to an input terminal of the second inverter via the first transistor, wherein an output terminal of the second inverter is electrically connected to the input terminal of the first inverter via the second transistor, wherein an electrode of the first capacitor is electrically connected to the input terminal of the second inverter, and wherein an electrode of the second capacitor is electrically connected to the input terminal of the first inverter, the method comprising the steps of:
supplying a potential of data to an input terminal of the first inverter via the first selection transistor and the second transistor;
outputting a potential of an output terminal of the first inverter as an output signal via the second selection transistor;
supplying a potential of the output terminal of the first inverter to an input terminal of the second inverter via the first transistor;
supplying a potential of an output terminal of the second inverter to the input terminal of the first inverter via the second transistor; and
turning off the first transistor and the second transistor, before stopping the supply of the power-supply voltage to the first inverter and the second inverter.
6. The method for driving a signal processing circuit according to claim 5 , wherein the first transistor and the second transistor are controlled so that when one of the first transistor and the second transistor is in an on state, the other is in an on state.
7. The method for driving a signal processing circuit according to claim 5 ,
wherein the first transistor and the second transistor have the same conductivity type, and
wherein a first control signal input to a gate of the first transistor and a second control signal input to a gate of the second transistor are the same signal.
8. The method for driving a signal processing circuit according to claim 6 ,
wherein the first transistor and the second transistor have the same conductivity type, and
wherein a first control signal input to a gate of the first transistor and a second control signal input to a gate of the second transistor are the same signal.
9. A storage device comprising:
a storage element comprising an input terminal, an output terminal, a first inverter, a second inverter, a first selection transistor, a second selection transistor, a first transistor, a second transistor, a first capacitor, and a second capacitor,
wherein each of the first transistor and the second transistor comprises an oxide semiconductor layer including a channel,
wherein an input terminal of the first inverter is electrically connected to the input terminal of the storage element via the first selection transistor and the second transistor,
wherein an output terminal of the first inverter is electrically connected to the output terminal of the storage element via the second selection transistor,
wherein the output terminal of the first inverter is electrically connected to an input terminal of the second inverter via the first transistor,
wherein an output terminal of the second inverter is electrically connected to the input terminal of the first inverter via the second transistor,
wherein an electrode of the first capacitor is electrically connected to the input terminal of the second inverter, and
wherein an electrode of the second capacitor is electrically connected to the input terminal of the first inverter.
10. The storage device according to claim 9 , wherein the first inverter and the second inverter are an inverter or a clocked inverter.
11. The storage device according to claim 9 , wherein the oxide semiconductor layer comprises an In—Ga—Zn—O-based oxide semiconductor.
12. The storage device according to claim 10 , wherein the oxide semiconductor layer comprises an In—Ga—Zn—O-based oxide semiconductor.