Abstract:
A semiconductor device suitable for low-voltage driving. The semiconductor device includes a first transistor, a second transistor, a power supply line, a circuit, and a memory circuit. The first transistor controls electrical continuity between the circuit and the power supply line. The memory circuit stores data for setting a gate potential of the first transistor. The second transistor controls electrical continuity between an output node of the memory circuit and a gate of the first transistor. The second transistor is a transistor with an ultralow off-state current, for example, an oxide semiconductor transistor. In a period for operating the circuit, a first potential is input to the power supply line and the second transistor is turned off. In a period for updating the gate potential of the first transistor, a second potential is input to the power supply line. The second potential is higher than the first potential.
Abstract:
A semiconductor device suitable for low-voltage driving. The semiconductor device includes a first transistor, a second transistor, a power supply line, a circuit, and a memory circuit. The first transistor controls electrical continuity between the circuit and the power supply line. The memory circuit stores data for setting a gate potential of the first transistor. The second transistor controls electrical continuity between an output node of the memory circuit and a gate of the first transistor. The second transistor is a transistor with an ultralow off-state current, for example, an oxide semiconductor transistor. In a period for operating the circuit, a first potential is input to the power supply line and the second transistor is turned off. In a period for updating the gate potential of the first transistor, a second potential is input to the power supply line. The second potential is higher than the first potential.
Abstract:
In a CMOS image sensor in which a plurality of pixels is arranged in a matrix, a transistor in which a channel formation region includes an oxide semiconductor is used for each of a charge accumulation control transistor and a reset transistor which are in a pixel portion. After a reset operation of the signal charge accumulation portion is performed in all the pixels arranged in the matrix, a charge accumulation operation by the photodiode is performed in all the pixels, and a read operation of a signal from the pixel is performed per row. Accordingly, an image can be taken without a distortion.
Abstract:
A semiconductor device that suppresses operation delay due to stop and restart of the supply of a power supply potential is provided. A potential corresponding to data held while power supply potential is continuously supplied is backed up in a node connected to a capacitor while the supply of the power supply potential is stopped. Then, by utilizing change in resistance of a channel in a transistor whose gate is the node, the data is restored with restart of the supply of the power supply potential. Note that by supplying a high potential to the node before the data back up, high-speed and accurate data back up is possible.
Abstract:
A low-power semiconductor device is provided. A memory device applicable to a multi-context programmable logic device (PLD) includes at least memory cells the number of which is the same as the number of contexts. Output nodes of the memory cells are electrically connected to an output node of a configuration memory through different path transistors. A circuit including a transistor and a capacitor makes a gate potential of the path transistor higher than a high-level potential. This prevents a decrease in the potential of the output node of the configuration memory due to the threshold voltage of the path transistor without an increase in power consumption.
Abstract:
To provide a semiconductor device having a novel configuration, in which a malfunction and power consumption are reduced. A data holding circuit which includes a flipflop including first and second latch circuits and a shadow register including a nonvolatile memory portion; and a control signal generation circuit which generates a first control signal supplied to the first latch circuit and a second control signal supplied to the second latch circuit are included. The shadow register is a circuit which controls data saving or data restoring between the first and second latch circuits on the basis of a saving control signal or a restore control signal. The control signal generation circuit is a circuit which generates the first and second control signals at L level in a period during which data is saved or restored, on the basis of a clock signal, the saving control signal, and the restore control signal.
Abstract:
A semiconductor device includes a photodiode, a first transistor, a second transistor, and a third transistor. The second transistor and the third transistor have a function of retaining a charge accumulated in a gate of the first transistor. In a period during which the second transistor and the third transistor are off, a voltage level of a voltage applied to a gate of the second transistor is set to be lower than a voltage level of a source of the second transistor and a voltage level of a drain of the second transistor, and a voltage level of a voltage applied to a gate of the third transistor is set to be lower than a voltage level of a source of the third transistor and a voltage level of a drain of the third transistor.