Abstract: A first field-effect transistor provided over a substrate in which an insulating region is provided over a first semiconductor region and a second semiconductor region is provided over the insulating region; an insulating layer provided over the substrate; a second field-effect transistor that is provided one flat surface of the insulating layer and includes an oxide semiconductor layer; and a control terminal are provided. The control terminal is formed in the same step as a source and a drain of the second field-effect transistor, and a voltage for controlling a threshold voltage of the first field-effect transistor is supplied to the control terminal.

Abstract: An object is to provide a power feeding system and a power feeding method which are more convenient for a power feeding user at the power receiving end, without causing increases in complexity and size of devices. An object is to provide a power feeding system and a power feeding method which also allow a power feeding provider (a company) which feeds power (at the power transmitting end) to supply power without waste. A power feeding device which wirelessly supplies power to a power receiver detects the position and the resonant frequency of the power receiver by receiving a position and resonant frequency detection signal using a plurality of sub-carriers having different frequencies from the power receiver, and controls the frequency of a power signal to be transmitted to the power receiver on the basis of the information. An efficient power feeding service can be offered by transmitting a power signal to the power receiver at an optimum frequency for high power transmission efficiency.

Abstract: A storage device in which held voltage is prevented from decreasing due to feedthrough in writing data to the storage device at high voltage is provided. The storage device includes a write circuit, a bit line, a word line, a transistor, and a capacitor. A gate of the transistor is electrically connected to the word line. One of a source and a drain of the transistor is electrically connected to the bit line. The other of the source and the drain of the transistor is electrically connected to one terminal of the capacitor. The other terminal of the capacitor is electrically connected to a ground. The write circuit includes an element holding write voltage and a circuit gradually decreasing voltage from the element holding write voltage. The write voltage is output from the write circuit to the word line.

Abstract: An object is to provide a power feeding system and a power feeding method which are more convenient for a power feeding user at the power receiving end. An object is to provide a power feeding system and a power feeding method which also allow a power feeding provider (a company) which feeds power (at the power transmitting end) to supply power without waste. A power feeding device which wirelessly supplies power to a power receiver detects the position and the resonant frequency of the power receiver to be supplied with power, and controls the frequency of a power signal to be transmitted to the power receiver on the basis of the information. An efficient power feeding service can be offered by transmitting a power signal to the power receiver at an optimum frequency for high power transmission efficiency.

Abstract: The data in a volatile memory may conventionally be lost even in case of a very short time power down or supply voltage drop such as an outage or sag. In view of the foregoing, an object is to extend data retention time even with a volatile memory for high-speed data processing. Data retention time can be extended by backing up the data content stored in the volatile memory in a memory including a capacitor and an oxide semiconductor transistor.

Abstract: To reduce power consumption of a circuit (TEDC) which detects timing errors in a main flip-flop by determining whether or not output data signals of the main flip-flop and a shadow flip-flop correspond. The TEDC includes a power gating circuit (PGC) which performs power gating of the shadow FF and a reset circuit (RSTC) which resets an output signal of the shadow FF. The PGC makes the shadow FF in an active mode only when error detection needs to be performed; other than that, the PGC makes the shadow FF in a power saving mode. The RSTC supplies a certain voltage to an output terminal of the shadow FF in the power saving mode to suppress malfunction of the TEDC. A transistor using an oxide semiconductor is used to supply the voltage to the output terminal.

Abstract: An object is to solve all of the following problems caused when a volatile register and a non-volatile register are used as registers in a processor: degradation of the integrity of data stored in the non-volatile register; loss of data security due to the processor and a non-volatile memory device that are provided apart from each other; and slow data processing speed due to wiring delay or the like caused by these devices provided apart from each other. When data maintained in the volatile register is stored in the non-volatile register before supply of power supply voltage is stopped, the data is encrypted by an encryption circuit and stored in a non-volatile memory device that is provided separately from the processor. Then, the data stored in the non-volatile register is compared with the compressed and encrypted data stored in the non-volatile memory device.

Abstract: A sense amplifier according to the present invention for detecting a potential difference of signals input to a first input terminal and a second input terminal, includes a first means for applying voltages corresponding to threshold voltages of first and second transistors to gate-source voltages of the first and second transistors, and a second means for transferring signals input to the first and second input terminals to gates of the first and second transistors. In this case, a threshold variation of the first and second transistors is corrected.

Abstract: To provide a semiconductor device including an RFID which can transmit and receive individual information without checking of the remaining charge of a battery or a replacing operation of the battery in accordance with deterioration over time of the battery for driving, and can maintain an excellent state for transmission and reception of individual information even when power of a radio wave or an electromagnetic wave from outside is insufficient. A battery (also described as a secondary battery) is provided as a power supply for supplying power to the RFID. Then, when power which is obtained from a signal received from outside is larger than predetermined power, its surplus power is stored in the battery; and when the power which is obtained from the signal received from outside is smaller than the predetermined power, power which is obtained from the battery is used for the power for driving.

Abstract: A semiconductor device having a power-saving circuit. The semiconductor device includes an input-output terminal and a holding circuit. When the input-output terminal is used, an inverter loop of the holding circuit is made not to operate by controlling a switch, and when the input-output terminal is not used, the inverter loop of the holding circuit operate by controlling the switch. Power consumption of the holding circuit can be reduced. An OS transistor is preferably used for the switch.

Abstract: To read multilevel data from a memory cell having a transistor using silicon and a transistor using an oxide semiconductor, without switching a signal for reading the multilevel data in accordance with the number of the levels of the multilevel data. The potential of the bit line is precharged, the electrical charge of the bit line is discharged via a transistor for writing data, and the potential of the bit line which is changed by the discharging is read as multilevel data. With such a structure, the potential corresponding to data held in a gate of the transistor can be read by only one-time switching of a signal for reading data.

Abstract: To read multilevel data from a memory cell having a transistor using silicon and a transistor using an oxide semiconductor, without switching a signal for reading the multilevel data in accordance with the number of the levels of the multilevel data. The electrical charge of a bit line is discharged, the potential of the bit line is charged via a transistor for writing data, and the potential of the bit line which is changed by the charging is read as multilevel data. With such a structure, the potential corresponding to data held in a gate of the transistor can be read by only one-time switching of a signal for reading data.

Abstract: An object is to provide a power feeding system and a power feeding method which are more convenient for a power feeding user at the power receiving end. An object is to provide a power feeding system and a power feeding method which also allow a power feeding provider (a company) which feeds power (at the power transmitting end) to supply power without waste. A power feeding device which wirelessly supplies power to a power receiver detects the position and the resonant frequency of the power receiver to be supplied with power, and controls the frequency of a power signal to be transmitted to the power receiver on the basis of the information. An efficient power feeding service can be offered by transmitting a power signal to the power receiver at an optimum frequency for high power transmission efficiency.

Abstract: The data in a volatile memory may conventionally be lost even in case of a very short time power down or supply voltage drop such as an outage or sag. In view of the foregoing, an object is to extend data retention time even with a volatile memory for high-speed data processing. Data retention time can be extended by backing up the data content stored in the volatile memory in a memory including a capacitor and an oxide semiconductor transistor.

Abstract: In a semiconductor device performing pipeline processing with the use of a reading portion reading an instruction and an arithmetic portion performing an operation in accordance with the instruction, the instruction held in the reading portion is transmitted from the flip-flop to the memory when branch prediction turns out to be wrong. Note that the arithmetic portion controls transmission and reception of the instruction between the flip-flop and the memory which are included in the reading portion. This enables elimination of redundant operations in the reading portion in the case where an instruction read by the reading portion after the branch prediction turns out to be wrong is a subroutine, or the like. That is, the instruction held in the memory is transmitted back to the flip-flop without rereading of the same instruction by the reading portion, whereby the instruction can be output to the arithmetic portion.

Abstract: 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.

Abstract: In a semiconductor device including a control circuit and a memory, the memory includes at least a sector for preventing additional writing and an information sector. When data for preventing additional writing is written to the sector for preventing additional writing and information is written to the information sector which is electrically connected to the sector for preventing additional writing, additional writing to the information sector is impossible.

Abstract: The invention provides a processor obtained by forming a high functional integrated circuit using a polycrystalline semiconductor over a substrate which is sensitive to heat, such as a plastic substrate or a plastic film substrate. Moreover, the invention provides a wireless processor, a wireless memory, and an information processing system thereof which transmit and receive power or signals wirelessly. According to the invention, an information processing system includes an element forming region including a transistor which has at least a channel forming region formed of a semiconductor film separated into islands with a thickness of 10 to 200 nm, and an antenna. The transistor is fixed on a flexible substrate. The wireless processor in which a high functional integrated circuit including the element forming region is formed and the semiconductor device transmit and receive data through the antenna.

Abstract: A semiconductor device including a first transistor and a second transistor and a capacitor which are over the first transistor is provided. A semiconductor layer of the second transistor includes an offset region. In the second transistor provided with an offset region, the off-state current of the second transistor can be reduced. Thus, a semiconductor device which can hold data for a long time can be provided.

Abstract: An object is to provide a power feeding system and a power feeding method which are more convenient for a power feeding user at the power receiving end, without causing increases in complexity and size of devices. An object is to provide a power feeding system and a power feeding method which also allow a power feeding provider (a company) which feeds power (at the power transmitting end) to supply power without waste. A power feeding device which wirelessly supplies power to a power receiver detects the position and the resonant frequency of the power receiver by receiving a position and resonant frequency detection signal using a plurality of sub-carriers having different frequencies from the power receiver, and controls the frequency of a power signal to be transmitted to the power receiver on the basis of the information. An efficient power feeding service can be offered by transmitting a power signal to the power receiver at an optimum frequency for high power transmission efficiency.