Abstract: A driving method of a semiconductor device that takes three-dimensional images with short duration is provided. In a first step, a light source starts to emit light, and first potential corresponding to the total amount of light received by a first photoelectric conversion element and a second photoelectric conversion element is written to a first charge accumulation region. In a second step, the light source stops emitting light and second potential corresponding to the total amount of light received by the first photoelectric conversion element and the second photoelectric conversion element is written to a second charge accumulation region. In a third step, first data corresponding to the potential written to the first charge accumulation region is read. In a fourth step, second data corresponding to the potential written to the second charge accumulation region is read.

Abstract: To provide an operation method of a semiconductor device in which a variation in arithmetic operation results is reduced. The semiconductor device includes first and second cell arrays and first to fifth circuits. First, third standard data is written from the fourth circuit to the second cell array, and first standard data is written from the first circuit to the first cell array. Then, second standard data is transmitted from the second circuit to the first cell array, a result of a product-sum operation of the first standard data and the second standard data is input from the first cell array to the third circuit, and fourth standard data corresponding to the result of the product-sum operation is transmitted from the third circuit to the second cell array.

Abstract: An occupant protection device which can protect an occupant without delay is provided. An image taken by an imaging device is analyzed to judge whether there is an object approaching the subject car. In the case where a collision between the object and the subject car is judged to be inevitable, an airbag device is activated before the collision, whereby the occupant can be protected without delay. By using selenium for a light-receiving element of the imaging device, an accurate image can be obtained even under low illuminance. Imaging in a global shutter system leads to an accurate image with little distortion. This enables more accurate image analysis.

Abstract: A semiconductor device that can perform product-sum operation with low power consumption is provided. The semiconductor device includes first and second circuits; the first circuit includes a first holding node and the second circuit includes a second holding node. The first circuit is electrically connected to first and second input wirings and first and second wirings, the second circuit is electrically connected to the first and second input wirings and the first and second wirings, and the first and second circuits each have a function of holding first and second potentials corresponding to first data at the first and second holding nodes. When a potential corresponding to second data is input to each of the first and second input wirings, the first circuit outputs a current to one of the first wiring and the second wiring and the second circuit outputs a current to the other of the first wiring and the second wiring.

Abstract: An electronic device having an eye tracking function is provided. The electronic device includes a display device and an optical system. The display device includes a first light-emitting element, a second light-emitting element, a sensor portion, and a driver circuit portion. The sensor portion includes a light-receiving element. The first light-emitting element has a function of emitting infrared light or visible light. The second light-emitting element has a function of emitting light of a color different from that of light emitted from the first light-emitting element. When the first light-emitting element emits infrared light, the light-receiving element has a function of detecting the infrared light that is emitted from the first light-emitting element and reflected by an eyeball of a user.

Abstract: A semiconductor device with a novel structure is provided. The semiconductor device includes a cell array performing a product-sum operation of a first layer and a product-sum operation of a second layer in an artificial neural network, a first circuit from which first data is input to the cell array, and a second circuit to which second data is output from the cell array. The cell array includes a plurality of cells. The cell array includes a first region and a second region. In a first period, the first region is supplied with the t-th (t is a natural number greater than or equal to 2) first data from the first circuit and outputs the t-th second data according to the product-sum operation of the first layer to the second circuit. In the first period, the second region is supplied with the (t+1)-th first data from the first circuit and outputs the (t+1)-th second data according to the product-sum operation of the second layer to the first circuit.

Abstract: The operation speed of a semiconductor device is improved. The semiconductor device includes a first memory region and a second memory region; in the semiconductor device, a first memory cell in the first memory region is superior to a second memory cell in the second memory region in data retention characteristics such as a large storage capacitance or a large channel length-channel width ratio (L/W) of a transistor. When the semiconductor device is used as a cache memory or a main memory device of a processor, the first memory region mainly stores a start-up routine and is not used as a work region for arithmetic operation, and the second memory region is used as a work region for arithmetic operation. The first memory region becomes an accessible region when the processor is booted, and the first memory region becomes an inaccessible region when the processor is in normal operation.

Abstract: A highly sensitive imaging device that can perform imaging even under a low illuminance condition is provided. One electrode of a photoelectric conversion element is electrically connected to one of a source electrode and a drain electrode of a first transistor and one of a source electrode and a drain electrode of a third transistor. The other of the source electrode and the drain electrode of the first transistor is electrically connected to a gate electrode of the second transistor. The other electrode of the photoelectric conversion element is electrically connected to a first wiring. A gate electrode of the first transistor is electrically connected to a second wiring. When a potential supplied to the first wiring is HVDD, the highest value of a potential supplied to the second wiring is lower than HVDD.

Abstract: To provide a novel electronic device. The electronic device includes a housing and a display device. The display device includes a first layer, a second layer, and a third layer. The first layer, the second layer, and the third layer are provided in different layers. The first layer includes a driver circuit and an arithmetic circuit. The second layer includes pixel circuits and a cell array. The third layer includes light-receiving devices and light-emitting devices. The pixel circuits each have a function of controlling light emission of the light-emitting device. The driver circuit has a function of controlling the pixel circuits. The arithmetic circuit has a function of performing arithmetic processing on the basis of first data corresponding to currents output from the light-receiving devices and second data corresponding to a potential held in the cell array.

Abstract: A solid-state imaging device with high productivity and improved dynamic range is provided. In the imaging device including a photoelectric conversion element having an i-type semiconductor layer, functional elements, and a wiring, an area where the functional elements and the wiring overlap with the i-type semiconductor in a plane view is preferably less than or equal to 35%, further preferably less than or equal to 15%, and still further preferably less than or equal to 10% of the area of the i-type semiconductor in a plane view. Plural photoelectric conversion elements are provided in the same semiconductor layer, whereby a process for separating the respective photoelectric conversion elements can be reduced. The respective i-type semiconductor layers in the plural photoelectric conversion elements are separated by a p-type semiconductor layer or an n-type semiconductor layer.

Abstract: A semiconductor device capable of product-sum operation with low power consumption is provided. The semiconductor device includes first and second circuits; the first circuit includes a first holding portion and a first transistor, and the second circuit includes a second holding portion and a second transistor. The first and second circuits are each electrically connected to first and second input wirings and first and second wirings. The first holding portion has a function of holding a first current flowing through the first transistor, and the second holding portion has a function of holding a second current flowing through the second transistor. The first and second currents are determined in accordance with first data. When a potential corresponding to second data is input to the first and second input wirings, the first circuit outputs a current to one of the first wiring and the second wiring and the second circuit outputs a current to the other of the first wiring and the second wiring.

Abstract: A neuron circuit can switch between two functions: as an input neuron circuit, and as a hidden neuron circuit. An error circuit can switch between two functions: as a hidden error circuit, and as an output neuron circuit. A switching circuit is configured to be capable of changing the connections between the neuron circuit, a synapse circuit, and the error circuit. The synapse circuit includes an analog memory that stores data that corresponds to the connection strength between the input neuron circuit and the hidden neuron circuit or between the hidden neuron circuit and the output neuron circuit, a writing circuit that changes the data in the analog memory, and a weighting circuit that weights an input signal in reaction to the data of the analog memory and outputs the weighted output signal. The analog memory includes a transistor comprising an oxide semiconductor with extremely low off-state current.

Abstract: A driving method of a semiconductor device that takes three-dimensional images with short duration is provided. In a first step, a light source starts to emit light, and first potential corresponding to the total amount of light received by a first photoelectric conversion element and a second photoelectric conversion element is written to a first charge accumulation region. In a second step, the light source stops emitting light and second potential corresponding to the total amount of light received by the first photoelectric conversion element and the second photoelectric conversion element is written to a second charge accumulation region. In a third step, first data corresponding to the potential written to the first charge accumulation region is read. In a fourth step, second data corresponding to the potential written to the second charge accumulation region is read.

Abstract: A semiconductor device resistant to a high temperature with low power consumption is provided. The semiconductor device includes a first and a second circuit, a first and a second cell, and a first and a second wiring. The first cell includes a first transistor, and the second cell includes a second transistor. The first and the second transistor operate in a subthreshold region. The first cell is electrically connected to the first circuit through the first wiring, the first cell is electrically connected to the second circuit through the second wiring, and the second cell is electrically connected to the second circuit through the second wiring. The first cell sets a current flowing through the first transistor to a first current and the second cell sets a current flowing through the second transistor to a second current. At this time, a potential corresponding to the second current is input from the second wiring to the first cell.

Abstract: A semiconductor device that can perform product-sum operation with low power is provided. The semiconductor device includes a switching circuit. The switching circuit includes first to fourth terminals. The switching circuit has a function of selecting one of the third terminal and the fourth terminal as electrical connection destination of the first terminal, and selecting the other of the third terminal and the fourth terminal as electrical connection destination of the second terminal, on the basis of first data. The switching circuit includes a first transistor and a second transistor each having a back gate. The switching circuit has a function of determining a signal-transmission speed between the first terminal and one of the third terminal and the fourth terminal and a signal-transmission speed between the second terminal and the other of the third terminal and the fourth terminal on the basis of potentials of the back gates. The potentials are determined by second data.

Abstract: An oscillator capable of quick startup is provided. A transistor is provided between an output terminal of a certain stage inverter and an input terminal of the following stage inverter included in the voltage controlled oscillator. With the use of the on resistance of the transistor, the oscillation frequency of the clock signal is controlled. While supply of the power supply voltage is stopped, a signal that is input to the input terminal of the inverter just before supply of the power supply voltage is stopped is stored by turning off the transistor. This operation makes it possible to immediately output a clock signal that has the same frequency as that before supply of the power supply voltage is stopped at the time when the power supply voltage is supplied again.

Abstract: An object is to provide a pixel structure of a display device including a photosensor which prevents changes in an output of the photosensor and a decrease in imaging quality. The display device has a pixel layout structure in which a shielding wire is disposed between an FD and an imaging signal line (a PR line, a TX line, or an SE line) or between the FD and an image-display signal line in order to reduce or eliminate parasitic capacitance between the FD and a signal line for the purpose of suppressing changes in the potential of the FD. An imaging power supply line, image-display power supply line, a GND line, a common line, or the like whose potential is fixed, such as a common potential line, is used as a shielding wire.

Abstract: A display device that is suitable for increasing its size is provided.

Abstract: A semiconductor device that can perform product-sum operation with low power consumption is provided. The semiconductor device includes first and second circuits; the first circuit includes a first holding node and the second circuit includes a second holding node. The first circuit is electrically connected to first and second input wirings and first and second wirings, the second circuit is electrically connected to the first and second input wirings and the first and second wirings, and the first and second circuits each have a function of holding first and second potentials corresponding to first data at the first and second holding nodes. When a potential corresponding to second data is input to each of the first and second input wirings, the first circuit outputs a current to one of the first wiring and the second wiring and the second circuit outputs a current to the other of the first wiring and the second wiring.

Abstract: A highly sensitive imaging device that can perform imaging even under a low illuminance condition is provided. One electrode of a photoelectric conversion element is electrically connected to one of a source electrode and a drain electrode of a first transistor and one of a source electrode and a drain electrode of a third transistor. The other of the source electrode and the drain electrode of the first transistor is electrically connected to a gate electrode of the second transistor. The other electrode of the photoelectric conversion element is electrically connected to a first wiring. A gate electrode of the first transistor is electrically connected to a second wiring. When a potential supplied to the first wiring is HVDD, the highest value of a potential supplied to the second wiring is lower than HVDD.