Abstract: A test-target circuit is constructed of circuit blocks each comprising low-Vth MOS transistors including address buffers and a timing generator. A test enable signal for indication of a test, an operation selection signal for indication of an operation, and a block selection signal used to select a desired circuit block are provided. A high-Vth NMOS and a high-Vth PMOS transistor are provided in order to provide to a test circuit one of detected currents of the circuit blocks that was selected by placing a block selection signal and the test enable signal in the state of HIGH.

Abstract: A semiconductor circuit includes an input, an output, and a first transistor and a second transistor coupled in series to a power source. The first transistor is coupled closer to the power source than the second transistor is, and the first transistor has a higher threshold voltage than a threshold voltage of the second transistor. The semiconductor circuit further includes a capacitor which is coupled between the first transistor and the second transistor.

Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.

Abstract: A memory array divided into a plurality of sub-memory-arrays is disposed on a chip so that, if a specified sub-memory-array is selected by a sub-memory-array selecting circuit, a normal read/write operation is performed with respect to the sub-memory-array based on an address indicated by a group of external address signals. At the same time, a clock generator for self-refresh mounted on a chip generates a word-line basic clock for self-refresh and a word-line basic clock for refresh, thereby selecting the word lines in the sub-memory-arrays which have not been selected. Prior to a predetermined time at which the sub-memory-array subjected to a refresh operation is subsequently selected, a refresh halt signal is outputted so as to forcibly halt the refresh operation, thereby preventing insufficient recharging of a memory cell. Each of the plurality of sub-memory-arrays stores, of sequential sets of image data, data on one frame or one field.

Abstract: A semiconductor memory of the present invention includes: a plurality of memory cells; a pair of local bit lines connected to the plurality of memory cells; a local sense amplifier for amplifying a potential difference between the pair of local bit lines; a pair of global bit lines electrically connected to the pair of local bit lines through a switch; and a global sense amplifier for amplifying a potential difference between the pair of global bit lines, wherein the local sense amplifier includes a plurality of transistors, each of the plurality of transistors included in the local sense amplifier is a transistor of a first conductivity type, and the global sense amplifier includes a transistor of a second conductivity type different from the first conductivity type.

Abstract: A driver circuit which drives a signal line includes a first output section for outputting a reference voltage potential to the signal line during a first period and a second output section for outputting one of a first information voltage potential and a second information voltage potential in accordance with an input signal during a second period.

Abstract: A CPU acting as a mother chip, in combination with a DRAM acting as a subsidiary chip, is mounted. A mode output circuit is able to set the storage capacity of the DRAM as well as the refresh cycle of the DRAM for forwarding to a mode input circuit of the CPU through a mode output terminal of the DRAM and a mode input terminal of the CPU. The CPU controls an address generator according to the data from the mode input circuit, to set the number of bits of address data for access to the DRAM according to the DRAM storage capacity and the DRAM refresh cycle.

Abstract: In plural internal logic circuits, plural transistors having the same function are merged into a single merged transistor. This merged transistor is interposed between a ground and a virtual ground line connected with a ground node of an inverter included in each of the internal logic circuits, and has a threshold voltage higher than a threshold voltage of a transistor included in each inverter. The merged transistor is controlled in accordance with a block selecting signal. Since the merged transistor is merged among the internal logic circuits, its gate width can be set larger, resulting in attaining a high speed operation of each inverter. During a standby, a leakage current can be suppressed since the merged transistor is in an off-state. During an operation, a leakage current can be suppressed in an unselected circuit block since the merged transistor is in an off-state.

Abstract: A memory array divided into a plurality of sub-memory-arrays is disposed on a chip so that, if a specified sub-memory-array is selected by a sub-memory-array selecting circuit, a normal read/write operation is performed with respect to the sub-memory-array based on an address indicated by a group of external address signals. At the same time, a clock generator for self-refresh mounted on a chip generates a word-line basic clock for self-refresh and a word-line basic clock for refresh, thereby selecting the word lines in the sub-memory-arrays which have not been selected. Prior to a predetermined time at which the sub-memory-array subjected to a refresh operation is subsequently selected, a refresh halt signal is outputted so as to forcibly halt the refresh operation, thereby preventing insufficient recharging of a memory cell. Each of the plurality of sub-memory-arrays stores, of sequential sets of image data, data on one frame or one field.

Abstract: A semiconductor circuit includes an input, an output, and a first transistor and a second transistor coupled in series to a power source. The first transistor is coupled closer to the power source than the second transistor is, and the first transistor has a higher threshold voltage than a threshold voltage of the second transistor. The semiconductor circuit further includes a capacitor which in coupled between the first transistor and the second transistor.

Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.

Abstract: A semiconductor memory device according to the present invention includes a plurality of blocks. A plurality of first selection signals, second selection signals, and third selection signals are provided to the blocks.

Abstract: In a synchronous DRAM, a redundancy judging circuit has a frequency dividing circuit and a plurality of judging circuits each having two address comparing circuits and one output circuit. When an internal CAS signal having an activating period of time according to a data burst length, is activated, the frequency dividing circuit divides the frequency of an internal continuous clock signal having the same time period of one cycle and the same phase as those of an external clock signal, and generates complementary clock signals each having a time period of one cycle twice the time period of one cycle of the internal continuous clock signal.

Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.

Abstract: A memory array divided into a plurality of sub-memory-arrays is disposed on a chip so that, if a specified sub-memory-array is selected by a sub-memory-array selecting circuit, a normal read/write operation is performed with respect to the sub-memory-array based on an address indicated by a group of external address signals. At the same time, a clock generator for self-refresh mounted on a chip generates a word-line basic clock for self-refresh and a word-line basic clock for refresh, thereby selecting the word lines in the sub-memory-arrays which have not been selected. Prior to a predetermined time at which the sub-memory-array subjected to a refresh operation is subsequently selected, a refresh halt signal is outputted so as to forcibly halt the refresh operation, thereby preventing insufficient recharging of a memory cell. Each of the plurality of sub-memory-arrays stores, of sequential sets of image data, data on one frame or one field.

Abstract: When a memory chip is in a standby mode, a ground power supply line of a flip-flop forming a memory cell is intermittently placed in the floating state. A switching NMOS transistor is connected between the ground power supply line and a power supply VSS. The gate of the NMOS transistor is controlled by an activation signal. When entering the floating state, the ground power supply line is charged due to an off-leakage current flowing in the transistor of the memory cell. As a result, the voltage of the ground power supply line is increased from the voltage of the power supply VSS. Accordingly, the off-leakage current of the memory cell is reduced, whereby the standby-time power consumption of the memory chip is decreased. When the voltage of the ground power supply line keeps going up, it becomes impossible to read data held in the memory cell in a short time, resulting in the data being lost. In order to prevent the loss of the data, the switching NMOS transistor is made to intermittently turn on.

Abstract: A memory cell includes a first inverter and a second inverter connected with each other through the output node of one of the inverters and the input node of the other inverter, and first and second transistors. Each of the transistors connected with a word line at its gate electrode is interposed between one of a bit line pair and each memory node. This data holding circuit includes an element for increasing a memory cell supply potential for driving the pair of inverters to be higher than a supply potential applied to peripheral circuits, or an element for decreasing a ground voltage for driving the pair of inverters to be lower than a ground voltage applied to the peripheral circuits.

Abstract: When a memory chip is in a standby mode, a ground power supply line of a flip-flop forming a memory cell is intermittently placed in the floating state. A switching NMOS transistor is connected between the ground power supply line and a power supply VSS. The gate of the NMOS transistor is controlled by an activation signal. When entering the floating state, the ground power supply line is charged due to an off-leakage current flowing in the transistor of the memory cell. As a result, the voltage of the ground power supply line is increased from the voltage of the power supply VSS. Accordingly, the off-leakage current of the memory cell is reduced, whereby the standby-time power consumption of the memory chip is decreased. When the voltage of the ground power supply line keeps going up, it becomes impossible to read data held in the memory cell in a short time, resulting in the data being lost. In order to prevent the loss of the data, the switching NMOS transistor is made to intermittently turn on.

Abstract: In a driver circuit for driving a pair of data lines, the amplitude of a differential input signal is reduced from 2.5 V to 0.6 V, which is smaller than a conventional lower-limit source voltage (approximately 1.5 V). The amplitude of the differential signal transmitted through the pair of data lines is amplified to 2.5 V by an amplifying circuit and the resulting signal is then latched by a latch circuit. After the latching by the latch circuit, the operation of the amplifying circuit is halted. The driver circuit is constituted solely by a plurality of NMOS transistors so as not to increase a leakage current flowing in the off state. Here, the threshold voltage of the NMOS transistor positioned on the ground side is reduced to a conventional lower-limit value (0.3 V to 0.6 V), while the threshold voltage of the NMOS transistor on the power-source side to a value lower than the above lower-limit value (0 V to 0.3 V), thereby enhancing a driving force of the NMOS transistor on the power-source side.

Abstract: In a synchronous DRAM, a redundancy judging circuit has a frequency dividing circuit and a plurality of judging circuits each having two address comparing circuits and one output circuit. When an internal CAS signal having an activating period of time according to a data burst length, is activated, the frequency dividing circuit divides the frequency of an internal continuous clock signal having the same time period of one cycle and the same phase as those of an external clock signal, and generates complementary clock signals each having a time period of one cycle twice the time period of one cycle of the internal continuous clock signal.