摘要:
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.
摘要:
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.
摘要:
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.
摘要:
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.
摘要:
A semiconductor memory device comprising memory cells arranged in a matrix with plural pairs of bit lines to be column addressed and connected to sense amplifiers, and word lines to be row addressed and divided into divisional word lines. Output signals of sense amplifiers selected by the column addressing are transferred to respective data lines. The divisional word lines are time-sequentially activated corresponding to the row addressing with the activated states of any two sequential divisional word lines overlapped for a fractional time of the full activation time. The sense amplifiers are grouped into plural groups with respective common column addresses. Each group of sense amplifiers have their outputs to be applied to respective data lines connected to a serial/parallel converter.
摘要:
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.
摘要:
N-piece redundant address comparing circuits are individually composed of impedance converting circuits, so that information using redundancy is transmitted as an impedance value. Consequently, even though the N becomes larger as the capacity of a memory becomes larger, a signal line having large capacitance and the node of a redundant judging circuit are not charged or discharged. A high-speed operation can be realized without being affected by the capacitance of the signal line or by the capacitance of the node of the redundant judging circuit.
摘要:
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.
摘要:
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.
摘要:
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.