Oki Semiconductor Co., Ltd.

Oki Electric Industry Co., Ltd.

Lapis Semiconductor Co., Ltd.

Powerchip Technology Corporation

Zentel Japan Corporation

Akihiro Hirota

Junichi Suyama

Wataru Nagai

Shota Ohtsubo

Takashi Kubo

Masaru Haraguchi

Bunsho Kuramori

Jun Setogawa

Hironori Iga

Mineo Noguchi

Kazukiyo Fukudome

Masahiro Ishihara

Mitsuru Yoneyama

A semiconductor memory device is provided with a row control circuit, in order to dissolve a Row Hammer issue. The row control circuit is configured to: (A) latches one of (a) a target address upon issuing of an ACTIVE command to the semiconductor memory device, and (b) a row address of a victim cell in which data of a memory cell is affected by the target address, as a victim address by using a predetermined row address latch method; and then, (B) refreshes the victim cell having the victim address by a predetermined refresh method upon issuing of a REFRESH command.

Semiconductor memory device for preventing occurrence of row hammer issue

A semiconductor memory apparatus performs a selection in a normal readout/write-in mode and an automatic refreshing mode and includes a sense amplifier reading out data from a memory device, a first switching device connecting a first power supply voltage acting as an overdrive voltage to a first power supply intermediate node during a first period and then connecting a second power supply voltage acting as an array voltage to the first power supply intermediate node, a second switching device connecting the fourth power supply voltage to a second power supply intermediate node of the sense amplifier when the sense amplifier is driven, a first capacitor connected to the overdrive voltage and charging it, a third switching device switched on in the automatic refreshing mode, and a voltage generator generating a third power supply voltage and applying it and the first power supply voltage in parallel through the third switching device.

Semiconductor memory apparatus

An internal power source voltage generating circuit of a semiconductor memory and a corresponding method shorten an access delay upon transition of a data reading operation in an address period shorter than a prescribed minimum period to an operation in the prescribed minimum period. While a boosted voltage of an external power source voltage is supplied to the semiconductor memory as the internal power source voltage via an output line connected to one end of a condenser. A reference low potential is applied to the other end of the condenser and the external power source voltage is applied to the output line, thereby charging the condenser. If the internal power source voltage is lower than a threshold voltage, the internal power source voltage on the output line is boosted by applying the external power source voltage to the other end of the condenser.

Internal power source voltage generating circuit of semiconductor memory and method for generating internal power source voltage

An internal pulse waveform shaping circuit provided to an IC chip generates an internal pulse monitor signal that changes in a predetermined direction at a rise timing of an internal pulse signal during a period in which a first enable signal is asserted and a second enable signal is de-asserted and then continues in the changed state for a predetermined period of time or longer, and generates the internal pulse monitor signal that changes in the predetermined direction at a fall timing of the pulse signal during a period in which the first enable signal is de-asserted and the second enable signal is asserted and then continues in the changed state for the predetermined period of time or longer. The generated internal pulse monitor signal is output to a tester for detecting the pulse width of the internal pulse signal.

Semiconductor device and pulse width detection method

There is provided a reference potential generating circuit of a semiconductor memory, including: a first MOS transistor group that includes a plurality of first MOS transistors that are connected in series; a second MOS transistor that is connected in series to the first MOS transistor group; a third MOS transistor that is connected in parallel to the circuit in which the first MOS transistor group and the second MOS transistor are connected in series, has a gate connected to a connection point of the first MOS transistor group and the second MOS transistor, and corrects a reference potential from a connection point of the first MOS transistors; and a fourth MOS transistor that is connected to the gate of the third MOS transistor, and decreases the potential of the gate of the third MOS transistor when a permission signal to supply power to the semiconductor memory is input.

Reference potential generating circuit of semiconductor memory

There is provided a start-up circuit of an internal power supply of a semiconductor memory, including: an odd number of inverters that are connected in series and output a signal indicating whether or not to start to supply power from an internal power supply circuit of the semiconductor memory to an internal power supply circuit, and a discharge unit that is connected to an output side of an inverter at an odd-numbered stage and discharges charges remaining at the connection point between the inverter at the odd-numbered stage and the inverter at the stage immediately thereafter, after supply of power to operate the inverters is stopped.

Start-up circuit of internal power supply of semiconductor memory

The present invention provides a semiconductor testing apparatus and method capable of reliably determining whether a semiconductor memory is good or bad. A '1' reading test of each cell corresponding to one bit at a first step is first performed on a memory cell array. '0' writing of each cell corresponding to one bit at a second step and a &#x201c;0&#x201d; reading test of each cell corresponding to one bit at a third step are executed on the memory cell array. Thus, the time taken from the supply of power to the start of the &#x201c;0&#x201d; reading test of the reference cell at the third step can be significantly shortened. As a result, a defect of a reference bit line due to a breaking or high resistance of a gate of a reference column switch transistor corresponding to a normally ON transistor can be screened.

Semiconductor testing apparatus and method

An internal power supply control circuit of a semiconductor memory includes a periodic signal generating unit that generates a periodic signal to generate a permission signal to intermittently permit supply of power from an internal power supply circuit of the semiconductor memory to an internal circuit thereof with a predetermined period, when a mode changes from a normal operation mode where power is always supplied from the internal power supply circuit to the internal circuit to a standby mode where consumption power is further suppressed as compared with consumption power in the normal operation mode, and a permission signal output unit that outputs the permission signal synchronized with the periodic signal to the internal power supply circuit, when a mode signal indicating any mode of the normal operation mode and the standby mode and the periodic signal are input and the input mode signal indicates the standby mode.

Internal power supply control circuit of semiconductor memory

A trimming circuit which comprises a shunt circuit having two shunt resistors and two shunt ON/OFF switches and connected in parallel with a series resistor circuit. The middle point of the shunt circuit is connected to a connection point of the series resistor circuit, the resistance ratio thereof with respect to the connection point being equal to the resistance ratio of the shunt resistors.

Trimming circuit

A power-source controller for reducing current consumption while a DRAM is in standby, includes a mode detection circuit inverting a disable signal having an L-level under the enable state and having an H-level under the disable state; an internal-power-source driver circuit having first and second transistors; and an internal-power-source reference circuit setting first and second driver control signals respectively to L-level and H-level when an L-level disable signal is input to turn on the first transistor and turn off the second transistor, supplying an external-power-source voltage as an internal-power-source voltage, setting the first driver control signal to H-level when an H-level disable signal is input, controlling the level of the second driver control signal to turn off the second transistor and control the first transistor, and supplying an internal power-source voltage lower than the external-power-source voltage.

DRAM power-source controller that reduces current consumption during standby

A low power consumption type dynamic random access memory (DRAM) operable with reduced current consumption responsive to an external signal, without causing occurrence of malfunction during low current consumption. An input circuit for receiving signals, a memory array for holding data, and a peripheral circuit for controlling the memory array are driven by an internal voltage supplied by two groups of internal voltage receiving circuits, while an output circuit for outputting signals is driven by an external power supply. The two groups of internal voltage receiving circuits are deactivated in response to an externally provided power supply control signal, and the output circuit is controlled so as to be in a high impedance condition with voltage of the external power supply being applied thereto.

Dynamic random access memory with low power consumption

There provides a low power consumption type dynamic random access memory (DRAM) with reduced current consumption in the DRAM by a signal from outside and without causing occurrence of malfunction at times of low current consumption. An input circuit for receiving signals, a memory array for holding data, and a peripheral circuit for controlling the memory array are driven by an internal voltage supplied by two groups of internal voltage receiving circuits while an output circuit for outputting signals is driven by an external power supply. The two groups of internal voltage receiving circuits are deactivated in response to a power supply control signal CONT inputted from outside, and the output circuit is controlled so as to be in a high impedance condition with voltage of the external power supply being applied thereto.

A sense circuit for a DRAM circuit in which small potential difference between bit lines and is produced when the memory cell in the memory cell array is connected to one of the bit lines. The sense circuit starts sensing and amplifying when the sense starting signal changes to 'L' level. An inverter provides a sense activating signal of 'H' level to an NMOS device, while another inverter provides a sense activating signal of 'L' level to a PMOS device. Sense amplifiers 33 are then activated and the potential difference between the bit lines and is amplified. Since the 'L' level of the sense activating signal that is generated by the inverter is set to a value midway between a first power potential VSS and a second power potential VCC, the conductive resistance of the PMOS device is higher than that of a conventional circuit supplied with the first power potential VSS. Consequently, the voltage drop due to the PMOS device increases and power noise is reduced.

Growing community of inventors

Tokyo, Japan

Akihiro Hirota