Abstract: An input circuit has an input buffer and a detection circuit. The input buffer receives an external signal and outputs an internal signal. The detection circuit detects whether or not the external signal is provided. The input buffer outputs the internal signal when an output of the detection circuit indicates that the external signal is provided. This arrangement shortens the lock-on time of an internal circuit (synchronous circuit).

Abstract: According to the present invention, a memory circuit requiring refresh operations a first circuit which receives a command in synchronization with a clock signal, and which generates a first internal command internally and a second circuit which generates a second internal command, i.g. a refresh command, internally in a prescribed refresh cycle. And an internal circuit, according to said first internal command, executes corresponding control through clock-synchronous operations, and when said refresh command is issued, sequentially executes control corresponding to the refresh command and control corresponding to said first internal command through clock-asynchronous operations. According to the present invention, when a refresh timing signal is generated, the refresh operation can be intrupted among the external command operations.

Abstract: Disclosed is a semiconductor device for outputting an output signal with a given phase held relative to an external clock despite a difference in characteristic, a change in temperature, and a fluctuation in supply voltage. The semiconductor device comprises an input circuit for inputting the external clock and outputting a reference signal, an output circuit for receiving an output timing signal and outputting an output signal according to the timing of the output timing signal, and an output timing control circuit for controlling the output timing so that the output signal exhibits a given phase relative to the external clock.

Abstract: The invention relates to a clock synchronous type semiconductor device that accepts an input signal inputted from the exterior in synchronization with a clock signal. The semiconductor device according to the invention includes an input signal receiving unit that receives an input signal inputted from the exterior, where the receiving is done in synchronization with a clock signal; a clock timing selecting unit for outputting a clock selecting signal; and a clock generating unit that, in response to receiving a clock selecting signal and an external clock signal, generates a clock signal at a predetermined timing which corresponds to a signal level of the clock selecting signal, and outputs the clock signal to the input signal receiving unit, wherein it is possible to securely accept an input signal regardless of the frequency of the external clock signal.

Abstract: A semiconductor memory device, which refreshes memory cells to retain data, has a first refresh mode and a second refresh mode. The first refresh mode is a mode for refreshing all of the memory cells, and the second refresh mode is a mode for refreshing a part of the memory cells. By refreshing only designated areas where data must be retained, power consumption in a refresh operation can be reduced, drastically cutting power consumption in a power-down mode.

Abstract: A data signal is output from an output circuit of a first chip and sent to a data input terminal in the second chip via a data lead line based on an output clock in first chip, which is sent to the second chip. And an input circuit in a second chip receives the data signal and transfers it inside in response to a transfer clock that has been generated from the output clock in the first chip. In synchronism with a single reference clock in the first chip, therefore, a data signal can be transferred to the second chip from the first chip at a high speed.

Abstract: A semiconductor device for generating first and second internal clocks complementary with each other from an external clock and usable for both a system of a type using a complementary clock and a system of a type generating a 180° phase clock internally, is disclosed. A first clock input circuit (buffer) is supplied with a first external clock and outputs a first internal clock. A second clock input circuit (buffer) is supplied with a second external clock complementary with the first external clock and outputs a second clock. A ½ phase clock generating circuit generates a ½ phase shift signal 180° out of phase with the first internal clock. A second external clock state detection circuit judges whether the second external clock is input to the second clock input buffer.

Abstract: A data signal is output from an output circuit of a first chip and sent to a data input terminal in the second chip via a data lead line based on an output clock in first chip, which is sent to the second chip. And an input circuit in a second chip receives the data signal and transfers it inside in response to a transfer clock that has been generated from the output clock in the first chip. In synchronism with a single reference clock in the first chip, therefore, a data signal can be transferred to the second chip from the first chip at a high speed.

Abstract: A self-timing control circuit relating to the present invention comprises a clock cycle counting circuit for counting ocillation pulses during a period corresponding to a cycle of the master clock and generating a clock cycle count value. The count value for a period corresponding to the cycle of the master clock is calculated with this clock cycle counting circuit. The self-timing control circuit further comprises a control clock generating portion for generating the control clock, as timed by synchronizing with the master clock, starting a count of the oscillation pulses, and counting up to the clock cycle count value. As a result, the control clock generated is delayed from the master clock by the time taken to count to the measured count value. The timing of the control clock is delayed from the master clock by one cycle or an integer multiple thereof.

Abstract: A semiconductor device for generating first and second internal clocks complementary with each other from an external clock and usable for both a system of a type using a complementary clock and a system of a type generating a 180° phase clock internally, is disclosed. A first clock input circuit (buffer) is supplied with a first external clock and outputs a first internal clock. A second clock input circuit (buffer) is supplied with a second external clock complementary with the first external clock and outputs a second clock. A ½ phase clock generating circuit generates a ½ phase shift signal 180° out of phase with the first internal clock. A second external clock state detection circuit judges whether the second external clock is input to the second clock input buffer.

Abstract: A semiconductor memory device, which refreshes memory cells to retain data, has a first refresh mode and a second refresh mode. The first refresh mode is a mode for refreshing all of the memory cells, and the second refresh mode is a mode for refreshing a part of the memory cells. By refreshing only designated areas where data must be retained, power consumption in a refresh operation can be reduced, drastically cutting power consumption in a power-down mode.

Abstract: A data signal is output from an output circuit of a first chip and sent to a data input terminal in the second chip via a data lead line based on an output clock in first chip, which is sent to the second chip. And an input circuit in a second chip receives the data signal and transfers it inside in response to a transfer clock that has been generated from the output clock in the first chip. In synchronism with a single reference clock in the first chip, therefore, a data signal can be transferred to the second chip from the first chip at a high speed.

Abstract: The present invention is an integrated circuit device having a self timing control circuit for generating an input loading timing signal whose phase is adjusted with an external clock, where loading of input signals supplied from outside, such as a command input signal, address input signal and data input signal, to internal circuits is forbidden when the self timing control circuit is adjusting phase. And when the self timing control circuit finishes adjusting the phase to a certain degree, the loading operation of an input signal at the input circuit using the input loading timing signal is enabled. To execute such an operation, the input circuit generates an input loading control signal based on a lock-on signal or adjustment signal of the DLL circuit, or based on an input stop cancellation signal, for example. The input circuit controls the stop and restart of loading of the input signal according to this input loading control signal.

Abstract: The present invention omits a variable delay circuit (10 in FIG. 1) inside a DLL circuit, and instead, creates a timing synchronization circuit, which generates a second reference clock. The timing synchronization circuit shifts the phase of a first reference clock generated by a frequency divider to the timing of a timing signal generated from the other variable delay circuit so that the second reference clock matches to the timing signal. Then, a phase comparator compares the divided first reference clock to a variable clock that delays the second reference clock, and controls the delay time of the variable delay circuit so that both clocks are in phase. As a result, one variable delay circuit can be omitted, and a DLL circuit that uses a divided clock can be configured.

Abstract: The present invention is a DLL circuit, which delays a first clock, and generates a control clock having a predetermined phase relation with this first clock. The DLL circuit comprises a variable delay circuit for varying the delay of the first clock; a phase comparator for comparing the phases of the first clock against that of a second clock, generated by delaying for a predetermined time the output of the variable delay circuit, and for generating a phase comparison result signal; and a delay control circuit for supplying to the variable delay circuit a delay control signal, which controls this delay quantity in response to the phase comparison result signal.

Abstract: A semiconductor memory includes memory cell blocks, a burst-length information generating circuit which generates burst-length information based on a burst length, and a block enable circuit which receives the burst-length information. The block enable circuit selectively enables one of the memory cell blocks when the burst length is equal to or shorter than a predetermined burst length and selectively enables a plurality of memory cell blocks based on the burst length when the burst length is longer than the predetermined burst length. Data are read from the above-mentioned one or plurality of memory cell blocks.

Abstract: A semiconductor integrated circuit device includes a DLL circuit. The DLL circuit includes a frequency divider which frequency-divides an input clock at a frequency dividing ratio which is varied depending on a frequency of the input clock and thus results in a dummy clock and a reference clock. A delay system includes a variable delay circuit which delays the dummy clock. A control circuit controls a delay amount of the variable delay circuit so that a phase of a delayed dummy clock from the delay system and the reference clock becomes zero.

Abstract: A semiconductor memory device includes memory cells, word lines connected to the memory cells, bit lines connected to the memory cells, and a first circuit which resets the bit lines to a reset potential which is based on data read in a previous read cycle.

Abstract: A system and a semiconductor device for realizing such a system are disclosed. The system uses at least a semiconductor device for retrieving an input signal in synchronism with an internal clock generated from an external clock, the input signal remaining effectively in synchronism with the external clock. Even in the case where a phase difference develops between a clock and a signal at the receiving end, or even in the case where a phase difference develops between a clock input circuit and other signal input circuits in the semiconductor device at the receiving end, data can be transferred at high speed. Each input circuit of the semiconductor device at the receiving end includes an input timing adjusting circuit for adjusting the phase of the clock applied to the input circuit in such a manner that the input circuit retrieves the input signal in an effective and stable state.

Abstract: A switch 17 for short-circuiting is connected between the outputs of circuits 15 and 16 each of which outputs a pair of complementary signals .0.S1 and .0.R1. The circuits 15 and 16, and the switch 17 are controlled by a changeover control circuit 18 in response to an input signal .0.A1. To effectively utilizes electric charge which has become unnecessary on a complementary signal line pair, the circuit 18 comprises an edge detecting circuit for providing a pulse to the switch 17 to make it on in response to the edge of the signal .0.A1, and a state control circuit for making the outputs of the circuits 15 and 16 in a high impedance state while the switch 17 being on, and for making the logic states of the signals .0.S1 and .0.R1 completely transit in response to disappearance of the pulse while the switch 17 being off.