Synchronous semiconductor memory device for controlling cell operations by using frequency information of a clock signal
First Claim
1. A synchronous semiconductor memory device comprising:
- a state control circuit producing output signals for setting operation states;
an address buffer for buffering an inputted address;
a mode register producing output signals for setting operation modes in response to an output signal from said state control circuit and an inputted address from said address buffer;
a frequency information generating circuit for outputting frequency information corresponding to frequency of a clock signal in response to the output signal from said state control circuit and the inputted address from said address buffer; and
a driving circuit for activating a word line in response to the output signal from the state control circuit, an output signal from the mode register, and in accordance with the frequency information from the frequency information generating circuit.
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Abstract
The synchronous semiconductor memory device includes a frequency information generating circuit for outputting a plurality of frequency information corresponding to the frequency of the clock signal in response to a state control signal and an internal address in order to adjust a point of time to disable and precharge a word line by a frequency information corresponding to a frequency of a clock signal. Therefore, even though a high frequency clock signal is inputted, the word line is disabled and precharged when a cell node is charged enough. In this way, it can prevent from failing cell operations and promotes operation efficiency of the synchronous semiconductor memory device.
24 Citations
12 Claims
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1. A synchronous semiconductor memory device comprising:
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a state control circuit producing output signals for setting operation states;
an address buffer for buffering an inputted address;
a mode register producing output signals for setting operation modes in response to an output signal from said state control circuit and an inputted address from said address buffer;
a frequency information generating circuit for outputting frequency information corresponding to frequency of a clock signal in response to the output signal from said state control circuit and the inputted address from said address buffer; and
a driving circuit for activating a word line in response to the output signal from the state control circuit, an output signal from the mode register, and in accordance with the frequency information from the frequency information generating circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
a burst length control circuit for generating a burst end command signal in response to the output signals of the state control circuit and the output signals of the mode register by using the frequency information of the frequency information generating circuit;
an auto precharge operation control circuit for generating an auto precharge operation command signal in response to the burst length end command signal of the burst length control circuit and an output signal of the state control circuit; and
a row control circuit for activating a word line, wherein the burst length end command signal indicates an end of the burst length and the auto precharge operation command signal controls auto precharge operation.
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3. The memory device of claim 2, wherein said burst length control circuit includes a burst length counter for counting the number of clocks of the clock signal and for controlling a point of time to generate the burst length end command signal.
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4. The memory device of claim 2, wherein said burst length control circuit includes a delay circuit for delaying the point of time to generate the burst length end command signal by delaying the clock signal.
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5. The memory device of claim 2, wherein said burst length control circuit includes a pulse width adjusting circuit for controlling the point of time to generate the burst lenght end command signal by adjusting the pulse width of the clock signal.
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6. The memory device of claim 1, wherein said frequency information generating circuit includes means for storing the frequency information corresponding to the frequency of the clock signal.
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7. The memory device of claim 1, wherein said frequency information generating circuit includes means for detecting a frequency of the clock signal, and means for outputting the frequency information corresponding to the detected result.
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8. The memory device of claim 1, wherein said frequency information generating circuit includes:
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a plurality of fuses;
means for cutting off the fuse corresponding to the frequency of the clock signal; and
means for outputting information of the fuse-cutting as the frequency information.
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9. The memory device of claim 1, wherein said clock signal is an external clock signal supplied from an external source.
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10. The memory device of claim 1, wherein said clock signal is an internal clock signal generated by an external clock signal.
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11. A synchronous semiconductor memory device comprising:
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a state control circuit producing output signals for setting operation states;
an address buffer for buffering an inputted address;
a mode register producing output signals for setting operation modes in response to an output signal from said state control circuit and an inputted address from said address buffer;
a frequency information generating circuit including means for detecting a frequency of a clock signal and means for outputting the frequency information corresponding to the detected frequency in response to the output signal from said state control circuit and the inputted address from said address buffer; and
a driving circuit for activating a word line in accordance with the output signal from the state control circuit, an output signal from the mode register, and the frequency information from the frequency information generating circuit.
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12. A synchronous semiconductor memory device comprising:
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a state control circuit producing output signals for setting operation states;
an address buffer for buffering an inputted address;
a mode register producing output signals for setting operation modes in response to an output signal from said state control circuit and an inputted address from said address buffer;
a frequency information generating circuit for detecting and outputting frequency information of a clock signal in response to the output signal of said state control circuit and the inputted address of said address buffer, said frequency information generating circuit including means for cutting off a fuse corresponding to a frequency of the clock signal and for outputting information of the fuse-cutting as the frequency information; and
a driving circuit for activating a word line in accordance with the output signal of the state control circuit, an output signal of the mode register, and the frequency information of the frequency information generating circuit.
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Specification