Circuit for controlling an enabling time of an internal control signal according to an operating frequency of a memory device and the method thereof

1. A circuit for controlling an enabling period of an internal control signal in accordance with variation of an operating frequency in a memory device, the circuit comprising:

a pulse width adjusting circuit comprised of a first delay circuit and a NAND gate at least one of a NAND gate and a NOR gate, which changes a pulse width of an input signal in accordance with the operating frequency, said NAND gate at least one of a NAND gate and a NOR gate receiving the input signal and an output signal of the first delay circuit, the first delay circuit receiving the input signal and a clock signal of the memory device and adjusting a delay time in accordance with a frequency of the clock signal until the input signal is applied to an input terminal of the NAND gate at least one of a NAND gate and a NOR gate;

a signal transmission circuit for buffering a signal outputted from the pulse width adjusting circuit; and

an output circuit for outputting a first signal to control an operation of a data bus of the memory device in response to a signal outputted from the signal transmission circuit, wherein as the clock signal duration shortens, the pulse width of the first signal is narrower.

2. The circuit of claim 1 wherein the first delay circuit comprises a second delay circuit for receiving the input signal and a third delay circuit for receiving a signal transferred from the second delay circuit:

wherein a delay time of the second delay circuit varies in accordance with variation of the frequency of the clock signal; wherein a delay time of the third delay circuit varies in accordance with variation of an operation voltage of the memory device; and

wherein an output signal of the third delay circuit is applied to the NAND gate at least one of a NAND gate and a NOR gate.

3. The circuit of claim 2 , wherein the first delay circuit further comprises: a frequency detector for detecting variation of the frequency of the clock signal; and a voltage detector for detecting variation of the operation voltage of the memory device.

4. The circuit claim 2 , wherein the first delay circuit further comprises a fourth delay circuit for delaying a signal transferred from the third delay circuit for a predetermined time.

5. The circuit of claim 4 , wherein a delay time of the fourth delay circuit is controlled by an address signal and the fourth delay circuit is a delay path used in a test mode of the memory device.

6. The circuit of claim 2 wherein as the frequency of the clock signal increases, a pulse width of the first signal is narrower.

7. The circuit of claim 2 , wherein as the operation voltage of the memory device increases, a pulse width of the first signal is wider.

8. The circuit of claim 1 wherein the at least one of a NAND gate and a NOR gate is a NAND gate.

9. A method of controlling an enabling period of an internal control signal according to varying operating frequency in a memory device, with the circuit of claim 1 , the method comprising:

providing the circuit of claim 1 ;

changing a pulse width of an input signal in the pulse width adjusting circuit;

buffering the signal outputted from the pulse width adjusting circuit in the signal transmission circuit; and

outputting a first signal in the output circuit to control the operation of the data bus of the memory device in response to the signal outputted from the signal transmission circuit, wherein as the clock signal duration shortens, the pulse width of the first signal is narrower.

10. The method of claim 9 further comprising:

receiving the input signal by a second delay circuit in the first delay circuit; and

receiving a signal transferred from the second delay circuit by a third delay circuit,

wherein a delay time of the second delay circuit varies in accordance with variation of the frequency of the clock signal,

wherein a delay time of the third delay circuit varies in accordance with variation of an operation voltage of the memory device, and

wherein an output signal of the third delay circuit is applied to the at least one of a NAND gate and a NOR gate.

11. The method of claim 10 , further comprising:

detecting variation of the frequency of the clock signal in a frequency detector of the first delay circuit; and

detecting variation of the operation voltage of the memory device in a voltage detector.

12. The method of claim 10 , further comprising:

delaying a signal transferred from the third delay circuit for a predetermined time by a fourth delay circuit in the first delay circuit.

13. The method of claim 12 , wherein a delay time of the fourth delay circuit is controlled by an address signal and the fourth delay circuit is a delay path used in a test mode of the memory device.

14. The method of claim 10 , wherein as the frequency of the clock signal increases, a pulse width of the first signal is narrower.

15. The method of claim 10 , wherein as the operation voltage of the memory device increases, a pulse width of the first signal is wider.