Digital logic devices with extremely skewed trip points and reset circuitry for rapidly propagating signal edges and systems including same

• US 6,917,222 B2
• Filed: 01/03/2003
• Issued: 07/12/2005
• Est. Priority Date: 08/03/2001
• Status: Expired due to Term

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Porter, John D., Weber, Larren G., Gans, Dean D.
• Primary Examiner(s): Tokar, Michael
• Assistant Examiner(s): Mai, Lam T.
• Application Number:
  US10/336,527
• Publication Number:
  US 20030094973A1
• Time in Patent Office: 921 Days
• Field of Search: 326/26, 326/27, 326/82, 326/17, 326/93, 327/264, 327/172, 365/154, 365/233
• US Class Current: 326/93
• CPC Class Codes: H03K 19/01721 by means of a pull-up or down element

Abstract

The invention includes digital logic devices with extremely skewed trip points and reset circuitry for rapidly propagating signal edges. Embodiments of skewed logic devices in accordance with the present invention include inverters, buffers, NOR gates and NAND gates for rapidly propagating a selected “fast” edge of an input signal. Additional embodiments include pulse stretchers, memory devices, substrates, computer systems and methods incorporating the skewed logic devices of the present invention. Each embodiment of a skewed logic device of the present invention is configured to propagate either a fast rising edge or fast falling edge of an output signal, i.e., the “fast” edge, at rates comparable to those of domino logic. An advantage of the skewed logic devices of the present invention over conventional CMOS logic devices is rapid edge propagation. Additionally, virtually all of the input gate loading is devoted to the fast edge being propagated. Additionally, the reset networks, as disclosed herein, are buffered by at least two gates, thus reducing loading seen by the input or the output of the skewed logic device.

Claims

1. A computer system comprising:

an input device;

an output device;

a processor device operably coupled to said input device and said output device; and

a memory device operably coupled to said processor device, said memory device including a skewed logic device, said skewed logic device selected from one of a skewed inverter rising logic device, a skewed inverter falling logic device, a skewed buffer rising logic device, a skewed buffer falling logic device, a skewed NOR falling logic device, a skewed NOR rising logic device, a skewed NAND falling logic device and a skewed NAND rising logic device, each of said logic devices including;

a logic gate having a large channel width ratio for receiving an input signal and rapidly propagating an output edge onto an output signal in response to an input edge of the input signal;

a reset network connected in parallel with said logic gate for resetting said output signal after said output edge has been propagated onto said output signal; and

a feedback delay circuit connected in parallel with said reset network for delaying and returning said output signal back to said reset network.

2. The computer system of claim 1, wherein said skewed logic device is selected from the group consisting of a skewed inverter rising logic device, a skewed inverter falling logic device, a skewed NAND rising logic device, a skewed NAND falling logic device, a skewed NOR falling logic device, a skewed NOR rising logic device, a skewed buffer rising logic device and a skewed buffer falling logic device.

5. The computer system of claim 1, wherein when said skewed logic device comprises a skewed inverter rising logic device, said logic gate comprising a fast inverter rising wherein said large channel comprises a large p/n channel width ratio for receiving an input signal and rapidly propagating a rising edge onto an output signal in response to receiving a falling edge on said input signal.

6. The computer system of claim 1, wherein when said skewed logic device comprises a skewed inverter falling logic device, said logic gate comprising a fast inverter falling wherein said large channel comprises a large n/p channel width ratio for receiving an input signal and rapidly propagating a falling edge onto an output signal in response to receiving a rising edge on said input signal.

7. The computer system of claim 1, wherein when said skewed logic device comprises a skewed buffer rising logic device, said logic gate comprising:

a fast inverter falling wherein said large channel comprises a large n/p channel width ratio for receiving a rising edge of an input signal and rapidly propagating a falling edge of an intermediate signal in response thereto; and

a fast inverter rising having a large p/n channel width ratio and in series with said fast inverter for receiving said rapidly propagated falling edge of said intermediate signal and rapidly propagating a rising edge on an output signal.

8. The computer system of claim 1, wherein when said skewed logic device comprises a skewed buffer falling logic device, said logic gate comprising:

a fast inverter rising wherein said large channel comprises a large p/n channel width ratio for receiving a falling edge of an input signal and rapidly propagating a rising edge of an intermediate signal in response thereto; and

a fast inverter falling wherein said large channel comprises a large n/p channel width ratio and in series with said rising fast inverter for receiving said rapidly propagated rising edge of said intermediate signal and rapidly propagating a falling edge on an output signal.

9. The computer system of claim 1, wherein when said skewed logic device comprises a skewed NOR falling logic device, said logic gate comprising a fast NOR gate falling having a large n/p channel width ratio for receiving a first input signal and a second input signal and rapidly propagating a falling edge of an output signal in response to a rising edge on either of said first input signal or said second input signal.

10. The computer system of claim 1, wherein when said skewed logic device comprises a skewed NOR rising logic device, said logic gate comprising a fast NOR gate rising having a large p/n channel width ratio for receiving a first input signal and a second input signal and rapidly propagating a rising edge of an output signal in response to a falling edge on both of said first input signal and said second input signal.

11. The computer system of claim 1, wherein when said skewed logic device comprises a skewed NAND falling logic device, said logic gate comprising a fast NAND gate falling having a large n/p channel width ratio for receiving both a first input signal and a second input signal and rapidly propagating a falling edge of an output signal in response to rising edges on both said first input signal and said second input signal.

12. The computer system of claim 1, wherein when said skewed logic device comprises a skewed NAND rising logic device, said logic gate comprising a fast NAND gate rising having a large p/n channel width ratio for receiving both a first input signal and a second input signal and rapidly propagating a rising edge of an output signal in response to falling edges on either said first input signal or said second input signal.

13. The computer system of claim 1, wherein said memory device is selected from the group consisting of dynamic random access memory (DRAM), double data rate SDRAM (DDR SDRAM), RAMBUS®

DRAM (RDRAM®

), extended data-out DRAM (EDO DRAM), fast-page-mode DRAM (FPM DRAM), static random access memory (SRAM), SyncBurst®

SRAM, Zero Bus Turnaround®

SRAM (ZBT®

SRAM), Quad Data Rate®

SRAM (QDR®

SRAM), DDR synchronous SRAM (DDR SRAM) and nonvolatile electrically block-erasable programmable read only memory (Flash).

3. A semiconductor substrate comprising:

a plurality of integrated circuit (IC) dice, each IC die of said plurality of IC dice including a skewed logic device, said skewed logic device selected from one of a skewed inverter rising logic device, a skewed inverter falling logic device, a skewed buffer rising logic device, a skewed buffer falling logic device, a skewed NOR falling logic device, a skewed NOR rising logic device, a skewed NAND falling logic device and a skewed NAND rising logic device, each of said logic devices including;

a logic gate having a large channel width ratio for receiving an input signal and rapidly propagating an output edge onto an output signal in response to an input edge of the input signal;

a reset network connected in parallel with said logic sate for resetting said output signal after said output edge has been propagated onto said output signal; and

a feedback delay circuit connected in parallel with said reset network for delaying and returning said output signal back to said reset network.

4. The semiconductor substrate of claim 3, wherein said skewed logic device is selected from the group consisting of a skewed inverter rising logic device, a skewed inverter falling logic device, a skewed NAND rising logic device, a skewed NAND falling logic device, a skewed NOR falling logic device, a skewed NOR rising logic device, a skewed buffer rising logic device and a skewed buffer falling logic device.