WO2010030572A2 - Self reset clock buffer in memory devices - Google Patents
Self reset clock buffer in memory devices Download PDFInfo
- Publication number
- WO2010030572A2 WO2010030572A2 PCT/US2009/056026 US2009056026W WO2010030572A2 WO 2010030572 A2 WO2010030572 A2 WO 2010030572A2 US 2009056026 W US2009056026 W US 2009056026W WO 2010030572 A2 WO2010030572 A2 WO 2010030572A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- clock signal
- clock
- cross
- coupled
- circuit
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/22—Read-write [R-W] timing or clocking circuits; Read-write [R-W] control signal generators or management
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11C—STATIC STORES
- G11C7/00—Arrangements for writing information into, or reading information out from, a digital store
- G11C7/22—Read-write [R-W] timing or clocking circuits; Read-write [R-W] control signal generators or management
- G11C7/225—Clock input buffers
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
- H03K3/027—Generators characterised by the type of circuit or by the means used for producing pulses by the use of logic circuits, with internal or external positive feedback
- H03K3/037—Bistable circuits
-
- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K3/00—Circuits for generating electric pulses; Monostable, bistable or multistable circuits
- H03K3/02—Generators characterised by the type of circuit or by the means used for producing pulses
- H03K3/027—Generators characterised by the type of circuit or by the means used for producing pulses by the use of logic circuits, with internal or external positive feedback
- H03K3/037—Bistable circuits
- H03K3/0372—Bistable circuits of the master-slave type
Definitions
- This disclosure generally relates to integrated circuits (ICs).
- the disclosure relates to memory devices and, even more specifically, to clock buffering in memory devices.
- a memory device or memory can generally be described as hardware that can store data for later retrieval.
- a clock buffer is an important element in memory operation.
- One purpose of the clock buffer is to produce a control clock for the memory from an external clock.
- an internal clock signal provides synchronous timing within the memory.
- This internal clock signal is separate from the external clock of the circuitry that may be attached to the memory. Placing a complete clock generator within the memory is an expensive solution and occupies a large area of circuitry. Therefore, conventional memory uses a clock buffer to generate the internal memory clock from an external circuitry's clock.
- the internal memory clock controls timing of events such as latching memory addresses, bit line pre-charging, and selecting word lines.
- a conventional clock buffer accepts an input clock signal as well as other signals from external circuitry and generates an output clock (internal memory clock) signal under certain combinations of the input signals.
- a clock driver couples to the input clock signal as well as a delayed clock signal and outputs an intermediate clock signal.
- the clock driver generally has several transistors including a pFET configured to pull up the intermediate clock signal upon a reset signal and nFETs in series configured to pull-down upon a combination of a clock signal, delayed clock signal, and chip select signal.
- the intermediate clock signal is buffered through the use of a keeper circuit including two inverters.
- a clock inverter generates the output clock signal from the intermediate clock signal.
- One problem is that the pull down path of the clock generator is enabled by the external clock and disabled by a hard delay of the same external clock. The delay is required to ensure that the output of the clock generator is already pulled down when pull down by the clock generator is disabled. If the delay is not long enough, the clock generator will fail resulting in failure of the entire clock buffer circuit to output the desired internal memory clock.
- the chip select line must stay low.
- the time the chip select line must stay low is the hold time and must be longer than the clock delay implemented in the circuit.
- the clock delay is on the order of 100-1000 picoseconds and commonly 300 picoseconds.
- the length of the hold time also affects the setup time for inputs to the memory latches. Use of a delay circuit in the clock buffer can cause timing violations leading to unstable memory operation.
- the length of the optimal delay time varies across PVT conditions. Thus, the delay is often set longer than the minimum time required under ideal conditions. Consequently, the clock delay can be problematic.
- a third problem in the conventional design is the use of two nFET transistors in the pull-down circuit.
- Two nFETs are used to perform the logic function of combining the clock and the delayed clock signals.
- nFETs are relatively large devices that require increased circuit area and, therefore, decrease the storage density of the memory. Additionally, the capacitance of the two nFETs increases the load on the external clock.
- a fourth problem lies in the use of a latch in the keeper circuit of the conventional clock buffer circuit.
- the clock generator contends with the keeper circuit to change the memory clock from low to high or high to low. Under certain process conditions, such as low supply voltage or low temperature, the clock generator may not be capable of changing the output clock.
- Conventional supply voltages are over one volt and some are now less than one volt. Supply voltages in the range of 0.8- 0.9 volts lead to conventional clock buffer failure. A failure of this type results in an incorrect output clock signal and failure in the memory circuitry.
- a memory device includes a cross-coupled logic circuit.
- the cross-coupled logic circuit has at least two logic gates in which an output of at least one of the logic gates is coupled to an input of at least one of the logic gates.
- the cross-coupled logic circuit is coupled to an input for accepting a clock signal.
- the memory device also includes a clock driver operable to generate a clock signal from the output of the cross-coupled logic circuit.
- a feedback loop from the clock signal to the cross-coupled logic circuit controls the cross-coupled logic circuit.
- a clock buffering circuit includes a cross-coupled logic circuit.
- the cross-coupled logic circuit has at least two logic gates in which an output of at least one of the logic gates is coupled to an input of at least one of the logic gates.
- the cross-coupled logic circuit is coupled to an input for accepting a clock signal.
- the cross-coupled logic circuit also includes a clock driver operable to generate a clock signal from the output of the cross-coupled logic circuit.
- a feedback loop from the clock signal to the cross-coupled logic circuit controls the cross-coupled logic circuit.
- a method for generating a clock signal includes receiving an input clock signal, generating a control signal from a cross-coupled logic circuit accepting input from the input clock signal and a feedback loop, driving a clock signal with the control signal, and feeding back the clock signal to a clock driver in the feedback loop.
- a memory device includes means for cross-coupling an input clock signal and generating an output.
- the memory device also includes means for driving the output to generate a clock signal.
- a memory device includes means for feeding back the clock signal to the means for cross-coupling.
- FIGURE 1 is a circuit diagram showing a conventional clock buffer.
- FIGURE 2 is a circuit diagram showing an exemplary clock buffer featuring self reset functionality.
- FIGURE 3 is a timing diagram illustrating operation of an exemplary clock buffer featuring self reset functionality.
- FIGURE 4 is a block diagram showing an exemplary wireless communication system in which an embodiment of the disclosure may be advantageously employed.
- FIGURE 1 is a circuit diagram showing a conventional clock buffer.
- a conventional electrical circuit 10 for clock buffering has inputs including a supply voltage 101, V DD , a reset signal 102, RESET, an input clock signal 103, CLK, and a chip select signal 104, CS_N.
- a clock delay circuit 11 in the memory electrical circuit 10 includes an even number of inverters that can be adjusted to obtain correct timing as discussed earlier.
- a clock driver 12 includes a pFET 121 coupled to the supply voltage 101 and the reset signal 102.
- the clock driver 12 also has an nFET 122 coupled to the clock signal 102 and an FET 123.
- the nFET 123 is coupled to the clock delay circuit 11 and a reference ground 124.
- the clock driver 12 produces an intermediate clock signal 105, RCLK l.
- a keeper circuit 13 includes two inverters used to buffer the intermediate clock signal 105, RCLK l.
- a clock inverter 14 delivers the output memory clock signal 106, RCLK.
- the keeper circuit 13 drives the intermediate clock signal 105, RCLK l to maintain the signal when the intermediate clock signal 105, RCLK l, would otherwise be floating.
- the conventional clock buffer illustrated in FIGURE 1 has accompanying disadvantages such as problems resulting from the use of a hard delay, increased circuit area consumption by three transistors, increased load on the input clock line, large chip select signal 104, CS N, hold time and contention of the output clock signal 106, RCLK, by the keeper circuit 13.
- FIGURE 2 is a circuit diagram showing an exemplary clock buffer featuring self reset functionality.
- An electrical circuit 20 includes self reset functionality that resets the clock driver following pull down of the output clock signal using feedback from the output clock to the cross-coupled logic circuit.
- the electrical circuit 20 has inputs including a supply voltage 201, V DD , a reset signal 202, RESET, an input clock signal 203, CLK, and a chip select signal 204, CS N.
- the electrical circuit 20 has an output clock signal 206, RCLK.
- a cross-coupled logic circuit 210 couples the input clock signal
- the clock driver 220 includes a pFET 221 coupled to the supply voltage 201 and the reset signal 202.
- the clock driver 220 also has an nFET 222 coupled to the cross-coupled logic circuit 210 and a ground 223.
- An intermediate clock signal 205, RCLK l is output from the clock driver 220.
- a clock inverter 230 couples to the intermediate clock signal 205, RCLK l, and provides the output clock signal 206, RCLK.
- a feedback loop 250 interposed between the output clock 206, RCLK, and the cross-coupled logic circuit 210 provides an output clock signal 207, RCLKl, to the cross-coupled logic circuit 210.
- a keeper circuit 240 interposed between the output clock signal 206, RCLK, and the intermediate clock signal 205, RCLK l, includes a tri- state inverter 241 controlled by the reset signal 202 and the cross coupled logic circuit 210.
- the keeper circuit 240 drives the intermediate clock signal 205, RCLK l to maintain the signal when the intermediate clock signal 205, RCLK l, would otherwise be floating.
- FIGURE 3 is a timing diagram illustrating operation of an exemplary clock buffer featuring self reset functionality.
- a timing diagram 30 includes the chip select signal 204, CS_N, the input clock signal 203, CLK, the intermediate clock signal 205, RCLK l, the reset signal 202, RESET, and the output clock signal 206, RCLK.
- An initial state of the memory circuit 300 includes the chip select signal 204, CS_N, high indicating the memory is disabled. At a state 301 the chip select signal 204, CS_N, goes low indicating the memory has been enabled.
- the first half of the clock cycle begins at a state 302 when the input clock signal 203, CLK, begins a rising edge.
- the chip select signal 204, CS_N remains low for at least a two gate delay following the rising edge of the input clock signal 203, CLK.
- the rising edge of the input clock signal 203, CLK changes the output of the cross-coupled logic circuit 210 to high, which closes the nFET 222 and pulls down the intermediate clock signal 205, RCLK l.
- the output clock 206, RCLK rises in response to the intermediate clock signal 205, RCLK l, being low.
- the feedback loop signal 207, RCLKl goes low causing the output of the cross-coupled logic circuit 210 to open the transistor 222.
- the tri-state inverter 240 is enabled when the reset signal 202, RESET, is high and the output of the cross-coupled logic circuit 210 is low.
- the keeper circuit 240 continues to maintain the intermediate clock signal 205, RCLK l, while both the nFET 222 and the pFET 221 are open.
- the second half of the clock cycle begins at state 305 when the reset signal 305, RESET, falls.
- the tri-state inverter 240 is disabled when the reset signal 305, RESET, falls.
- the pFET 221 closes to pull the intermediate clock signal 205, RCLK l, high. With the tri-state inverter 241 disabled, no contention of the intermediate clock signal 205, RCLK l, occurs.
- the output clock signal 206, RCLK goes low in response to the intermediate clock signal 205, RCLK l, being high. This completes illustration of one cycle of the clock buffer circuit operation.
- One advantage of the disclosed circuitry is the self reset functionality.
- the clock driver pull down path is disabled by feedback circuitry when the internal memory clock pulls down.
- the self reset capability is enabled by cross- coupled logic circuitry coupling the input clock signal and feedback from the output clock to the clock driver.
- a second advantage of the disclosed circuitry is the shortened length of time necessary to hold the chip select line as a result of the cross-coupled circuitry.
- the chip select line must be low long enough to ensure the memory clock pull down has occurred.
- the cross-coupled circuitry resets the pull-down transistor after the memory clock pulls down replacing the delay circuitry previously used. Shortening the chip select hold time reduces timing violations.
- a third advantage of the disclosed circuitry is the removal of one nFET from the clock driver of the conventional clock buffer circuit. Only a single nFET is needed when the cross-coupled circuitry is used. The use of fewer transistors results in higher performance, less occupied circuit area, and lower load on the input clock line.
- a fourth advantage of the disclosed circuitry is the replacement of the latch circuitry with a tri-state inverter.
- Using the tri-state inverter as part of the keeper circuit prevents contention of the memory clock line between the keeper circuit and the clock driver.
- the pull-up transistor will be able to pull-up the intermediate clock signal without competition from the keeper circuit.
- lower supply voltages such as less than one volt, will not cause failure in the clock buffer circuit, enabling more power efficient circuits to be designed.
- FIGURE 4 shows an exemplary wireless communication system
- FIGURE 4 shows three remote units 420, 430, and 450 and two base stations 440. It will be recognized that typical wireless communication systems may have many more remote units and base stations. Remote units 420, 430, and 450 include IC devices 425A, 425B, and 425C, having the disclosed clock buffering circuit. It will be recognized that any device containing memory may also include the clock buffering circuit disclosed here, including the base units.
- FIGURE 4 shows forward link signals 480 from the base stations 440 and the remote units 420, 430, and 450 and reverse link signals 490 from the remote units 420, 430, and 450 to base stations 440.
- remote unit 420 is shown as a mobile telephone
- remote unit 430 is shown as a portable computer
- remote unit 450 is shown as a fixed location remote unit in a wireless local loop system.
- the remote units may be cell phones, hand-held personal communication systems (PCS) units, portable data units such as personal data assistants, or fixed location data units such as meter reading equipment.
- PCS personal communication systems
- FIGURE 4 illustrates remote units according to the teachings of the disclosure, the disclosure is not limited to these exemplary illustrated units. The disclosure may be suitably employed in any device which includes memory devices.
- Coupling refers to any method available to transmit signals from one location to a second location either directly or indirectly. This commonly includes electrical connections.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011526226A JP5543465B2 (en) | 2008-09-09 | 2009-09-04 | Automatic reset (SELFRESET) clock buffer in memory device |
KR1020117008289A KR101261397B1 (en) | 2008-09-09 | 2009-09-04 | Self reset clock buffer in memory devices |
EP09753242.8A EP2351034B1 (en) | 2008-09-09 | 2009-09-04 | Self reset clock buffer in memory devices |
CN200980134766.6A CN102144263B (en) | 2008-09-09 | 2009-09-04 | Self reset clock buffer in memory devices |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US12/207,011 US8000165B2 (en) | 2008-09-09 | 2008-09-09 | Self reset clock buffer in memory devices |
US12/207,011 | 2008-09-09 |
Publications (2)
Publication Number | Publication Date |
---|---|
WO2010030572A2 true WO2010030572A2 (en) | 2010-03-18 |
WO2010030572A3 WO2010030572A3 (en) | 2010-05-06 |
Family
ID=41278484
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2009/056051 WO2010030577A1 (en) | 2008-09-09 | 2009-09-04 | Self reset clock buffer in memory devices |
PCT/US2009/056026 WO2010030572A2 (en) | 2008-09-09 | 2009-09-04 | Self reset clock buffer in memory devices |
Family Applications Before (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2009/056051 WO2010030577A1 (en) | 2008-09-09 | 2009-09-04 | Self reset clock buffer in memory devices |
Country Status (7)
Country | Link |
---|---|
US (2) | US8000165B2 (en) |
EP (1) | EP2351034B1 (en) |
JP (1) | JP5543465B2 (en) |
KR (1) | KR101261397B1 (en) |
CN (1) | CN102144263B (en) |
TW (1) | TW201023205A (en) |
WO (2) | WO2010030577A1 (en) |
Families Citing this family (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8248848B1 (en) | 2007-10-01 | 2012-08-21 | Marvell International Ltd. | System and methods for multi-level nonvolatile memory read, program and erase |
US7825689B1 (en) * | 2009-08-14 | 2010-11-02 | Texas Instruments Incorporated | Functional-input sequential circuit |
US8677199B2 (en) * | 2010-02-16 | 2014-03-18 | Apple Inc. | Pulse dynamic logic gates with mux-D scan functionality |
US8493119B2 (en) * | 2010-12-13 | 2013-07-23 | Apple Inc. | Scannable flip-flop with hold time improvements |
US9223365B2 (en) | 2013-03-16 | 2015-12-29 | Intel Corporation | Method and apparatus for controlled reset sequences without parallel fuses and PLL'S |
WO2017079709A2 (en) * | 2015-11-08 | 2017-05-11 | Fabian Lis | An energy harvesting power-assist system and method for light vehicles |
US9607674B1 (en) * | 2016-01-06 | 2017-03-28 | Qualcomm Incorporated | Pulse latch reset tracking at high differential voltage |
KR101714984B1 (en) * | 2016-08-29 | 2017-03-09 | 인하대학교 산학협력단 | Method and Apparatus for Regionally Self-resetting Circuit |
US10516391B2 (en) * | 2017-12-12 | 2019-12-24 | Micron Technology, Inc. | Apparatuses and methods for data transmission offset values in burst transmissions |
CN112466357A (en) * | 2020-12-07 | 2021-03-09 | 普冉半导体(上海)股份有限公司 | Memory data reading system |
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US6222791B1 (en) | 2000-06-15 | 2001-04-24 | Artisan Components, Inc. | Slew tolerant clock input buffer and a self-timed memory core thereof |
US6329867B1 (en) | 1997-04-25 | 2001-12-11 | Texas Instruments Incorporated | Clock input buffer with noise suppression |
Family Cites Families (7)
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JPH0373491A (en) * | 1989-08-14 | 1991-03-28 | Hitachi Ltd | Semiconductor storage device |
JPH07130166A (en) * | 1993-09-13 | 1995-05-19 | Mitsubishi Electric Corp | Semiconductor storage device and synchronization type semiconductor storage device |
US6809570B2 (en) * | 2003-01-21 | 2004-10-26 | Hewlett-Packard Development Company, L.P. | Clock gater circuit |
TWI237265B (en) * | 2003-08-13 | 2005-08-01 | Ip First Llc | Non-inverting domino register |
JP4717373B2 (en) | 2004-05-20 | 2011-07-06 | 富士通セミコンダクター株式会社 | Semiconductor memory |
KR100772689B1 (en) | 2006-09-29 | 2007-11-02 | 주식회사 하이닉스반도체 | Memory device which includes small clock buffer |
US7646658B2 (en) * | 2007-05-31 | 2010-01-12 | Qualcomm Incorporated | Memory device with delay tracking for improved timing margin |
-
2008
- 2008-09-09 US US12/207,011 patent/US8000165B2/en active Active
-
2009
- 2009-09-04 EP EP09753242.8A patent/EP2351034B1/en active Active
- 2009-09-04 WO PCT/US2009/056051 patent/WO2010030577A1/en not_active Application Discontinuation
- 2009-09-04 WO PCT/US2009/056026 patent/WO2010030572A2/en active Application Filing
- 2009-09-04 JP JP2011526226A patent/JP5543465B2/en active Active
- 2009-09-04 CN CN200980134766.6A patent/CN102144263B/en active Active
- 2009-09-04 KR KR1020117008289A patent/KR101261397B1/en active IP Right Grant
- 2009-09-09 TW TW098130424A patent/TW201023205A/en unknown
-
2010
- 2010-06-03 US US12/792,982 patent/US7948824B2/en active Active
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6329867B1 (en) | 1997-04-25 | 2001-12-11 | Texas Instruments Incorporated | Clock input buffer with noise suppression |
US6222791B1 (en) | 2000-06-15 | 2001-04-24 | Artisan Components, Inc. | Slew tolerant clock input buffer and a self-timed memory core thereof |
Also Published As
Publication number | Publication date |
---|---|
WO2010030577A1 (en) | 2010-03-18 |
US20100238756A1 (en) | 2010-09-23 |
JP2012502402A (en) | 2012-01-26 |
KR101261397B1 (en) | 2013-05-07 |
KR20110067123A (en) | 2011-06-21 |
EP2351034A2 (en) | 2011-08-03 |
US20100061161A1 (en) | 2010-03-11 |
JP5543465B2 (en) | 2014-07-09 |
CN102144263A (en) | 2011-08-03 |
TW201023205A (en) | 2010-06-16 |
US7948824B2 (en) | 2011-05-24 |
WO2010030572A3 (en) | 2010-05-06 |
US8000165B2 (en) | 2011-08-16 |
EP2351034B1 (en) | 2016-08-24 |
CN102144263B (en) | 2014-10-22 |
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