US6570944B2
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for data recovery in a synchronous chip-to-chip system
Assignee: Rambus Inc
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Filing: 2001-06-25
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Granted: 2003-05-27
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Expires: 2021-06-25
Abstract
Abstract An apparatus that reduces sampling errors for data communicated between devices uses phase information acquired from a timing reference signal such as a strobe signal to align a data-sampling signal for sampling a data signal that was sent along with the timing reference signal. The data-sampling signal may be provided by adjustably delaying a clock signal according to the phase information acquired from the strobe signal. The data-sampling signal may also have an improved waveform compared to the timing reference signal, including a fifty percent duty cycle and sharp transitions. The phase information acquired from the timing reference signal may also be used for other purposes, such as aligning received data with a local clock domain, or transmitting data so that it arrives at a remote device in synchronism with a reference clock signal at the remote device.
Inventors
- 👤 Scott C. Best
- 👤 Richard E. Warmke
- 👤 David B. Roberts
- 👤 Frank Lambrecht
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 00:05
CPC Classifications
H; H03; H03L; H03L7/00; H03L7/06; H03L7/08; H03L7/081; H03L7/0812; H03L7/0814; G; G06; G06F; G06F1/00; G06F1/04; G06F1/10; G11; G11C; G11C11/00; G11C11/21; G11C11/34; G11C11/40; G11C11/401; G11C11/4063; G11C11/407; G11C11/4076; G11C11/409; G11C11/4091; G11C7/00; G11C7/10; G11C7/1078; G11C7/1087; G11C7/22; G11C7/222; H03L7/07; H04; H04L; H04L7/00; H04L7/02; H04L7/033; H04L7/0337; G11C2207/00; G11C2207/10; G11C2207/107; G11C7/04
Claims Analysis
Total Claims: 31
Claim 1
Independent Claim
129 words
An apparatus comprising: a variable delay circuit to generate a data-sampling signal that is delayed relative to a reference clock signal according to a delay control signal; a control circuit coupled to receive the data-sampling signal from the variable delay circuit and to receive a timing reference signal from a data transmitting device, the control circuit including circuitry to determine a phase difference between the data-sampling signal and the timing reference signal and to generate the delay control signal according to the phase difference; and a receive circuit coupled to receive the data-sampling signal from the variable delay circuit and to receive a data signal from the data transmitting device, the receive circuit including circuitry to sample the data signal in response to a transition of the data-sampling signal.
Claim 2
Independent Claim
129 words
An apparatus comprising: a variable delay circuit to generate a data-sampling signal that is delayed relative to a reference clock signal according to a delay control signal; a control circuit coupled to receive the data-sampling signal from the variable delay circuit and to receive a timing reference signal from a data transmitting device, the control circuit including circuitry to determine a phase difference between the data-sampling signal and the timing reference signal and to generate the delay control signal according to the phase difference; and a receive circuit coupled to receive the data-sampling signal from the variable delay circuit and to receive a data signal from the data transmitting device, the receive circuit including circuitry to sample the data signal in response to a transition of the data-sampling signal.
Claim 3
Dependent Claim
23 words
The apparatus of claim 1 , wherein the phase difference between the data-sampling signal and the timing reference signal is approximately ninety degrees.
Claim 4
Dependent Claim
28 words
The apparatus of claim 1 , wherein the receive circuit is adapted to sample the data signal in response to rising and falling transitions of the data-sampling signal.
Claim 5
Dependent Claim
50 words
The apparatus of claim 1 , wherein the timing reference signal has a plurality of rising transitions and a plurality of falling transitions, and the control circuit is adapted to determine the phase difference based upon only one of the plurality of rising transitions and the plurality of falling transitions.
Claim 6
Dependent Claim
73 words
The apparatus of claim 1 , wherein the receive circuit is adapted to sample the data signal in response to a rising and a falling transition of the data-sampling signal, the timing reference signal has a plurality of rising transitions and a plurality of falling transitions, and the control circuit is adapted to determine the phase difference based upon only one of the plurality of rising transitions and the plurality of falling transitions.
Claim 7
Dependent Claim
17 words
The apparatus of claim 1 , wherein the timing reference signal is transmitted synchronously with data signal.
Claim 8
Dependent Claim
39 words
The apparatus of claim 1 , wherein the variable delay circuit includes a plurality of delays through which the reference clock signal passes, with a number of the delays selected by the control signal to generate the data-sampling signal.
Claim 9
Dependent Claim
26 words
The apparatus of claim 1 , further comprising a mechanism configured to read, with the reference clock signal, the data signal sampled by the receive circuit.
Claim 10
Dependent Claim
48 words
The apparatus of claim 1 , further comprising a transmit state derived from the control signal and controlling an interpolator to output a transmit timing signal that is input to a data transmit circuit that is adapted to send data according to transitions of the transmit timing signal.
Claim 11
Dependent Claim
36 words
The apparatus of claim 1 , further comprising a duty cycle correction circuit operably coupled to the variable delay circuit and adapted to modify an output of the variable delay circuit to generate the data-sampling signal.
Claim 12
Dependent Claim
31 words
The apparatus of claim 1 , further comprising first and second receive circuits adapted to sample respective first and second data signals in response to the transition of the data-sampling signal.
Claim 13
Dependent Claim
59 words
The apparatus of claim 11 , further comprising a plurality of delay elements connectable between the variable delay circuit and the plurality of receive circuits, such that the data-sampling signal passes through a different number of the delay elements in traveling to the first receive circuit than the data-sampling signal passes through in traveling to the second receive circuit.
Claim 14
Independent Claim
90 words
An apparatus comprising: a variable delay circuit adapted to generate a data-sampling signal that is delayed relative to a reference clock signal according to a control signal; a control circuit operably coupled to the variable delay circuit and adapted to determine a phase difference between the data-sampling signal and a strobe signal and to generate the control signal according to the phase difference; and a receive circuit operably coupled to the variable delay circuit and adapted to sample a data signal in response to a transition of the data-sampling signal.
Claim 15
Independent Claim
90 words
An apparatus comprising: a variable delay circuit adapted to generate a data-sampling signal that is delayed relative to a reference clock signal according to a control signal; a control circuit operably coupled to the variable delay circuit and adapted to determine a phase difference between the data-sampling signal and a strobe signal and to generate the control signal according to the phase difference; and a receive circuit operably coupled to the variable delay circuit and adapted to sample a data signal in response to a transition of the data-sampling signal.
Claim 16
Dependent Claim
22 words
The apparatus of claim 13 , wherein the phase difference between the data-sampling signal and the strobe signal is approximately ninety degrees.
Claim 17
Dependent Claim
28 words
The apparatus of claim 13 , wherein the receive circuit is adapted to sample the data signal in response to rising and falling transitions of the data-sampling signal.
Claim 18
Dependent Claim
49 words
The apparatus of claim 13 , wherein the strobe signal has a plurality of rising transitions and a plurality of falling transitions, and the control circuit is adapted to determine the phase difference based upon only one of the plurality of rising transitions and the plurality of falling transitions.
Claim 19
Dependent Claim
72 words
The apparatus of claim 13 , wherein the receive circuit is adapted to sample the data signal in response to a rising and a falling transition of the data-sampling signal, the strobe signal has a plurality of rising transitions and a plurality of falling transitions, and the control circuit is adapted to determine the phase difference based upon only one of the plurality of rising transitions and the plurality of falling transitions.
Claim 20
Dependent Claim
16 words
The apparatus of claim 17 , wherein the strobe signal is transmitted synchronously with data signal.
Claim 21
Dependent Claim
39 words
The apparatus of claim 13 , wherein the variable delay circuit includes a plurality of delays through which the reference clock signal passes, with a number of the delays selected by the control signal to generate the data-sampling signal.
Claim 22
Dependent Claim
26 words
The apparatus of claim 13 , further comprising a mechanism configured to read, with the reference clock signal, the data signal sampled by the receive circuit.
Claim 23
Dependent Claim
48 words
The apparatus of claim 13 , further comprising a transmit state derived from the control signal and controlling an interpolator to output a transmit timing signal that is input to a data transmit circuit that is adapted to send data according to transitions of the transmit timing signal.
Claim 24
Dependent Claim
36 words
The apparatus of claim 13 , further comprising a duty cycle correction circuit operably coupled to the variable delay circuit and adapted to modify an output of the variable delay circuit to generate the data-sampling signal.
Claim 25
Dependent Claim
31 words
The apparatus of claim 13 , further comprising first and second receive circuits adapted to sample respective first and second data signals in response to the transition of the data-sampling signal.
Claim 26
Dependent Claim
59 words
The apparatus of claim 23 , further comprising a plurality of delay elements connectable between the variable delay circuit and the plurality of receive circuits, such that the data-sampling signal passes through a different number of the delay elements in traveling to the first receive circuit than the data-sampling signal passes through in traveling to the second receive circuit.
Claim 27
Dependent Claim
34 words
The apparatus of claim 13 , further comprising a plurality of delay elements connectable to the variable delay circuit such that the phase difference between the data-sampling signal and a strobe signal is adjustable.
Claim 28
Independent Claim
130 words
A system for transferring information, the system comprising: a first device including a data transmitter adapted to generate a data signal and a timing reference transmitter adapted to generate a timing reference signal; and a second device coupled to the first device and including a delay-locked loop adapted to delay a clock signal and thereby create a data-sampling signal having a predetermined phase relationship with the timing reference signal, and a receive circuit adapted to sample the data signal with the data-sampling signal, wherein the delay-locked loop includes first and second outputs, the first output providing a phase-lock signal that is approximately in phase with the timing reference signal, and the second output providing the data-sampling signal that is approximately ninety degrees out of phase with the timing reference signal.
Claim 29
Independent Claim
130 words
A system for transferring information, the system comprising: a first device including a data transmitter adapted to generate a data signal and a timing reference transmitter adapted to generate a timing reference signal; and a second device coupled to the first device and including a delay-locked loop adapted to delay a clock signal and thereby create a data-sampling signal having a predetermined phase relationship with the timing reference signal, and a receive circuit adapted to sample the data signal with the data-sampling signal, wherein the delay-locked loop includes first and second outputs, the first output providing a phase-lock signal that is approximately in phase with the timing reference signal, and the second output providing the data-sampling signal that is approximately ninety degrees out of phase with the timing reference signal.
Claim 30
Independent Claim
131 words
A system for transferring information, the system comprising: a first device including a data transmitter adapted to generate a data signal and a strobe transmitter adapted to generate a strobe signal; and a second device coupled to the first device and including a delay-locked loop adapted to delay a clock signal and thereby create a data-sampling signal having a predetermined phase relationship with the strobe signal, and a receive circuit adapted to sample the data signal with the data-sampling signal, wherein the delay-locked loop includes first and second outputs, the first output providing a phase-lock signal that is configured to be approximately in phase with the strobe signal, and the second output providing the data-sampling signal that is configured to be approximately ninety degrees out of phase with the strobe signal.
Claim 31
Independent Claim
131 words
A system for transferring information, the system comprising: a first device including a data transmitter adapted to generate a data signal and a strobe transmitter adapted to generate a strobe signal; and a second device coupled to the first device and including a delay-locked loop adapted to delay a clock signal and thereby create a data-sampling signal having a predetermined phase relationship with the strobe signal, and a receive circuit adapted to sample the data signal with the data-sampling signal, wherein the delay-locked loop includes first and second outputs, the first output providing a phase-lock signal that is configured to be approximately in phase with the strobe signal, and the second output providing the data-sampling signal that is configured to be approximately ninety degrees out of phase with the strobe signal.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2006-05-26 | 2006-11-25 | 2007-05-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2010-05-26 | 2010-11-25 | 2011-05-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2014-05-26 | 2014-11-25 | 2015-05-27 | $7700.00 | Window Closed / Lapsed |