Systems And Methods For Distributing A Clock Signal

• US 20090302952A1
• Filed: 12/29/2006
• Published: 12/10/2009
• Est. Priority Date: 12/29/2005
• Status: Active Grant

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Shepard, Kenneth L., Chan, Steven, Xu, Zheng
• Granted Patent: US 7,880,551 B2
• Time in Patent Office: Days
• US Class Current: 331/48
• CPC Class Codes: G06F 1/00 Details not covered by groups G06F3/00 - G06F13/00 and G06F21/00 architectures of general purpose stored program computers G06F15/76
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew
• CPC Class Codes: H03L 5/00 Automatic control of voltage, current, or power
• CPC Class Codes: H03L 7/081 provided with an additional controlled phase shifter H03L7/0998 takes precedence
• CPC Class Codes: H03L 7/087 using at least two phase detectors or a frequency and phase detector in the loop
• CPC Class Codes: H03L 7/24 using a reference signal directly applied to the generator

Abstract

Systems and methods for distributing a clock signal are disclosed. In some embodiments, systems for distributing a clock signal include a plurality of resonant oscillators, each comprising an inductor; and a differential clock grid that distributes the clock signal. The differential clock grid is coupled to the plurality of resonant oscillators and the clock signal, and the inductances of the inductors are configured such that a resonant frequency of the plurality of resonant oscillators is substantially equal to the frequency of the clock signal.

Claims

1. A system for distributing a clock signal comprising:

a plurality of resonant oscillators, each comprising an inductor; and

a differential clock grid, coupled to the plurality of resonant oscillators and the clock signal, that distributes the clock signal,

wherein the inductances of the inductors are configured such that a resonant frequency of the plurality of resonant oscillators is substantially equal to the frequency of the clock signal.

2. The system of claim 1, further comprising an injection locker that provides the clock signal from an external source to the differential clock grid.

3. The system of claim 2, wherein the injection locker is an injection locking tree providing a clock signal to the plurality of resonant oscillators.

4. The system of claim 1, further comprising a plurality of H-treelets coupling the differential clock grid to the plurality of resonant oscillators.

5. The system of claim 1, wherein each of the plurality of resonant oscillators further comprises a gain element to maintain oscillation.

6. The system of claim 1, wherein each of the plurality of resonant oscillators further includes a tunable capacitor for tuning the resonant oscillator.

7. The system of claim 6, wherein the tunable capacitor is digitally tunable.

8. The system of claim 1, wherein the inductors are spiral inductors.

9. The system of claim 1, further comprising a de-skewing circuit for aligning the phase of the clock signal between each of the plurality of resonant oscillators.

10. The system of claim 1, further comprising a gain element coupled to each of the plurality of resonant oscillators to provide gain to the clock signal.

11. The system of claim 10, further comprising an automatic amplitude control circuit for adjusting the gain of the gain element.

12. A method for distributing a clock signal comprising:

driving a differential clock grid with the clock signal; and

coupling a plurality of resonant oscillators to the differential clock grid, wherein each resonant oscillator comprises an inductor with an inductance such that a resonant frequency of the plurality of resonant oscillators is substantially equal to the frequency of the clock signal,

wherein the differential clock grid distributes the clock signal.

13. The method of claim 12, further comprising adjusting the resonant frequency of the plurality of resonant oscillators.

14. The method of claim 12, further comprising aligning the phase of the clock signal between each of the plurality of resonant oscillators.

15. The method of claim 12, further comprising compensating for loss using a gain element.

16. The method of claim 15, further comprising automatically adjusting the gain of the gain element.

17. The method of claim 12, further comprising injection locking the clock signal from an external source.

18. The method of claim 17, further comprising using an injection locking tree to provide the clock signal to the plurality of resonant oscillators.

19. A system for distributing a clock signal comprising:

a means for storing and discharging at least part of the energy of the clock signal at a frequency substantially equal to the frequency of the clock signal; and

a means for differentially distributing the clock signal connected to the means for storing and discharging at least part of the energy of a clock signal.

20. The system of claim 19, further comprising means for maintaining oscillation connected to the means for storing and discharging the energy of a clock signal.

21. The system of claim 20, further comprising means for adjusting a gain of the means for maintaining oscillation.

22. The system of claim 21, further comprising means for aligning the phase of the clock signal between each of the means for storing and discharging at least part of the energy of the clock signal.