Tunable Sector Buffer for Wide Bandwidth Resonant Global Clock Distribution

• US 20150234422A1
• Filed: 05/07/2015
• Published: 08/20/2015
• Est. Priority Date: 02/05/2013
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bucelot, Thomas J., Drake, Alan J., Groves, Robert A., Hibbeler, Jason D., Kim, Yong I., Pang, Liang-Teck, Reohr, William R., Restle, Phillip J., Thomson, Michael G.R.
• Granted Patent: US 9,612,612 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 1/10 Distribution of clock signals , e.g. skew
• CPC Class Codes: G06F 1/324 by lowering clock frequency
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A wide bandwidth resonant clock distribution comprises a clock grid configured to distribute a clock signal to a plurality of components of an integrated circuit and a tunable sector buffer configured to receive the clock signal and provide an output to the clock grid. The tunable sector buffer is configured to set latency and slew rate of the clock signal based on an identified resonant or non-resonant mode.

Claims

1. A wide bandwidth resonant clock distribution comprising:

a clock grid configured to distribute a clock signal to a plurality of components of an integrated circuit; and

a tunable sector buffer configured to receive the clock signal and provide an output to the clock grid, wherein the tunable sector buffer is configured to set latency and slew rate of the clock signal based on an identified resonant or non-resonant mode,

wherein the tunable sector buffer comprising a plurality of NOR gate fingers, a plurality of first inverter fingers, a plurality of NAND gate fingers, and a plurality of second inverter fingers.

2. The clock distribution of claim 1, wherein the identified resonant or non-resonant mode is determined based on a frequency of the clock signal.

3. The clock distribution of claim 1, wherein the tunable sector buffer receives an enable signal and the clock signal, wherein the tunable sector buffer comprises a NOR gate that receives the clock signal and an inverted enable signal and provides output to a first inverter, wherein the tunable sector buffer further comprises a NAND gate that receives the clock signal and the enable signal and provides output to a second inverter, wherein the tunable sector buffer further comprises a first transistor and a second transistor connected in series, wherein a gate node of the first transistor connects to an output of the first inverter and a source node of the first transistor connects to a first reference voltage, wherein a gale node of the second transistor connects to an output of the second inverter and a drain node of the second transistor connects to a second reference voltage, and wherein a drain node of the first transistor connects to a source node of the second transistor, wherein the source node of the second transistor provides an output of the tunable sector buffer.

4. The clock distribution of claim 3, wherein, configuring the tunable sector butler comprises configuring the NOR gate to have a first beta value, configuring the first inverter to have a second beta value, configuring the NAND gate to have a third beta value, wherein the first beta value, the second beta value, the third beta value, and the fourth beta value control slew rates and latency based on the identified resonant or non-resonant mode.

5. The clock distribution of claim 4, wherein configuring the tunable sector buffer comprises configuring the NOR gate, the first inverter, the NAND gate, and the second inverter such that the first beta value, the second beta value, the third beta value, and the fourth beta value prevent shoot-through current in output.

7. The dock distribution of claim 1, wherein configuring the tunable sector buffer comprises connecting one or more of the plurality of NOR gate fingers and one or more of the plurality of NAND gate fingers for large gain or large driver size.

8. The clock distribution of claim 7, wherein connecting one or more of the plurality of NOR gate fingers and one or more of the plurality of NAND gate fingers comprises connecting the one or more of the plurality of NOR gate fingers and the one or more of the plurality of NAND gate fingers in parallel.

9. The clock distribution of claim 8, wherein connecting the one or more of the plurality of NOR gate fingers and the one or more of the plurality of NAND gate fingers in parallel comprises connecting the one or more of the plurality of NOR gate fingers and the one or more of the plurality of NAND gate fingers in linear steps.

10. The clock distribution of claim 8, wherein connecting the one or more of the plurality of NOR gate fingers and the one or more of the plurality of NAND gate fingers in parallel comprises connecting the one or more of the plurality of NOR gate fingers and the one or more of the plurality of NAND gate fingers in geometric steps, wherein each step size is proportionally larger than a previous step size.

11. The clock distribution of claim 7, wherein connecting one or more of the plurality of NOR gate fingers and one or more of the plurality of NAND gate fingers comprises connecting the one or more of the plurality of NOR gate fingers and the one or more of the plurality of NAND gate fingers in a metal layer of the integrated circuit.

12. The clock distribution of claim 3, wherein configuring the tunable sector buffer comprises connecting one or more of the plurality of first inverter fingers and one or more of the plurality of second inverter fingers for small gain, small driver, low power.

13. The clock distribution of claim 12, wherein connecting one or more of the plurality of first inverter fingers and one or more of the plurality of second inverter fingers comprises connecting the one or more of the plurality of first inverter fingers and the one or more of the plurality of second inverter fingers in parallel.

14. The clock distribution of claim 13, wherein connecting the one or more of the plurality of first inverter fingers and the one or more of the plurality of second inverter fingers in parallel comprises connecting the one or more of the plurality of first inverter fingers and the one or more of the plurality of second inverter fingers in linear steps.

15. The clock distribution of claim 13, wherein connecting the one or more of the plurality of first inverter fingers and the one or more of the plurality of second inverter fingers in parallel comprises connecting the one or more of the plurality of first inverter fingers and the one or more of the plurality of second inverter fingers in geometric steps, wherein each step size is proportionally larger than a previous step size.

16. The clock distribution of claim 12, wherein connecting one or more of fee plurality of first inverter fingers and one or more of the plurality of second inverter fingers comprises connecting the one or more of the plurality of first inverter fingers and the one or more of the plurality of second inverter fingers in a metal layer of the integrated circuit.

17. The clock distribution of claim 3, wherein configuring the tunable sector buffer comprises configuring the first transistor with a first channel width and configuring the second transistor with a second channel width, wherein the first channel width and the second channel width control slew rates and power levels.

18. The clock distribution of claim 3, wherein the tunable sector buffer further comprises a plurality of first transistor fingers and a plurality of second transistor fingers.

19. The clock distribution of claim 18, wherein configuring the tunable sector buffer comprises connecting one or more of the plurality of first transistor fingers and one or more of the plurality of second transistor fingers for small gain, high power.

20. The clock distribution of claim 19, wherein connecting one or more of the plurality of first transistor fingers and one or more of the plurality of second transistor fingers comprises connecting the one or more of the plurality of first transistor fingers and the one or more of the plurality of second transistor fingers in parallel.

21. The clock distribution of claim 20, wherein connecting the one or more of the plurality of first transistor fingers and the one or more of the plurality of second transistor fingers is parallel comprises connecting the one or more of the plurality of first transistor fingers and the one or more of the plurality of second transistor fingers in linear steps.

22. The clock distribution of claim 20, wherein connecting the one or more of the plurality of first transistor fingers and the one or more of the plurality of second transistor fingers In parallel comprises connecting the one or more of the plurality of first transistor fingers and the one or more of the plurality of second transistor fingers in geometric steps, wherein each step size is proportionally larger than a previous step size.

23. The clock distribution of claim 3, wherein the first transistor is a p-channel field effect transistor (PFET) and wherein the second transistor is an n-channel field effect transistor (NFET).

6. (canceled)

24. A wide bandwidth resonant clock distribution comprising:

a clock grid configured to distribute a clock signal to a plurality of components of an integrated circuit; and

a plurality of tunable sector buffer stages, wherein each tunable sector buffer stage is configured to receive the clock signal and provide an output to the clock grid, wherein each tunable sector buffer stage comprises at least one selectable tunable sector buffer, wherein each tunable sector buffer is configured to set latency and slew rate of the clock signal based on an Identified resonant or non-resonant mode,

wherein each tunable sector buffer comprises a plurality of NOR gate fingers, a plurality of first invert fingers, a plurality of NAND gate fingers, and a plurality of second inverter fingers.

25. The clock distribution of claim 24, wherein, each given tunable sector buffer receives a corresponding enable signal and the clock signal, wherein each given tunable sector buffer comprises a NOR gale that receives the clock signal and an inverted enable signal and provides output to a first inverter, wherein each given tunable sector buffer further comprises a NAND gate that receives the clock signal and the enable signal and provides output to a second inverter, wherein each given tunable sector buffer further comprises a first transistor and a second transistor connected in series, wherein a gate node of the first transistor connects to an output of the first inverter and a source node of the first transistor connects to a first reference voltage, wherein a gate node of the second transistor connects to an output of the second inverter and a drain node of the second transistor connects to a second reference voltage, and wherein a drain node of the first transistor connects to a source node of the second transistor, wherein the source node of the second transistor provides an output of the given tunable sector buffer.

26. The clock distribution of claim 25, wherein configuring a given tunable sector buffer comprises configuring the NOR gate to have a first beta value, configuring the first inverter to have a second beta value, configuring the NAND gate to have a third beta value, wherein the first beta value, the second beta value, the third beta value, and the fourth beta value control slew rates and latency based on the Identified resonant or non-resonant mode.

27. The clock distribution of claim 25, wherein configuring a given tunable sector buffer comprises configuring the first transistor with a first channel width and configuring the second transistor with a second channel width, wherein the first channel width and the second channel width control slew rates and power levels.

28. A method for wide bandwidth resonant clock distribution, the method comprising:

identifying a resonant mode for an integrated circuit based, on a frequency of a clock signal for the integrated circuit wherein the integrated circuit comprises a plurality of components, a clock grid configured to distribute the clock signal to the plurality of components, and a tunable sector buffer configured to receive the clock signal and provide an output to the clock grid; and

configuring the tunable sector buffer to set latency and slew rate of the clock signal; and

configuring the at least one tunable resistance switch to dynamically switch the at least one inductor in or out of the clock distribution to effect the identified resonant mode,

wherein the tunable sector buffer comprises a plurality of NOR gate fingers, a plurality of first inverter fingers, a plurality of NAND gate fingers, and a plurality of second inverter fingers.

29. The method of claim 28, wherein the tunable sector buffer receives an enable signal and the clock signal wherein the tunable sector buffer comprises a NOR gate that receives the clock signal and an inverted enable signal and provides output to a first inverter, wherein the tunable sector buffer further comprises a NAND gate that receives the clock signal and the enable signal and provides output to a second inverter, wherein the tunable sector buffer further comprises a first transistor and a second transistor connected in series, wherein a gate node of the first transistor connects to an output of the first inverter and a source node of the first transistor connects to a first reference voltage, wherein a gate node of the second transistor connects to an output of the second inverter and a drain node of the second transistor connects to a second reference voltage, and wherein a drain node of the first transistor connects to a source node of the second transistor, wherein the source node of the second transistor provides an output of the tunable sector buffer.

30. The method of claim 29, wherein configuring the tunable sector buffer comprises configuring the NOR gate to have a first beta value, configuring the first inverter to have a second beta value, configuring the NAND gate to have a third beta value, wherein the first beta value, the second beta value, the third beta value, and the fourth beta value control slew rates and latency based on the identified resonant or non-resonant mode.

31. The method of claim 29, wherein configuring a given tunable sector buffer comprises configuring the first transistor with a first channel width and configuring the second transistor with a second channel width, wherein the first channel width and the second channel width control slew rates and power levels.