International Business Machines Corporation

Thomas J Bucelot

Phillip John Restle

Alan J Drake

Liang-Teck Pang

Jason D Hibbeler

William Robert Reohr

David Wen-Hao Shan

Michael G R Thomson

Robert Allen Groves

Yong I Kim

Robert Louis Franch

Aditya Bansal

Christos Vezyrtzis

Mrigank Sharad

David W Shan

Gregory Scott Still

Joshua D Friedrich

A clock driver control scheme for a resonant clock distribution network provides robust operation by controlling a pulse width of the output of clock driver circuits that drive the resonant clock distribution network so that changes are sequenced. The clock driver control circuit controls the clock driver circuits in the corresponding sector according to a selected operating mode via a plurality of control signals provided to corresponding clock driver circuits. The pulse widths differ for at least some of the sectors during operation of digital circuits within the integrated circuit having clock inputs coupled to the resonant clock distribution network. The different pulse widths may be a transient difference that is imposed in response to a mode or frequency change of the global clock that provides an input to the clock driver circuits.

Sequenced pulse-width adjustment in a resonant clocking circuit

A pulse-drive resonant clock with on-the fly mode changing provides robust operation in a resonant clock distribution network, in particular for processor circuits having a dynamically-varied operating frequency. The clock drivers for the resonant clock distribution network include a pulse width control circuit having selectable operating modes corresponding to multiple clocking modes of the resonant clock distribution network. The pulse width control circuit includes a delay line that has a selectable delay length to provide pulse enable signals that control the pulse widths of the clock drivers in a sector of the resonant clock distribution network. The delay line responds to a mode control signal so that at least one pulse width of the output is changed from a first pulse width to a second pulse width without generating half-cycles with a pulse width narrower than the first or second pulse width.

Pulse-drive resonant clock with on-the-fly mode change

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.

Tunable sector buffer for wide bandwidth resonant global clock distribution

A clock driver is provided. The clock driver includes a multi-stage delay cell having an input, a positive pulse driving branch, a negative pulse driving branch, and an output. The input is for receiving an original version of a reference clock signal input to the clock driver and used to generate a global clock signal. The output is connected to the positive pulse driving branch and the negative pulse driving branch. The clock driver further includes a pulse generator having positive and negative pulse generator portions respectively connected to outputs of the positive and negative pulse driving branches. The pulse generator generates, at any given time, one of a positive pulse and a negative pulse responsive to a positive pulse enable signal and a negative pulse enable signal, respectively, and the original version of the reference clock signal input to the clock driver without modification.

Clock buffers with pulse drive capability for power efficiency

A clock driver and corresponding method are provided. The clock driver includes a multi-stage delay cell having logic circuitry and a plurality of serially connected delay elements. An input of the delay elements receives an original version of a reference clock signal input to the clock driver and used to generate a global clock signal. An output of the delay elements connects to positive and negative pulse driving branches formed from the logic circuitry. The clock driver further includes a pulse generator forming positive and negative pulse generator portions respectively connected to outputs of the positive and negative pulse driving branches. The pulse generator generates, at any given time, one of a positive pulse and a negative pulse responsive to a positive pulse enable signal and a negative pulse enable signal, respectively, and the original version of the reference clock signal input to the clock driver without modification.

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, a tunable sector buffer configured to receive the clock signal and provide an output to the clock grid, at least one inductor, at least one tunable resistance switch, and a capacitor network. The tunable sector buffer is programmable to set latency and slew rate of the clock signal. The inductor, tunable resistance switch, and capacitor network are connected between the clock grid and a reference voltage. The at least one tunable resistance switch is programmable to dynamically switch the at least one inductor in or out of the clock distribution to effect at least one resonant mode of operation or a non-resonant mode of operation based on a frequency of the clock signal.

Wide bandwidth resonant global clock distribution

Described is an integrated circuit having a clock distribution network capable of transitioning from a non-resonant clock mode to a first resonant clock mode Transitions between clock modes or between various resonant clock frequencies are done gradually over a series of clock cycles. In example, when transitioning from a non-resonant clock mode to a first resonant clock mode, a strength of a clock sector driver is reduced over a series of clock cycles, and individual ones of a plurality of resonant switches associated with resonant circuits are modified in coordination with reducing the strength of the clock sector driver.

Changing resonant clock modes

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, at least one inductor, at least one tunable resistance switch, and a capacitor network. The inductor, tunable resistance switch, and capacitor network are connected between the clock grid and a reference voltage. The at least one tunable resistance switch is programmable to dynamically switch the at least one inductor in or out of the clock distribution to effect at least one resonant mode of operation or a non-resonant mode of operation based on a frequency of the clock signal.

Variable resistance switch for wide bandwidth resonant global clock distribution

There is provided a clock distribution network for synchronizing global clock signals within a 3D chip stack having two or more strata. On each of the two or more strata, the clock distribution network includes a clock grid having a plurality of sectors for providing the global clock signals to various chip locations, a multiple-level buffered clock tree for driving the clock grid and including at least a root and a plurality of clock buffers, and one or more multiplexers for providing the global clock signals to at least a portion of the buffered clock tree. Inputs of at least some of the plurality of clock buffers on each of the two or more strata are shorted together using chip-to-chip interconnects to reduce skewing of the global clock signals with respect to the various chip locations.

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Wappingers Falls, NY, United States of America

Thomas J Bucelot