Sun Microsystems, Inc.

Microsoft Technology Licensing, LLC

Apple Inc.

Mosys, Inc.

Wave Computing, Inc.

Shaishav A Desai

Claude R Gauthier

Anup S Mehta

Devendra N Tawari

Pradeep R Trivedi

Charles Walter Boecker

Edgardo F Klass

Brian J Campbell

Minhan Chen

Sridhar Narayanan

Raymond A Heald

Alvin Wang

Michael Raymond Trombley

Gajendra Prasad Singh

Prashant Choudhary

Ping Lu

Farzad Chehrazi

Srinivasa Gopaladhine

Eric Groen

Chethan Rao

Saman Behtash

Haidang Lin

Simon S Li

Md Masum Hossain

In a calibrated digital phase-locked-loop (DPLL) circuit, during a normal operating mode, a control value provided to a digitally controlled oscillator (DCO) is updated by a feedback circuit to keep an output clock generated by the DCO synchronized with a reference clock. The feedback circuit includes a time-to-digital converter (TDC) circuit to measure a phase difference as a time interval. In a calibration operating mode of the calibrated DPLL circuit, calibration of a resolution of a time measurement of the time interval measured by the TDC is performed in the feedback circuit while the control value provided to the DCO is kept constant. Calibrating the TDCs in each of the DPLLs in an integrated circuit (IC) to a nominal resolution in this manner improves synchronization of the clock domains. In some examples, the TDC circuit is a Vernier type circuit and calibration sets a delay difference to a nominal resolution.

Digital phase-locked loops (PLL) including closed-loop time-to-digital converter (TDC) gain calibration circuits and related methods

A domain control circuit includes a power regulator to supply power for a first domain on a power rail and a sequencing circuit to control the power regulator, and a clock gate signal to activate the domain. The sequencing circuit receives a domain control signal to control activation and deactivation of the domain. The domain control circuit deactivates the clock gate signal to the domain after controlling the power regulator to supply power for the domain on a power rail. In this manner, a voltage droop in a supply voltage on a power rail is reduced. In some examples, the clock gate signal to the domain is deactivated after a voltage increase on the power rail. In some examples, the power regulator includes a plurality of parallel regulator circuits and a regulator control circuit to determine a number of the parallel regulator circuits to be activated to power the domain.

Domain clock and power activation control circuit to reduce voltage droop and related methods

A peak detector comprises multiple small-size amplitude detection circuits coupled in parallel to signal inputs at which a signal is received from a VCO. Each amplitude detection circuit generates a voltage on an output, indicating a voltage peak or amplitude of a first signal input and a second signal input (specifically, differential output of VCO). At a given time, only one small-size amplitude detection circuit is activated to load VCO, reducing the impact on LC resonant frequency. The plurality of small-size detection circuits work sequentially, and an automatic averaging of their outputs can significantly improve the peak detector fluctuation (caused by process variation and device mismatch) compared to each single small-size amplitude detection circuit.

Peak voltage amplitude detectors tolerant to process variation and device mismatch and related methods

A digital signal processor includes analog to digital converters to convert an analog voltage to digital voltage in unit intervals of an analog signal. A decision feedback equalizer (DFE) determines a first level of a digital sum of a digital voltage in a first UI and digital voltages of adjacent UIs (taps). The DFE identifies predetermined sequences of levels of consecutive UIs that include the first level and selects one of the predetermined sequences to decode digital data encoded in the analog signal in the UI. The DSP may be programmable to include taps from UIs that may affect the first UI. The predetermined sequences may include levels of the digital sums of consecutive UIs of the analog signal. The predetermined sequences may be identified in a look-up table based on the first level.

Digital signal processors providing scalable decision feedback equalization (DFE) employing sequence selection and related methods

Methods and circuits for analyzing a signal and adjusting parameters of an equalizer for a signal. The signal is received at a receiver over a channel wherein the signal has a wave form. The signal is equalized at an equalizer using an adjustable parameter for the equalization. Data points from the signal are sampled between upper and lower limits of a threshold at an error sampler. A performance metric of the signal is computed based on a statistical density of the data points from the signal between the upper and lower limits of the threshold.

Methods and circuits for adjusting parameters of a transceiver

Disclosed embodiments select a proper hum frequency reference by utilizing one or more functional logic circuits within a cluster. The slowest logic circuit is determined, and an instance of that logic circuit is used in timing circuitry for the cluster. Multiple logic circuits with similar characteristics are incorporated into the timing circuit. Each cluster is interconnected to a second level timing circuit. Each cluster inputs timing information into the second level timing circuit. The second level timing circuit then determines when the next cycle, or tic, of the self-generated clock starts, and the process repeats, providing a self-generated clock signal.

Hum generation using representative circuitry

A clock gater circuit comprises a plurality of transistors having source-drain connections forming a stack between a first node and a supply node. A given logical state on the first node causes a corresponding logical state on an output clock of the clock gater circuit. In one embodiment, a first transistor of the plurality of transistors has a gate coupled to receive an enable input signal. A second transistor is connected in parallel with the first transistor, and has a gate controlled responsive to a test input signal to ensure that the output clock is generated even if the enable input signal is not in an enabled state. In another embodiment, the plurality of transistors comprises a first transistor having a gate controlled responsive to a clock input of the clock gater circuit and a second transistor having a gate controlled responsive to an output of a delay circuit. The delay circuit comprises at least one inverter, wherein an input of the delay circuit is the clock input, and wherein a first inverter of the delay circuit is coupled to receive a test input signal and is configured to force a first logical state on an output of the first inverter responsive to an assertion of the test input signal.

Clock gater with test features and low setup time

The subject innovation relates to systems and/or methodologies for generating a low jitter large frequency tuning LC-based phase-locked loop circuit for multi-speed clocking applications. In addition to a plurality of noise reduction features, the phase-locked loop includes programmable charge pump and loop filter that enable a wide loop bandwidth, a programmable VCO that enables a wide VCO frequency range and a per lane clock divider that further enables a wide PLL frequency range. Furthermore, an auto-calibration circuit ensures that the VCO included in the PLL receives the optimum current for noise reduction across the VCO frequency range.

Low jitter large frequency tuning LC PLL for multi-speed clocking applications

A system and method of adjusting a sense amplifier includes providing an amplification control parameter to the sense amplifier. A temperature of the sense amplifier is monitored and the amplification control parameter to the sense amplifier is adjusted according to the temperature of the sense amplifier.

Sense amplifier thermal correction scheme

A plurality of on-chip temperature sensors are selectively distributed across an integrated circuit. The temperature sensors generate signals indicative of operating temperatures experienced by the portions of the integrated circuit on which the temperature sensors are disposed. Based on the temperatures of the portions of the integrated circuit, operation of particular circuitry of the integrated circuit is dynamically adjusted to counteract the effects of undesirable or unexpected operating temperatures.

Dynamic circuit operation adjustment based on distributed on-chip temperature sensors

A method and apparatus for adjusting clock skew involves using a plurality of oscillators distributed across the apparatus where at least one of the plurality of oscillators has a frequency dependent on a characteristic of the apparatus. A processor is arranged to adjust a bias generator dependent on the frequency. The bias generator is arranged to adjust a delay through a tunable buffer. The tunable buffer is arranged to propagate a clock signal dependent on the adjustment of the delay through the tunable buffer dependent on the bias generator.

Clock skew reduction technique based on distributed process monitors

An invention is provided for an adaptive keeper circuit. The adaptive keeper circuit includes a first keeper transistor having a first terminal in electrical communication with a power supply and a second terminal in electrical communication with an internal dynamic node. In addition, a second keeper transistor is included that is configured in parallel to the first keeper transistor. The second keeper transistor also has a first terminal in electrical communication with the power supply. The second keeper transistor can be added to the first keeper transistor using a feedback bit line, which is configured to control current flow between the second keeper transistor and the internal dynamic node based on a state of the feedback bit line. The state of the feedback bit line is based on a process corner characteristic of the die. Additional keeper transistors and corresponding feedback bit lines can be added to the keeper circuit to increase flexibility.

Adaptive keeper sizing for dynamic circuits based on fused process corner data

An invention is disclosed for a process monitor based keeper scheme for dynamic circuits. A semiconductor die having a process monitor based keeper scheme of the embodiments of the present invention generally includes a plurality of dynamic circuits, each having an adaptive keeper circuit capable of being adjusted based on a bit code. In addition, a plurality of process monitors is included. Each process monitor is disposed within a corresponding die block, which defines a local area of the die. The process monitors are capable of detecting process corner data for the corresponding die block. In communication with each process monitor and the plurality of dynamic circuits is a test processor unit. The test processor unit obtains process corner data for each die block from the process monitor disposed within the die block, and provides a bit code based on the process corner data to the dynamic circuits disposed within the die block.

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San Jose, CA, United States of America

Shaishav A Desai