International Business Machines Corporation

Glen Arthur Wiedemeier

Daniel Mark Dreps

Chad Andrew Marquart

John Cummings Schiff

Kyu-hyoun Kim

Yang You

Wiren Dale Becker

Jose A Hejase

Si T Win

Dereje G Yilma

Venkat Harish Nammi

Jeffrey Kwabena Okyere

Paul William Coteus

Michael Anthony Sorna

Christopher W Steffen

Pier Andrea Francese

Erik English

Kirk Edward Morrow

Joel David Ziegelbein

Michael Wayne Harper

Jethro C Law

Vikram B Raj

Nathan Ross Blanchard

Dan P Bernard

Daniel Joseph Friedman

Frank David Ferraiolo

Sudipto Chakraborty

Hillery C Hunter

Jieming Qi

James David Strom

Marcel A Kossel

Thomas Helmut Toifl

Robert J Reese

Seongwon Kim

Matthew James Paschal

Bao G Truong

Peter A Smith

Carrie Ellen Cox

Eric John Lukes

Timothy O Dickson

John Greg Massey

Akil Khamisi Sutton

Bruce George Rudolph

Hector Saenz

Dhaval R Sejpal

William Edward Ansley

Tyler Bohlke

James Crugnale

John C Schief

Ze Zhang

A power saving improvement in an injection locked oscillator (ILO) used is described. The ILO circuitry comprises a feedback path to provide a finecal (M-bit fine calibration signal). The feedback path need not be active at all times; only when an event occurs that requires the feedback path to update the value of the finecal signal. A monitor is provided to sense the occurrence of such event which may be, for examples, an end of a time period or a predetermined change in temperature. When the event occurs, the feedback path is activated to update the value of the finecal signal.

Multi-phase clock generation circuit with digital calibration

Embodiments include thermally coupled aware device placement in the schematic design stage of the development of an integrated circuit. Aspects of the invention include obtaining a schematic design of a macro, the schematic design including a plurality of devices disposed within the macro. Aspects also include determining an initial temperature for each of the plurality of devices, where the initial temperature due to self-heating. Aspects further include determining, iteratively for each of the plurality of devices, an uplift temperature, where the uplift temperature for a first device of the plurality of devices is determined based on the initial temperature of each of the other plurality of devices and a distance between the first device and each of the other plurality of devices as encoded in the schematic design. Aspects also include modifying the schematic design of the macro based on a determination that the uplift temperature of at least one of the plurality of devices is above a threshold value.

Thermally coupled aware device placement

Aspects of the invention include receiving, by a controller, an indication of a chip initialization for a duty cycle correction (DCC) circuit, wherein the duty cycle correction circuit includes a main path including a main multiplexer (MUX) having a first input and a main driver circuit, a replica path including a replica MUX having a second input and a replica driver circuit, a selection MUX connected to the main path and the replica path, operating the selection MUX, during a period for the chip initialization, to select the main path as an input to the selection MUX, inputting a pre-defined data pattern to the main path, comparing an output of the selection MUX with the pre-defined data pattern to determine duty cycle issue, and generating an adjustment vector based on the determined duty cycle issue.

Dual duty cycle correction loop for a serializer/deserializer (SerDes) transmitter output

A first oscillator signal and a second oscillator signal are transmitted to a processing unit. The first oscillator signal has a finite frequency or phase offset relative to the second oscillator signal. A first clock signal that is derived from the first oscillator signal is selected as a primary clock to clock the processing unit. A second clock signal derived from the second oscillator signal is aligned to the first clock signal. If a fault is detected on the first clock signal, the second clock signal is selected as the primary clock to clock the processing unit. Upon being selected as the primary clock, the phase of the second is stretched by one fixed phase for one clock cycle.

Redundant clock switch

Provided are embodiments for operating a high-speed deserializer. Embodiments can include receiving a clock slip signal to enable operation of the slip pulse generation circuit, and generating a slip pulse signal using the slip pulse-controlled clock generation circuit, wherein the slip pulse signal is programmable to slip one or more bits of a serial input data. Embodiments can also include generating a plurality of deserialization clocks for sampling the serial input data using the slip pulse-controlled clock generation circuit, wherein the plurality of deserialization clocks are generated simultaneously with each other, and providing the plurality of deserialization clocks to the deserializer to selectively sample the serial input data.

High-speed deserializer with programmable and timing robust data slip function

Aspects of the invention include a phase rotator, that is located at a built-in self-test (BIST) path of a receiver, receiving a clock signal from an on-chip clock. The phase rotator shifts the phases of the clock signal. The phase rotator transmits the shifted clock signal to a binary sequence generator, that is located at the receiver. The binary sequence generator outputs a binary sequence, where the binary sequence generator is driven by the shifted clock signal.

Self-contained built-in self-test circuit with phase-shifting abilities for high-speed receivers

A high-speed voltage clamping circuit includes p-type field effect transistor (PFET) biasing circuit, an n-type field effect transistor (NFET) biasing circuit, and a field effect transistor (FET) clamp circuit. The PFET biasing circuit is configured to generate a PFET biasing voltage. The NFET biasing circuit is configured to generate a NFET biasing voltage. The FET clamp circuit is in signal communication with the PFET biasing circuit and the NFET biasing circuit. The PFET biasing circuit controls operation of the clamping circuit in response to a voltage overshoot event and the NFET biasing circuit controls operation of the clamping circuit in response to a voltage undershoot event.

High-speed voltage clamp for unterminated transmission lines

A method includes determining a phase error for a first clock signal and a second clock signal and determining an offset based on the phase error for the first clock signal and the second clock signal. The method also includes adding the offset to a phase of the first clock signal to produce a first adjusted clock signal and subtracting the offset from a phase of the second clock signal to produce a second adjusted clock signal. A phase error for the first adjusted clock signal and the second adjusted clock signal is smaller than the phase error for the first clock signal and the second clock signal.

Adjustable phase shifter

A method includes connecting inputs of a first plurality of interpolation branches to a first clock signal, connecting inputs of a second plurality of interpolation branches to a second clock signal, and connecting inputs of a third plurality of interpolation branches to a third clock signal. The method also includes combining outputs of the first plurality of interpolation branches, the second plurality of interpolation branches, and the third plurality of interpolation branches to produce an output clock signal and adjusting a phase of the output clock signal by connecting an input of an interpolation branch of the third plurality of interpolation branches to the second clock signal.

Phase rotator

Aspects of the invention include a driver arranged at a stand-alone receiver that is configured to receive a binary sequence from a pseudorandom binary sequence (PRBS) generator arranged at the receiver. The driver is configured to adjust the signal characteristics of the binary sequence to simulate channel loss at the receiver. The driver is further configured to output the adjusted binary sequence to a downstream data path of the receiver to enable the receiver to perform a self-test.

Built-in-self-test and characterization of a high speed serial link receiver

A method and apparatus are described to implement a bandpass filter in a current mode logic (CML) stage of a clock tree in an electronic system. The bandpass filter has a bandpass filter transfer function to attenuate frequencies lower than and higher than a carrier frequency. The bandpass filter uses adjustable active inductors and capacitive source degeneration. Adjustable resistors may be controlled to move a peak frequency of the bandpass filter transfer function to a higher or lower frequency. The adjustable active inductors and capacitive degeneration may consist of field effect transistors.

Jitter attenuation buffer structure

A method and apparatus in a receiver to determine if a high speed communication link is in an idle mode or in an active mode. Signals during the idle mode are of lower amplitude and lower frequency compared to amplitude and frequency in the active mode. A signal detector in the receiver determines if the high speed communication link has transitioned from idle mode to active mode and, if so, wakes up high power circuitry in the receiver to receive data.

Versatile signal detector circuit using common mode shift with all-pass characteristics

Embodiments described herein include a quadrature phase corrector (QPC) which includes multiple differential amplifies for correcting the phase of one or more clock signals. In one embodiment, the differential amplifiers are arranged in an input stage, cross-coupled stage, and ring stage. The input stage receives and buffers the input clock signal (or signals). The cross-coupled stage includes one or more latches that force one clock signal high and another low which causes the QPC to oscillate. The ring stage outputs four clock signals with adjusted phases relative to the input clock signals. In one example, the ring stage outputs a quadrature clock signal that includes four clock signals phase shifted by 90 degrees.

Open-loop quadrature clock corrector and generator

Embodiments of the present disclosure provide methods for using a compliance model to determine compatibility of a channel with a bus's chip I/O circuitry at its ends. The method includes identifying at least one design criteria and obtaining boundary sets of frequency domain parameters for compliant signal channels known to achieve the design criteria. In certain embodiments, the boundary sets may be derived using a genetic algorithm. The method further includes verifying whether a particular signal channel is compliant by comparing values of frequency domain parameters for the particular channel to one or more of the boundary sets of frequency domain parameters for the known compliant channels.

Frequency-domain high-speed bus signal integrity compliance model

Embodiments of the present disclosure provide methods for testing channel compliance. The method generally includes identifying at least one design criteria and determining boundary sets of frequency domain parameters for compliant signal channels known to achieve the design criteria. The boundary sets may be used for verifying whether a particular signal channel is compliant by comparing values of frequency domain parameters for the particular channel to one or more of the boundary sets of frequency domain parameters for the known compliant channels.

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Austin, TX, United States of America

Glen Arthur Wiedemeier