Apple Inc.

Ryan D Bartling

Jafar Savoj

Brian S Leibowitz

Daniel J Fritchman

Shah M Sharif

A hybrid receiver circuit included in a computer system may include both an analog and an ADC-based receiver circuit. A front-end circuit generates different equalized signals based on received signals that encode a serial data stream that includes multiple data symbols. Depending on a baud rate of the serial data stream, either the digital receive circuit or the analog receiver circuit is activated to provide the desired performance and power consumption over the range of possible baud rates. The ADC-based receiver circuit may include multiple analog-to-digital converter circuits with different resolutions that can be selected for different baud rates.

Hybrid serial receiver circuit

A serial data receiver circuit included in a computer system may include a front-end circuit, a sample circuit that includes multiple analog-to-digital converter circuits, and a recovery circuit. The sample circuit may sample a serial data stream at different times that correspond to even-numbered and odd-numbered symbols in the serial data stream. The recovery circuit may use different coefficients to process the respective samples of the even-numbered and odd-numbered symbols in order to recover the data symbols encoded in the serial data stream.

Serial data receiver with even/odd mismatch compensation

A serial data receiver circuit included in a computer system may include both an analog and an ADC-based receiver circuit. A front-end circuit generates different equalized signals based on received signals that encode a serial data stream that includes multiple data symbols. During startup of a communication channel, phase information generated by the analog receiver circuit may be used to generate clock signals for the ADC-based receiver circuit. After a period of time, the ADC-based receiver circuit can generate its own phase information to be used in the generation of the clock signals.

Serial receiver circuit with follower skew adaptation

A serial data receiver circuit included in a computer system may include a front-end circuit, a sample circuit that includes multiple analog-to-digital converter circuits, and a recovery circuit. The front-end circuit may generate an equalized signal using multiple signals that encode a serial data stream of multiple data symbols. Based on a baud rate of the serial data stream, a determined number of the multiple analog-to-digital converter circuits sample, using a recovered clock signal, the equalized signal at the respective times to generate corresponding samples. The recovery circuit generates, using the samples, the recovered clock signal and recovered data symbols.

Latency reduction in analog-to-digital converter-based receiver circuits

A receiver converter circuit included in a computer system may receive multiple signals that encode a serial data stream that encode multiple data symbols. To correct for baseline wander, the receiver circuit may generate a disparity signal that is used to control the application of a differential voltage to the multiple signals. The receiver circuit may also employ the disparity signal to generate a gradient against which the magnitude of differential voltage is calibrated.

Baseline wander cancelation

A reference voltage generation circuit (or bandgap circuit) having a flipped-gate transistor is disclosed. A bandgap circuit according to the disclosure includes first, second, third and fourth transistors. The first transistor is a flipped-gate transistor having a gate terminal of an opposite polarity (e.g., an n-channel metal oxide semiconductor, or NMOS, transistor having a gate terminal with a p-type polysilicon implant). The second third and fourth transistors have a corresponding type polysilicon implants (e.g., NMOS transistors having respective gate terminals with an n-type polysilicon implant). The circuit is configured to generate a reference voltage equal to a sum of gate-source voltages of the first and third transistors, minus respective gate-source voltages of the second and fourth transistors.

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Sunnyvale, CA, United States of America

Ryan D Bartling