Patents by Inventor Kamran Farzan
Kamran Farzan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 11750426Abstract: A signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.Type: GrantFiled: July 13, 2022Date of Patent: September 5, 2023Assignee: Rambus Inc.Inventors: Kamran Farzan, Dongyun Lee
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Patent number: 11728835Abstract: An apparatus including a signal generation circuitry to provide a stream of digital signals carrying data. The apparatus includes a storage circuitry to provide a plurality of transmit levels corresponding to respective predetermined equalization levels; selection circuitry to select a transmit level from among the plurality of transmit levels based on the digital signals carrying data. Each of the plurality of transmit levels is a respective input signal to the selection circuitry. The apparatus includes a digital-to-analog converter (DAC) circuitry configured to receive the selected transmit level and convert the selected transmit level to an analog signal of the selected transmit level.Type: GrantFiled: September 1, 2021Date of Patent: August 15, 2023Assignee: Rambus, Inc.Inventor: Kamran Farzan
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Publication number: 20230006869Abstract: A signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.Type: ApplicationFiled: July 13, 2022Publication date: January 5, 2023Inventors: Kamran Farzan, Dongyun Lee
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Patent number: 11394591Abstract: A signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.Type: GrantFiled: December 30, 2020Date of Patent: July 19, 2022Assignee: Rambus Inc.Inventors: Kamran Farzan, Dongyun Lee
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Publication number: 20220060203Abstract: An apparatus that includes transmit driver architecture.Type: ApplicationFiled: September 1, 2021Publication date: February 24, 2022Inventor: Kamran Farzan
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Patent number: 11196595Abstract: A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.Type: GrantFiled: October 12, 2020Date of Patent: December 7, 2021Assignee: Rambus Inc.Inventors: Kamran Farzan, Aaron Ali
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Patent number: 11139842Abstract: A method and related apparatus for outputting an analog signal are disclosed. A plurality of transmit levels corresponding to respective predetermined equalization levels is provided. A stream of digital signals carrying data is provided. A transmit level from among the plurality of transmit levels based on the digital signals carrying data is selected. The selected transmit level is received, the selected transmit level is converted to an analog signal of the selected transmit level, and the analog signal of the selected transmit level is output over a signal interface.Type: GrantFiled: March 5, 2020Date of Patent: October 5, 2021Assignee: Rambus Inc.Inventor: Kamran Farzan
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Publication number: 20210203530Abstract: A signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.Type: ApplicationFiled: December 30, 2020Publication date: July 1, 2021Inventors: Kamran Farzan, Dongyun Lee
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Publication number: 20210091980Abstract: A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.Type: ApplicationFiled: October 12, 2020Publication date: March 25, 2021Inventors: Kamran FARZAN, Aaron ALI
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Patent number: 10887137Abstract: A signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.Type: GrantFiled: March 12, 2020Date of Patent: January 5, 2021Assignee: Rambus Inc.Inventors: Kamran Farzan, Dongyun Lee
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Patent number: 10841138Abstract: A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.Type: GrantFiled: June 14, 2019Date of Patent: November 17, 2020Assignee: Rambus Inc.Inventors: Kamran Farzan, Aaron Ali
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Publication number: 20200295978Abstract: A signal transmitter circuit includes an output driver circuit configured to transmit a signal using a multi-level pulse amplitude modulation (PAM) scheme comprising a plurality of discreet signal levels. During operation, the output driver initiates a first transition of the signal to a first level of the multi-level PAM scheme from a second level of the multi-level PAM scheme, and initiates a second transition of the signal to the first level from a third level of the multi-level PAM scheme. The signal transmitter further includes a control circuit configured to control a slew rate of the signal transmitter circuit to cause the signal to reach a threshold voltage level at a first time, the first time occurring a first duration of time after the first transition is initiated, and to cause the signal to reach the threshold voltage level at a second time, the second time occurring the first duration of time after the second transition is initiated.Type: ApplicationFiled: March 12, 2020Publication date: September 17, 2020Inventors: Kamran Farzan, Dongyun Lee
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Publication number: 20200287576Abstract: A method and related apparatus for outputting an analog signal are disclosed. A plurality of transmit levels corresponding to respective predetermined equalization levels is provided. A stream of digital signals carrying data is provided. A transmit level from among the plurality of transmit levels based on the digital signals carrying data is selected. The selected transmit level is received, the selected transmit level is converted to an analog signal of the selected transmit level, and the analog signal of the selected transmit level is output over a signal interface.Type: ApplicationFiled: March 5, 2020Publication date: September 10, 2020Inventor: Kamran Farzan
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Publication number: 20190394071Abstract: A hybrid voltage mode (VM) and current mode (CM) four-level pulse amplitude modulation (PAM-4) transmitter circuits (a.k.a. drivers) is calibrated using a configurable replica circuit and calibration control circuitry. The replica circuit includes an on-chip termination impedance to mimic a receiver's termination impedance. The amount of level enhancement provided by the current mode circuitry is calibrated by adjusting the current provided to the output node and sunk from the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving an intermediate PAM-4 level. After the level enhancement has been set, the non-linearity between levels is calibrated by adjusting the amount of current provided to the output node by the replica current mode circuitry while the replica voltage mode circuitry is driving a maximum output voltage level.Type: ApplicationFiled: June 14, 2019Publication date: December 26, 2019Inventors: Kamran FARZAN, Aaron ALI
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Patent number: 8878568Abstract: A high speed transmit driver is provided, along with methods to improve driver slew rate, decrease transmit jitter, improve termination accuracy, and decrease sensitivity to supply noise.Type: GrantFiled: October 24, 2012Date of Patent: November 4, 2014Assignee: Semtech CorporationInventors: Kamran Farzan, Mehrdad Ramezani, David Cassan, Angus McLaren, Saman Sadr