Patents by Inventor Chaitanya Palusa
Chaitanya Palusa 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: 11962441Abstract: A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.Type: GrantFiled: July 25, 2022Date of Patent: April 16, 2024Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.Inventors: Chaitanya Palusa, Rob Abbott, Wei-Li Chen, Po-Hsiang Lan, Dirk Pfaff, Cheng-Hsiang Hsieh
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Patent number: 11784855Abstract: A data receiver circuit includes a summer circuit configured to receive an input signal that encodes multiple data symbols, and combine the input signal with a feedback signal to generate an equalized input signal, which is used to generate a clock signal. The data receiver circuit also includes multiple data slicer circuits that sample, using the clock signal and multiple voltage offsets, the equalized input signal to generate multiple samples of a particular data symbol. A precursor compensation circuit included in the data receiver circuit may generate an output value for the particular data symbol using the multiple samples. The data receiver circuit also includes a post cursor compensation circuit that generates the feedback signal using at least one of the multiple samples and a value of a previously received sample.Type: GrantFiled: January 13, 2023Date of Patent: October 10, 2023Assignee: Oracle International CorporationInventors: Xun Zhang, Chaitanya Palusa, Dawei Huang, Muthukumar Vairavan, Jianghui Su
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Publication number: 20230155867Abstract: A data receiver circuit includes a summer circuit configured to receive an input signal that encodes multiple data symbols, and combine the input signal with a feedback signal to generate an equalized input signal, which is used to generate a clock signal. The data receiver circuit also includes multiple data slicer circuits that sample, using the clock signal and multiple voltage offsets, the equalized input signal to generate multiple samples of a particular data symbol. A precursor compensation circuit included in the data receiver circuit may generate an output value for the particular data symbol using the multiple samples. The data receiver circuit also includes a post cursor compensation circuit that generates the feedback signal using at least one of the multiple samples and a value of a previously received sample.Type: ApplicationFiled: January 13, 2023Publication date: May 18, 2023Inventors: Xun Zhang, Chaitanya Palusa, Dawei Huang, Muthukumar Vairavan, Jianghui Su
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Patent number: 11558223Abstract: A data receiver circuit includes a summer circuit configured to receive an input signal that encodes multiple data symbols, and combine the input signal with a feedback signal to generate an equalized input signal, which is used to generate a clock signal. The data receiver circuit also includes multiple data slicer circuits that sample, using the clock signal and multiple voltage offsets, the equalized input signal to generate multiple samples of a particular data symbol. A precursor compensation circuit included in the data receiver circuit may generate an output value for the particular data symbol using the multiple samples. The data receiver circuit also includes a post cursor compensation circuit that generates the feedback signal using at least one of the multiple samples and a value of a previously received sample.Type: GrantFiled: January 25, 2022Date of Patent: January 17, 2023Assignee: Oracle International CorporationInventors: Xun Zhang, Chaitanya Palusa, Dawei Huang, Muthukumar Vairavan, Jianghui Su
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Publication number: 20220360476Abstract: A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.Type: ApplicationFiled: July 25, 2022Publication date: November 10, 2022Applicant: Taiwan Semiconductor Manufacturing Company, Ltd.Inventors: Chaitanya Palusa, Rob Abbott, Wei-Li Chen, Po-Hsiang Lan, Dirk Pfaff, Cheng-Hsiang Hsieh
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Patent number: 11398933Abstract: A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.Type: GrantFiled: February 1, 2021Date of Patent: July 26, 2022Assignee: Taiwan Semiconductor Manufacturing Company, Ltd.Inventors: Chaitanya Palusa, Rob Abbott, Wei-Li Chen, Po-Hsiang Lan, Dirk Pfaff, Cheng-Hsiang Hsieh
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Publication number: 20220191071Abstract: A data receiver circuit includes a summer circuit configured to receive an input signal that encodes multiple data symbols, and combine the input signal with a feedback signal to generate an equalized input signal, which is used to generate a clock signal. The data receiver circuit also includes multiple data slicer circuits that sample, using the clock signal and multiple voltage offsets, the equalized input signal to generate multiple samples of a particular data symbol. A precursor compensation circuit included in the data receiver circuit may generate an output value for the particular data symbol using the multiple samples. The data receiver circuit also includes a post cursor compensation circuit that generates the feedback signal using at least one of the multiple samples and a value of a previously received sample.Type: ApplicationFiled: January 25, 2022Publication date: June 16, 2022Inventors: Xun Zhang, Chaitanya Palusa, Dawei Huang, Muthukumar Vairavan, Jianghui Su
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Publication number: 20220158878Abstract: An optimized pulse shaping clock data recovery system is provided that includes a slicer configured to receive a signal and provide an initial set of tentative decisions to a decision feedforward equalizer, where the decision feedforward equalizer provides a fully equalized output signal. The slicer may be incorporated as part of decision feedback equalizer to provide better quality tentative decisions. The clock data recovery system also receives the first output signal that is partially equalized in such a way as to optimally shape it for a clock to sample it at an ideal location by providing an adjustment signal to the analog to digital controller.Type: ApplicationFiled: January 31, 2022Publication date: May 19, 2022Applicant: Taiwan Semiconductor Manufacturing Company, Ltd.Inventors: Chaitanya Palusa, Rob Abbott, Rolando Ramirez, Wei-Li Chen, Dirk Pfaff, Cheng-Hsiang Hsieh, Fan-ming Kuo
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Patent number: 11240075Abstract: An optimized pulse shaping clock data recovery system is provided that includes a slicer configured to receive a signal and provide an initial set of tentative decisions to a decision feedforward equalizer, where the decision feedforward equalizer provides a fully equalized output signal. The slicer may be incorporated as part of decision feedback equalizer to provide better quality tentative decisions. The clock data recovery system also receives the first output signal that is partially equalized in such a way as to optimally shape it for a clock to sample it at an ideal location by providing an adjustment signal to the analog to digital controller.Type: GrantFiled: January 25, 2021Date of Patent: February 1, 2022Assignee: TAIWAN SEMICONDUCTOR MANUFACTURING COMPANY, LTD.Inventors: Chaitanya Palusa, Rob Abbott, Rolando Ramirez, Wei-Li Chen, Dirk Pfaff, Cheng-Hsiang Hsieh, Fan-ming Kuo
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Patent number: 11240073Abstract: A data receiver circuit includes a summer circuit configured to receive an input signal that encodes multiple data symbols, and combine the input signal with a feedback signal to generate an equalized input signal, which is used to generate a clock signal. The data receiver circuit also includes multiple data slicer circuits that sample, using the clock signal and multiple voltage offsets, to generate multiple samples for a particular data symbol. A precursor compensation circuit included in the data receiver circuit may generate an output value for the particular data symbol using the multiple samples. The data receiver circuit also includes a post cursor compensation circuit that generates the feedback signal using at least one of the multiple samples and a value of a previously received sample.Type: GrantFiled: October 31, 2019Date of Patent: February 1, 2022Assignee: Oracle International CorporationInventors: Xun Zhang, Chaitanya Palusa, Dawei Huang, Muthukumar Vairavan, Jianghui Su
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Publication number: 20210218605Abstract: An optimized pulse shaping clock data recovery system is provided that includes a slicer configured to receive a signal and provide an initial set of tentative decisions to a decision feedforward equalizer, where the decision feedforward equalizer provides a fully equalized output signal. The slicer may be incorporated as part of decision feedback equalizer to provide better quality tentative decisions. The clock data recovery system also receives the first output signal that is partially equalized in such a way as to optimally shape it for a clock to sample it at an ideal location by providing an adjustment signal to the analog to digital controller.Type: ApplicationFiled: January 25, 2021Publication date: July 15, 2021Inventors: Chaitanya Palusa, Rob Abbott, Rolando Ramirez, Wei-Li Chen, Dirk Pfaff, Cheng-Hsiang Hsieh, Fan-ming Kuo
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Publication number: 20210160107Abstract: A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.Type: ApplicationFiled: February 1, 2021Publication date: May 27, 2021Inventors: Chaitanya Palusa, Rob Abbott, Wei-Li Chen, Po-Hsiang Lan, Dirk Pfaff, Cheng-Hsiang Hsieh
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Publication number: 20210135907Abstract: A data receiver circuit includes a summer circuit configured to receive an input signal that encodes multiple data symbols, and combine the input signal with a feedback signal to generate an equalized input signal, which is used to generate a clock signal. The data receiver circuit also includes multiple data slicer circuits that sample, using the clock signal and multiple voltage offsets, to generate multiple samples for a particular data symbol. A precursor compensation circuit included in the data receiver circuit may generate an output value for the particular data symbol using the multiple samples. The data receiver circuit also includes a post cursor compensation circuit that generates the feedback signal using at least one of the multiple samples and a value of a previously received sample.Type: ApplicationFiled: October 31, 2019Publication date: May 6, 2021Inventors: Xun Zhang, Chaitanya Palusa, Dawei Huang, Muthukumar Vairavan, Jianghui Su
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Patent number: 10911272Abstract: A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.Type: GrantFiled: January 13, 2020Date of Patent: February 2, 2021Inventors: Chaitanya Palusa, Rob Abbott, Wei-Li Chen, Po-Hsiang Lan, Dirk Pfaff, Cheng-Hsiang Hsieh
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Patent number: 10904044Abstract: An optimized pulse shaping clock data recovery system is provided that includes a slicer configured to receive a signal and provide an initial set of tentative decisions to a decision feedforward equalizer, where the decision feedforward equalizer provides a fully equalized output signal. The slicer may be incorporated as part of decision feedback equalizer to provide better quality tentative decisions. The clock data recovery system also receives the first output signal that is partially equalized in such a way as to optimally shape it for a clock to sample it at an ideal location by providing an adjustment signal to the analog to digital controller.Type: GrantFiled: January 13, 2020Date of Patent: January 26, 2021Inventors: Chaitanya Palusa, Rob Abbott, Rolando Ramirez, Wei-Li Chen, Dirk Pfaff, Cheng-Hsiang Hsieh, Fan-ming Kuo
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Publication number: 20200252248Abstract: An optimized pulse shaping clock data recovery system is provided that includes a slicer configured to receive a signal and provide an initial set of tentative decisions to a decision feedforward equalizer, where the decision feedforward equalizer provides a fully equalized output signal. The slicer may be incorporated as part of decision feedback equalizer to provide better quality tentative decisions. The clock data recovery system also receives the first output signal that is partially equalized in such a way as to optimally shape it for a clock to sample it at an ideal location by providing an adjustment signal to the analog to digital controller.Type: ApplicationFiled: January 13, 2020Publication date: August 6, 2020Inventors: Chaitanya Palusa, Rob Abbott, Rolando Ramirez, Wei-Li Chen, Dirk Pfaff, Cheng-Hsiang Hsieh, Fan-ming Kuo
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Publication number: 20200252247Abstract: A multi-tap Differential Feedforward Equalizer (DFFE) configuration with both precursor and postcursor taps is provided. The DFFE has reduced noise and/or crosstalk characteristics when compared to a Feedforward Equalizer (FFE) since DFFE uses decision outputs of slicers as inputs to a finite impulse response (FIR) unlike FFE which uses actual analog signal inputs. The digital outputs of the tentative decision slicers are multiplied with tap coefficients to reduce noise. Further, since digital outputs are used as the multiplier inputs, the multipliers effectively work as adders which are less complex to implement. The decisions at the outputs of the tentative decision slicers are tentative and are used in a FIR filter to equalize the signal; the equalized signal may be provided as input to the next stage slicers. The bit-error-rate (BER) of the final stage decisions are lower or better than the BER of the previous stage tentative decisions.Type: ApplicationFiled: January 13, 2020Publication date: August 6, 2020Inventors: Chaitanya Palusa, Rob Abbott, Wei-Li Chen, Po-Hsiang Lan, Dirk Pfaff, Cheng-Hsiang Hsieh
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Patent number: 10142089Abstract: Embodiments include systems and methods for improving link performance and tracking capability of a baud-rate clock data recovery (CDR) system using transition pattern detection. For example, a multi-level signal is received via a data channel and converted to a pseudo-NRZ signal. CDR early/late voting can be derived from the converted (baud-rate) pseudo-NRZ signal and from error signals from the received PAM4 signal, and the voting can be implemented with different phase error detector (PED) functional approaches. Different approaches can yield different CDR performance characteristics and can tend to favor different PAM4 transition patterns. Embodiments can identify jittery patterns for a particular CDR implementation and can add features to the CDR to filter out those patterns from being used for CDR early/late voting.Type: GrantFiled: March 22, 2017Date of Patent: November 27, 2018Assignee: ORACLE INTERNATIONAL CORPORATIONInventors: Yuhan Yao, Xun Zhang, Dawei Huang, Jianghui Su, Muthukumar Vairavan, Chaitanya Palusa
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Publication number: 20180278405Abstract: Embodiments include systems and methods for improving link performance and tracking capability of a baud-rate clock data recovery (CDR) system using transition pattern detection. For example, a multi-level signal is received via a data channel and converted to a pseudo-NRZ signal. CDR early/late voting can be derived from the converted (baud-rate) pseudo-NRZ signal and from error signals from the received PAM4 signal, and the voting can be implemented with different phase error detector (PED) functional approaches. Different approaches can yield different CDR performance characteristics and can tend to favor different PAM4 transition patterns. Embodiments can identify jittery patterns for a particular CDR implementation and can add features to the CDR to filter out those patterns from being used for CDR early/late voting.Type: ApplicationFiled: March 22, 2017Publication date: September 27, 2018Inventors: Yuhan Yao, Xun Zhang, Dawei Huang, Jianghui Su, Muthukumar Vairavan, Chaitanya Palusa
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Publication number: 20180278406Abstract: Embodiments enable built-in sinusoidal jitter injection, for example, in a serializer/deserializer (SERDES) circuit. For example, embodiments can receive a tracking profile that corresponds to a predetermined sinusoidal jitter (SJ) profile and a predetermined phase interpolator (PI) profile. A shift determination can be made for each of a plurality of insertion times according to the tracking profile, the shift determination indicating whether to adjust phase interpolation of the SERDES circuit. At each of the plurality of insertion times, a phase adjustment signal can be generated as a function of the shift determination. For example, the phase adjustment signal can indicate a control code for a phase interpolator coupled to a clock generator of the SERDES, and the signal can be output to the phase interpolator. Some implementations adjust the phase interpolator in response to the phase adjustment signal, such that the phase interpolator injects SJ that substantially tracks the SJ profile.Type: ApplicationFiled: March 21, 2017Publication date: September 27, 2018Inventors: Chaitanya Palusa, Dawei Huang, Jiangyuan Li, Pradeep Nagarajan