Patents by Inventor Narasimhan Rajagopal

Narasimhan Rajagopal 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).

  • Patent number: 11962318
    Abstract: In described examples, an analog to digital converter (ADC), having an input operable to receive an analog signal and an output operable to output a digital representation of the analog signal, includes a voltage to delay (VD) block. The VD block is coupled to the input of the ADC and generates a delay signal responsive to a calibration signal. A backend ADC is coupled to the VD block, and receives the delay signal. The backend ADC having multiple stages including a first stage. A calibration engine is coupled to the multiple stages and the VD block. The calibration engine measures an error count of the first stage and stores a delay value of the first stage for which the error count is minimum.
    Type: Grant
    Filed: January 5, 2022
    Date of Patent: April 16, 2024
    Assignee: Texas Instruments Incorporated
    Inventors: Himanshu Varshney, Viswanathan Nagarajan, Charls Babu, Narasimhan Rajagopal, Eeshan Miglani, Visvesvaraya A Pentakota
  • Patent number: 11881867
    Abstract: In described examples, a circuit includes a calibration engine. The calibration engine generates multiple input codes. A digital to analog converter (DAC) is coupled to the calibration engine, and generates a first calibration signal in response to a first input code of the multiple input codes. An analog to digital converter (ADC) is coupled to the DAC, and generates multiple raw codes responsive to the first calibration signal. A storage circuit is coupled to the ADC and stores a first output code corresponding to the first input code. The first output code is obtained using the multiple raw codes generated by the ADC.
    Type: Grant
    Filed: September 7, 2021
    Date of Patent: January 23, 2024
    Assignee: Texas Instruments Incorporated
    Inventors: Narasimhan Rajagopal, Eeshan Miglani, Chirag Chandrahas Shetty, Neeraj Shrivastava, Shagun Dusad, Srinivas Kumar Reddy Naru, Nithin Gopinath, Charls Babu, Shivam Srivastava, Viswanathan Nagarajan, Jagannathan Venkataraman, Harshit Moondra, Prasanth K, Visvesvaraya Appala Pentakota
  • Publication number: 20230387932
    Abstract: A circuit includes a nonlinear analog-to-digital converter (ADC) configured to provide a first digital output based on an analog input signal. The circuit also includes a linearization circuit having a lookup table (LUT) memory configured to store initial calibration data. The linearization circuit is coupled to the nonlinear ADC and is configured to: determine updated calibration data based on the initial calibration data; replace the initial calibration data in the LUT memory with the updated calibration data; and provide a second digital output at a linearization circuit output of the linearization circuit based on the first digital output and the updated calibration data.
    Type: Application
    Filed: May 26, 2022
    Publication date: November 30, 2023
    Inventors: Narasimhan RAJAGOPAL, Nithin GOPINATH, Viswanathan NAGARAJAN, Neeraj SHRIVASTAVA, Visvesvaraya A. PENTAKOTA, Harshit MOONDRA, Abhinav CHANDRA
  • Patent number: 11641216
    Abstract: Techniques maintaining receiver reliability, including determining a present attenuation level for an attenuator, wherein the attenuation level is set by a gain controller, determining a relative reliability threshold based on the present attenuation level, receiving a radio frequency (RF) signal, determining a voltage level of the received RF signal, comparing the voltage level of the received RF signal to the relative reliability threshold to determine that a reliability condition exists, and overriding, in response to the determination that the reliability condition exists, the present attenuation level set by the gain controller with an override attenuation level based on the present attenuation level.
    Type: Grant
    Filed: March 8, 2022
    Date of Patent: May 2, 2023
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Sarma Sundareswara Gunturi, Jagannathan Venkataraman, Jawaharlal Tangudu, Narasimhan Rajagopal, Eeshan Miglani
  • Patent number: 11438001
    Abstract: A method of using an analog-to-digital converter system includes receiving a sampled voltage corresponding to one of an input voltage and a known voltage, causing preamplifiers to generate output signals based on the sampled voltage, generating first and second signals based on the output signals, causing a delay-resolving delay-to-digital backend to generate a single-bit digital signal representing an order of receipt of the first and second signals, and adjusting one or more of the preamplifiers based on the digital signal. The disclosure also relates to a system which includes a voltage-to-delay frontend and a delay-resolving backend, and to a method which includes causing a delay comparator to generate a single-bit digital signal representing an order of receipt of input signals, causing the comparator to transmit a residue delay signal to a succeeding comparator, and transmitting a signal to adjust one or more of the preamplifiers based on the digital signal.
    Type: Grant
    Filed: December 24, 2020
    Date of Patent: September 6, 2022
    Assignee: Texas Instruments Incorporated
    Inventors: Narasimhan Rajagopal, Chirag Chandrahas Shetty, Neeraj Shrivastava, Prasanth K, Eeshan Miglani
  • Publication number: 20220247420
    Abstract: In described examples, a circuit includes a calibration engine. The calibration engine generates multiple input codes. A digital to analog converter (DAC) is coupled to the calibration engine, and generates a first calibration signal in response to a first input code of the multiple input codes. An analog to digital converter (ADC) is coupled to the DAC, and generates multiple raw codes responsive to the first calibration signal. A storage circuit is coupled to the ADC and stores a first output code corresponding to the first input code. The first output code is obtained using the multiple raw codes generated by the ADC.
    Type: Application
    Filed: September 7, 2021
    Publication date: August 4, 2022
    Inventors: Narasimhan Rajagopal, Eeshan Miglani, Chirag Chandrahas Shetty, Neeraj Shrivastava, Shagun Dusad, Srinivas Kumar Reddy Naru, Nithin Gopinath, Charls Babu, Shivam Srivastava, Viswanathan Nagarajan, Jagannathan Venkataraman, Harshit Moondra, Prasanth K, Visvesvaraya Appala Pentakota
  • Publication number: 20220247421
    Abstract: In described examples, a circuit includes a multiplexer. The multiplexer receives an input voltage and a calibration signal. An analog-to-digital converter (ADC) is coupled to the multiplexer and generates an output code in response to the calibration signal. A storage circuit is coupled to the ADC and stores the input code representative of the calibration signal at an address corresponding to the output code. The stored input code includes an index value and a coarse value.
    Type: Application
    Filed: January 31, 2022
    Publication date: August 4, 2022
    Inventors: Visvesvaraya Appala Pentakota, Srinivas Kumar Reddy Naru, Chirag Shetty, Eeshan Miglani, Neeraj Shrivastava, Narasimhan Rajagopal, Shagun Dusad
  • Publication number: 20220224349
    Abstract: In described examples, an analog to digital converter (ADC), having an input operable to receive an analog signal and an output operable to output a digital representation of the analog signal, includes a voltage to delay (VD) block. The VD block is coupled to the input of the ADC and generates a delay signal responsive to a calibration signal. A backend ADC is coupled to the VD block, and receives the delay signal. The backend ADC having multiple stages including a first stage. A calibration engine is coupled to the multiple stages and the VD block. The calibration engine measures an error count of the first stage and stores a delay value of the first stage for which the error count is minimum.
    Type: Application
    Filed: January 5, 2022
    Publication date: July 14, 2022
    Inventors: Himanshu Varshney, Viswanathan Nagarajan, Charls Babu, Narasimhan Rajagopal, Eeshan Miglani, Visvesvaraya A. Pentakota
  • Publication number: 20220209782
    Abstract: A method of using an analog-to-digital converter system includes receiving a sampled voltage corresponding to one of an input voltage and a known voltage, causing preamplifiers to generate output signals based on the sampled voltage, generating first and second signals based on the output signals, causing a delay-resolving delay-to-digital backend to generate a single-bit digital signal representing an order of receipt of the first and second signals, and adjusting one or more of the preamplifiers based on the digital signal. The disclosure also relates to a system which includes a voltage-to-delay frontend and a delay-resolving backend, and to a method which includes causing a delay comparator to generate a single-bit digital signal representing an order of receipt of input signals, causing the comparator to transmit a residue delay signal to a succeeding comparator, and transmitting a signal to adjust one or more of the preamplifiers based on the digital signal.
    Type: Application
    Filed: December 24, 2020
    Publication date: June 30, 2022
    Inventors: Narasimhan RAJAGOPAL, Chirag Chandrahas SHETTY, Neeraj SHRIVASTAVA, Prasanth K, Eeshan MIGLANI
  • Publication number: 20220190856
    Abstract: Techniques maintaining receiver reliability, including determining a present attenuation level for an attenuator, wherein the attenuation level is set by a gain controller, determining a relative reliability threshold based on the present attenuation level, receiving a radio frequency (RF) signal, determining a voltage level of the received RF signal, comparing the voltage level of the received RF signal to the relative reliability threshold to determine that a reliability condition exists, and overriding, in response to the determination that the reliability condition exists, the present attenuation level set by the gain controller with an override attenuation level based on the present attenuation level.
    Type: Application
    Filed: March 8, 2022
    Publication date: June 16, 2022
    Inventors: Sarma Sundareswara GUNTURI, Jagannathan VENKATARAMAN, Jawaharlal TANGUDU, Narasimhan RAJAGOPAL, Eeshan MIGLANI
  • Patent number: 11316526
    Abstract: An analog-to-digital converter includes a voltage-to-delay device, such as a pre-amplifier array, for generating a delay signal based on a first voltage, and delay-based stages for generating digital signals based on the delay signal. In operation, the delay signal is transmitted to a first delay-based stage, or to an intermediate delay-based stage, bypassing the first delay-based stage, to overcome non-linearity of previous stages. If desired, different pre-amplifiers may be used to generate signals for calibration of different delay-based stages. The present disclosure may also involve converting to pseudo-static signals before signals are handed over to a calibration engine, to ease timing and preserve interface area and power. If desired, simple delay elements may be used to correct for non-linearity in a delay-based analog-to-digital converter. The present disclosure may be employed, if desired, in connection with any suitable cascade of non-linear stages.
    Type: Grant
    Filed: December 18, 2020
    Date of Patent: April 26, 2022
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Narasimhan Rajagopal, Visvesvaraya Appala Pentakota, Eeshan Miglani
  • Patent number: 11316525
    Abstract: An analog-to-digital converter system includes a digital-to-analog converter for generating calibration voltages based on digital input codes, and an analog-to-digital converter, connected to the digital-to-analog converter, for receiving the calibration voltages from the digital-to-analog converter, for receiving sampled voltages, for generating digital output codes based on the calibration voltages, and for generating digital output codes based on the sampled voltages. The analog-to-digital converter system may have a lookup table, connected to the analog-to-digital converter, for storing the first digital output codes in association with the digital input codes. A method of calibrating an analog-to-digital converter system is also disclosed.
    Type: Grant
    Filed: January 26, 2021
    Date of Patent: April 26, 2022
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Visvesvaraya Appala Pentakota, Narasimhan Rajagopal, Chirag Chandrahas Shetty, Prasanth K, Neeraj Shrivastava, Eeshan Miglani, Jagannathan Venkataraman
  • Patent number: 11309902
    Abstract: In described examples, a stochastic comparator includes a first comparator that compares an input signal and a primary threshold to generate a first signal. A second comparator compares the input signal and the primary threshold to generate a second signal. A decision block generates a control signal in response to the first signal, the second signal and a PRBS (pseudo random binary sequence) signal. A XOR gate generates a detection signal in response the first signal and the second signal.
    Type: Grant
    Filed: December 16, 2019
    Date of Patent: April 19, 2022
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Srinivas Kumar Reddy Naru, Narasimhan Rajagopal, Shagun Dusad, Viswanathan Nagarajan, Visvesvaraya Appala Pentakota
  • Patent number: 11303312
    Abstract: Techniques maintaining receiver reliability, including determining a present attenuation level for an attenuator, wherein the attenuation level is set by a gain controller, determining a relative reliability threshold based on the present attenuation level, receiving a radio frequency (RF) signal, determining a voltage level of the received RF signal, comparing the voltage level of the received RF signal to the relative reliability threshold to determine that a reliability condition exists, and overriding, in response to the determination that the reliability condition exists, the present attenuation level set by the gain controller with an override attenuation level based on the present attenuation level.
    Type: Grant
    Filed: December 4, 2020
    Date of Patent: April 12, 2022
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Sarma Sundareswara Gunturi, Jagannathan Venkataraman, Jawaharlal Tangudu, Narasimhan Rajagopal, Eeshan Miglani
  • Publication number: 20210175914
    Abstract: Techniques maintaining receiver reliability, including determining a present attenuation level for an attenuator, wherein the attenuation level is set by a gain controller, determining a relative reliability threshold based on the present attenuation level, receiving a radio frequency (RF) signal, determining a voltage level of the received RF signal, comparing the voltage level of the received RF signal to the relative reliability threshold to determine that a reliability condition exists, and overriding, in response to the determination that the reliability condition exists, the present attenuation level set by the gain controller with an override attenuation level based on the present attenuation level.
    Type: Application
    Filed: December 4, 2020
    Publication date: June 10, 2021
    Inventors: Sarma Sundareswara GUNTURI, Jagannathan VENKATARAMAN, Jawaharlal TANGUDU, Narasimhan RAJAGOPAL, Eeshan MIGLANI
  • Publication number: 20200119743
    Abstract: In described examples, a stochastic comparator includes a first comparator that compares an input signal and a primary threshold to generate a first signal. A second comparator compares the input signal and the primary threshold to generate a second signal. A decision block generates a control signal in response to the first signal, the second signal and a PRBS (pseudo random binary sequence) signal. A XOR gate generates a detection signal in response the first signal and the second signal.
    Type: Application
    Filed: December 16, 2019
    Publication date: April 16, 2020
    Inventors: Srinivas Kumar Reddy NARU, Narasimhan RAJAGOPAL, Shagun DUSAD, Viswanathan NAGARAJAN, Visvesvaraya Appala PENTAKOTA
  • Patent number: 10541700
    Abstract: In described examples, a stochastic comparator includes a first comparator that compares an input signal and a primary threshold to generate a first signal. A second comparator compares the input signal and the primary threshold to generate a second signal. A decision block generates a control signal in response to the first signal, the second signal and a PRBS (pseudo random binary sequence) signal. A XOR gate generates a detection signal in response the first signal and the second signal.
    Type: Grant
    Filed: January 16, 2019
    Date of Patent: January 21, 2020
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Srinivas Kumar Reddy Naru, Narasimhan Rajagopal, Shagun Dusad, Viswanathan Nagarajan, Visvesvaraya Appala Pentakota
  • Patent number: 10419036
    Abstract: A pipeline ADC comprising an ADC segment and a digital backend coupled to the ADC segment. In some examples the ADC is configured to receive an analog signal, generate a first partial digital code representing a first sample of the analog signal, and generate a second partial digital code representing a second sample of the analog signal. In some examples the digital backend is configured to receive the first and second partial digital codes from the ADC segment, generate a combined digital code based at least partially on the first and second partial digital codes, determine a gain error of the ADC segment based at least partially on a first correlation of a PRBS with a difference between the first and second partial digital codes, and apply a first correction to the combined digital code based at least partially on the gain error of the ADC segment.
    Type: Grant
    Filed: September 10, 2018
    Date of Patent: September 17, 2019
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Viswanathan Nagarajan, Srinivas Kumar Reddy Naru, Narasimhan Rajagopal
  • Publication number: 20190280703
    Abstract: In described examples, a stochastic comparator includes a first comparator that compares an input signal and a primary threshold to generate a first signal. A second comparator compares the input signal and the primary threshold to generate a second signal. A decision block generates a control signal in response to the first signal, the second signal and a PRBS (pseudo random binary sequence) signal. A XOR gate generates a detection signal in response the first signal and the second signal.
    Type: Application
    Filed: January 16, 2019
    Publication date: September 12, 2019
    Inventors: Srinivas Kumar Reddy NARU, Narasimhan RAJAGOPAL, Shagun DUSAD, Viswanathan NAGARAJAN, Visvesvaraya Appala PENTAKOTA
  • Publication number: 20190007071
    Abstract: A pipeline ADC comprising an ADC segment and a digital backend coupled to the ADC segment. In some examples the ADC is configured to receive an analog signal, generate a first partial digital code representing a first sample of the analog signal, and generate a second partial digital code representing a second sample of the analog signal. In some examples the digital backend is configured to receive the first and second partial digital codes from the ADC segment, generate a combined digital code based at least partially on the first and second partial digital codes, determine a gain error of the ADC segment based at least partially on a first correlation of a PRBS with a difference between the first and second partial digital codes, and apply a first correction to the combined digital code based at least partially on the gain error of the ADC segment.
    Type: Application
    Filed: September 10, 2018
    Publication date: January 3, 2019
    Inventors: Viswanathan NAGARAJAN, Srinivas Kumar Reddy NARU, Narasimhan RAJAGOPAL