Patents by Inventor Prashanth Drakshapalli

Prashanth Drakshapalli 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).

  • Publication number: 20260095135
    Abstract: This application relates to sensing of signals with a common-mode variation. Embodiments describe a switching driver circuit with a modulator configured to control modulation of an output node between different switching voltages and a current sensor configured to sense a voltage drop across a sense resistor connected in series with the output node. The current sensor performs sensing during a first time window that occurs at regular intervals and the modulator avoids any transition in switching voltage at the first output node during the first time window. Embodiments also describe a sensing circuit for sensing a differential voltage with a common-mode variation which has a first sensing portion implemented to provide a floating voltage domain and a second sensing portion implemented to provide a static voltage domain. At least one switched capacitor provides a boundary between the voltage domains and is switched to transfer charge between the voltage domains.
    Type: Application
    Filed: September 25, 2025
    Publication date: April 2, 2026
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Zhaohui HE, Prashanth DRAKSHAPALLI, Lingli ZHANG, John L. MELANSON
  • Patent number: 12556149
    Abstract: A method for calibrating a fully-differential input system may include determining a first voltage of a first node of the fully-differential input system, wherein the first node is coupled at the first node to a plurality of first resistors in a first star configuration, determining a second voltage of a second node of the fully-differential input system, wherein the second node is coupled at the second node to a plurality of second resistors in a second star configuration, each resistor of the plurality of second resistors corresponding to a respective resistor of the plurality of first resistors, and trimming individual resistances of the plurality of first resistors and the plurality of second resistors in order to maintain a difference of a first voltage at the first node and a second voltage of the second node at approximately zero.
    Type: Grant
    Filed: June 24, 2022
    Date of Patent: February 17, 2026
    Assignee: Cirrus Logic Inc.
    Inventors: Zhaohui He, Neel Pramanik, Lingli Zhang, Wei Xu, Prashanth Drakshapalli
  • Patent number: 12556143
    Abstract: An amplifier circuit may include a first gain stage configured to receive an input signal at the first gain stage input and apply a first gain to the input signal to generate a first gain stage output signal at the first gain stage output, a second gain stage configured to receive the first gain stage output signal at the second gain stage input and apply a second gain to the first gain stage output signal to generate a second gain stage output signal at the second gain stage output, a feedforward gain stage configured to receive the input signal at the feedforward gain stage input and apply a feedforward gain to the input signal to generate a feedforward gain stage output signal at the feedforward gain stage output, and a compensation network coupled between the first gain stage output and the feedforward gain stage output.
    Type: Grant
    Filed: January 18, 2023
    Date of Patent: February 17, 2026
    Assignee: Cirrus Logic Inc.
    Inventors: Neel Pramanik, Prashanth Drakshapalli
  • Publication number: 20250379343
    Abstract: A system may include a battery, a protection field-effect transistor electrically coupled to a first terminal of the battery, such that when the protection field-effect transistor is deactivated, substantially zero electrical current flows to and from the battery, and a battery management system electrically coupled to the protection field-effect transistor and configured to sense a first voltage across the protection field-effect transistor and control the protection field-effect transistor based on the first voltage.
    Type: Application
    Filed: October 3, 2024
    Publication date: December 11, 2025
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Prashanth DRAKSHAPALLI, Luke LAPOINTE, Anindya BHATTACHARYA
  • Publication number: 20240243701
    Abstract: An amplifier circuit may include a first gain stage configured to receive an input signal at the first gain stage input and apply a first gain to the input signal to generate a first gain stage output signal at the first gain stage output, a second gain stage configured to receive the first gain stage output signal at the second gain stage input and apply a second gain to the first gain stage output signal to generate a second gain stage output signal at the second gain stage output, a feedforward gain stage configured to receive the input signal at the feedforward gain stage input and apply a feedforward gain to the input signal to generate a feedforward gain stage output signal at the feedforward gain stage output, and a compensation network coupled between the first gain stage output and the feedforward gain stage output.
    Type: Application
    Filed: January 18, 2023
    Publication date: July 18, 2024
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Neel PRAMANIK, Prashanth DRAKSHAPALLI
  • Patent number: 11782101
    Abstract: A data acquisition system (DAS) for acquiring data from a Hall effect sensor includes one or more state variables, a multiplexer that periodically rotates a signal from the Hall effect sensor, and a controller that resets the one or more state variables in synchronization with rotation of the signal. The state variables may be digital states in a digital memory or voltages of capacitors the controller forces to a reset voltage. The state variables may be included in a noise-shaping SAR ADC, a delta-sigma ADC, a digital filter, an integrator, an analog filter, a VCO, an incremental ADC or an auxiliary ADC-assisted incremental ADC, or an auxiliary ADC of the DAS.
    Type: Grant
    Filed: August 6, 2020
    Date of Patent: October 10, 2023
    Assignee: Cirrus Logic, Inc.
    Inventors: Prashanth Drakshapalli, John L. Melanson, Anindya Bhattacharya, Seung Bae Lee
  • Publication number: 20230122151
    Abstract: A method for calibrating a fully-differential input system may include determining a first voltage of a first node of the fully-differential input system, wherein the first node is coupled at the first node to a plurality of first resistors in a first star configuration, determining a second voltage of a second node of the fully-differential input system, wherein the second node is coupled at the second node to a plurality of second resistors in a second star configuration, each resistor of the plurality of second resistors corresponding to a respective resistor of the plurality of first resistors, and trimming individual resistances of the plurality of first resistors and the plurality of second resistors in order to maintain a difference of a first voltage at the first node and a second voltage of the second node at approximately zero.
    Type: Application
    Filed: June 24, 2022
    Publication date: April 20, 2023
    Applicant: Cirrus Logic International Semiconductor Ltd.
    Inventors: Zhaohui HE, Neel PRAMANIK, Lingli ZHANG, Wei XU, Prashanth DRAKSHAPALLI
  • Patent number: 11290120
    Abstract: A data acquisition system (DAS) for processing an input signal from a resistive sensor (e.g., Hall effect sensor) includes a sensor signal path that digitizes the input signal. An input impedance of the sensor signal path attenuates the input signal. A gain error corrector applies a gain error correction factor in a digital domain of the DAS to the digitized input signal to compensate for a loading effect to the resistive sensor. The sensor signal path includes an inverting amplifier that provides low distortion for the input signal and an ADC (e.g., delta-sigma, SAR, pipelined, auxiliary) that digitizes the input signal. A sensor characterization path digitizes the sensor resistance which the gain error corrector uses, along with the inverting amplifier input impedance, to calculate the gain error correction factor.
    Type: Grant
    Filed: August 6, 2020
    Date of Patent: March 29, 2022
    Assignee: Cirrus Logic, Inc.
    Inventors: Seung Bae Lee, John L. Melanson, Anindya Bhattacharya, Prashanth Drakshapalli
  • Publication number: 20220045689
    Abstract: A data acquisition system (DAS) for processing an input signal from a resistive sensor (e.g., Hall effect sensor) includes a sensor signal path that digitizes the input signal. An input impedance of the sensor signal path attenuates the input signal. A gain error corrector applies a gain error correction factor in a digital domain of the DAS to the digitized input signal to compensate for a loading effect to the resistive sensor. The sensor signal path includes an inverting amplifier that provides low distortion for the input signal and an ADC (e.g., delta-sigma, SAR, pipelined, auxiliary) that digitizes the input signal. A sensor characterization path digitizes the sensor resistance which the gain error corrector uses, along with the inverting amplifier input impedance, to calculate the gain error correction factor.
    Type: Application
    Filed: August 6, 2020
    Publication date: February 10, 2022
    Inventors: Seung Bae Lee, John L. Melanson, Anindya Bhattacharya, Prashanth Drakshapalli
  • Publication number: 20220043077
    Abstract: A data acquisition system (DAS) for acquiring data from a Hall effect sensor includes one or more state variables, a multiplexer that periodically rotates a signal from the Hall effect sensor, and a controller that resets the one or more state variables in synchronization with rotation of the signal. The state variables may be digital states in a digital memory or voltages of capacitors the controller forces to a reset voltage. The state variables may be included in a noise-shaping SAR ADC, a delta-sigma ADC, a digital filter, an integrator, an analog filter, a VCO, an incremental ADC or an auxiliary ADC-assisted incremental ADC, or an auxiliary ADC of the DAS.
    Type: Application
    Filed: August 6, 2020
    Publication date: February 10, 2022
    Inventors: Prashanth Drakshapalli, John L. Melanson, Anindya Bhattacharya, Seung Bae Lee
  • Patent number: 11231732
    Abstract: A power managed voltage reference quickly provides accurate operation when enabled and also avoids back-charging power supply rails when disabled. When disabled, the voltage reference filter capacitor is decoupled from the voltage reference buffer and coupled to a pre-charge source having a voltage magnitude greater than the reference voltage. When the voltage reference is enabled, the capacitor is coupled to a discharge path and the voltage across the capacitor is detected to determine when to decouple the capacitor from the discharge path and couple the capacitor to the voltage reference buffer. The capacitor voltage is also detected while disabling the voltage reference. Back-charging the pre-charge supply is prevented by coupling the capacitor to the discharge path until the magnitude of the capacitor voltage is less than the lowest voltage specified for the pre-charge supply, then coupling the capacitor to the pre-charge supply to prepare for enabling the voltage reference.
    Type: Grant
    Filed: July 7, 2020
    Date of Patent: January 25, 2022
    Assignee: CIRRUS LOGIC, INC.
    Inventors: Chandra Prakash, Prashanth Drakshapalli
  • Publication number: 20220011797
    Abstract: A power managed voltage reference quickly provides accurate operation when enabled and also avoids back-charging power supply rails when disabled. When disabled, the voltage reference filter capacitor is decoupled from the voltage reference buffer and coupled to a pre-charge source having a voltage magnitude greater than the reference voltage. When the voltage reference is enabled, the capacitor is coupled to a discharge path and the voltage across the capacitor is detected to determine when to decouple the capacitor from the discharge path and couple the capacitor to the voltage reference buffer. The capacitor voltage is also detected while disabling the voltage reference. Back-charging the pre-charge supply is prevented by coupling the capacitor to the discharge path until the magnitude of the capacitor voltage is less than the lowest voltage specified for the pre-charge supply, then coupling the capacitor to the pre-charge supply to prepare for enabling the voltage reference.
    Type: Application
    Filed: July 7, 2020
    Publication date: January 13, 2022
    Inventors: Chandra Prakash, Prashanth Drakshapalli
  • Patent number: 10187934
    Abstract: An electronic system and method include a controller to actively control transfer of excess energy to an auxiliary-winding of an auxiliary power dissipation circuit. The excess energy is a transfer of energy from a primary winding of a switching power converter to the auxiliary-winding of the auxiliary power dissipation circuit. In at least one embodiment, the electronic system is a lighting system that includes a triac-based dimmer. The excess energy is energy drawn through the primary-side winding of the switching power converter to provide operational compatibility between a dimmer through which a power supply provides energy to the switching power converter and a load to which the switching power converter provides energy.
    Type: Grant
    Filed: March 14, 2014
    Date of Patent: January 22, 2019
    Assignee: PHILIPS LIGHTING HOLDING B.V.
    Inventors: John L. Melanson, Prashanth Drakshapalli, Siddharth Maru, Rahul Singh
  • Patent number: 10122282
    Abstract: An electronic system and method include a controller to actively control power transfer from a primary winding of a switching power converter to an auxiliary-winding of an auxiliary power supply. The switching power converter is controlled and configured such that during transfer of power to the auxiliary-winding, the switching power converter does not transfer charge to one or more secondary-windings of the switching power converter. Thus, the switching power converter isolates one or more secondary transformer winding currents from an auxiliary-winding current. By isolating the charge delivered to the one or more secondary-windings from charge delivered to the auxiliary-winding, the controller can accurately determine an amount of charge delivered to the secondary-windings and, thus, to a load.
    Type: Grant
    Filed: October 28, 2016
    Date of Patent: November 6, 2018
    Assignee: PHILIPS LIGHTING HOLDING B.V.
    Inventors: John L. Melanson, Prashanth Drakshapalli, Siddharth Maru
  • Patent number: 9941848
    Abstract: In accordance with embodiments of the present disclosure, a transconductance with capacitances feedback compensation amplifier may include a capacitor in parallel with an inner feedback loop of the amplifier for providing cascade compensation to the amplifier.
    Type: Grant
    Filed: October 21, 2014
    Date of Patent: April 10, 2018
    Assignee: Cirrus Logic, Inc.
    Inventors: Ramin Zanbaghi, Aaron Brennan, Johann Gaboriau, Prashanth Drakshapalli, Vamsikrishna Parupalli
  • Patent number: 9609701
    Abstract: A bipolar junction transistor (BJT) may be used in a power stage DC-to-DC converter, such as a converter in LED-based light bulbs. The power stage may be operated by a controller to maintain a desired current output to the LED load. The controller may operate the power stage by monitoring a start and end of a reverse recovery time of the BJT. Information regarding the start and end of the reverse recovery time may be used in the control of the power stage to improve efficiency of the power stage.
    Type: Grant
    Filed: February 27, 2015
    Date of Patent: March 28, 2017
    Assignee: Cirrus Logic, Inc.
    Inventors: John L. Melanson, Ramin Zanbaghi, Thirumalai Rengachari, Prashanth Drakshapalli, Rahul Singh, Arnab Kumar Dutta
  • Publication number: 20170047850
    Abstract: An electronic system and method include a controller to actively control power transfer from a primary winding of a switching power converter to an auxiliary-winding of an auxiliary power supply. The switching power converter is controlled and configured such that during transfer of power to the auxiliary-winding, the switching power converter does not transfer charge to one or more secondary-windings of the switching power converter. Thus, the switching power converter isolates one or more secondary transformer winding currents from an auxiliary-winding current. By isolating the charge delivered to the one or more secondary-windings from charge delivered to the auxiliary-winding, the controller can accurately determine an amount of charge delivered to the secondary-windings and, thus, to a load.
    Type: Application
    Filed: October 28, 2016
    Publication date: February 16, 2017
    Inventors: John L. MELANSON, Prashanth DRAKSHAPALLI, Siddharth MARU
  • Patent number: 9521712
    Abstract: Multiple measurements may be obtained via a single pin of an integrated circuit (IC) to set multiple control parameters of a light emitting diode (LED) controller within the IC. For example, a first input signal may be applied from the IC to two or more components via a single IC pin. A first output signal may be obtained from the two or more components via the single IC pin. A second input signal may be applied from the IC to the two or more components via the single IC pin, and a second output signal may be obtained from the two or more components via the single IC pin. A first parameter and a second parameter of the two or more components may be calculated based, at least in part, on the first output signal and the second output signal obtained via the single IC pin.
    Type: Grant
    Filed: July 29, 2014
    Date of Patent: December 13, 2016
    Assignee: Cirrus Logic, Inc.
    Inventors: John L. Melanson, Arnab Kumar Dutta, Stephen Hodapp, Prashanth Drakshapalli
  • Patent number: 9520794
    Abstract: An electronic system and method include a controller to operate in a start-up mode to accelerate driving a load to an operating voltage and then operates in a post-start-up mode. A start-up condition occurs when the controller detects that a load voltage is below a predetermined voltage threshold level. The predetermined voltage threshold level is set so that the controller will boost the voltage to an operating value of a load voltage at a faster rate than during normal, steady-state operation. The controller causes a switching power converter to provide charge to the load at a rate in accordance with a start-up mode until reaching an energy-indicating threshold. When the energy-indicating threshold has been reached, the controller causes the switching power converter to (i) decrease the amount of charge provided to the load relative to the charge provided during the start-up mode and (ii) operate in a distinct post-start-up-mode.
    Type: Grant
    Filed: March 14, 2013
    Date of Patent: December 13, 2016
    Assignee: PHILIPS LIGHTING HOLDING B.V
    Inventors: Siddharth Maru, Zhaohui He, Mohit Sood, Prashanth Drakshapalli, Rahul Singh
  • Patent number: 9484832
    Abstract: An electronic system and method include a controller to actively control power transfer from a primary winding of a switching power converter to an auxiliary-winding of an auxiliary power supply. The switching power converter is controlled and configured such that during transfer of power to the auxiliary-winding, the switching power converter does not transfer charge to one or more secondary-windings of the switching power converter. Thus, the switching power converter isolates one or more secondary transformer winding currents from an auxiliary-winding current. By isolating the charge delivered to the one or more secondary-windings from charge delivered to the auxiliary-winding, the controller can accurately determine an amount of charge delivered to the secondary-windings and, thus, to a load.
    Type: Grant
    Filed: December 14, 2012
    Date of Patent: November 1, 2016
    Assignee: KONINKLIJKE PHILIPS N.V.
    Inventors: John L. Melanson, Prashanth Drakshapalli, Siddharth Maru