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).

  • 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: 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: 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: 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
  • Publication number: 20160255685
    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: Application
    Filed: February 27, 2015
    Publication date: September 1, 2016
    Inventors: John L. Melanson, Ramin Zanbaghi, Thirumalai Rengachari, Prashanth Drakshapalli, Rahul Singh, Arnab Kumar Dutta
  • Patent number: 9335429
    Abstract: A low power analog-to-digital converter configured to sense sensor signals may include a loop filter and a feedback digital-to-analog converter. The loop filter may have a loop filter input configured to receive an input current signal from a sensor and generate an output signal responsive to the input current signal. The feedback digital-to-analog converter may have a feedback output configured to generate a current-mode or charge-mode feedback output signal responsive to the output signal, the feedback output coupled to the loop filter input in order to combine the input current signal and the feedback output signal at the input.
    Type: Grant
    Filed: March 3, 2015
    Date of Patent: May 10, 2016
    Assignee: Cirrus Logic, Inc.
    Inventors: John L. Melanson, Rahul Singh, Prashanth Drakshapalli, Dale Brummel, Stephen T. Hodapp
  • Patent number: 9329614
    Abstract: In one embodiment a heating mechanism is provided with an integrated circuit for testing and calibration purposes. During production testing, heating elements may be activated in order to quickly bring an integrated circuit up to operating temperature for temperature testing or calibration. Once the operating test temperature has been reached, the circuit can be quickly and easily tested to show it is operable within the design temperature range and/or to obtain calibration data to correct for temperature drift. Calibration data may be used to create correction data, which may be stored within the integrated circuit. During normal operation, the correction data may be used to compensate for variations in operation due to temperature.
    Type: Grant
    Filed: March 15, 2013
    Date of Patent: May 3, 2016
    Assignee: Cirrus Logic, Inc.
    Inventors: Prashanth Drakshapalli, John L. Melanson, Rod Holley, Thirumalai Rengachari, Ruoxin Jiang, Eric Swanson
  • Patent number: 9263964
    Abstract: In accordance with systems and methods of the present disclosure, an apparatus for providing compatibility between a load having a reactive impedance and a secondary winding of an electronic transformer may include a power converter and a circuit. The power converter may be configured to transfer electrical energy from the secondary winding to the load. The circuit may be configured to charge an energy storage device coupled to the power converter following start-up of the electronic transformer in order to increase a voltage of the energy storage device to at least a voltage level sufficient for the electronic transformer to enter steady-state operation.
    Type: Grant
    Filed: August 21, 2013
    Date of Patent: February 16, 2016
    Assignee: Philips International, B.V.
    Inventors: Michael A. Kost, Wesley L. Mokry, Prashanth Drakshapalli, Stephen T. Hodapp, Firas Azrai
  • Patent number: 9225252
    Abstract: A power distribution system and method includes a controller that is configured to control a switching power converter. In at least one embodiment, the controller includes a compensation current control circuit to control a compensation current that reduces and, in at least one embodiment, approximately eliminates variations in current drawn by the controller during a particular operational time period. In at least one embodiment, the power distribution system is a lamp that includes the controller, a switching power converter, and one or more light sources, such as light emitting diodes.
    Type: Grant
    Filed: March 11, 2014
    Date of Patent: December 29, 2015
    Inventors: Prashanth Drakshapalli, Rahul Singh, Siddharth Maru, John L. Melanson
  • Publication number: 20150171889
    Abstract: A low power analog-to-digital converter configured to sense sensor signals may include a loop filter and a feedback digital-to-analog converter. The loop filter may have a loop filter input configured to receive an input current signal from a sensor and generate an output signal responsive to the input current signal. The feedback digital-to-analog converter may have a feedback output configured to generate a current-mode or charge-mode feedback output signal responsive to the output signal, the feedback output coupled to the loop filter input in order to combine the input current signal and the feedback output signal at the input.
    Type: Application
    Filed: March 3, 2015
    Publication date: June 18, 2015
    Inventors: John L. Melanson, Rahul Singh, Prashanth Drakshapalli, Dale Brummel, Stephen T. Hodapp
  • Patent number: 8970413
    Abstract: A low power analog-to-digital converter (ADC) may sense current output of a geophone instead of voltage. The output of the geophone may be terminated through a resistor into a virtual ground of an integrator, which may be located inside a current mode delta-sigma analog-to-digital converter. The integrator may have a current mode or a charge mode feedback. Thus, the geophone may experience constant or substantially constant impedance terminated into a virtual ground. This approach may eliminate an instrumentation amplifier from a geophone sensing circuit, while still allowing for accurate sensing of geophone signals. The instrumentation amplifier is a major current consumer from the signal path, so its elimination may significantly reduce power consumption. The instrumentation amplifier may be eliminated, at least in part because of the provision of the resistance into a virtual ground of an integrator of the delta-sigma ADC.
    Type: Grant
    Filed: March 13, 2013
    Date of Patent: March 3, 2015
    Assignee: Cirrus Logic, Inc.
    Inventors: John L. Melanson, Rahul Singh, Prashanth Drakshapalli, Dale Brummel