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).
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Patent number: 11782101Abstract: 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: GrantFiled: August 6, 2020Date of Patent: October 10, 2023Assignee: Cirrus Logic, Inc.Inventors: Prashanth Drakshapalli, John L. Melanson, Anindya Bhattacharya, Seung Bae Lee
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Publication number: 20230122151Abstract: 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: ApplicationFiled: June 24, 2022Publication date: April 20, 2023Applicant: Cirrus Logic International Semiconductor Ltd.Inventors: Zhaohui HE, Neel PRAMANIK, Lingli ZHANG, Wei XU, Prashanth DRAKSHAPALLI
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Patent number: 11290120Abstract: 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: GrantFiled: August 6, 2020Date of Patent: March 29, 2022Assignee: Cirrus Logic, Inc.Inventors: Seung Bae Lee, John L. Melanson, Anindya Bhattacharya, Prashanth Drakshapalli
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Publication number: 20220045689Abstract: 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: ApplicationFiled: August 6, 2020Publication date: February 10, 2022Inventors: Seung Bae Lee, John L. Melanson, Anindya Bhattacharya, Prashanth Drakshapalli
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Publication number: 20220043077Abstract: 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: ApplicationFiled: August 6, 2020Publication date: February 10, 2022Inventors: Prashanth Drakshapalli, John L. Melanson, Anindya Bhattacharya, Seung Bae Lee
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Patent number: 11231732Abstract: 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: GrantFiled: July 7, 2020Date of Patent: January 25, 2022Assignee: CIRRUS LOGIC, INC.Inventors: Chandra Prakash, Prashanth Drakshapalli
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Publication number: 20220011797Abstract: 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: ApplicationFiled: July 7, 2020Publication date: January 13, 2022Inventors: Chandra Prakash, Prashanth Drakshapalli
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Patent number: 10187934Abstract: 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: GrantFiled: March 14, 2014Date of Patent: January 22, 2019Assignee: PHILIPS LIGHTING HOLDING B.V.Inventors: John L. Melanson, Prashanth Drakshapalli, Siddharth Maru, Rahul Singh
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Patent number: 10122282Abstract: 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: GrantFiled: October 28, 2016Date of Patent: November 6, 2018Assignee: PHILIPS LIGHTING HOLDING B.V.Inventors: John L. Melanson, Prashanth Drakshapalli, Siddharth Maru
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Patent number: 9941848Abstract: 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: GrantFiled: October 21, 2014Date of Patent: April 10, 2018Assignee: Cirrus Logic, Inc.Inventors: Ramin Zanbaghi, Aaron Brennan, Johann Gaboriau, Prashanth Drakshapalli, Vamsikrishna Parupalli
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Patent number: 9609701Abstract: 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: GrantFiled: February 27, 2015Date of Patent: March 28, 2017Assignee: Cirrus Logic, Inc.Inventors: John L. Melanson, Ramin Zanbaghi, Thirumalai Rengachari, Prashanth Drakshapalli, Rahul Singh, Arnab Kumar Dutta
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Publication number: 20170047850Abstract: 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: ApplicationFiled: October 28, 2016Publication date: February 16, 2017Inventors: John L. MELANSON, Prashanth DRAKSHAPALLI, Siddharth MARU
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Patent number: 9521712Abstract: 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: GrantFiled: July 29, 2014Date of Patent: December 13, 2016Assignee: Cirrus Logic, Inc.Inventors: John L. Melanson, Arnab Kumar Dutta, Stephen Hodapp, Prashanth Drakshapalli
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Patent number: 9520794Abstract: 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: GrantFiled: March 14, 2013Date of Patent: December 13, 2016Assignee: PHILIPS LIGHTING HOLDING B.VInventors: Siddharth Maru, Zhaohui He, Mohit Sood, Prashanth Drakshapalli, Rahul Singh
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Patent number: 9484832Abstract: 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: GrantFiled: December 14, 2012Date of Patent: November 1, 2016Assignee: KONINKLIJKE PHILIPS N.V.Inventors: John L. Melanson, Prashanth Drakshapalli, Siddharth Maru
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Publication number: 20160255685Abstract: 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: ApplicationFiled: February 27, 2015Publication date: September 1, 2016Inventors: John L. Melanson, Ramin Zanbaghi, Thirumalai Rengachari, Prashanth Drakshapalli, Rahul Singh, Arnab Kumar Dutta
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Patent number: 9335429Abstract: 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: GrantFiled: March 3, 2015Date of Patent: May 10, 2016Assignee: Cirrus Logic, Inc.Inventors: John L. Melanson, Rahul Singh, Prashanth Drakshapalli, Dale Brummel, Stephen T. Hodapp
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Patent number: 9329614Abstract: 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: GrantFiled: March 15, 2013Date of Patent: May 3, 2016Assignee: Cirrus Logic, Inc.Inventors: Prashanth Drakshapalli, John L. Melanson, Rod Holley, Thirumalai Rengachari, Ruoxin Jiang, Eric Swanson
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Patent number: 9263964Abstract: 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: GrantFiled: August 21, 2013Date of Patent: February 16, 2016Assignee: Philips International, B.V.Inventors: Michael A. Kost, Wesley L. Mokry, Prashanth Drakshapalli, Stephen T. Hodapp, Firas Azrai
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Patent number: 9225252Abstract: 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: GrantFiled: March 11, 2014Date of Patent: December 29, 2015Inventors: Prashanth Drakshapalli, Rahul Singh, Siddharth Maru, John L. Melanson