Patents by Inventor Aatmesh Shrivastava
Aatmesh Shrivastava 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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Publication number: 20170104452Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.Type: ApplicationFiled: December 22, 2016Publication date: April 13, 2017Applicant: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton H. Calhoun, Aatmesh Shrivastava
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Publication number: 20170098999Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.Type: ApplicationFiled: December 17, 2016Publication date: April 6, 2017Applicant: University of Virginia Patent FoundationInventors: Benton Calhoun, Aatmesh Shrivastava
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Patent number: 9590638Abstract: An ultra-low power clock source includes a compensated oscillator and an uncompensated oscillator coupled by a comparator circuit. In an example, the compensated oscillator is more stable than the uncompensated oscillator with respect to changes in one or more of temperature, voltage, age, or other environmental parameters. The uncompensated oscillator includes a configuration input configured to adjust an operating characteristic of the uncompensated oscillator. In an example, the uncompensated oscillator is adjusted using information from the comparator circuit about a comparison of output signals from the compensated oscillator and the uncompensated oscillator.Type: GrantFiled: September 6, 2013Date of Patent: March 7, 2017Assignee: University of Virginia Patent FoundationInventors: Benton H. Calhoun, Aatmesh Shrivastava
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Publication number: 20170033740Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.Type: ApplicationFiled: May 23, 2016Publication date: February 2, 2017Applicant: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton H. Calhoun, Aatmesh Shrivastava
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Publication number: 20170012531Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.Type: ApplicationFiled: September 19, 2016Publication date: January 12, 2017Applicant: University of Virginia Patent FoundationInventors: Benton Calhoun, Aatmesh Shrivastava
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Patent number: 9490698Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.Type: GrantFiled: March 30, 2016Date of Patent: November 8, 2016Assignee: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton Calhoun, Aatmesh Shrivastava
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Publication number: 20160211747Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.Type: ApplicationFiled: March 30, 2016Publication date: July 21, 2016Applicant: University of Virginia Patent FoundationInventors: Benton Calhoun, Aatmesh Shrivastava
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Patent number: 9350294Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.Type: GrantFiled: January 12, 2015Date of Patent: May 24, 2016Assignee: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton Calhoun, Aatmesh Shrivastava
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Patent number: 9325240Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.Type: GrantFiled: January 20, 2015Date of Patent: April 26, 2016Assignee: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton H. Calhoun, Aatmesh Shrivastava
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Publication number: 20160041570Abstract: In some embodiments, an apparatus includes a bandgap reference circuit having a first bipolar junction transistor (BJT) that can receive a current from a node having a terminal voltage and can output a base emitter voltage. The apparatus also includes a second bipolar junction transistor (BJT) having a device width greater than a device width of the first BJT. The second BJT can receive a current from a node having a terminal voltage and output a base emitter voltage. In such embodiments, the apparatus also includes a reference generation circuit operatively coupled to the first BJT and the second BJT, where the reference generation circuit can generate a bandgap reference voltage based on the base emitter voltage of the first BJT and the base emitter voltage of the second BJT.Type: ApplicationFiled: October 12, 2015Publication date: February 11, 2016Applicant: PSIKICK, INC.Inventor: Aatmesh Shrivastava
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Patent number: 9164528Abstract: Apparatus and method for controlling inductor current in a switch mode power supply. In one embodiment, a switch mode power supply includes an inductor, a high-side switch coupled to the inductor, a low-side switch coupled to the inductor, and a controller. The controller is coupled to at least one of the high-side switch and the low-side switch. The controller includes a first capacitor and a current source. The controller is configured to control timing of current switching to the inductor by enabling current flow through the at least one of the high-side switch and the low-side switch based on time to charge the first capacitor via the current source. The time is a function of voltage across the inductor.Type: GrantFiled: February 15, 2013Date of Patent: October 20, 2015Assignee: TEXAS INSTRUMENTS INCORPORATEDInventors: Aatmesh Shrivastava, Yogesh Ramadass
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Patent number: 9158320Abstract: In some embodiments, an apparatus includes a bandgap reference circuit having a first bipolar junction transistor (BJT) that can receive a current from a node having a terminal voltage and can output a base emitter voltage. The apparatus also includes a second bipolar junction transistor (BJT) having a device width greater than a device width of the first BJT. The second BJT can receive a current from a node having a terminal voltage and output a base emitter voltage. In such embodiments, the apparatus also includes a reference generation circuit operatively coupled to the first BJT and the second BJT, where the reference generation circuit can generate a bandgap reference voltage based on the base emitter voltage of the first BJT and the base emitter voltage of the second BJT.Type: GrantFiled: August 7, 2014Date of Patent: October 13, 2015Assignee: PsiKick, Inc.Inventor: Aatmesh Shrivastava
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Publication number: 20150214894Abstract: A low voltage crystal oscillator (XTAL) driver with feedback controlled duty cycling for ultra low power biases an amplifier for an XTAL in the sub-threshold operating regime. A feedback control scheme can be used to bias the amplifier for an XTAL biased in the sub-threshold operating regime. The amplifier of a XTAL oscillator can be duty cycled to save power, e.g., the XTAL driver can be turned off to save power when the amplitude of the XTAL oscillation reaches a maximum value in range; but be turned back on when the amplitude of the XTAL oscillation starts to decay, to maintain the oscillation before it stops. In addition or alternatively, a feedback control scheme to duty cycle the amplifier of a XTAL oscillator can be used to monitor the amplitude of the oscillation.Type: ApplicationFiled: January 12, 2015Publication date: July 30, 2015Applicant: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton H. Calhoun, Aatmesh Shrivastava
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Publication number: 20150214955Abstract: An ultra-low power clock source includes a compensated oscillator and an uncompensated oscillator coupled by a comparator circuit. In an example, the compensated oscillator is more stable than the uncompensated oscillator with respect to changes in one or more of temperature, voltage, age, or other environmental parameters. The uncompensated oscillator includes a configuration input configured to adjust an operating characteristic of the uncompensated oscillator. In an example, the uncompensated oscillator is adjusted using information from the comparator circuit about a comparison of output signals from the compensated oscillator and the uncompensated oscillator.Type: ApplicationFiled: September 6, 2013Publication date: July 30, 2015Applicant: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton H. CALHOUN, Aatmesh SHRIVASTAVA
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Publication number: 20150207411Abstract: The low input voltage boost converter with peak inductor current control and offset compensated zero detection provide a boost converter scheme to harvest energy from sources with small output voltages. Some embodiments described herein includes a thermoelectric boost converter that combines an IPEAK control scheme with offset compensation and duty cycled comparators to enable energy harvesting from TEG inputs as low as 5 mV to 10 mV, and the peak inductor current is independent to first order of the input voltage and output voltage. A control circuit can be configured to sample the input voltage (VIN) and then generate a pulse with a duration inversely proportional to VIN so as to control the boost converter switches such that a substantially constant peak inductor current is generated.Type: ApplicationFiled: January 20, 2015Publication date: July 23, 2015Applicant: UNIVERSITY OF VIRGINIA PATENT FOUNDATIONInventors: Benton H. Calhoun, Aatmesh Shrivastava
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Publication number: 20140285014Abstract: In some embodiments, an apparatus includes a single-inductor multiple-output (SIMO) direct current (DC-DC) converter circuit, with the SIMO DC-DC converter circuit having a set of output nodes. The apparatus also includes a panoptic dynamic voltage scaling (PDVS) circuit operatively coupled to the SIMO DC-DC converter circuit, where the PDVS circuit has a set of operational blocks with each operational block from the set of operational blocks drawing power from one supply voltage rail from a set of supply voltage rails. Additionally, each output node from the set of output nodes is uniquely associated with a supply voltage rail from the set of supply voltage rails.Type: ApplicationFiled: March 14, 2014Publication date: September 25, 2014Inventors: Benton H. Calhoun, Aatmesh Shrivastava
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Patent number: 8797072Abstract: Integrated Circuits (ICs) comprising circuits configured to generate a power on reset (POR) pulse are disclosed. An IC comprises a power supply sense circuit configured to generate a sense signal in response to a transition of a power supply signal from a first level to a second level, and a pulse generation circuit coupled with the power supply sense circuit. The pulse generation circuit is configured to generate a power on reset (POR) pulse of a threshold duration based on the sense signal. The IC further includes a reset generation circuit coupled with the pulse generation circuit to receive the POR pulse. The reset generation circuit is configured to generate a reset pulse based on the POR signal and of at least one control signal, where the reset pulse is configured to be utilized to perform a reset of one or more elements of the integrated circuit.Type: GrantFiled: January 30, 2014Date of Patent: August 5, 2014Assignee: Texas Instruments IncorporatedInventors: Aatmesh Shrivastava, Rajesh Yadav
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Publication number: 20140145762Abstract: Integrated Circuits (ICs) comprising circuits configured to generate a power on reset (POR) pulse are disclosed. An IC comprises a power supply sense circuit configured to generate a sense signal in response to a transition of a power supply signal from a first level to a second level, and a pulse generation circuit coupled with the power supply sense circuit. The pulse generation circuit is configured to generate a power on reset (POR) pulse of a threshold duration based on the sense signal. The IC further includes a reset generation circuit coupled with the pulse generation circuit to receive the POR pulse. The reset generation circuit is configured to generate a reset pulse based on the POR signal and of at least one control signal, where the reset pulse is configured to be utilized to perform a reset of one or more elements of the integrated circuit.Type: ApplicationFiled: January 30, 2014Publication date: May 29, 2014Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Aatmesh Shrivastava, Rajesh Yadav
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Publication number: 20140145767Abstract: Integrated Circuits (ICs) comprising circuits configured to generate a power on reset (POR) pulse are disclosed. An IC comprises a power supply sense circuit configured to generate a sense signal in response to a transition of a power supply signal from a first level to a second level, and a pulse generation circuit coupled with the power supply sense circuit. The pulse generation circuit is configured to generate a power on reset (POR) pulse of a threshold duration based on the sense signal. The IC further includes a reset generation circuit coupled with the pulse generation circuit to receive the POR pulse. The reset generation circuit is configured to generate a reset pulse based on the POR signal and of at least one control signal, where the reset pulse is configured to be utilized to perform a reset of one or more elements of the integrated circuit.Type: ApplicationFiled: January 30, 2014Publication date: May 29, 2014Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Aatmesh Shrivastava, Rajesh Yadav
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Publication number: 20140103898Abstract: Apparatus and method for controlling inductor current in a switch mode power supply. In one embodiment, a switch mode power supply includes an inductor, a high-side switch coupled to the inductor, a low-side switch coupled to the inductor, and a controller. The controller is coupled to at least one of the high-side switch and the low-side switch. The controller includes a first capacitor and a current source. The controller is configured to control timing of current switching to the inductor by enabling current flow through the at least one of the high-side switch and the low-side switch based on time to charge the first capacitor via the current source. The time is a function of voltage across the inductor.Type: ApplicationFiled: February 15, 2013Publication date: April 17, 2014Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Aatmesh SHRIVASTAVA, Yogesh RAMADASS