Patents by Inventor Stefano Pietri
Stefano Pietri 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: 20190250656Abstract: A back bias voltage generator circuit includes a first resistive element connected in series with a second resistive element; a first amplifier having a first input coupled to an input voltage, a second input coupled to a first node at a first terminal of the first resistive element, and an output coupled to an N-polarity metal-oxide semiconductor (NMOS) bias voltage node. A second amplifier has a first input coupled to a symmetrical voltage, a second input coupled to a second node between a second terminal of the first resistive element and a first terminal of the second resistive element, and an output coupled to a P-polarity metal-oxide semiconductor (PMOS) bias voltage node and the second terminal of the second resistive element. The symmetrical voltage is between a highest supply voltage and a lowest supply voltage coupled to the first amplifier.Type: ApplicationFiled: February 9, 2018Publication date: August 15, 2019Inventors: Ricardo Pureza Coimbra, Javier Mauricio Olarte Gonzalez, Ivan Carlos Ribeiro do Nascimento, Felipe Ricardo Clayton, Stefano Pietri, Charles Eric Seaberg
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Patent number: 10110244Abstract: A digital to analog converter (DAC) includes a first sub-DAC configured to convert most significant bits (MSBs) of digital input data, the first sub-DAC including a first array of resistors, a second sub-DAC configured to convert at least some least significant bits (LSBs) of the digital input data, the second sub-DAC including a second array of resistors, and a first scaling resistor connected between the first and second sub-DACs, wherein the first scaling resistor has a resistance value that is based on the number of resistors in the second sub-DAC.Type: GrantFiled: December 7, 2017Date of Patent: October 23, 2018Assignee: NXP USA, Inc.Inventors: Stefano Pietri, James Robert Feddeler, Michael Todd Berens, Yizhong Zhang
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Patent number: 9897649Abstract: An integrated circuit facilitates a self test routine that verifies proper operation of an analog comparator. In response to entering the self test routine, the voltage provided to an input of a comparator is changed from being at an operating voltage supply to being at a self test voltage that is used to verify operation of the comparator. In response to the comparator operating properly, the self test voltage provided to the input of the comparator is replaced with the operating voltage supply, and normal operation resumes. The duration of the self test cycle is based upon the amount of time during which the self test voltage is provided to the comparator is asynchronous in nature, and therefore not a function of a clock signal.Type: GrantFiled: September 14, 2015Date of Patent: February 20, 2018Assignee: NXP USA, INC.Inventors: Juxiang Ren, Chris C. Dao, Stefano Pietri
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Patent number: 9898625Abstract: A method and apparatus for limiting access to an integrated circuit (IC) upon detection of abnormal conditions is provided. At least one of abnormal voltage detection, abnormal temperature detection, and abnormal clock detection are provided with low power consumption. Both abnormally low and abnormally high parameter values (e.g. abnormally low or high voltage, temperature, or clock frequency) may be detected. Abnormal clock detection may also detect a stopped clock signal, including a clock signal stopped at a low logic level or at a high logic level. Furthermore, abnormal clock detection may detect an abnormal duty cycle of a clock signal. A sampled bandgap reference may be used to provide accurate voltage and current references while consuming a minimal amount of power. Upon detection of an abnormal parameter value, one or more tamper indications may be provided to initiate tampering countermeasures, such as limiting access to the IC.Type: GrantFiled: June 1, 2015Date of Patent: February 20, 2018Assignee: NXP USA, INC.Inventors: Alfredo Olmos, James R. Feddeler, Miten H. Nagda, Stefano Pietri
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Patent number: 9891277Abstract: An integrated circuit includes a normal voltage detector configured to detect a normal voltage at which the integrated circuit being fully functional. A first voltage detector detects a first voltage that is less than the normal voltage. A second voltage detector detects a second voltage that is less than the first voltage. A reset module is coupled to a supply voltage, the normal voltage detector, the first voltage detector, and the second voltage detector. The reset module includes test logic to, when the supply voltage rises to the first voltage from the second voltage, perform a pass/fail test when the integrated circuit is in a pass/fail test mode, and perform a power up reset when the integrated circuit in not in the pass/fail test mode.Type: GrantFiled: September 30, 2014Date of Patent: February 13, 2018Assignee: NXP USA, Inc.Inventors: Joel R. Knight, James B. Eifert, Stefano Pietri, Steven K. Watkins
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Patent number: 9697065Abstract: A method for managing a reset process in a processing system is provided. The method includes enabling a watch dog unit based on a power-on reset (POR) event. A stuck in reset condition indication is received at the watch dog unit and used to determine whether the received reset condition indication corresponds to an unintentional reset condition. If the received reset condition indication is an indication of an unintentional reset condition, a watch dog POR trigger signal is generated and a reset state machine is repeated for system recovery.Type: GrantFiled: March 9, 2016Date of Patent: July 4, 2017Assignee: NXP USA, Inc.Inventors: Kumar Abhishek, Steven K. Watkins, Garima Sharda, James M. Giandelone, Stefano Pietri, Thomas H. Luedeke
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Patent number: 9658294Abstract: A test method and system are provided for testing a switched mode power supply in open loop on an automated test equipment device by applying a low frequency waveform signal (209) to a compensator filter (225) and simultaneously capturing and processing the input (223) and output (222) to the compensator filter (225) to determine the phase difference therebetween.Type: GrantFiled: November 4, 2011Date of Patent: May 23, 2017Assignee: NXP USA, INC.Inventors: Stefano Pietri, Chris C. Dao, Garrin S. Felber
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Publication number: 20170063371Abstract: A substrate bias circuit and method for biasing a substrate are provided. A substrate bias circuit includes a first voltage source, a second voltage source, a diode coupled between the first voltage source and the second voltage source, and a plurality of transistors, each transistor in the plurality of transistors having a substrate terminal. In one example, the first voltage source supplies, via the diode, the substrate terminal of a first transistor of the plurality of transistors during a power-up, and the second voltage source supplies the substrate terminal of the first transistor after the power-up.Type: ApplicationFiled: August 26, 2015Publication date: March 2, 2017Inventors: CHRIS C. DAO, STEFANO PIETRI, JUXIANG REN, ROBERT S. RUTH
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Patent number: 9584118Abstract: A substrate bias circuit and method for biasing a substrate are provided. A substrate bias circuit includes a first voltage source, a second voltage source, a diode coupled between the first voltage source and the second voltage source, and a plurality of transistors, each transistor in the plurality of transistors having a substrate terminal. In one example, the first voltage source supplies, via the diode, the substrate terminal of a first transistor of the plurality of transistors during a power-up, and the second voltage source supplies the substrate terminal of the first transistor after the power-up.Type: GrantFiled: August 26, 2015Date of Patent: February 28, 2017Assignee: NXP USA, INC.Inventors: Chris C. Dao, Stefano Pietri, Juxiang Ren, Robert S. Ruth
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Patent number: 9442501Abstract: A semiconductor device including a voltage regulator is disclosed. The voltage regulator may include a multipath amplifier stage, a driver stage coupled to the multipath amplifier stage, a dynamic compensation circuit coupled to the multipath amplifier stage, and a current compensation circuit. The dynamic compensation circuit may be operable to provide a varying level of compensation to the multipath amplifier stage, where the varying level of compensation proportional to a current level associated with the load; and the current compensation circuit may be operable to allow a minimum current level at the driver stage.Type: GrantFiled: May 27, 2014Date of Patent: September 13, 2016Assignee: Freescale Semiconductor, Inc.Inventors: Stefano Pietri, Chris C. Dao, Andre Luis Vilas Boas
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Patent number: 9444405Abstract: An amplifier system includes a low offset amplifier having a first signal input, a second signal input, an output, a resistive digital to analog converter (RDAC) coupled between a first amplifying terminal and a second amplifying terminal of the amplifier that provides offset control, and a current supply coupled to the RDAC. The amplifier system further includes a low offset amplifier having a first signal input, a second signal input, an output, a resistive digital to analog converter coupled between a first amplifying terminal and a second amplifying terminal of the amplifier that provides offset control, and a current supply coupled to the RDAC. The amplifier system also further includes a load coupled to the output and to the second input of the amplifier and a controller coupled to the RDAC that provides an offset control of the first and second inputs by controlling the RDAC.Type: GrantFiled: September 24, 2015Date of Patent: September 13, 2016Assignee: Freescale Semiconductor, Inc.Inventors: Chris C. Dao, Stefano Pietri
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Patent number: 9362904Abstract: A system having a power on reset circuit including a voltage divide), a multiplexer coupled to two outputs of the voltage divider, a first comparator coupled to the multiplexer and a reference, a logic gate coupled to the first comparator, a second comparator coupled to one of the two outputs of the voltage divider, and an emulation gate coupled to the second comparator.Type: GrantFiled: February 28, 2014Date of Patent: June 7, 2016Assignee: Freescale Semiconductor, Inc.Inventors: Chris C. Dao, Stefano Pietri, Juxiang Ren
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Publication number: 20160091561Abstract: An integrated circuit includes a normal voltage detector configured to detect a normal voltage at which the integrated circuit being fully functional. A first voltage detector detects a first voltage that is less than the normal voltage. A second voltage detector detects a second voltage that is less than the first voltage. A reset module is coupled to a supply voltage, the normal voltage detector, the first voltage detector, and the second voltage detector. The reset module includes test logic to, when the supply voltage rises to the first voltage from the second voltage, perform a pass/fail test when the integrated circuit is in a pass/fail test mode, and perform a power up reset when the integrated circuit in not in the pass/fail test mode.Type: ApplicationFiled: September 30, 2014Publication date: March 31, 2016Inventors: JOEL R. KNIGHT, JAMES B. EIFERT, STEFANO PIETRI, STEVEN K. WATKINS
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Patent number: 9285813Abstract: A supply voltage regulation system for an IC including a temperature sensor that detects temperature of the IC, a scaling resistor coupled between a power grid and a feedback node of the IC, a regulator amplifier that compares a voltage of the feedback node with a reference voltage for developing a supply voltage for the IC, and a temperature scaling circuit that drives a scaling current to the scaling resistor via the feedback node to adjust the supply voltage based on temperature. The temperature scaling circuit may include one or more comparators that compare a temperature signal with corresponding temperature thresholds for selectively applying one or more bias currents to the scaling resistor. The scaling resistor may be coupled to a hot point of the power grid. A voltage difference between a hot point of a ground grid may be converted to a bias current applied to the scaling resistor.Type: GrantFiled: May 20, 2014Date of Patent: March 15, 2016Assignee: FREESCALE SEMICONDUCTOR, INC.Inventors: Stefano Pietri, Juxiang Ren, Chris C. Dao, Anis M. Jarrar
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Publication number: 20160003908Abstract: An integrated circuit facilitates a self test routine that verifies proper operation of an analog comparator. In response to entering the self test routine, the voltage provided to an input of a comparator is changed from being at an operating voltage supply to being at a self test voltage that is used to verify operation of the comparator. In response to the comparator operating properly, the self test voltage provided to the input of the comparator is replaced with the operating voltage supply, and normal operation resumes. The duration of the self test cycle is based upon the amount of time during which the self test voltage is provided to the comparator is asynchronous in nature, and therefore not a function of a clock signal.Type: ApplicationFiled: September 14, 2015Publication date: January 7, 2016Inventors: Juxiang Ren, Chris C. Dao, Stefano Pietri
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Publication number: 20150346748Abstract: A semiconductor device including a voltage regulator is disclosed. The voltage regulator may include a multipath amplifier stage, a driver stage coupled to the multipath amplifier stage, a dynamic compensation circuit coupled to the multipath amplifier stage, and a current compensation circuit. The dynamic compensation circuit may be operable to provide a varying level of compensation to the multipath amplifier stage, where the varying level of compensation proportional to a current level associated with the load; and the current compensation circuit may be operable to allow a minimum current level at the driver stage.Type: ApplicationFiled: May 27, 2014Publication date: December 3, 2015Inventors: STEFANO PIETRI, CHRIS C. DAO, ANDRE LUIS VILAS BOAS
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Publication number: 20150338864Abstract: A supply voltage regulation system for an IC including a temperature sensor that detects temperature of the IC, a scaling resistor coupled between a power grid and a feedback node of the IC, a regulator amplifier that compares a voltage of the feedback node with a reference voltage for developing a supply voltage for the IC, and a temperature scaling circuit that drives a scaling current to the scaling resistor via the feedback node to adjust the supply voltage based on temperature. The temperature scaling circuit may include one or more comparators that compare a temperature signal with corresponding temperature thresholds for selectively applying one or more bias currents to the scaling resistor. The scaling resistor may be coupled to a hot point of the power grid. A voltage difference between a hot point of a ground grid may be converted to a bias current applied to the scaling resistor.Type: ApplicationFiled: May 20, 2014Publication date: November 26, 2015Applicant: FREESCALE SEMICONDUCTOR, INC.Inventors: STEFANO PIETRI, JUXIANG REN, CHRIS C. DAO, ANIS M. JARRAR
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Publication number: 20150317496Abstract: A method and apparatus for limiting access to an integrated circuit (IC) upon detection of abnormal conditions is provided. At least one of abnormal voltage detection, abnormal temperature detection, and abnormal clock detection are provided with low power consumption. Both abnormally low and abnormally high parameter values (e.g. abnormally low or high voltage, temperature, or clock frequency) may be detected. Abnormal clock detection may also detect a stopped clock signal, including a clock signal stopped at a low logic level or at a high logic level. Furthermore, abnormal clock detection may detect an abnormal duty cycle of a clock signal. A sampled bandgap reference may be used to provide accurate voltage and current references while consuming a minimal amount of power. Upon detection of an abnormal parameter value, one or more tamper indications may be provided to initiate tampering countermeasures, such as limiting access to the IC.Type: ApplicationFiled: June 1, 2015Publication date: November 5, 2015Inventors: Alfredo Olmos, James R. Feddeler, Miten H. Nagda, Stefano Pietri
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Patent number: 9134395Abstract: An integrated circuit facilitates a self test routine that verifies proper operation of an analog comparator. In response to entering the self test routine, the voltage provided to an input of a comparator is changed from being at an operating voltage supply to being at a self test voltage that is used to verify operation of the comparator. In response to the comparator operating properly, the self test voltage provided to the input of the comparator is replaced with the operating voltage supply, and normal operation resumes. The duration of the self test cycle is based upon the amount of time during which the self test voltage is provided to the comparator is asynchronous in nature, and therefore not a function of a clock signal.Type: GrantFiled: March 7, 2012Date of Patent: September 15, 2015Assignee: Freescale Semiconductor, Inc.Inventors: Juxiang Ren, Chris C. Dao, Stefano Pietri
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Publication number: 20150247893Abstract: A system having a power on reset circuit including a voltage divide), a multiplexer coupled to two outputs of the voltage divider, a first comparator coupled to the multiplexer and a reference, a logic gate coupled to the first comparator, a second comparator coupled to one of the two outputs of the voltage divider, and an emulation gate coupled to the second comparator.Type: ApplicationFiled: February 28, 2014Publication date: September 3, 2015Inventors: CHRIS C. DAO, STEFANO PIETRI, JUXIANG REN