Patents by Inventor Mark D. Maddox

Mark D. Maddox 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: 10637495
    Abstract: A successive-approximation-register analog-to-digital converter (SAR ADC) typically includes circuitry for implementing bit trials that converts an analog input to a digital output bit by bit. The circuitry for bit trials are usually weighted (e.g., binary weighted), and these bit weights are not always ideal. Calibration algorithms can calibrate or correct for non-ideal bit weights and usually prefer these bit weights to be signal-independent so that the bit weights can be measured and calibrated/corrected easily. Embodiments disclosed herein relate to a unique circuit design of an SAR ADC, where each bit capacitor or pair of bit capacitors (in a differential design) has a corresponding dedicated on-chip reference capacitor. The speed of the resulting ADC is fast due to the on-chip reference capacitors (offering fast reference settling times), while errors associated with non-ideal bit weights of the SAR ADC are signal-independent (can be easily measured and corrected/calibrated).
    Type: Grant
    Filed: December 20, 2018
    Date of Patent: April 28, 2020
    Assignee: ANALOG DEVICES, INC.
    Inventors: Junhua Shen, Mark D. Maddox, Ronald Alan Kapusta
  • Publication number: 20190123760
    Abstract: A successive-approximation-register analog-to-digital converter (SAR ADC) typically includes circuitry for implementing bit trials that converts an analog input to a digital output bit by bit. The circuitry for bit trials are usually weighted (e.g., binary weighted), and these bit weights are not always ideal. Calibration algorithms can calibrate or correct for non-ideal bit weights and usually prefer these bit weights to be signal-independent so that the bit weights can be measured and calibrated/corrected easily. Embodiments disclosed herein relate to a unique circuit design of an SAR ADC, where each bit capacitor or pair of bit capacitors (in a differential design) has a corresponding dedicated on-chip reference capacitor. The speed of the resulting ADC is fast due to the on-chip reference capacitors (offering fast reference settling times), while errors associated with non-ideal bit weights of the SAR ADC are signal-independent (can be easily measured and corrected/calibrated).
    Type: Application
    Filed: December 20, 2018
    Publication date: April 25, 2019
    Applicant: Analog Devices, Inc.
    Inventors: Junhua SHEN, Mark D. Maddox, Ronald Alan KAPUSTA
  • Patent number: 10205462
    Abstract: A successive approximation register analog-to-digital converter (SAR ADC) typically includes circuitry for implementing bit trials that converts an analog input to a digital output bit by bit. The circuitry for bit trials are usually weighted (e.g., binary weighted), and these bit weights are not always ideal. Calibration algorithms can calibrate or correct for non-ideal bit weights and usually prefer these bit weights to be signal independent so that the bit weights can be measured and calibrated/corrected easily. Embodiments disclosed herein relate to a unique circuit design of an SAR ADC, where each bit capacitor or pair of bit capacitors (in a differential design) has a corresponding dedicated on-chip reference capacitor. The speed of the resulting ADC is fast due to the on-chip reference capacitors (offering fast reference settling times), while errors associated with non-ideal bit weights of the SAR ADC are signal independent (can be easily measured and corrected/calibrated).
    Type: Grant
    Filed: November 23, 2015
    Date of Patent: February 12, 2019
    Assignee: ANALOG DEVICES, INC.
    Inventors: Junhua Shen, Mark D. Maddox, Ronald Alan Kapusta
  • Patent number: 10038452
    Abstract: During operation of a SAR ADC, several of the MSBs can be preloaded with predetermined bit decisions prior to carrying out bit trials. A system and method can be provided for incrementally preloading the predetermined bit decisions such as to maintain voltages present at comparator inputs within a limited range of acceptable input voltages.
    Type: Grant
    Filed: July 13, 2017
    Date of Patent: July 31, 2018
    Assignee: Analog Devices, Inc.
    Inventors: Baozhen Chen, Edward C. Guthrie, Michael C. W. Coln, Mark D. Maddox
  • Publication number: 20180091165
    Abstract: During operation of a SAR ADC, several of the MSBs can be preloaded with predetermined bit decisions prior to carrying out bit trials. A system and method can be provided for incrementally preloading the predetermined bit decisions such as to maintain voltages present at comparator inputs within a limited range of acceptable input voltages.
    Type: Application
    Filed: July 13, 2017
    Publication date: March 29, 2018
    Inventors: Baozhen Chen, Edward C. Guthrie, Michael C.W. Coln, Mark D. Maddox
  • Patent number: 9716513
    Abstract: During operation of a SAR ADC, it is possible to exceed the voltage limits of a comparator by presenting voltages at the comparator input that exceed a limited range of acceptable input voltages. The present disclosure provides a system and method such as for delivering a common mode compensation voltage such that voltages present at the comparator inputs can be within the limited range of acceptable input voltages.
    Type: Grant
    Filed: August 3, 2016
    Date of Patent: July 25, 2017
    Assignee: Analog Devices, Inc.
    Inventors: Baozhen Chen, Mark D. Maddox, Zhichao Tan
  • Patent number: 9712181
    Abstract: During operation of a SAR ADC, several of the MSBs can be preloaded with predetermined bit decisions prior to carrying out bit trials. A system and method can be provided for incrementally preloading the predetermined bit decisions such as to maintain voltages present at comparator inputs within a limited range of acceptable input voltages.
    Type: Grant
    Filed: September 23, 2016
    Date of Patent: July 18, 2017
    Assignee: Analog Devices, Inc.
    Inventors: Baozhen Chen, Edward C. Guthrie, Michael C. W. Coln, Mark D. Maddox
  • Patent number: 9641189
    Abstract: When reservoir capacitors are moved on-chip for individual bit decisions, a successive approximation register analog-to-digital converter (SAR ADC) has an addition source of error which can significantly affect the performance of the SAR ADC. Calibration techniques can be applied to measure and correct for such error in an SAR ADC using decide-and-set switching. Specifically, a calibration technique can expose the effective bit weight of each bit under test using a plurality of special input voltages and storing a calibration word for each bit under test to correct for the error. Such a calibration technique can lessen the need to store a calibration word for each possible output word to correct the additional source of error. Furthermore, another calibration technique can expose the effective bit weight of each bit under test without having to generate the plurality of special input voltages.
    Type: Grant
    Filed: June 23, 2015
    Date of Patent: May 2, 2017
    Assignee: ANALOG DEVICES, INC.
    Inventors: Mark D. Maddox, Michael Coln, Gary R. Carreau, Baozhen Chen
  • Publication number: 20160182078
    Abstract: A successive approximation register analog-to-digital converter (SAR ADC) typically includes circuitry for implementing bit trials that converts an analog input to a digital output bit by bit. The circuitry for bit trials are usually weighted (e.g., binary weighted), and these bit weights are not always ideal. Calibration algorithms can calibrate or correct for non-ideal bit weights and usually prefer these bit weights to be signal independent so that the bit weights can be measured and calibrated/corrected easily. Embodiments disclosed herein relate to a unique circuit design of an SAR ADC, where each bit capacitor or pair of bit capacitors (in a differential design) has a corresponding dedicated on-chip reference capacitor. The speed of the resulting ADC is fast due to the on-chip reference capacitors (offering fast reference settling times), while errors associated with non-ideal bit weights of the SAR ADC are signal independent (can be easily measured and corrected/calibrated).
    Type: Application
    Filed: November 23, 2015
    Publication date: June 23, 2016
    Applicant: ANALOG DEVICES, INC.
    Inventors: JUNHUA SHEN, Mark D. Maddox, Ronald Alan Kapusta
  • Publication number: 20160182077
    Abstract: When reservoir capacitors are moved on-chip for individual bit decisions, a successive approximation register analog-to-digital converter (SAR ADC) has an addition source of error which can significantly affect the performance of the SAR ADC. Calibration techniques can be applied to measure and correct for such error in an SAR ADC using decide-and-set switching. Specifically, a calibration technique can expose the effective bit weight of each bit under test using a plurality of special input voltages and storing a calibration word for each bit under test to correct for the error. Such a calibration technique can lessen the need to store a calibration word for each possible output word to correct the additional source of error. Furthermore, another calibration technique can expose the effective bit weight of each bit under test without having to generate the plurality of special input voltages.
    Type: Application
    Filed: June 23, 2015
    Publication date: June 23, 2016
    Applicant: ANALOG DEVICES, INC.
    Inventors: Mark D. Maddox, MICHAEL COLN, GARY R. CARREAU, BAOZHEN CHEN
  • Patent number: D508267
    Type: Grant
    Filed: March 17, 2004
    Date of Patent: August 9, 2005
    Assignee: Homes & Land Affiliates, LLC
    Inventor: Mark D. Maddox