US20180360359A1 - Systems and Methods for Measuring Oxygen in a Patient's Bloodstream - Google Patents

Systems and Methods for Measuring Oxygen in a Patient's Bloodstream Download PDF

Info

Publication number
US20180360359A1
US20180360359A1 US15/622,846 US201715622846A US2018360359A1 US 20180360359 A1 US20180360359 A1 US 20180360359A1 US 201715622846 A US201715622846 A US 201715622846A US 2018360359 A1 US2018360359 A1 US 2018360359A1
Authority
US
United States
Prior art keywords
light
light emitting
target
charge
amount
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Abandoned
Application number
US15/622,846
Other languages
English (en)
Inventor
John Jude O'Donnell
Colin G. Lyden
Michael C.W. Coln
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Analog Devices International ULC
Original Assignee
Analog Devices International ULC
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US15/622,846 priority Critical patent/US20180360359A1/en
Application filed by Analog Devices International ULC filed Critical Analog Devices International ULC
Assigned to ANALOG DEVICES GLOBAL reassignment ANALOG DEVICES GLOBAL ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: LYDEN, COLIN G., O'DONNELL, JOHN JUDE, COLN, MICHAEL C.W.
Priority to EP18177455.5A priority patent/EP3415091B1/en
Priority to EP20217910.7A priority patent/EP3824810B1/en
Priority to CN201810612732.4A priority patent/CN109077735B/zh
Priority to KR1020180068138A priority patent/KR20180136401A/ko
Publication of US20180360359A1 publication Critical patent/US20180360359A1/en
Priority to US16/854,657 priority patent/US20200245915A1/en
Assigned to ANALOG DEVICES GLOBAL UNLIMITED COMPANY reassignment ANALOG DEVICES GLOBAL UNLIMITED COMPANY CHANGE OF NAME (SEE DOCUMENT FOR DETAILS). Assignors: ANALOG DEVICES GLOBAL
Assigned to Analog Devices International Unlimited Company reassignment Analog Devices International Unlimited Company ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ANALOG DEVICES GLOBAL UNLIMITED COMPANY
Priority to KR1020240054957A priority patent/KR20240058825A/ko
Abandoned legal-status Critical Current

Links

Images

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552—Details of sensors specially adapted therefor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/145—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455—Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7235—Details of waveform analysis
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/72—Signal processing specially adapted for physiological signals or for diagnostic purposes
    • A61B5/7271—Specific aspects of physiological measurement analysis
    • A61B5/7275—Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/0228—Control of working procedures; Failure detection; Spectral bandwidth calculation
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/02—Details
    • G01J1/08—Arrangements of light sources specially adapted for photometry standard sources, also using luminescent or radioactive material
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01J—MEASUREMENT OF INTENSITY, VELOCITY, SPECTRAL CONTENT, POLARISATION, PHASE OR PULSE CHARACTERISTICS OF INFRARED, VISIBLE OR ULTRAVIOLET LIGHT; COLORIMETRY; RADIATION PYROMETRY
    • G01J1/00—Photometry, e.g. photographic exposure meter
    • G01J1/42—Photometry, e.g. photographic exposure meter using electric radiation detectors
    • G01J1/44—Electric circuits
    • G01J1/46—Electric circuits using a capacitor
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B2560/00—Constructional details of operational features of apparatus; Accessories for medical measuring apparatus
    • A61B2560/02—Operational features
    • A61B2560/0204—Operational features of power management
    • A61B2560/0209—Operational features of power management adapted for power saving
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00—Measuring for diagnostic purposes; Identification of persons
    • A61B5/68—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6801—Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be attached to or worn on the body surface
    • A61B5/6813—Specially adapted to be attached to a specific body part
    • A61B5/6825—Hand
    • A61B5/6826—Finger

Definitions

  • the present disclosure relates to systems and methods for determining saturation of peripheral oxygen in a patient's bloodstream.
  • Certain photometry devices can sense a saturation of peripheral oxygen in a patient's bloodstream.
  • light can be provided by means of a power supply (e.g., a battery) a power regulating element (e.g., an LED driver) and a light source (e.g., an LED).
  • the power regulating element may be comprised of more than one element (e.g. a voltage regulator and a linear current driver) or just one element (e.g., a linear current driver).
  • a large amount of power can be wasted in the electronics separating the power supply from the light emitting elements. For example, 100 mW of power can be consumed by the LED driver itself while 150 mW of power can be provided to the light emitting elements.
  • the inventors have recognized, among other things, that it may be advantageous to use an inductor based driver and eliminate, at least, the use of the linear LED driver and possibly the voltage regulating element as well, such as to reduce an amount of power wasted in a photometry system, such as a photometry system that can sense a saturation of peripheral oxygen in a patient's bloodstream.
  • the disclosure can feature a photometry method.
  • the method can include emitting light to at least a portion of a target using a variable amplitude current pulse, such as to generate the emitted light.
  • the method can also include determining an amount of charge used in the variable amplitude current pulse.
  • the method can also include detecting light received from the at least a portion of the target in response to the emitted light.
  • the method can also include integrating a current associated with the received light in response to the emitted light.
  • the method can also include determining a characteristic of the target using an indication of the integrated current and an indication of the amount of charge used in the variable amplitude current pulse.
  • the method can also include emitting light at different wavelengths and measuring a differential response to determine a composition characteristic of the target.
  • the method can also include collecting and storing the charge used in the variable amplitude current pulse.
  • the method can also include recycling the stored charge used in the variable amplitude current pulse, such as to further emit light to the at least a portion of the target using an additional variable amplitude current pulse, and detecting light received from the at least a portion of the target in response to the further emitted light, and integrating a current associated with the received light in response to the further emitted light.
  • the method can also include determining a characteristic of the target using an indication of the integrated current associated with the received light in response to the emitted light, an indication of charge used in the variable amplitude current pulse, an indication of the integrated current associated with the received light in response to the further emitted light, and an indication of charge used in the additional variable amplitude current pulse.
  • the disclosure can feature a photometry device.
  • the photometry device can include a first LED, such as to emit light to a target in response to a first current through the first LED.
  • the photometry device can also include a second LED, such as to emit light to the target, such as in response to a second current through the second LED.
  • the photometry device can also include an inductor, such as can be coupled to the first and second LEDs, such as to store energy associated with at least one of the first and second currents.
  • the photometry device can also include a switch, such as to selectively couple a terminal of the inductor to first and second reference voltage nodes.
  • the photometry device can also include a capacitor, such as for forming a tank circuit with the inductor for storing energy.
  • the charge can be stored on the capacitor using the first current through the first LED, and charge can be discharged from the capacitor using the second current through the second LED.
  • the photometry device can also include a photosensitive element, such as to receive emitted light from the first LED and the second LED and integration circuitry, such as to determine a charge corresponding to an amount of light received from the first LED and the second LED.
  • the photometry device can also include control circuitry, such as to determine a characteristic of the target using an indication of the charge corresponding to the amount of light received from the first LED and the second LED, and an indication of the charge stored on the first capacitor.
  • the disclosure can feature a system for photometry of a target.
  • the system can include a first light emitting element, such as can be connected by a switching element to a first voltage source having a first voltage value, wherein the first light emitting element can transmit light through at least a portion of the target.
  • the system can also include a charge storage element, such as to receive and store an amount of charge corresponding to a current delivered to the first light emitting element by the first voltage source.
  • the system can also include control circuitry, such as to determine a first potential across the charge storage element, activate the switching element to connect the first voltage source to the first light emitting element, determine a second potential across the charge storage element, and determine an amount of charge stored on the charge storage element corresponding to an amount of light emitted by the first light emitting element from a difference between the second potential and the first potential.
  • control circuitry such as to determine a first potential across the charge storage element, activate the switching element to connect the first voltage source to the first light emitting element, determine a second potential across the charge storage element, and determine an amount of charge stored on the charge storage element corresponding to an amount of light emitted by the first light emitting element from a difference between the second potential and the first potential.
  • the system can also include a photosensitive element, such as to receive a portion of the light emitted by the first light emitting element and convert the received portion of light into an electrical signal, and integration circuitry, such as to integrate the electrical signal to determine an amount of charge corresponding to the amount of light
  • the control circuitry can determine an amount of light absorbed by the portion of the target from a ratio of the amount of charge corresponding to an amount of light emitted by the first light emitting element and the amount of charge corresponding to the amount of light received.
  • the system can also include a second light emitting element, such as can be connected by the switching element to a second voltage source having a second voltage value, wherein the second light emitting element can be configured to transmit light through the portion of the target, and the control circuitry can activate the switching element to deliver the charge stored on the charge storage element as a second electrical current through the second light emitting element.
  • the photosensitive element can receive a portion of the light transmitted by the second light emitting element through the portion of the target.
  • the control circuitry can determine a third electrical potential across the charge storage element, and determine an amount of charge corresponding to an amount of light emitted by the second light emitting element from a difference between the third electrical potential and the second electrical potential.
  • the control circuitry can determine an amount of light absorbed by the portion of the target from a ratio of the amount of charge corresponding to an amount of light emitted by the second light emitting element and the amount of charge corresponding to the amount of light received from the second light emitting element.
  • a wavelength of the first light emitting element can be different from a wavelength of the second light emitting element and a difference in light absorbed by the portion of the target between the first wavelength and the second wavelength can be used to provide a measure of peripheral O 2 saturation.
  • the disclosure can feature a photometry device.
  • the photometry device can include an LED, such as to emit light to a target in response to a first current through the LED.
  • the photometry device can also include an inductor, such as can be coupled to the LED, such as to store energy associated with the first current.
  • the photometry device can also include a capacitor, such as can form a tank circuit with the inductor for storing energy. Charge can be stored on the capacitor using the first current through the LED, and charge can be discharged from the capacitor, such as to provide a second current through the LED.
  • the photometry device can also include a plurality of switches, such as to reverse the polarity of the LED to allow the second current to flow from the capacitor and through the LED.
  • the disclosure can feature a photometry device.
  • the photometry device can include a first LED, such as to emit light to a target in response to a current through the first LED.
  • the photometry device can also include a first capacitor, such as to store charge from the current through the first LED.
  • the photometry device can also include a second LED, such as to emit light to the target in response to current through the second LED provided by recycling stored charge from the first capacitor.
  • the second LED can be antiparallel with the first LED.
  • the photometry device can also include a first inductor, coupled to antiparallel arrangement of the first and second LEDs, such as to form an energy-storage tank circuit with the first capacitor.
  • the photometry device can also include a switch, such as to selectively couple a first terminal of the first inductor to different first and second bias voltages.
  • FIG. 1A illustrates a diagram of a photometry system.
  • FIG. 1B illustrates a diagram of variable amplitude current pulses as a function of time.
  • FIG. 1C illustrates an example of a diagram of absorbance of light as a function of a wavelength.
  • FIG. 1D illustrates a diagram of a patient's arterial volume as a function of time.
  • FIG. 1E illustrates a diagram of hemoglobin and oxygenated hemoglobin in a patient's artery.
  • FIGS. 2A and 2B illustrate an example of operation of a photometry system.
  • FIG. 3 illustrates an example of a transmitter in a photometry system.
  • FIG. 4 illustrates an example of a transmitter in a photometry system
  • FIG. 5 illustrates an example of a transmitter in a photometry system.
  • FIG. 6 illustrates a method of operation of a photometry system.
  • a driver element e.g., a linear current source
  • the one or more light emitting elements can emit light to a target and a photosensitive element and detection circuitry can detect a portion of emitted light passing through the target.
  • the detected fractions of emitted light passing through the target can provide an indication of a chemical concentration in the target, such as a saturated peripheral oxygen level.
  • the inventors have recognized, among other things, that it may be advantageous to use an inductor based driver and eliminate the use of the linear element (e.g., a linear current driver, linear LED driver, or linear current source), such as to reduce an amount of power wasted in a photometry system.
  • an inductor based driver can disadvantageously provide variable amplitude current pulses to the one or more light emitting elements, whereas in photometry devices using a linear driver (e.g., a linear current driver, linear LED driver, or linear current source), the current pulses can be constant (e.g., the current pulses can be constant within 14 bits of accuracy during a time interval where an absorbance is being measured) such that system measurement accuracy is maintained.
  • a linear driver e.g., a linear current driver, linear LED driver, or linear current source
  • the current pulses can be constant (e.g., the current pulses can be constant within 14 bits of accuracy during a time interval where an absorbance is being measured) such that system measurement accuracy is maintained.
  • the inventors have additionally recognized, among other things, that the system inaccuracies, such as those introduced by the variation in the pulse amplitudes may be mitigated by storing and measuring an amount of charge corresponding to the variable amplitude current pulses provided to the one or more light emitting elements and to use an integrating transimpedance amplifier to determine an amount of light emitted by the one or more light emitting elements.
  • FIG. 1A illustrates an example of a photometry system 100 operating with a reduced power consumption and having a self-quenching configuration.
  • the photometry system 100 can include a transmitter 120 and a receiver 150 .
  • the transmitter 120 can include a first voltage source 122 , an electrical ground 124 , a switch 126 , an inductor 128 , a first light emitting diode 130 , a second light emitting diode 132 , and a programmable capacitor 134 .
  • the receiver 150 can include a photodiode 152 , a transimpedance amplifier 154 , a feedback capacitor 156 , a multiplexer 158 , an analog-to-digital converter 160 , and control circuitry 162 .
  • the combination of the amplifier 154 and the feedback capacitor 156 constitutes an integrating transimpedance amplifier which those skilled in the art will recognize can be realised with various circuit configurations.
  • the switch 126 can be configured to connect either the first voltage source 122 or the electrical ground 124 , to the inductor 128 .
  • the inductor can be connected to the switch 126 , the first light emitting diode 130 and the second light emitting diode 132 .
  • the first light emitting diode 130 can be connected to the inductor 128 and the programmable capacitor 134 .
  • the second light emitting diode 132 can be connected to the inductor 128 and the programmable capacitor 134 .
  • the programmable capacitor 134 can be connected to the first light emitting diode 130 , the second light emitting diode 132 , an electrical ground 124 , and the multiplexer 158 .
  • the photodiode 152 can be connected an input terminal of the transimpedance amplifier 154 .
  • the feedback capacitor 156 can be connected between an input terminal and an output terminal of the transimpedance amplifier 154 .
  • the output of the transimpedance amplifier 154 can be connected to the multiplexer 158 .
  • the output of the multiplexer 158 can be connected to the input of the analog-to-digital converter 160 .
  • the output of the analog-to-digital converter 160 can be connected to the control circuitry 162 .
  • the switch 126 can be activated, such as to connect the first voltage source 122 to the inductor 128 , such as to provide a first variable amplitude current pulse to the first light emitting diode 130 .
  • the first voltage source 122 can have a voltage value of about 5V.
  • an increasing current can flow from the first voltage source 122 and through the inductor 128 and the first light emitting diode 130 .
  • a voltage drop across the first light emitting diode 130 can be about 1.5 V.
  • a charge corresponding to the increasing current flowing through the first light emitting diode 130 can be stored by the programmable capacitor 134 , such as can provide an increasing voltage at a node (Vx) of the transmitter 120 .
  • the increasing voltage at the node (Vx) can provide an increasing voltage at a node (Vy) of the transmitter 120 , which in turn can provide a decreasing voltage drop across the inductor 128 .
  • the decreasing voltage drop across the inductor 128 can slow the rate of increase of current flow until a voltage drop across the inductor 128 is zero, at which time the current flowing through the first light emitting diode 130 can begin to decrease.
  • the current flowing through the first light emitting diode 130 can then continue to decrease until the current through the first light emitting diode 130 is reduced to zero.
  • the current decreasing to zero can be referred to as a self-quenching effect.
  • a self-quenching effect can be desirable, such as to avoid the need for precisely timed switching elements.
  • the shape of the first variable amplitude current pulse can include a half-sinusoidal shape 180 , such as that shown in FIG. 1B .
  • the shape of the first variable amplitude current pulse can be adjusted, such as by adjusting a capacitance value of the programmable capacitor 134 or by adjusting an inductance value of the inductor 128 .
  • a charge stored on the programmable capacitor 134 can correspond to the total charge provided to the first light emitting diode 130 by the first variable amplitude current pulse.
  • the first light emitting diode 130 can emit light to a target 148 (e.g., a finger or earlobe), such as in response to the first variable amplitude current pulse provided to the first light emitting diode 130 .
  • An amount of charge corresponding to the first variable amplitude current pulse provided to the first light emitting diode 130 can be determined by measuring a voltage drop across the programmable capacitor 134 before activating the switch 126 to connect the first voltage source 122 to the inductor 128 and again after the current through the first light emitting diode 130 has dropped to zero.
  • the measured voltage drops can be provided to the multiplexer 158 and can be digitized by the analog-to-digital converter 160 before being provided to the control circuitry 162 .
  • the control circuitry 162 can determine a charge corresponding to the first variable amplitude current pulse from the measured voltage drops.
  • the determined charge corresponding to the first variable amplitude current pulse can be used to normalize or compensate for variations in voltage supplied by the voltage source 122 .
  • the photodiode 152 can receive light emitted by the target 140 in response to light emitted by the first light emitting diode 130 .
  • the transimpedance amplifier 154 and the feedback capacitor 156 can integrate a received signal from the photodiode 152 to provide an output signal to the multiplexer 158 .
  • the output signal provided by the transimpedance amplifier 154 can represent an amount of light received from the target 148 corresponding to the first variable amplitude current pulse.
  • the multiplexer 158 can provide the output signal provided by the transimpedance amplifier 154 to the analog-to-digital converter 160 .
  • the analog-to-digital converter 160 can digitize the received output signal and can provide a digitized version of the output signal to the control circuitry 162 .
  • the control circuitry 162 can then determine a first fraction of light emitted by the first light emitting diode 130 and received from the target 148 by the photodiode 152 by comparing the determined amount of charge corresponding to the first variable amplitude current pulse and an amount of light received from the target 148 corresponding to the first variable amplitude current pulse.
  • the first fraction of light can be indicative of an absorbance of light emitted by the first light emitting diode 130 and absorbed by the target 148 .
  • the switch 126 can be activated to connect the inductor 128 to the electrical ground 124 , such as to recycle the charge stored on the programmable capacitor 134 and provide a second variable amplitude current pulse to the second light emitting diode 132 .
  • the activation of the switch 126 to connect the inductor 128 to the electrical ground 124 does not require precision timing because of the self-quenching configuration of the photometry circuit 100 .
  • an increasing current can flow from the programmable capacitor 134 and through the second light emitting diode 132 and the inductor 128 .
  • the current flowing from the programmable capacitor 134 can correspond to charge stored on the programmable capacitor 134 during activation of the first light emitting diode 130 .
  • the current flowing from the programmable capacitor 134 can reduce a stored charge on the programmable capacitor 134 , such as can provide a decreasing voltage at the node (Vx).
  • the decreasing voltage at the node (Vx) can provide a decreasing voltage at the first node (Vy), which in turn can provide a decreasing voltage drop across the inductor 128 .
  • the decreasing voltage drop across the inductor 128 can slow the rate of increase of current flow until a voltage drop across the inductor 128 is zero, at which time the current flowing through the second light emitting diode 132 can begin to decrease.
  • the current flowing through the first light emitting diode 130 can then continue to decrease until the current through the second light emitting diode 132 is reduced to zero.
  • the second light emitting diode 132 can be removed and further switching elements can be added, such as to provide the second variable amplitude current pulse to the first light emitting diode 130 .
  • the second light emitting diode 132 can emit light to the target 148 (e.g., a finger or earlobe), such as in response to the second variable amplitude current pulse provided to the second light emitting diode 132 .
  • a ratio of the charge corresponding to the first variable amplitude current pulse and the second variable amplitude current pulse can be independent of variations in a supply voltage, such as that provided by the voltage source 122 .
  • An amount of charge corresponding to the second variable amplitude current pulse provided to the second light emitting diode 132 can be determined by measuring a voltage drop across the programmable capacitor 134 after activating the switch 126 to connect the electrical ground 124 to the inductor 128 and again after the current through the second light emitting diode 132 has dropped to zero.
  • the measured voltage drops can be provided to the multiplexer 158 and can be digitized by the analog-to-digital converter 160 before being provided to the control circuitry 162 .
  • the control circuitry 162 can determine a charge corresponding to the second variable amplitude current pulse from the measured voltage drops.
  • the determined charge corresponding to the second variable amplitude current pulse can be used to normalize or compensate for variations in voltage supplied by the voltage source 122 .
  • the photodiode 152 can receive light emitted by the target 148 in response to light emitted by the second light emitting diode 132 .
  • the transimpedance amplifier 154 and the feedback capacitor 156 can integrate a received signal from the photodiode 152 to provide an output signal to the multiplexer 158 .
  • the output signal provided by the transimpedance amplifier 154 can represent an amount of light received from the target 148 corresponding to the second variable amplitude current pulse.
  • the multiplexer 158 can provide the output signal provided by the transimpedance amplifier 154 to the analog-to-digital converter 160 .
  • the analog-to-digital converter 160 can digitize the received output signal and can provide a digitized version of the output signal to the control circuitry 162 .
  • the control circuitry 162 can then determine a second fraction of light emitted by the second light emitting diode 132 and received from the target 148 by the photodiode 152 by comparing the determined amount of charge corresponding to the second variable amplitude current pulse and an amount of light received from the target 148 corresponding to the second variable amplitude current pulse.
  • the second fraction of light can be indicative of an absorbance of light emitted by the second light emitting diode 132 and absorbed by the target 148 .
  • a wavelength of the first light emitting diode 130 and the second light emitting diode 132 can be different and a peripheral oxygen saturation can be determined from the first fraction of light and the second fraction of light.
  • a wavelength of the first light emitting diode 130 can be in the infrared band and a wavelength of the second light emitting diode 132 can be in the red band.
  • a charge stored on the programmable capacitor 134 can be used to normalize or compensate a charge corresponding to an amount of light received by the photodiode 152
  • the impact of variations in a value of the voltage source 122 e.g., the value of the voltage supply can have an average value of about 5V and can vary by about 20 mV
  • a peripheral oxygen saturation measurement can have an accuracy of about 0.1% where a charge stored on the programmable capacitor 134 can be used to normalize or compensate a charge corresponding to an amount of light received by the photodiode 152 .
  • the accuracy can be reduced very significantly (e.g., by as much as 40%) such as can be inadequate for medical purposes.
  • FIG. 1B illustrates a diagram of variable amplitude current pulses as a function of time.
  • the variable amplitude current pulses can be provided by a photometry system, such as the photometry system 100 .
  • a first variable amplitude current pulse 180 and a second variable amplitude current pulse 182 can be provided in succession.
  • the first variable amplitude current pulse 180 and the second variable amplitude current pulse 182 can include a half-sinusoidal shape.
  • the first variable amplitude current pulse 180 can be provided to a first light emitting diode, such as the first light emitting diode 130 that can then emit a first variable amplitude light pulse in response.
  • the first variable amplitude light pulse can be an infrared light pulse.
  • the second variable amplitude current pulse 182 can be provided to a second light emitting diode, such as the second light emitting diode 132 that can then emit a second variable amplitude light pulse in response.
  • the second variable amplitude light pulse can be a red light pulse.
  • FIG. 1C illustrates an example of a diagram of absorbance of light as a function of a wavelength of light for hemoglobin (Hb) and oxygenated hemoglobin (HbO 2 ).
  • the ratio of the absorbances of hemoglobin (Hb) and oxygenated hemoglobin can be significantly lower for infrared light than for red light.
  • a saturated peripheral oxygen measurement can be determined from a difference in absorbance for red light and infrared light.
  • the photometry system 100 can measure an absorbance of the target 148 for red light and for infrared light to determine a saturated peripheral oxygen of a patient.
  • FIG. 1D illustrates a diagram of a patient's arterial volume as a function of time.
  • the patient's arteries can be slightly elastic and can change volume in response to heartbeat pressure variations.
  • the control circuitry 162 can discriminate between light received from arteries and light received from finger, bone, tissue, or veins based at least in part on the changing arterial volume as a function of time.
  • FIG. 1E illustrates a diagram of hemoglobin and oxygenated hemoglobin in a patient's artery.
  • a saturated peripheral oxygen measurement can correspond to a percentage of hemoglobin binding sites occupied by oxygen.
  • 75% of the hemoglobin binding sites are occupied by oxygen, corresponding to a saturated peripheral oxygen of 75%.
  • a healthy patient typically has over 95% of hemoglobin binding sites occupied by oxygen.
  • FIGS. 2A and 2B illustrate an example of simulated results in a photometry system, such as the photometry system 100 illustrated in FIG. 1 , where the photometry system 100 can be used as a pulse oximeter to measure a peripheral oxygen saturation in a patient.
  • FIG. 2B shows a zoomed-in region 250 of FIG. 2A .
  • the simulated results can include an ideal photoplethysmogram trace 210 , a light emitting diode current 215 , a capacitor voltage 220 , a difference between a sampled high voltage across a capacitor and a sampled low voltage across a capacitor 225 , a photoplethysmogram trace including power supply noise 230 , and a compensated photoplethysmogram 235 .
  • the ideal photoplethysmogram trace 210 can correspond to the situation where there is no noise introduced by a power supply, such as the first voltage source 122 .
  • the light emitting diode current 215 can correspond to current passing through the first light emitting diode 130 and the second light emitting diode 132 .
  • the capacitor voltage 220 can correspond to a voltage drop across the capacitor 134 .
  • the difference between the sampled high voltage across a capacitor and the sampled low voltage across a capacitor 225 can correspond to a measured voltage of the capacitor 134 before and after the first and second variable amplitude current pulses are delivered to the first and second light emitting diodes 130 and 132 , respectively.
  • the difference between the sampled high voltage across a capacitor and the sampled low voltage across a capacitor 225 can correspond to an amount of energy delivered by a variable amplitude current pulse, such as the first variable amplitude current pulse delivered to the first light emitting diode 130 and the second variable amplitude current pulse 132 delivered to the second light emitting diode 132 .
  • the photoplethysmogram trace 230 can correspond to the situation where there is noise introduced by a power supply, such as the first voltage source 122 .
  • the difference between the sampled high voltage across the capacitor and the sampled low voltage across the capacitor can be used to reduce or eliminate the supply noise present on the photoplethysmogram trace 230 .
  • the photoplethysmogram trace can be divided or normalized by the difference between the sampled high voltage across the capacitor and the sampled low voltage across the capacitor to reduce or eliminate noise introduced by the power supply.
  • FIG. 3 illustrates another example of a transmitter 120 .
  • the transmitter 120 can include an inductor 328 , switches 326 , 338 , 340 , 342 , and 344 , a first capacitor 336 , a second capacitor 334 , a first light emitting diode 330 , a second light emitting diode 332 , a voltage source 322 , and an electrical ground 324 .
  • the switch 126 can be activated, such as to connect the voltage source 322 to the inductor 328 .
  • the switches 342 and 344 can also be activated, such as to connect the first capacitor 336 , and the second capacitor 334 to the inductor 328 .
  • a current can flow from the voltage source 322 , through the inductor 328 , and to the first capacitor 336 , and the second capacitor 334 .
  • a charge corresponding to the current can be stored on the first and second capacitors 336 and 334 . Similar to the transmitter 120 as described above, the current flowing to the first capacitor 336 and the second capacitor 334 can first increase, before deceasing to zero.
  • the switches 326 , 338 , 340 , 342 , and 344 can be activated, such as to provide a connection from the first capacitor 336 to the first light emitting diode 330 , while isolating the second capacitor 334 , the voltage source 322 , and the second light emitting diode 332 .
  • the charge stored on the first capacitor 336 can then flow through the first light emitting diode 330 , such as to provide a first variable amplitude current pulse to the first light emitting diode 330 .
  • the first light emitting diode 330 can emit light to a target, such as the target 148 , such as in response to the first variable amplitude current pulse provided to the first light emitting diode 330 .
  • the switches 326 , 338 , 340 , 342 , and 344 can be activated, such as to provide a connection from the second capacitor 334 to the second light emitting diode 332 , while isolating the first capacitor 336 , the voltage source 322 , and the first light emitting diode 330 .
  • the charge stored on the second capacitor 334 can then flow through the second light emitting diode 332 , such as to provide a second variable amplitude current pulse to the second light emitting diode 332 .
  • the second light emitting diode 332 can emit light to a target, such as the target 148 , such as in response to the second variable amplitude current pulse provided to the second light emitting diode 332 .
  • the switch 326 can be activated, such as to connect the inductor 328 to an electrical ground 324 , such as to moderate energy stored in the inductor 328 and the first and second capacitors 336 and 334 .
  • each of the first and second capacitors 336 and 334 can be discharged to drive each the first and second light emitting diodes 330 and 332 .
  • the shape of the first variable amplitude current pulse and the second variable amplitude current pulse can be half-sinusoidal.
  • the receiver 150 can receive and process the received light from the target 148 , similar to that described above with respect to FIG. 1A .
  • FIG. 4 illustrates another example of a transmitter 120 .
  • the transmitter 120 can include a voltage source 422 , an electrical ground 424 , a switch 426 , an inductor 428 , a first light emitting diode 430 , and a second light emitting diode 432 .
  • the switch can be activated, such as to connect the voltage source 422 to the inductor 428 , such as to provide a first variable amplitude current pulse to the first light emitting diode 430 .
  • An increasing current can flow through the inductor 428 and the first light emitting diode 430 .
  • An amount of energy can be stored in a magnetic field of the inductor 428 , such as due to the current flowing through the inductor.
  • the first light emitting diode 430 can emit light to a target, such as the target 148 , such as in response to the first variable amplitude current pulse provided to the first light emitting diode 430 .
  • the switch 426 can be activated, such as to disconnect the inductor from the voltage source 422 and connect the inductor to the second light emitting diode 432 .
  • the energy stored in the magnetic field of the inductor 428 can then be recycled and the inductor 428 can provide a second variable amplitude current pulse to the second light emitting diode 432 .
  • the second variable amplitude current pulse provided by the inductor 428 to the second light emitting diode 432 can correspond to the energy stored in a magnetic field of the inductor 428 during delivery of the first variable amplitude current pulse to the first light emitting diode 430 .
  • the second light emitting diode 432 can emit light to a target, such as the target 148 , such as in response to the second variable amplitude current pulse provided to the second light emitting diode 432 .
  • the first variable amplitude current pulse and the second variable amplitude current pulse can be sawtooth shaped and the current through the inductor can be approximately triangular in shape.
  • a magnitude of the variable amplitude current pulses can be adjusted by adjusting a value of the inductor 428 .
  • the receiver 150 can receive and process the received light from the target 148 , similar to that described above with respect to FIG. 1A .
  • the energy stored in the magnetic field of the inductor 428 can be determined by measuring the magnetic field, such as with a Hall device, a magnetoresistive sensor, or by adding another winding to the inductor 428 to make it a transformer and then monitoring a waveform on the second winding. The measured magnetic field can be used to normalize or compensate for variations in voltage supplied by the voltage source 422 .
  • FIG. 5 illustrates another example of a transmitter 120 .
  • the transmitter 120 can include a voltage source 522 , an electrical ground 524 , switches 526 , 534 , and 536 , an inductor 528 , a first light emitting diode 530 , and a second light emitting diode 532 .
  • the switches 526 , 534 , and 536 can be activated, such as to connect the voltage source 522 to the inductor 528 , such as to provide a first variable amplitude current pulse to the first light emitting diode 530 .
  • the switch 536 can prevent a current from flowing through the second light emitting diode 532 .
  • An increasing current can flow through the inductor 528 and the first light emitting diode 530 .
  • An amount of energy can be stored in a magnetic field of the inductor 528 , such as due to the current flowing through the inductor 528 .
  • the first light emitting diode 530 can emit light to a target, such as the target 148 , such as in response to the first variable amplitude current pulse provided to the first light emitting diode 530 .
  • the switch 526 can be activated, such as to disconnect the inductor 528 from the voltage source 522 and connect the inductor 528 to the electrical ground 524 .
  • the switches 534 and 536 can also be activated, such as to provide a second variable amplitude current pulse to the second light emitting diode 532 .
  • the switch 534 can prevent a current from flowing to the first light emitting diode 530 .
  • the energy stored in the magnetic field of the inductor 528 can then be recycled and the inductor 528 can provide a second variable amplitude current pulse to the second light emitting diode 532 .
  • the second variable amplitude current pulse provided by the inductor 528 to the second light emitting diode 532 can correspond to the energy stored in a magnetic field of the inductor 528 during delivery of the first variable amplitude current pulse to the first light emitting diode 530 .
  • the second light emitting diode 532 can emit light to a target, such as the target 148 , such as in response to the second variable amplitude current pulse provided to the second light emitting diode 532 .
  • the first variable amplitude current pulse and the second variable amplitude current pulse can be sawtooth shaped and the current through the inductor can be approximately triangular in shape.
  • a magnitude of the variable amplitude current pulses can be adjusted by adjusting a value of the inductor 528 .
  • the receiver 150 can receive and process the received light from the target 148 , similar to that described above with respect to FIG. 1A .
  • the energy stored in the magnetic field of the inductor 528 can be determined by measuring the magnetic field, such as with a Hall device, a magnetoresistive sensor, or by adding another winding to the inductor 528 to make it a transformer and then monitoring a waveform on the second winding.
  • the measured magnetic field can be used to normalize or compensate for variations in voltage supplied by the voltage source 522 .
  • FIG. 6 illustrates a method of operation of a photometry system, such as the photometry system 100 .
  • a light emitting diode such as the light emitting diode 130 or 132 can emit light to at least a portion of a target, such as the target 148 using a variable amplitude current pulse to generate the emitted light (step 610 ).
  • Control circuitry such as control circuitry 162 can determine an amount of charge used in the variable amplitude current pulse that passed through the light emitting diode, such as by measuring a voltage drop across a programmable capacitor, such as the programmable capacitor 134 (step 620 ).
  • a photodiode such as the photodiode 152 can detect light received from the at least a portion of the target in response to the emitted light (step 630 ).
  • An integrating transimpedance amplifier such as the transimpedance amplifier 154 and the feedback capacitor 156 can integrate a current associated with the received light in response to the emitted light (step 640 ).
  • the control circuitry 162 can determine a characteristic of the target 148 using an indication of the integrated current and an indication of the amount of charge used in the variable amplitude current pulse, wherein the control circuitry 162 can compensate for light intensity variations of the light emitting diode by using the indication of the amount of charge used in the variable amplitude current pulse (step 650 ).
  • the present inventor also contemplates examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.
  • the usage in this document controls.
  • the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.”
  • the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated.
  • Method examples described herein can be machine or computer-implemented at least in part. Some examples can include a computer-readable medium or machine-readable medium encoded with instructions operable to configure an electronic device to perform methods as described in the above examples.
  • An implementation of such methods can include code, such as microcode, assembly language code, a higher-level language code, or the like. Such code can include computer readable instructions for performing various methods. The code may form portions of computer program products. Further, in an example, the code can be tangibly stored on one or more volatile, non-transitory, or non-volatile tangible computer-readable media, such as during execution or at other times.
  • Examples of these tangible computer-readable media can include, but are not limited to, hard disks, removable magnetic disks, removable optical disks (e.g., compact disks and digital video disks), magnetic cassettes, memory cards or sticks, random access memories (RAMs), read only memories (ROMs), and the like.

Landscapes

  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • General Health & Medical Sciences (AREA)
  • Veterinary Medicine (AREA)
  • Biophysics (AREA)
  • Biomedical Technology (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Surgery (AREA)
  • Animal Behavior & Ethology (AREA)
  • Pathology (AREA)
  • Public Health (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Artificial Intelligence (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Physiology (AREA)
  • Psychiatry (AREA)
  • Signal Processing (AREA)
  • Power Engineering (AREA)
  • Measurement Of The Respiration, Hearing Ability, Form, And Blood Characteristics Of Living Organisms (AREA)
  • Measuring Pulse, Heart Rate, Blood Pressure Or Blood Flow (AREA)
  • Otolaryngology (AREA)
  • Investigating Or Analysing Materials By Optical Means (AREA)
US15/622,846 2017-06-14 2017-06-14 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream Abandoned US20180360359A1 (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US15/622,846 US20180360359A1 (en) 2017-06-14 2017-06-14 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream
EP18177455.5A EP3415091B1 (en) 2017-06-14 2018-06-13 Systems and methods for measuring oxygen in a patient's bloodstream
EP20217910.7A EP3824810B1 (en) 2017-06-14 2018-06-13 Systems and methods for measuring oxygen in a patient's bloodstream
CN201810612732.4A CN109077735B (zh) 2017-06-14 2018-06-14 用于测量患者血流中的氧的系统和方法
KR1020180068138A KR20180136401A (ko) 2017-06-14 2018-06-14 환자의 혈류 내 산소를 측정하기 위한 시스템 및 방법
US16/854,657 US20200245915A1 (en) 2017-06-14 2020-04-21 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream
KR1020240054957A KR20240058825A (ko) 2017-06-14 2024-04-24 환자의 혈류 내 산소를 측정하기 위한 시스템 및 방법

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US15/622,846 US20180360359A1 (en) 2017-06-14 2017-06-14 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US16/854,657 Continuation US20200245915A1 (en) 2017-06-14 2020-04-21 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream

Publications (1)

Publication Number Publication Date
US20180360359A1 true US20180360359A1 (en) 2018-12-20

Family

ID=62783993

Family Applications (2)

Application Number Title Priority Date Filing Date
US15/622,846 Abandoned US20180360359A1 (en) 2017-06-14 2017-06-14 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream
US16/854,657 Pending US20200245915A1 (en) 2017-06-14 2020-04-21 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream

Family Applications After (1)

Application Number Title Priority Date Filing Date
US16/854,657 Pending US20200245915A1 (en) 2017-06-14 2020-04-21 Systems and Methods for Measuring Oxygen in a Patient's Bloodstream

Country Status (4)

Country Link
US (2) US20180360359A1 (ko)
EP (2) EP3415091B1 (ko)
KR (2) KR20180136401A (ko)
CN (1) CN109077735B (ko)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6163715A (en) * 1996-07-17 2000-12-19 Criticare Systems, Inc. Direct to digital oximeter and method for calculating oxygenation levels
US20020049389A1 (en) * 1996-09-04 2002-04-25 Abreu Marcio Marc Noninvasive measurement of chemical substances
US20060206019A1 (en) * 2005-03-10 2006-09-14 Shenzhen Mindray Bio-Medical Electronics Co., Ltd. Method for measuring blood oxygen content under low perfusion
US20120232354A1 (en) * 2011-03-09 2012-09-13 Medtronic, Inc. Optical sensor system and measurement method
US20160143566A1 (en) * 2014-11-20 2016-05-26 Qualcomm Incorporated Circuitry to Allow Low Current Operation of a Device Capable of Determining a Blood Property
US20170099711A1 (en) * 2015-10-02 2017-04-06 Texas Instruments Incorporated Transmitter Architecture for Photoplethysmography Systems

Family Cites Families (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3165983B2 (ja) * 1992-06-15 2001-05-14 日本光電工業株式会社 パルスオキシメータ用発光素子駆動装置
US6226539B1 (en) * 1999-05-26 2001-05-01 Mallinckrodt, Inc. Pulse oximeter having a low power led drive
US6575912B1 (en) * 2001-10-16 2003-06-10 Pacesetter, Inc. Assessing heart failure status using morphology of a signal representative of arterial pulse pressure
US7400310B2 (en) * 2005-11-28 2008-07-15 Draeger Medical Systems, Inc. Pulse signal drive circuit
US20150335293A1 (en) * 2013-08-30 2015-11-26 Maxim Integrated Products, Inc. Systems and techniques to determine whether a signal is associated with a periodic biologic function
US20150196239A1 (en) * 2014-01-10 2015-07-16 Covidien Lp Method and apparatus for driving an emitter in a medical sensor
US20150289791A1 (en) * 2014-04-11 2015-10-15 Colin Rhodes Marcus Pulse Oximeter Using Burst Sampling
CN104622479A (zh) * 2014-12-10 2015-05-20 宫俊峰 一种无创血氧饱和度检测仪
US10251565B2 (en) * 2015-04-30 2019-04-09 Dna Medicine Institute, Inc. Multi-channel vitals device
CN105105763A (zh) * 2015-09-15 2015-12-02 成都汉康信息产业有限公司 安全易用的血氧饱和度检测装置
CN205658915U (zh) * 2016-03-03 2016-10-26 江苏鱼跃信息系统有限公司 血氧测量系统
CN106667459A (zh) * 2016-08-01 2017-05-17 江苏怡龙医疗科技有限公司 运动状态下的血氧饱和度监测装置

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6163715A (en) * 1996-07-17 2000-12-19 Criticare Systems, Inc. Direct to digital oximeter and method for calculating oxygenation levels
US20020049389A1 (en) * 1996-09-04 2002-04-25 Abreu Marcio Marc Noninvasive measurement of chemical substances
US20060206019A1 (en) * 2005-03-10 2006-09-14 Shenzhen Mindray Bio-Medical Electronics Co., Ltd. Method for measuring blood oxygen content under low perfusion
US20120232354A1 (en) * 2011-03-09 2012-09-13 Medtronic, Inc. Optical sensor system and measurement method
US20160143566A1 (en) * 2014-11-20 2016-05-26 Qualcomm Incorporated Circuitry to Allow Low Current Operation of a Device Capable of Determining a Blood Property
US20170099711A1 (en) * 2015-10-02 2017-04-06 Texas Instruments Incorporated Transmitter Architecture for Photoplethysmography Systems

Also Published As

Publication number Publication date
EP3824810B1 (en) 2024-05-15
EP3415091A2 (en) 2018-12-19
CN109077735B (zh) 2022-04-08
EP3824810A1 (en) 2021-05-26
EP3415091B1 (en) 2021-02-03
KR20180136401A (ko) 2018-12-24
US20200245915A1 (en) 2020-08-06
EP3415091A3 (en) 2019-06-26
CN109077735A (zh) 2018-12-25
KR20240058825A (ko) 2024-05-07

Similar Documents

Publication Publication Date Title
US6668183B2 (en) Diode detection circuit
US11980439B2 (en) Optical sensor system of a wearable device, a method for controlling operation of an optical sensor system and corresponding computer program product
CN107635456B (zh) 人体可穿戴设备及其操作方法
EP1722854A1 (en) Led forward voltage estimation in pulse oximeter
CN106535753B (zh) 光学心率传感器
AU2005216975A1 (en) Switch-mode oximeter led drive with a single inductor
US11344234B2 (en) Circuit arrangement for an optical monitoring system and method for optical monitoring
US9041582B2 (en) Organism state quantity measuring apparatus
US20150196239A1 (en) Method and apparatus for driving an emitter in a medical sensor
US9537473B2 (en) Digitally assisted analog dynamic range enhancer
US20200375484A1 (en) Light-to-digital converter
US20200245915A1 (en) Systems and Methods for Measuring Oxygen in a Patient's Bloodstream
US20170311823A1 (en) Optical trigger for measurement
US10588522B2 (en) Biological sensor
US20200260970A1 (en) Demodulating a signal from intermittently illuminated region
US9341680B2 (en) Selectable upper voltage range monitoring circuit
Pandey et al. An adaptive analog front end for a flexible PPG sensor patch with self-determined motion related DC drift removal
WO2017159396A1 (ja) 計測回路および駆動方法、並びに電子機器
US20210106316A1 (en) Wearable blood gas monitor
US10806345B2 (en) Apparatus and method for monitoring a physiological parameter
WO2014013813A1 (ja) 生体センサ
US11689209B2 (en) Analog-to-digital converter circuitry, an integrated circuit device, a photoplethysmogram detector, a wearable device and a method for analog-to-digital conversion
JP2010166963A (ja) 脈波増幅装置
US20180078140A1 (en) Biological signal detection device
KR20070020427A (ko) 심장 박동 감지 및 센서의 소비 전력 감소를 위한 장치

Legal Events

Date Code Title Description
AS Assignment

Owner name: ANALOG DEVICES GLOBAL, BERMUDA

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:O'DONNELL, JOHN JUDE;LYDEN, COLIN G.;COLN, MICHAEL C.W.;SIGNING DATES FROM 20170622 TO 20170627;REEL/FRAME:043042/0570

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: NON FINAL ACTION MAILED

STPP Information on status: patent application and granting procedure in general

Free format text: RESPONSE TO NON-FINAL OFFICE ACTION ENTERED AND FORWARDED TO EXAMINER

STPP Information on status: patent application and granting procedure in general

Free format text: FINAL REJECTION MAILED

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION

AS Assignment

Owner name: ANALOG DEVICES GLOBAL UNLIMITED COMPANY, BERMUDA

Free format text: CHANGE OF NAME;ASSIGNOR:ANALOG DEVICES GLOBAL;REEL/FRAME:059095/0868

Effective date: 20161130

AS Assignment

Owner name: ANALOG DEVICES INTERNATIONAL UNLIMITED COMPANY, IRELAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ANALOG DEVICES GLOBAL UNLIMITED COMPANY;REEL/FRAME:059107/0908

Effective date: 20181105