Low power pulse oximeter
First Claim
1. A low power pulse oximeter comprising:
- a sensor interface adapted to drive a pulse oximetry sensor and receive a corresponding input signal;
a processor that derives a physiological measurement corresponding to said input signal;
a display driver adapted to communicate said measurement to a display;
a controller gernerating a sampling control output to at least one of said sensor interface and said processor so as to reduce the average power consumption of said pulse oximeter consistent with a predetermined power target; and
a calculator that derives a signal status output responsive to said input signal, said signal status output being communicated to said controller to override said sampling control output, wherein said signal status output indicates the occurence of a physiological event.
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Accused Products
Abstract
A pulse oximeter adaptively samples an input signal from a sensor in order to reduce power consumption in the absence of overriding conditions. Various sampling mechanisms may be used individually or in combination, including reducing the duty cycle of a drive current to a sensor emitter, intermittently powering-down a front-end interface to a sensor detector, or increasing the time shift between processed data blocks. Both internal parameters and output parameters may be monitored to trigger or override a reduced power consumption state. In this manner, a pulse oximeter can lower power consumption without sacrificing performance during, for example, high noise conditions or oxygen desaturations.
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Citations
19 Claims
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1. A low power pulse oximeter comprising:
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a sensor interface adapted to drive a pulse oximetry sensor and receive a corresponding input signal;
a processor that derives a physiological measurement corresponding to said input signal;
a display driver adapted to communicate said measurement to a display;
a controller gernerating a sampling control output to at least one of said sensor interface and said processor so as to reduce the average power consumption of said pulse oximeter consistent with a predetermined power target; and
a calculator that derives a signal status output responsive to said input signal, said signal status output being communicated to said controller to override said sampling control output, wherein said signal status output indicates the occurence of a physiological event.
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2. A low pulse oximeter comprising:
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a sensor interface adapted to drive a pulse oximetry sensor and receive a corresponding input signal;
a processor that derives a physiological measurement corresponding to said input signal;
a display driver adapted to communicate said measurement to a display;
a controller generating a sampling control output to at least one of said sensor interface and said processor so as to reduce the average power consumption of said pulse oximeter consistent with a predetermined power target, wherein said sensor interface comprises a front-end adapted to receive said input signal from a detector portion of said sensor and to provide a corresponding digitized signal, and wherein said sampling control output determines a powered-down period of said front-end; and
confidence indicator that is responsive to a duration of said powered-down period, said confidence indicator communicated to said display driver.
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3. A low power pulse oximeter comprising:
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a sensor interface adapted to drive a pulse oximetry sensor and receive a corresponding input signal;
a processor that derives a physiological measurement corresponding to said input signal;
a display driver adapted to communicate said measurement to a display;
a controller generating a sampling control output to at least one of said sensor interface and said processor so as to reduce the average power consumption of said pulse oximeter consistent with a predetermined power target;
plurality of data blocks responsive to said input signal, wherein said sampling control output determines a time shift of successive ones of said data blocks. - View Dependent Claims (4)
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5. A low power pulse oximetry method comprising the steps of:
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storing a power target;
receiving an input signal from a pulse oximetry sensor;
calculating signal status related to said input signal;
calculating power status related to said power target; and
sampling based upon the result of said calculating signal status and said calculating power status steps. - View Dependent Claims (6, 7, 8, 9)
receiving a signal statistic related to said input signal;
receiving a physiological measurement related to said input signal;
determining a low signal quality condition from said signal statistic;
determining an event occurrence from said physiological measurement; and
indicating an override based upon said low signal quality condition or said event occurrence.
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7. The low power pulse oximetry method according to claim 6 wherein said calculating power status step comprises the substeps of:
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estimating an average power consumption for at least a portion of said pulse oximeter; and
indicating an above power target condition when said average power consumption is above said power target.
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8. The low power pulse oximetry method according to claim 7 wherein said sampling step comprises the substep of decreasing sampling as the result of said above power target condition, except during said override.
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9. The low power pulse oximetry method according to claim 6 wherein said sampling step comprises the substep of increasing sampling as the result of said override.
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10. A low power pulse oximetry method comprising the steps of:
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detecting an override related to a measure of signal quality or a physiological measurement event;
increasing said pulse oximeter to a higher power level when said override exists;
reducing said pulse oximeter to a lower power level if said override does not exist;
predetermining a target power level for a pulse oximeter; and
cycling between said lower power lever and said higher power level so that an average power consumption is consistent with said target power level.
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11. A low power pulse oximetry method comprising the steps of:
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detecting an override related to a measure of signal quality or a physiological measurement event;
increasing said pulse oximeter to a higher power level when said override exists; and
reducing said pulse oximeter to a lower power level if said override does not exist, wherein said reducing step comprises the substep of decreasing the duty cycle of an emitter driver output.
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12. A low power pulse oximetry method comprising the steps of:
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detecting an override related to a measure of signal quality or a physiological measurement event;
increasing said pulse oximeter to a higher power level when said override exist;
reducing said pulse oximeter to a lower power level if said override does not exist, wherein said reducing step comprises the substep of powering-down a detector front-end; and
displaying a confidence indication related to the duration of said powering-down substep.
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13. A low power pulse oximetry method comprising the steps of:
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detecting an override related to a measure of signal quality or a physiological measurement event;
increasing said pulse oximeter to a higher power level when said override exists;
reducing said pulse oximeter to a lower power level if said override does not exist, wherein said reducing step comprises the substep of increasing the time-shift of post-processor data blocks.
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14. A low power pulse oximeter comprising:
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a sensor interface adapted to receive an input signal from a sensor;
a signal processor configured to communicate with said sensor interface and to generate an internal parameter responsive to said input signal; and
a sampling controller responsive to said internal parameter so as to generate a sampling control to alter the power consumption of at least one of said senor interface and said signal processor, wherein said sampling controller is responsive to a predetermined power target in combination with said internal parameter so as to generate a sampling control to alter the power consumption of at least one of said sensor interface and said signal processor. - View Dependent Claims (15)
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16. A low power pulse oximeter comprising:
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a sensor interface adapted to receive an input signal from a sensor;
a signal processor configured to communicate with said sensor interface and to generate an internal parameter responsive to said input signal; and
a sampling controller responsive to said internal parameter so as to generate a sampling control to alter the power consumption of at least one of said sensor interface and said signal processor, wherein said processor generates a plurality of data blocks corresponding to said input signal, each of said data blocks having a time shift from a preceding one of said data blocks, said sampling control determining the amount of said time shift.
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17. A low power pulse oximeter comprising:
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an interface means for communicating with a sensor;
a processor means for generating an internal parameter and an output parameter; and
a controlller means for selectively reducing the power consumption of at least one of said interface means and said processor means based upon said parameters, wherein said interface means comprises a driver means for determining the duty cycle of emitter current to said sensor, and said driver means is responsive to said controller means.
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18. A low power pulse oximeter comprising:
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an interface means for communicating with a sensor;
a processor means for generating an internal parameter and an output parameter; and
a controller means for selectively reducing the power consumption of at least one of said interface means said processor means based upon said parameters, wherein said processor means comprises a post-processor means for determining a time shift between data blocks, and wherein said post-processor means is responsive to said controller means.
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19. a low power pulse oximeter comprising:
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an interface means for communication with a sensor;
a processor means for generating an internal parameter and an output parameter; and
a controller means for selectively reducing the power consumption of at least one of said interface means and said processor means based upon said parameters, wherein said controller means comprises;
a power status calculator means for generating a power indication of power consumption relative to a power target, and a control engine means in communications with said power status calculator means for generating a sampling control responsive to said power indication.
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Specification