SYSTEM AND METHOD OF POWER-SAVING IN MEMS SENSOR APPLICATIONS

• US 20140020445A1
• Filed: 09/27/2013
• Published: 01/23/2014
• Est. Priority Date: 02/09/2011
• Status: Active Grant

• Current Assignee: Texas Instruments, Inc.
• Original Assignee: Texas Instruments, Inc.
• Inventors: Waters, Deric Wayne, Huang, Jayawardan, Thukral, Saket
• Granted Patent: US 9,140,590 B2
• Time in Patent Office: Days
• US Class Current: 73/1.75
• CPC Class Codes: A61B 5/00 Measuring for diagnostic purposes radiation diagnosis A61B6/00; diagnosis by ultrasonic, sonic or infrasonic waves A61B8/00; Identification of persons
• CPC Class Codes: A61B 5/0006 ECG or EEG signals
• CPC Class Codes: A61B 5/0022 Monitoring a patient using a global network, e.g. telephone networks, internet
• CPC Class Codes: A61B 5/0537 Measuring body composition by impedance, e.g. tissue hydration or fat content
• CPC Class Codes: A61B 5/145 Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissuemeasuring of blood pressure or blood flow A61B5/02; non-radiation detecting or locating of foreign bodies in blood A61B5/06
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 8/488 involving Doppler signals
• CPC Class Codes: A61B 8/565 involving data transmission via a network
• CPC Class Codes: G01C 21/185 for gravity
• CPC Class Codes: G01C 23/00 Combined instruments indicating more than one navigational value, e.g. for aircraft; Combined measuring devices for measuring two or more variables of movement, e.g. distance, speed or acceleration
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01S 19/34 Power consumption
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G06F 1/32 Means for saving power
• CPC Class Codes: G06F 18/20 Analysing
• CPC Class Codes: G08B 21/0423 detecting deviation from an expected pattern of behaviour or schedule
• CPC Class Codes: G16H 15/00 ICT specially adapted for medical reports, e.g. generation or transmission thereof
• CPC Class Codes: G16H 20/30 relating to physical therapies or activities, e.g. physiotherapy, acupressure or exercising
• CPC Class Codes: G16H 40/40 for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades
• CPC Class Codes: G16H 40/67 : for remote operation
• CPC Class Codes: H04N 7/18 : Closed-circuit television [CCTV] systems, i.e. systems in which the video signal is not broadcast

Abstract

At least some of the embodiments are methods including detecting low user dynamics by a first MEMS sensor, determining a first sensor sampling rate value corresponding to the low user dynamics wherein the first sensor sampling rate value is less than a second sensor sampling rate value corresponding to high user dynamics, and adjusting a sampling rate of a second MEMS sensor to the first sensor sampling rate value.

Claims

1. A method comprising:

detecting if user dynamics are low indicated using an output of a first MEMS sensor;

if user dynamics are low;

determining a first sensor sampling rate value corresponding to the low user dynamics, wherein the first sensor sampling rate value is less than a second sensor sampling rate value corresponding to high user dynamics; and

adjusting a sampling rate of a second MEMS sensor to the first sensor sampling rate value.

3. The method of claim 1 further comprising:

calibrating the second MEMS sensor; and

restoring the first sampling rate value to the second sampling rate value during the calibrating.

4. The method of claim 3 further comprising:

after the calibrating, determining if user dynamics are low; and

if user dynamics are low, adjusting the sampling rate of the second MEMS sensor to the first sampling rate value.

5. The method of claim 1 further comprising disabling calibration of a third MEMS sensor in response to detecting low user dynamics.

6. The method of claim 1 wherein the second MEMS sensor comprises a first ADC and a second ADC, and wherein adjusting the sampling rate of the second MEMS sensor comprises selecting one of the first and second ADCs having the second sampling rate value.

7. The method of claim 1 wherein the second MEMS sensor comprises an ADC having a programmable sampling rate comprising an n-bit binary value and wherein adjusting the sampling rate of the second MEMS sensor comprises setting a programming value of the programmable sampling rate in which m least significant bits of the programming value are negated, and wherein m comprises a number of bits less than n.

8. The method of claim 1 further comprising determining a physical parameter selected from the group consisting of a yaw and a heading, the determining of the physical parameter comprising:

initializing a value of the physical parameter; and

if user dynamics are high, integrating a subset of samples, wherein the samples are obtained at the second sampling rate, to generate a new value of the physical parameter.

2. The method of claim 2 wherein the first MEMS sensor is different than the second MEMS sensor.

9. A system comprising:

a plurality of sensors;

a first logic unit coupled to an output of at least one sensor of the plurality of sensors, the first logic unit estimating user dynamics in response to an output signal from the at least one sensor;

second logic unit coupled to the first logic unit, the second logic unit generating a sampling rate value of a first MEMS sensor in response to an output signal from the first logic unit, and wherein the first MEMS sensor comprises a selectable sampling rate and wherein the selectable sampling rate is selected in response to the generated sampling rate value.

10. The system of claim 9 further comprising a sensor processor, the sensor processor comprising the first logic unit and the second logic unit.

11. The system of claim 9 wherein:

the second logic unit comprises a sampling rate engine and a rate control generator, the sampling rate engine configured to receive the output signal from the first logic unit, and

the rate control generator coupled to the sampling rate engine and generating an output signal in response to the sampling rate value, and wherein the rate control generator output signal is coupled to the first MEMS sensor and configured to select a sampling rate of the first MEMS sensor.

12. The system of claim 10 wherein the sensor processor is configured to estimate a physical parameter using sensor data from at least two sensors of the plurality of sensors.

13. The system of claim 9 wherein the first sensor comprises a first ADC and a second ADC, and wherein selecting a sampling rate of the first sensor comprises selecting one of the first and second ADCs having the sampling rate value.

14. The system of claim 9 wherein the first sensor comprises an ADC, the ADC comprising a programmable sampling rate, and wherein the first sensor selectable sampling rate is selected in response to a programming value received from the second logic unit.

15. The system of claim 14 wherein a programming value of the programmable sampling rate comprises an n-bit binary value and wherein m least significant bits of the programming value received from the second logic unit are negated, and wherein m comprises a number of bits less than n.

16. The system of claim 12 wherein the physical parameter is selected from the group consisting of:

a yaw; and

a heading.

17. A system comprising:

a plurality of sensors;

a sensor processor coupled to an output of each sensor of the plurality of sensors, the sensor processor estimating user dynamics in response to a first output signal of a first sensor of the plurality of sensors;

a sampling rate engine coupled to an output of the sensor processor, the sampling rate engine determining a sampling rate value of a second sensor of the plurality of sensors in response to a user dynamics value from the sensor processor; and

wherein the second sensor comprises a selectable sampling rate, the selectable sampling rate configured in response to the sampling rate value determined by the sampling rate engine.

18. The system of claim 17 further comprising a rate control generator configured to receive the sampling rate value determined by the sampling rate engine and coupled to the second sensor, wherein the selectable sampling rate is selected in response to an output of the rate control generator, the output of the rate control generator determined in response to the sampling rate value.

19. The system of claim 18 wherein the second sensor comprises a first ADC and a second ADC, and wherein the selectable sampling rate comprises one of a sampling rate of the first ADC and a sampling rate of the second ADC.

20. The system of claim 17 wherein the sensor processor is configured to estimate a physical parameter using sensor data from at least two sensors of the plurality of sensors.