Multi-dynamic-range sensor

• US 10,330,513 B2
• Filed: 05/27/2009
• Issued: 06/25/2019
• Est. Priority Date: 05/27/2009
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Ricks, Lamar Floyd, Bentley, Ian, Bey, Paul Prehn
• Primary Examiner(s): Nanithithadha, Navin
• Assistant Examiner(s): Tran, Tho Q
• Application Number:
  US12/473,174
• Publication Number:
  US 20100305465A1
• Time in Patent Office: 3,681 Days
• Field of Search: 341156, 341113, 341 55, 600538-540, 600529
• CPC Class Codes: A61B 5/0878 using temperature sensing means
• CPC Class Codes: G01F 1/696 Circuits therefor, e.g. constant-current flow meters
• CPC Class Codes: G01F 7/00 Volume-flow measuring devices with two or more measuring ranges; Compound meters

Abstract

A sensing system that produces a multi-dynamic range output is provided. In an illustrative embodiment, a first channel and a second channel receive an analog output signal from a sensing element. The first channel provides a first digital output signal that has a first dynamic range, and the second channel provides a second digital output signal that has a second narrower dynamic range. In some cases, the second narrower dynamic range falls within the first dynamic range, and the first digital output signal may provide a first resolution and the second digital output signal may provide a second greater resolution. The dynamic range and/or resolution of one or more of the first channel and second channel may be dynamically reconfigurable, if desired.

Claims

1. A respiration sensing system for sensing respiration of a patient, the respiration sensing system comprising:

a sensing element configured to sense a respiration flow rate, the sensing element configured to provide an analog output signal that is related to the sensed respiration flow rate;

a first channel configured to receive the analog output signal from the sensing element, the first channel including a first amplifier having a first gain and a first offset for providing a first amplified output signal to a first Analog-to-Digital Converter (ADC), the first amplifier in combination with the first Analog-to-Digital Converter (ADC) providing a first digital output signal that has a first dynamic range and a first resolution, the first resolution corresponding to a quantization of the first dynamic range using a first quantization level of the first ADC, wherein the first amplified output signal is offset, wherein the first ADC is included within the respiration sensing system;

a second channel configured to receive the analog output signal from the sensing element, the second channel including a second amplifier having a second gain different from the first gain for providing a second amplified output signal to a second Analog-to-Digital Converter (ADC), the second amplifier in combination with the second Analog-to-Digital Converter (ADC) providing a second digital output signal that has a second dynamic range and a second resolution, the second resolution corresponding to a quantization of the second dynamic range using a second quantization level of the second ADC, and wherein the second dynamic range is narrower than the first dynamic range, and the second resolution is higher than the first resolution, wherein the second amplified output signal is offset, wherein the second ADC is included within the respiration sensing system;

an output selector, formed as an integrated circuit, configured to receive the analog output signal from the sensing element and output the first digital output signal or the second digital output signal according to the analog output signal received by the output selector, wherein the output selector is configured to select and output the second digital output signal if the analog output signal is within the dynamic range of the second ADC and to select and output the first digital output signal if the analog output signal is outside the dynamic range of the second ADC;

wherein the output selector is configured to receive the first digital output signal for all analog output signals over the entire first dynamic range, and wherein the output selector is configured to receive the second digital output signal for all analog output signals over the entire second dynamic range; and

wherein the first offset and the second offset are adjustable and are configured to cause a level shift and/or a gain shift in the first channel and/or the second channel.

2. The respiration sensing system of claim 1,

wherein the second dynamic range is a subset of the first dynamic range.

3. The respiration sensing system of claim 1, wherein a number of bits of the quantization level of the first ADC is the same as a number of bits of the quantization level of the second ADC.

4. The respiration sensing system of claim 1, further comprising a third channel configured to receive the analog output signal from the sensing element, the third channel including a third Analog-to-Digital Converter (ADC) and providing a third digital output signal that has a third dynamic range different than the first and second dynamic ranges.

5. The respiration sensing system of claim 1, wherein the first dynamic range and/or the second dynamic range is dynamically reconfigurable.

6. The respiration sensing system of claim 1, further comprising signal processing electronics configured to perform linearization, temperature compensation, calibration, and/or translation on the first digital output signal and the second digital output signal;

and wherein the first gain is equal to one.

7. A flow sensing system for sensing a fluid flow in a fluid stream, the flow sensing system comprising:

a sensing element configured to sense a fluid flow in a fluid stream, the sensing element configured to provide an analog output signal that is related to the sensed fluid flow;

a first channel configured to receive the analog output signal from the sensing element, the first channel including a first amplifier having a first offset, provided in the first amplifier, for providing a first amplified output signal to a first Analog-to-Digital Converter (ADC), the first amplifier in combination with the first Analog-to-Digital Converter (ADC) providing a first digital output signal that has a first dynamic range, wherein the first amplified output signal is offset, wherein the first ADC is included within the flow sensing system; and

a second channel configured to receive the analog output signal from the sensing element, the second channel including a second amplifier having a second offset, provided in the second amplifier, different from the first offset for providing a second amplified output signal to a second Analog-to-Digital Converter (ADC), the second amplifier in combination with the second Analog-to-Digital Converter (ADC) configured to provide a second digital output signal that has a second dynamic range, wherein the second amplified output signal is offset, wherein the second ADC is included within the flow sensing system;

and

an output selector, formed as an integrated circuit, configured to receive the analog output signal from the sensing element and select and output either the first digital output signal or the second digital output signal according to the analog output signal. received by the output selector,

wherein;

the second dynamic range is narrower than the first dynamic range, the second dynamic range falls within or substantially falls within the first dynamic range, and a starting value of the first dynamic range is different than starting value of the second dynamic range as dictated by the first offset and the second offset;

wherein the first digital output signal has a first resolution corresponding to a quantization of the first dynamic range and the second digital output signal has a second resolution corresponding to a quantization of the second dynamic range, wherein the second resolution is greater than the first resolution;

wherein the first offset and the second offset are adjustable and are configured to cause a level shift and/or a gain shift in the first channel and/or the second channel; and

wherein the output selector is configured to select and output one of the first digital output signal or the second digital output signal based on the analog output signal from the sensing element.

8. The flow sensing system of claim 7, further comprising a third channel configured to receive the analog output signal from the sensing element, the third channel including a third amplifier having a third offset for providing a third amplified output signal to a third ADC, the third amplifier and the third ADC configured to provide a third digital output signal that has a third dynamic range different than the first dynamic range and the second dynamic range.

9. The flow sensing system of claim 7, wherein the quantization levels of the first ADC and the second ADC correspond to a common number of bits.

10. The flow sensing system of claim 7, wherein the sensing element includes a heat source and a number of temperature sensors.

11. The flow sensing system of claim 10, wherein at least one of the temperature sensors is positioned upstream of the heat source and at least one of the temperature sensors is positioned downstream of the heat source.

12. The flow sensing system of claim 11, wherein the heat source and the number of temperature sensors arc configured so that a flow rate of the fluid flow in a fluid stream creates a temperature differential between the at least one of the temperature sensors that is positioned upstream of the heat source and the at least one of the temperature sensors that is positioned downstream of the heat source.

13. The flow sensing system of claim 7, wherein the output selector is configured to provide the second digital output signal if the analog output signal is within the dynamic range of the second ADC and is configured to provide the first digital output signal if the analog output signal is outside the dynamic range of the second ADC.

14. The flow sensing system of claim 7, wherein the second dynamic range is dynamically reconfigurable.

15. The flow sensing system of claim 7, wherein the first amplifier has a first gain and the second amplifier has a second gain, wherein the second gain is higher than the first gain.

16. A method for sensing a fluid flow in a fluid stream, the method comprising:

sensing a fluid flow in a fluid stream with a sensing element and providing an analog signal that is related to the sensed fluid flow;

amplifying the sensed analog signal with a first amplifier having a first gain and a first offset to provide a first amplified analog signal;

offsetting the first amplified analog signal with the first amplifier;

converting the first amplified analog signal to a first digital signal with a first Analog- to-Digital Converter (ADC) having a first number of quantization levels to provide a first digital output signal that has a first dynamic range;

amplifying the sensed analog signal with a second amplifier having a second gain and a second offset to provide a second amplified analog signal, wherein the second gain is different than the first gain, wherein the first offset and the second offset are adjustable and are configured to cause a level shift and/or a gain shift in the first channel and/or the second channel;

offsetting the second amplified analog signal with the second amplifier;

converting the second amplified analog signal to a second digital signal with a second Analog-to-Digital Converter (ADC) having a second number of quantization levels to provide a second digital output signal that has a second dynamic range, wherein the second dynamic range is narrower than the first dynamic range, and the second dynamic range falls within or substantially falls within the first dynamic range;

providing the sensed analog signal, the first digital signal, and the second digital signal to an output selector formed as an integrated circuit;

selecting and outputting the second digital signal with an output selector according to the sensed analog signal provided to output selector if the sensed analog signal is within the dynamic range of the second ADC;

selecting and outputting the first digital signal with the output selector according to the sensed analog signal provided to the output selector if the sensed analog signal is outside the dynamic range of the second ADC; and

wherein the output selector receives the first digital output signal for all analog output signals over the entire dynamic range of the first ADC and the output selector receives the second digital output signal for all analog output signals over the entire dynamic range of the second ADC.

17. The method of claim 16, wherein the first digital signal has a first resolution and the second digital signal has a second resolution, wherein the second resolution is greater than the first resolution.

18. The method of claim 16, further comprising performing, with signal processing electronics, linearization, temperature compensation, calibration, and/or translation on the first digital output signal and the second digital output signal;

and wherein the first ADC and the second ADC have a common number of bits.

19. The method of claim 16, wherein the step of sensing the fluid flow in the fluid stream with a sensing element includes heating the fluid flow with a heat source and sensing a temperature of the fluid flow with one or more temperature sensors.

20. The method of claim 16, further comprising reconfiguring the second dynamic range.