PRESSURE MONITORING CIRCUITS AND METHODS

• US 20120136591A1
• Filed: 11/29/2010
• Published: 05/31/2012
• Est. Priority Date: 11/29/2010
• Status: Active Grant

• Current Assignee: Infineon Technologies AG
• Original Assignee: Infineon Technologies AG
• Inventors: LeMense, Thomas, Lange, Thomas
• Granted Patent: US 8,498,829 B2
• Time in Patent Office: Days
• US Class Current: 702/50
• CPC Class Codes: B60C 23/0474 Measurement control, e.g. setting measurement rate or calibrating of sensors; Further processing of measured values, e.g. filtering, compensating or slope monitoring
• CPC Class Codes: B60C 23/0488 Movement sensor, e.g. for sensing angular speed, acceleration or centripetal force
• CPC Class Codes: G01L 27/002 Calibrating, i.e. establishing true relation between transducer output value and value to be measured, zeroing, linearising or span error determination
• CPC Class Codes: G01L 7/00 Measuring the steady or quasi-steady pressure of a fluid or a fluent solid material by mechanical or fluid pressure-sensitive elements G01L11/004 takes precedence; transmitting or indicating the displacement of mechanical pressure-sensitive elements by electric , e.g., photoelectric or magnetic means G01L9/00; measuring differences of two or more pressure values G01L13/00; measuring two or more pressure values simultaneously G01L15/00

Abstract

In order to provide better resolution over a wider pressure range the previously available, the techniques disclosed herein set an output precision of an analog-to-digital converter (ADC) based on a control signal provided by a control element. The control signal sets the output precision of the ADC to a first level to measure an ambient pressure within a first pressure range; and signal sets the output precision of the ADC to a second level to measure an ambient pressure within a second pressure range.

Claims

1. A pressure monitoring system, comprising:

a pressure sensor to output an analog signal, wherein the analog signal has a signal level indicative of an ambient pressure sensed by the pressure sensor;

an analog-to-digital converter (ADC) to convert the analog signal to an N-bit digital signal representing one of 2^N unique output codes at a given time;

a control element to provide a control signal to the ADC, wherein the control signal causes the ADC to change from a first state in which the 2^N unique output codes are spaced over a first pressure range to a second state in which the 2^N unique output codes are spaced over a second pressure range.

2. The system of claim 1, further comprising:

a variable gain stage between the pressure sensor and the ADC, wherein the control signal causes the variable gain stage to change from a first gain to a second gain, thereby causing the ADC to change from the first state to the second state, respectively.

3. The system of claim 2, wherein the control element comprises a microcontroller to provide the control signal.

4. The system of claim 1, wherein the control element comprises a comparator to compare the analog signal with a pressure threshold, and wherein the control signal is based on the comparison.

5. The system of claim 1, further comprising:

a compensation module to apply a first plurality of compensation parameters during the first state and to apply a second plurality of compensation parameters during the second state, wherein the first and second plurality of compensation parameters account for non-linearities and other error contributors in the ADC and pressure sensor over the first and second pressure ranges, respectively.

6. The system of claim 1, wherein the first pressure range falls entirely within the second pressure range.

7. The system of claim 1, wherein the first pressure range only partially overlaps the second pressure range without falling entirely within the second pressure range.

8. The system of claim 1, wherein the first pressure range and second pressure range are non-overlapping.

9. The system of claim 1, wherein endpoints bounding the first pressure range are separated by a first difference that is greater than a second difference separating endpoints bounding the second pressure range.

10. The system of claim 9, wherein neighboring unique output codes in the first pressure range are spaced apart by a first distance, and wherein neighboring unique output codes in the second pressure range are spaced apart by a second distance.

11. A method of pressure monitoring, comprising:

receiving an analog pressure signal corresponding to an ambient pressure;

providing a control signal to convert the analog pressure signal to an N-bit digital signal, wherein when the control signal in a first state the N-bit digital signal represents 2^N unique output codes that are spaced over a first pressure range and wherein when the control signal in a second state the N-bit digital signal represents 2^N unique output codes that are spaced over a second pressure range.

12. The method of claim 11, further comprising:

upon receiving a request to monitor the ambient pressure, setting the control signal to the first state and storing a first digital pressure measurement and subsequently setting the control signal to the second state and storing a second digital pressure measurement.

13. The method of claim 12, further comprising:

selecting one of the first and second digital pressure measurements and providing the selected digital pressure measurement in response to the request to measure the ambient pressure.

14. A pressure monitoring system, comprising:

a pressure sensor to output an analog signal, wherein the analog signal has a signal level indicative of an ambient pressure sensed by the pressure sensor;

an analog-to-digital converter (ADC) to convert the analog signal to an N-bit digital signal representing one of 2^N unique output codes at a given time;

a controller to provide a control signal to the ADC, wherein the control signal causes the ADC to change from a first state in which the ambient pressure is attempted to be measured in a first pressure range to a second state in which the ambient pressure is attempted to be measured in a second pressure range; and

a variable gain stage between the pressure sensor and the ADC, wherein the control signal causes the variable gain stage to change from a first gain to a second gain, thereby causing the ADC to change from the first state to the second state, respectively.

15. The system of claim 14, wherein the first pressure range falls entirely within the second pressure range.

16. The system of claim 14, wherein the first pressure range only partially overlaps the second pressure range without falling entirely within the second pressure range.

17. The system of claim 14, wherein the first pressure range and second pressure range are non-overlapping.

18. A pressure monitoring system, comprising:

a pressure sensor to output an analog signal, wherein the analog signal has a signal level indicative of an ambient pressure sensed by the pressure sensor;

a comparator to compare the analog signal with a pressure threshold and provide a control signal based on the comparison; and

an analog-to-digital converter (ADC) to convert the analog signal to an N-bit digital signal, wherein the control signal causes the ADC to change from a first state in which the ambient pressure is attempted to be measured in a first pressure range to a second state in which the ambient pressure is attempted to be measured in a second pressure range.

19. The system of claim 18, wherein the first pressure range falls entirely within the second pressure range.

20. The system of claim 18, wherein the first pressure range only partially overlaps the second pressure range without falling entirely within the second pressure range.

21. The system of claim 18, wherein the first pressure range and second pressure range are non-overlapping.