Pressure sensors circuits

• US 20060137457A1
• Filed: 12/28/2004
• Published: 06/29/2006
• Est. Priority Date: 12/11/2003
• Status: Active Grant

• Current Assignee: Proteus Digital Health, Inc. (Otsuka Holdings Company Limited)
• Original Assignee: Proteus Biomedical, Inc. (Otsuka Holdings Company Limited)
• Inventors: Zdeblick, Mark
• Granted Patent: US 7,284,441 B2
• Time in Patent Office: Days
• US Class Current: 73/715
• CPC Class Codes: A61B 2562/02 Details of sensors specially adapted for in-vivo measurements
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/412 Detecting or monitoring sepsis
• CPC Class Codes: A61N 1/3627 for treating a mechanical deficiency of the heart, e.g. congestive heart failure or cardiomyopathy
• CPC Class Codes: A61N 1/36564 controlled by blood pressure
• CPC Class Codes: G01L 9/0042 Constructional details associated with semiconductive diaphragm sensors, e.g. etching, or constructional details of non-semiconductive diaphragms details about the integration or bonding of piezoresistor in or on the diaphragm G01L9/0052 and G01L9/0057 respectively
• CPC Class Codes: G01L 9/0055 bonded on a diaphragm
• CPC Class Codes: G01L 9/045 with electric temperature compensating means non electric temperature compensating means G01L19/04
• CPC Class Codes: G01L 9/065 with temperature compensating means non electric temperature compensating means G01L19/04

Abstract

Implantable pressure sensors and methods for making and using the same are provided. A feature of embodiments of the subject pressure sensors is that they are low-drift sensors. The subject sensors find use in a variety of applications.

Claims

1. A pressure sensor circuit comprising:

a Wheatstone bridge for measuring pressure on the circuit, wherein said Wheatstone bridge produces a first output signal representative of the potential across the Wheatstone bridge and a second output signal representative of said pressure;

an amplifier circuit for amplifying said first and second output signals;

an analog-to-digital converter for measuring the ratio of said amplified first and second output signals;

a multiplex interface coupled to at least one output of said analog-to-digital converter; and

a source for providing a reference signal to said Wheatstone bridge and for providing a reference signal to said analog-to-digital converter.

2. The circuit according to claim 1, wherein said Wheatstone bridge reference signal is a current signal.

3. The circuit according to claim 2, wherein said Wheatstone bridge reference signal is a voltage signal.

4. The circuit according to claim 1, wherein said circuit is provided on an implantable structure.

5. The circuit according to claim 4, wherein said implantable structure is configured for implantation into a heart chamber.

11. An implantable structure comprising a circuit according to claim 1.

12. The implantable structure according to claim 11, wherein said structure comprises a pressure sensor.

13. The implantable structure according to claim 12, wherein said structure exhibits a drift of no more than about 1 mmHg/year.

14. The implantable structure according to claim 12, wherein said structure exhibits little or no drift over a period of from about 1 to about 40 years.

15. The structure according to claim 12, wherein said structure has a length along an edge of no more than about 500 μ

m and width of nor more than about 100 μ

m.

16. The structure according to claim 12, wherein said structure has a sensitivity sufficient to measure pressure changes in a volume of about ±

1 mmHg.

17. The implantable structure according to claim 11, wherein said implantable structure is configured for implantation into a heart chamber.

18. An implantable structure comprising a circuit according to claim 5.

19. The implantable structure according to claim 18, wherein said structure comprises a pressure sensor.

20. The implantable structure according to claim 19, wherein said structure exhibits a drift of no more than about 1 mmHg/year.

21. The implantable structure according to claim 19, wherein said structure exhibits little or no drift over a period of from about 1 to about 40 years.

22. The structure according to claim 19, wherein said structure has a length along an edge of no more than about 500 μ

m and width of nor more than about 100 μ

m.

23. The structure according to claim 19, wherein said structure has a sensitivity sufficient to measure pressure changes in a volume of about ±

1 mmHg.

24. The implantable structure according to claim 18, wherein said implantable structure is configured for implantation into a heart chamber.

6. A pressure sensor circuit comprising:

a first Wheatstone bridge for measuring pressure on said circuit, wherein said first Wheatstone bridge produces an output signal representative of said pressure;

a second Wheatstone bridge for measuring strain on said circuit wherein said second Wheatstone bridge produces an output signal representative of said strain;

an amplifier circuit for amplifying said pressure output signal and said strain output voltage signal;

an analog-to-digital converter for measuring the ratio of said amplified pressure output signal to said amplified strain output signal; and

a multiplex interface coupled to the at least one output of the analog-to-digital converter.

7. The circuit according to claim 6, further comprising a source for providing a reference signal to said first and second Wheatstone bridges and for providing a reference signal to said analog-to-digital converter.

8. The circuit according to claim 7, wherein said amplifier circuit is a switching amplifier circuit.

9. The circuit according to claim 6, wherein said circuit is provided on an implantable structure.

10. The circuit according to claim 9, wherein said implantable structure is configured for implantation into a heart chamber.