Passive temperature compensation technique for MEMS devices

• US 20030200785A1
• Filed: 04/30/2002
• Published: 10/30/2003
• Est. Priority Date: 04/30/2002
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Platt, Wiliam P.
• Granted Patent: US 6,959,583 B2
• Time in Patent Office: Days
• US Class Current: 73/1.37
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

In an exemplary embodiment, a MEMS sensor using a passive temperature compensation technique may provide an uncompensated sense output. Additionally, a circuit coupled to the MEMS sensor may include a diode having a voltage drop. A compensated sense output may be formed by combining the uncompensated sense output with a diode output that is proportional to the voltage drop across the diode.

Claims

1. A system for providing a passive temperature compensation technique to a microelectromechanical system (MEMS) sensor comprising a circuit coupled to the MEMS sensor including at least one diode having a voltage drop, wherein a compensated sense output is formed by combining an uncompensated sense output with a diode output associated with the voltage drop.

2. The system of claim 1, wherein the voltage drop across the at least one diode is amplified by at least one operational amplifier and converted to the diode output.

3. The system of claim 1, wherein the MEMS sensor comprises a MEMS gyroscope.

4. The system of claim 3, wherein the MEMS gyroscope comprises a proof mass that oscillates in response to a drive signal.

5. The system of claim 4, wherein a Coriolis acceleration is generated in response to a rotation of the MEMS gyroscope, and the Coriolis acceleration is utilized for measuring a rate of rotation of the MEMS gyroscope.

6. The system of claim 4, wherein a change in capacitance between the proof mass and a sense plate generates a sense signal.

7. The system of claim 6, wherein the sense signal is converted to the uncompensated sense output.

8. The system of claim 6, wherein a sense processing unit demodulates and filters the sense signal to form the uncompensated sense output.

9. The system of claim 8, wherein the amplitude of the sense signal determines the uncompensated sense output.

10. The system of claim 1 further comprising a summing junction, wherein the summing junction combines the uncompensated sense output with the diode output to form the compensated sense output.

11. The system of claim 10, wherein the summing junction comprises an operational amplifier.

12. A system for providing a passive temperature compensation technique to a MEMS sensor comprising in combination:

the MEMS sensor providing a sense signal;

a sense processing unit operable to convert the sense signal into an uncompensated sense output;

at least one diode having a voltage drop;

at least one operational amplifier operable to amplify the voltage drop to form a diode output; and

a summing junction operable to combine the diode output with the uncompensated sense output to form a compensated sense output.

13. The system of claim 12, wherein the sense processing unit amplifies, demodulates, and filters the sense signal to form the uncompensated sense output.

14. The system of claim 12, wherein the MEMS sensor comprises a MEMS gyroscope.

15. The system of claim 14, wherein the MEMS gyroscope comprises a proof mass and a sense plate, and a change in capacitance between the proof mass and the sense plate generates the sense signal.

16. The system of claim 15, wherein the compensated sense output is used to calculate a Coriolis acceleration of the proof mass, and the Coriolis acceleration is used with a drive velocity of the proof mass to calculate a rate of rotation of the MEMS gyroscope.

17. A method using a passive temperature compensation technique to measure a rate of rotation of a MEMS gyroscope comprising in combination:

driving a proof mass of the MEMS gyroscope at a drive velocity;

rotating the MEMS gyroscope;

generating a sense signal based on a change in capacitance between the proof mass and a sense plate;

converting the sense signal into an uncompensated sense output;

combining the uncompensated sense output with a diode output to form a compensated sense output;

utilizing the compensated sense output for calculating a Coriolis acceleration; and

calculating the rate of rotation of the MEMS gyroscope from the Coriolis acceleration and drive velocity.

18. The method of claim 17, wherein converting the sense signal into the uncompensated sense output further comprises at least one of amplifying, demodulating, and filtering the sense signal.

19. The method of claim 17, wherein combining the uncompensated sense output with the diode output further comprises at least one of adding and subtracting the magnitude of the uncompensated sense output with the magnitude of the diode output.

20. The method of claim 17 further comprising generating the diode output based on a voltage drop across at least one diode.

21. The method of claim 20 further comprising amplifying the voltage drop across the at least one diode with at least one operational amplifier in order to create the diode output.