Passive temperature compensation technique for MEMS devices

• US 6,959,583 B2
• Filed: 04/30/2002
• Issued: 11/01/2005
• Est. Priority Date: 04/30/2002
• Status: Expired due to Fees

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Platt, William
• Primary Examiner(s): GARBER, CHARLES D
• Application Number:
  US10/135,538
• Publication Number:
  US 20030200785A1
• Time in Patent Office: 1,281 Days
• Field of Search: 73/13.7, 735/041.2, 735/041.4, 735/142.9
• 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) gyroscope, comprising in combination:

a MEMS gyroscope having an uncompensated sense output that is sensitive to temperature changes, wherein the uncompensated sense output is a voltage output;

a circuit coupled to the MEMS gyroscope, wherein the circuit includes a diode having an associated voltage drop, and wherein the diode has a temperature dependency that is substantially the same as the uncompensated sense output of the MEMS gyroscope; and

a compensated sense output formed by combining the uncompensated sense output of the MEMS gyroscope and a diode output associated with the voltage drop of the diode.

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 gyroscope comprises a proof mass that oscillates in response to a drive signal.

4. The system of claim 3, 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.

5. The system of claim 3, wherein a change in capacitance between the proof mass and a sense plate generates a sense signal.

6. The system of claim 5, wherein the sense signal is converted to the uncompensated sense output.

7. The system of claim 5, wherein a sense processing unit demodulates and filters the sense signal to form the uncompensated sense output.

8. The system of claim 7, wherein the amplitude of the sense signal determines the uncompensated sense output.

9. 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.

10. The system of claim 9, wherein the summing junction comprises an operational amplifier.

11. A system for providing a passive temperature compensation technique to a MEMS gyroscope, comprising in combination:

the MEMS gyroscope providing a sense signal that is sensitive to temperature changes;

a sense processing unit coupled to the MEMS gyroscope operable to convert the sense signal into an uncompensated sense output, wherein the uncompensated sense output is a DC voltage signal;

at least one diode having a voltage drop, wherein the diode has a temperature dependency that is substantially the same as the uncompensated sense output;

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

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

12. The system of claim 11, wherein the sense processing unit amplifies, demodulates, and filters the sense signal to form the uncompensated sense output.

13. The system of claim 11, 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.

14. The system of claim 13, 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.