System and method for reducing offset variation in multifunction sensor devices

• US 9,103,845 B2
• Filed: 03/08/2013
• Issued: 08/11/2015
• Est. Priority Date: 03/08/2013
• Status: Active Grant

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: Freescale Semiconductor, Inc. (NXP Semiconductors NV)
• Inventors: Schlarmann, Mark E., Fang, Deyou, Kraver, Keith L., Margules, Mike A., Sahara, Hiroto
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US13/791,329
• Publication Number:
  US 20140251009A1
• Time in Patent Office: 886 Days
• Field of Search: 735/041.2, 735/040.4, 735/10, 735/11, 734/93, 735/041.4
• US Class Current: 1/1
• CPC Class Codes: B81B 2201/0242 Gyroscopes
• CPC Class Codes: B81B 2201/0264 Pressure sensors
• CPC Class Codes: B81B 2207/03 Electronic circuits for micromechanical devices which are not application specific, e.g. for controlling, power supplying, testing, protecting
• CPC Class Codes: B81B 5/00 Devices comprising elements which are movable in relation to each other, e.g. comprising slidable or rotatable elements
• CPC Class Codes: B81B 7/02 containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS] B81B7/04 takes precedence
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719

Abstract

Systems and methods are provided for improved multifunction sensing. In these embodiments a multifunction sensing device (100) includes a microelectromechanical (MEMS) gyroscope (110) and at least a second sensor (112). The MEMS gyroscope (110) is configured to generate a first clock signal, and the second sensor includes a second clock signal. The multifunction sensing device further includes a reset mechanism (114), the reset mechanism (114) configured to generate a reset signal to set the relative periodic phase alignment of the second clock signal to the first clock signal. Consistently setting the relative periodic phase alignment of the clocks for the other sensor devices (112) to the clock of the MEMS gyroscope (110) can improve the performance of the devices by reducing the probability that varying output offsets will occur in the multiple sensing devices.

Claims

1. A multifunction sensing device, the multifunction sensing device comprising:

a microelectromechanical (MEMS) gyroscope, the MEMS gyroscope configured to generate a first clock signal;

a reset mechanism, the reset mechanism configured to generate a reset signal in response to an edge of the first clock signal; and

a second sensor, the second sensor including at least a second clock signal, the second sensor configured to receive the reset signal and to set relative periodic phase alignment between the second clock signal and the first clock signal in response to the reset signal.

2. The multifunction sensing device of claim 1 wherein the MEMS gyroscope additionally generates a master clock signal, and wherein the second sensor generates the second clock signal using the master clock signal such that the master clock signal and the second clock signal are synchronous.

3. The multifunction sensing device of claim 1 wherein the reset signal is additionally coupled to the MEMS gyroscope, and wherein the reset signal is used to reset a circuit that operates at a rate less than a rate of the first clock signal in the MEMS gyroscope.

4. The multifunction sensing device of claim 1 wherein the second sensor comprises a sensor selected from the group consisting of:

an inertial sensor and a pressure sensor, a magnetic sensor, an electromagnetic radiation sensor, a light sensor, a temperature sensor, a humidity sensor, a stress sensor, a strain sensor, and a chemical detection sensor.

5. The multifunction sensing device of claim 1 wherein the multifunction sensing device includes a third sensor including a third clock signal, and wherein the third sensor is configured to receive the reset signal and to set relative periodic phase alignment between the third clock signal and the first clock signal in response to the reset signal.

6. The multifunction sensing device of claim 1 wherein the reset mechanism is configured to receive a reset request signal, and wherein the reset mechanism is configured to generate the reset signal in response to the edge of the first clock signal by generating the reset signal in response to the edge of the first clock signal being received subsequent the reset request signal.

7. The multifunction sensing device of claim 1 wherein the first clock signal is phase-locked to mechanical oscillation of the MEMS gyroscope.

8. The multifunction sensing device of claim 1 wherein the first clock signal is a sub-harmonic of a clock which is phase-locked to mechanical oscillation of the MEMS gyroscope.

9. The multifunction sensing device of claim 1 wherein the second sensor is a MEMS sensor, and wherein the MEMS gyroscope and the second sensor are formed on a same substrate.

10. A sensing device, comprising:

a microelectromechanical (MEMS) gyroscope, the MEMS gyroscope configured to generate a first clock signal phase-locked to mechanical oscillation in the MEMS gyroscope or to a sub-harmonic of the mechanical oscillation;

a reset mechanism, the reset mechanism configured to receive the first clock signal and a reset request signal, and wherein the reset mechanism is configured to generate a reset signal in response to receiving the reset request signal and an edge of the first clock signal subsequent to receiving the reset request signal;

a second MEMS sensor, the second MEMS sensor including a second clock signal, and where the second MEMS sensor is selected from the group consisting of;

a MEMS inertial sensor and a MEMS pressure sensor, and wherein the second MEMS sensor is configured to receive the reset signal and to set relative periodic phase alignment between the second clock signal and the first clock signal in response to the reset signal; and

a third MEMS sensor, the third MEMS sensor including a third clock signal, and where the third MEMS sensor is selected from the group consisting of;

a MEMS inertial sensor and a MEMS pressure sensor, and wherein the third MEMS sensor is configured to receive the reset signal and to set relative periodic phase alignment between the third clock signal and the first clock signal in response to the reset signal.

11. The sensing device of claim 10 wherein the reset signal is additionally coupled to the MEMS gyroscope, and wherein the reset signal is used to reset a circuit that operates at a rate less than a rate of the first clock signal in the MEMS gyroscope.

12. A method of operating a multifunction sensing device, the multifunction sensing device including a microelectromechanical (MEMS) gyroscope and a second sensor, the method comprising:

generating a first clock signal in the MEMS gyroscope; and

setting relative periodic phase alignment between a second clock signal in the second sensor to the first clock signal.

13. The method of claim 12 wherein the second sensor comprises a sensor selected from the group consisting of:

an inertial sensor and a pressure sensor, a magnetic sensor, an electromagnetic radiation sensor, a light sensor, a temperature sensor, a humidity sensor, a stress sensor, a strain sensor, and a chemical detection sensor.

14. The method of claim 12 wherein the multifunction sensing device further includes a third sensor, and further comprising setting relative periodic phase alignment between a third clock signal in the third sensor to the first clock signal.

15. The method of claim 12 further comprising resetting a circuit that operates at a rate less than a rate of the first clock signal in the MEMS gyroscope.

16. The method of claim 12 wherein the setting relative periodic phase alignment between the second clock signal in the second sensor to the first clock signal comprises receiving the first clock signal and a reset request signal, and generating a reset signal in response to an edge of the first clock signal received subsequent the reset request signal.

17. The method of claim 12 wherein the first clock signal is phase-locked to mechanical oscillation of the MEMS gyroscope.

18. The method of claim 12 wherein the first clock signal is a sub-harmonic of a clock which is phase-locked to mechanical oscillation of the MEMS gyroscope.

19. The method of claim 12 wherein the setting relative periodic phase alignment between the second clock signal in the second sensor to the first clock signal comprises receiving a master clock signal using the master clock signal to generate the second clock signal.

20. The method of claim 12 wherein the second sensor is a MEMS sensor, and wherein the MEMS gyroscope and the second sensor are formed on a same substrate.