Systems and methods to overcome DC offsets in amplifiers used to start resonant micro-electro mechanical systems

• US 7,859,352 B2
• Filed: 10/15/2008
• Issued: 12/28/2010
• Est. Priority Date: 10/15/2008
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Sutton, Michael
• Primary Examiner(s): Pascal; Robert
• Assistant Examiner(s): Gannon; Levi
• Application Number:
  US12/252,176
• Publication Number:
  US 20100090773A1
• Time in Patent Office: 804 Days
• Field of Search: 331/116.M, 331/116.R, 331/154, 331/156, 331/158, 331/160, 331/185, 331/186, 331/182, 331/183, 310/311, 310/318, 310/319
• US Class Current: 331/160
• CPC Class Codes: G01C 19/5776 Signal processing not specific to any of the devices covered by groups G01C19/5607 - G01C19/5719
• CPC Class Codes: H03F 2200/375 Circuitry to compensate the offset being present in an amplifier
• CPC Class Codes: H03F 3/70 Charge amplifiers
• CPC Class Codes: H03H 9/02409 by application of a DC-bias voltage H03H9/02417 takes precedence
• CPC Class Codes: H03K 5/003 Changing the DC level reinsertion of dc component of a television signal H04N5/16

Abstract

Systems and methods for insuring successful initiation of a resonating micro-electro mechanical systems (MEMS). An example system includes a resonating sensor, a drive device, a charge amplifier, and a voltage gain circuit. At start up, the charge amplifier and voltage gain circuit receives signals from the resonating sensor, compensates this signal for DC offsets, and generates a clock signal for the drive, thus placing the resonating sensor in a steady state operating mode. The circuit includes a plurality of gain switches that are toggled to produce a glitch in the signal associated with the received signal. The glitch overcomes the DC offset. A comparator generates the clock signal for the drive device if a signal associated with the received signal exceeds a reference signal.

Claims

1. A resonating micro-electro mechanical systems (MEMS) device comprising:

a resonating sensor;

a drive device configured to send a drive signal to the resonating sensor; and

a circuit configured to receive signals from the resonating sensor and generate a clock signal for the drive device that compensates for a DC offset to put the resonating sensor in a steady state operating mode;

wherein the circuit comprises a plurality of gain switches being controllable for adjusting gain of the circuit.

2. The device of claim 1, wherein the circuit comprises a comparator configured to generate the clock signal for the drive device if a signal associated with the received signal exceeds a reference signal.

3. The device of claim 2, further comprising a controller configured to control operation of at least one of the plurality of gain switches for producing a glitch in the signal associated with the received signal, wherein the glitch overcomes the DC offset.

4. The device of claim 3, wherein the controller toggles at least one of the plurality of gain switches at a predefined frequency.

5. The device of claim 4, wherein the predefined frequency corresponds to a desired frequency of the resonator.

6. A resonating micro-electro mechanical systems (MEMS) method comprising:

receiving signals from a resonating sensor; and

a gain circuit generating a clock signal for a drive device that compensates for a DC offset to put the resonating sensor in a steady state operating mode;

wherein generating comprises controlling at least one of a plurality of gain switches for adjusting gain of the gain circuit.

7. The method of claim 6, wherein generating comprises generating the clock signal for the drive device if a signal associated with the received signal exceeds a reference signal.

8. The method of claim 7, wherein controlling operation of the at least one of the gain switches produces a glitch in the signal associated with the received signal, wherein the glitch overcomes the DC offset.

9. The method of claim 8, wherein controlling comprises toggling at least one of the plurality of gain switches at a predefined frequency.

10. The method of claim 9, wherein the predefined frequency corresponds to a desired frequency of a drive signal.

11. A resonating micro-electro mechanical systems (MEMS) device comprising:

a resonating sensor;

a drive device configured to send a drive signal to the resonating sensor; and

a circuit configured to receive signals from the resonating sensor; and

generate a

clock signal for the drive device that compensates for a DC offset to put the resonating sensor in a steady state operating mode;

wherein the circuit is further configured to inject a noise signal controllable for adjusting gain of the circuit.