Sensor-independent oscillation amplitude control

• US 6,765,305 B2
• Filed: 01/29/2003
• Issued: 07/20/2004
• Est. Priority Date: 04/12/2000
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Bauer, Wolfram, Artzner, Johannes, Mohaupt, Jens
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US10/257,454
• Publication Number:
  US 20030151394A1
• Time in Patent Office: 538 Days
• Field of Search: 290/1.R, 290/1.A, 323/201, 310/359, 310/316.01, 310/366
• US Class Current: 290/1.00R
• CPC Class Codes: G01C 19/5712 the devices involving a micromechanical structure

Abstract

A device is described for generating an electric voltage by which a body of a capacitive and/or inductive sensor capable of vibration, such as a capacitive micromechanical rotational rate sensor in particular, is induced to vibrate. In order to reduce the manufacturing cost of the sensor, a voltage generating device is provided which induces a constant mechanical deflection of the body capable of vibration, this deflection being independent of the manufacturing tolerances of the sensor.

Claims

1. A device for generating an electric voltage whereby a vibration of a body of at least one of a capacitive sensor and an inductive sensor capable of vibration is induced, comprising:

a voltage generating device that generates an electric voltage that is proportional to at least one of a resting capacitance and an induction of a magnetic field of the at least one of the capacitive sensor and the inductive sensor.

2. The device as recited in claim 1, wherein:

the at least one of the capacitive sensor and the inductive sensor includes a capacitive micromechanical rotational rate sensor.

3. The device as recited in claim 1, wherein:

the voltage generating device forms part of a regulating circuit for regulating an amplitude of the vibration of the body.

4. The device as recited in claim 3, wherein:

the voltage generating device includes a common-mode regulating apparatus that responds only to a common-mode signal at an input end.

5. The device as recited in claim 4, wherein at least one of:

the common-mode regulating apparatus includes a first adder and a regulator, and

an output of the regulator changes a voltage thereof in regulating operation until virtually no common-mode signal is applied at an input of the regulator.

6. The device as recited in claim 5, wherein:

the regulator includes an I regulator.

7. The device as recited in claim 5, wherein:

the at least one of the capacitive sensor and the inductive sensor includes two elements whose capacitance is variable over time in opposite directions, the two elements being formed in part by the body capable of vibration, and a change in capacitance of the two elements being detected separately in a first signal path and a second signal path.

8. The device as recited in claim 7, wherein:

an output signal of the first adder is sent to the input of the regulator,

a first input of the first adder picks up a first signal in the first signal path, and

a second input of the first adder picks up a second signal in the second signal path.

9. The device as recited in claim 8, further comprising:

a modulator, wherein at least one of;

an output signal of the regulator is sent to an input of the modulator, the modulator modulating the output signal of the regulator in accordance with a frequency of a voltage supplied to the two elements.

an output signal of the modulator is sent to a first terminal of a first capacitor having a first capacitance and to a first terminal of a second capacitor having a second capacitance,

a second terminal of the first capacitor is electrically connected to the first signal path, and

a second terminal of the second capacitor is electrically connected to the second signal path.

10. The device as recited in claim 9, further comprising:

an amplifier including a first input to which the output signal of the regulator is sent and for amplifying a voltage applied thereto by a factor that depends on the at least one of the capacitive sensor and the inductive sensor and that is one of proportional to and equal to a quotient of the first capacitance and the resting capacitance.

11. The device as recited in claim 10, further comprising:

a second adder, and

a demodulator, wherein;

an output signal of the first signal path is sent to a first input of the second adder,

an output signal of the second signal path is sent to a second input of the second adder, and

an output signal of the second adder is demodulated by a demodulator and sent to the amplifier for amplification.

12. The device as recited in claim 11, wherein:

the demodulator performs a demodulation using the frequency of the voltage supplied to the two elements.

13. The device as recited in claim 12, wherein:

an output voltage of the amplifier is kept constant.

14. The device as recited in claim 13, wherein:

the output voltage of the amplifier is proportional to the resting capacitance of the at least one of the capacitive sensor and the inductive sensor, and

an electric voltage is a reference variable of the regulating circuit for regulating the amplitude of the vibration of the body capable of vibration.