Temperature compensating device for micro-machined capacitive accelerometer

Abstract

The invention discloses a temperature compensating device for a micro-machined capacitive accelerometer. The temperature compensating device mainly comprises a coherent demodulator, a low pass filter and a temperature compensating circuit, wherein an output end of the coherent demodulator is connected with an input end of the low pass filter; and the output end of the low pass filter is connectedwith the input end of the low temperature compensating circuit. By taking the internal capacitance which changes with the temperature of the micro-machined capacitive accelerometer as a compensating reference signal of an output signal of the accelerometer, the temperature compensating device does not need a thermistor or an integrated temperature sensor for measuring the temperature of an acceleration sensor, so the structure of the temperature compensating device is simplified, and the cost is reduced; the influence on compensating precision due to temperature measurement error is eliminated, and the temperature compensating precision is improved; and no temperature sensor is needed to be arranged and used on the micro-machined capacitive accelerometer, so a temperature measurement error due to a temperature gradient of a metal pipe shell of the acceleration sensor is avoided, and the temperature compensating precision is further improved.

Description

technical field

[0001] The invention relates to the field of weak signal detection, in particular to a temperature compensation device for improving the temperature characteristics of a capacitive micromachined accelerometer. Background technique

[0002] The schematic diagram of the connection relationship between the capacitive micromachined accelerometer and its temperature compensation device in the prior art is as follows: figure 1 As shown, the system consists of a capacitive micromachined acceleration sensor, an analog processing circuit and a temperature compensation device. figure 1 In the above, the specific connection relationship between the capacitive micromachined accelerometer and its temperature compensation device is as follows: the output end of the high-frequency carrier generator is connected to the input end of the band-pass filter and the input end of the phase shifter respectively, and the output end of the band-pass filter It is connected with the ca...

Examples

Embodiment Construction

[0016] The capacitive micromechanical acceleration sensor is sensitive to the external acceleration signal, and converts the acceleration signal into a change in differential capacitance. The differential capacitance inside the sensor is converted into a differential voltage signal through the first charge amplifier and the second charge amplifier, and processed by the subsequent stage. The circuit can get the size of the input acceleration signal, so as to realize the detection of the acceleration. Since the key unit of the capacitive micromachined acceleration sensor is a capacitor, and when the temperature changes, the capacitance of the capacitor will also change, which will cause a change in the zero output signal of the accelerometer and affect the detection of the real acceleration signal by the accelerometer. In order to reduce the influence of temperature on the output signal of the capacitive micromachined accelerometer, it is necessary to use an effective temperature...

technical field

[0001] The invention relates to the field of weak signal detection, in particular to a temperature compensation device for improving the temperature characteristics of a capacitive micromachined accelerometer. Background technique

[0002] The schematic diagram of the connection relationship between the capacitive micromachined accelerometer and its temperature compensation device in the prior art is as follows: figure 1 As shown, the system consists of a capacitive micromachined acceleration sensor, an analog processing circuit and a temperature compensation device. figure 1 In the above, the specific connection relationship between the capacitive micromachined accelerometer and its temperature compensation device is as follows: the output end of the high-frequency carrier generator is connected to the input end of the band-pass filter and the input end of the phase shifter respectively, and the output end of the band-pass filter It is connected with the ca...

Examples

Embodiment Construction

[0016] The capacitive micromechanical acceleration sensor is sensitive to the external acceleration signal, and converts the acceleration signal into a change in differential capacitance. The differential capacitance inside the sensor is converted into a differential voltage signal through the first charge amplifier and the second charge amplifier, and processed by the subsequent stage. The circuit can get the size of the input acceleration signal, so as to realize the detection of the acceleration. Since the key unit of the capacitive micromachined acceleration sensor is a capacitor, and when the temperature changes, the capacitance of the capacitor will also change, which will cause a change in the zero output signal of the accelerometer and affect the detection of the real acceleration signal by the accelerometer. In order to reduce the influence of temperature on the output signal of the capacitive micromachined accelerometer, it is necessary to use an effective temperature...

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