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CN-122016080-A - Temperature measurement method and circuit based on MEMS driving signal intensity Q value detection

CN122016080ACN 122016080 ACN122016080 ACN 122016080ACN-122016080-A

Abstract

The invention provides a temperature measurement method based on MEMS driving signal intensity Q value detection, which comprises the steps of replacing PGA in a traditional driving loop with DPGA, adding a digital-to-analog converter ADC between the DPGA and a PI controller, forming a resonance maintenance loop between a MEMS resonator and a transimpedance amplifier TIA and DPGA, and enabling TIA output signals to pass through a rectifier and then be connected with reference voltage The method comprises the steps of subtracting, extracting a direct current component through a PI controller, controlling the gain of DPGA after the direct current signal output by the PI controller is quantized through an ADC (analog to digital converter), maintaining the amplitude of a resonance signal passing through the MEMS resonator constant, simultaneously calculating the gains of the MEMS resonator and a TIA (digital to analog converter), further obtaining the Q value of the MEMS resonator, and acquiring the temperature information of the MEMS resonator in real time through the signal quantized by the ADC based on the inverse relation between the Q value and the temperature.

Inventors

  • ZHAO JIAN
  • ZOU YUCHI

Assignees

  • 上海交通大学

Dates

Publication Date
20260512
Application Date
20251202

Claims (10)

  1. 1. The temperature measurement method based on MEMS driving signal intensity Q value detection is characterized by comprising the following steps: Replacing the PGA in the traditional driving loop with DPGA, and adding a digital-to-analog converter ADC between the DPGA and a PI controller; A resonance maintaining loop is formed between the MEMS resonator and the transimpedance amplifier TIA and between the TIA output signal and the reference voltage after passing through a rectifier Subtracting, and then extracting a direct current component through a PI controller; The direct current signal output by the PI controller is quantized by the ADC and then used for controlling the gain of the DPGA so as to maintain the amplitude of the resonance signal passing through the MEMS resonator constant; And acquiring temperature information of the MEMS resonator in real time through the signals quantized by the ADC based on the inverse relation between the Q value and the temperature.
  2. 2. The method for measuring temperature based on detection of the intensity Q value of a MEMS driving signal according to claim 1, wherein a notch filter is further provided between the ADC and the DPGA, and the notch filter is used for reducing noise generated by quantization of the ADC.
  3. 3. The method for measuring temperature based on detection of the Q value of the intensity of a MEMS driving signal according to claim 2, the notch filter is characterized in that the resonant frequency of the ADC quantized signal is The information at the position is filtered, so that noise aliasing into the drive loop is avoided to influence the resonance sine signal of the MEMS resonator.
  4. 4. The temperature measurement method based on the detection of the intensity Q value of the MEMS driving signal according to claim 2, wherein the notch filter is implemented in any one of the following ways: Setting a pole-zero pair at a target frequency point by adopting a second-order IIR structure, and realizing narrow-band depth inhibition with low operand; a window function or a frequency sampling method is utilized to design an FIR band-stop filter, and a linear phase is obtained while the notch effect is ensured; Constructing a comb-shaped FIR structure, and forming periodic notches through fixed tap intervals so as to inhibit a single frequency point under a specific condition; and (3) adopting an adaptive notch method, and utilizing an LMS or RLS algorithm to adjust parameters on line under the IIR or FIR frame so as to track an interference signal with slow drift of frequency.
  5. 5. The temperature measurement method based on MEMS driving signal intensity Q value detection of claim 1, wherein the DPGA comprises an operational amplifier and a capacitor array, wherein the input end of the operational amplifier is connected with a controllable input capacitor array, and the other capacitor array is connected between the input end and the output end in a bridging way; the ratio of the cross-over capacitance to the input capacitance determines the gain of the DPGA, and the programmable control of the gain of the DPGA amplifier is realized by changing the capacitance of the input capacitance array.
  6. 6. The method of claim 1, wherein controlling the gain of the DPGA to maintain a constant amplitude of the resonant signal through the MEMS resonator comprises: extracting frequency information of a sinusoidal signal in a driving loop through a frequency-to-digital converter FDC, wherein: FDC outputs a signal to TIA And measuring to obtain frequency information of the corresponding MEMS resonator, and calculating the difference value of the frequency information to obtain the frequency difference for reflecting the acceleration.
  7. 7. The method for measuring temperature based on detection of the Q value of the intensity of the driving signal of MEMS according to claim 1, wherein said obtaining the Q value of the MEMS resonator comprises: Transfer function of MEMS resonator The method comprises the following steps: In the formula, Is a constant related to the MEMS sensor itself, The resonance frequency is indicated as such, As a complex frequency variable in the laplace transform, The Q value of the MEMS resonator; the ADC quantized signal The value of (2) is the product of the MEMS resonator gain and TIA gain, and the expression is: In the formula, Representing the drive voltage of the MEMS resonator, Representing the output voltage of the TIA module, Representing the gain of the TIA; Wherein, the And Are all constant values, at the same time And resonant frequency Is also known, and the signal is then output by ADC The Q value of the MEMS resonator can be calculated in real time.
  8. 8. The temperature measurement method based on detection of the Q value of the intensity of the MEMS driving signal according to claim 1, wherein the acquiring the temperature information of the MEMS resonator in real time by the signal quantized by the ADC based on the inverse relation between the Q value and the temperature comprises: From the inverse relationship between the Q value of the MEMS resonator and the temperature, it is possible to obtain: In the formula, Representing the Q value of the MEMS resonator, Representing the temperature of the MEMS resonator structure, Representing that the two variables are in a direct proportion; Output signal by ADC And acquiring temperature information of the MEMS resonator in real time.
  9. 9. The silicon resonator in-situ temperature detection circuit based on drive power quantization comprises a traditional drive loop, and is characterized in that DPGA is adopted to replace PGA in the traditional drive loop, and a digital-to-analog converter ADC is inserted between the DPGA and a PI controller, wherein: A resonance maintaining loop is formed between the MEMS resonator and the transimpedance amplifier TIA and between the TIA output signal and the reference voltage after passing through a rectifier Subtracting, and then extracting a direct current component through a PI controller; The direct current signal output by the PI controller is quantized by the ADC and then used for controlling the gain of the DPGA so as to maintain the amplitude of the resonance signal passing through the MEMS resonator constant; And acquiring temperature information of the MEMS resonator in real time through the signals quantized by the ADC based on the inverse relation between the Q value and the temperature.
  10. 10. The silicon resonator in-situ temperature detection circuit based on drive power quantization as recited in claim 9, further comprising a notch filter between the ADC and the DPGA for reducing the ADC quantization noise versus frequency Is provided, the influence of the resonance signal of (a) is reduced.

Description

Temperature measurement method and circuit based on MEMS driving signal intensity Q value detection Technical Field The invention relates to the technical field of integrated circuit design, in particular to a temperature measurement method and circuit based on detection of a Q value of MEMS driving signal intensity. Background Resonant accelerometers (SOAs) represent a class of high-precision microelectromechanical system (MEMS) accelerometers with unique time modulation characteristics. The device has high sensitivity and excellent long-term stability, has remarkable microminiaturization potential, and is expected to balance between a low-cost MEMS capacitance accelerometer and a traditional quartz bending accelerometer, so that performance breakthrough in the fields of high-precision positioning, inertial navigation and the like is realized. However, key bias stability indicators remain limited by the characteristics of the silicon and MEMS packages, resulting in performance gaps compared to quartz accelerometers. One of the representative problems is temperature drift, which can cause resonance frequency drift and impair the long-term bias stability of the MEMS oscillator. Stress and silicon temperature coefficient as a function of temperature are the main causes of this problem. A common practice to solve the temperature drift problem from the circuitry level is to use a temperature drift fit of the on-chip temperature measured by a thermometer to the frequency to compensate. In order to solve the problem, various solutions are proposed by domestic and foreign researches. Literature H. K. Lee, R. Melamud, B. Kim, M. A. Hopcroft, J. C. Salvia and T. W. Kenny, "Electrostatic Tuning to Achieve Higher Stability Microelectromechanical Composite Resonators," in Journal of Microelectromechanical Systems, vol. 20, no. 6, pp. 1355-1365, Dec. 2011, doi: 10.1109/JMEMS.2011.2168083. obtains the temperature inside the resonator by placing a temperature sensor in the MEMS resonator, thereby performing temperature compensation. The literature D. Liu et al., "In-Situ Compensation on Temperature Coefficient of the Scale Factor for a Single-Axis Nano-g Force-Balance MEMS Accelerometer," in IEEE Sensors Journal, vol. 21, no. 18, pp. 19872-19880, 15 Sept.15, 2021, doi: 10.1109/JSEN.2021.3098797. uses the characteristic that the resistance value of the thermistor changes with temperature to build a peripheral compensation circuit for compensation by integrating the thermistor in the MEMS resonator. However, in-situ temperature measurement is difficult under dynamic temperature gradient by using the two methods, and the in-situ temperature is always lagged behind the probe temperature, so that the hysteresis phenomenon of a temperature curve is caused. The quality factor of a resonator has proven to be an ideal parameter as a temperature indicator and its distance from the MEMS structure is close to zero, as in literature KIM B, HOPCROFT M A, CANDLER R N, et al. Temperaturedependence of quality factor in MEMS resonators [J]. Journal ofMicroelectromechanical Systems, 2008, 17(3): 755-66.. an Amplitude Modulation (AM) method based on resonator amplification measurement is used for real-time quality factor monitoring, as in literature HOPCROFT M A, AGARWAL M, PARK K K, et al. Temperaturecompensation of a MEMS resonator using quality factor as a thermometer;proceedings of the 19th IEEE International Conference on Micro ElectroMechanical Systems (MEMS 2006), Istanbul, TURKEY, F Jan 22-26, 2006[C]. 2006.. but the Amplitude Modulation (AM) method is affected by circuit gain variations, thus making it difficult to achieve high-precision quality factor measurement. 2018. One approach to this problem has been proposed in literature Y. Wang et al.,"A MEMS Resonant Accelerometer With High Performance of Temperature Based on Electrostatic Spring Softening and Continuous Ring-Down Technique," in IEEE Sensors Journal, vol. 18, no. 17, pp. 7023-7031, 1 Sept.1, 2018, doi: 10.1109/JSEN.2018.2852647.. The quality factor is monitored in real time by adopting a continuous excitation-attenuation technology and used as a virtual thermometer, so that the measurement lag is reduced, and the temperature compensation accuracy is improved. However, the continuous excitation-attenuation method can make the amplitude of the signal in the resonator driving loop change continuously, and finally generate low-frequency noise through the amplitude stiffness coupling effect, so that the real-time quality factor measurement is difficult to complete under the condition of high-precision measurement. High accuracy real-time quality factor monitoring remains a key challenge for temperature compensation of resonant MEMS oscillators. No description or report of similar technology is found at present, and similar data at home and abroad are not collected. Disclosure of Invention Aiming at the defects in the prior art, the invention provides a temperature measuring m