CN115800926A - MEMS automatic gain control loop - Google Patents
MEMS automatic gain control loop Download PDFInfo
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Abstract
The invention provides a MEMS automatic gain control loop, which comprises: a MEMS inertial sensing portion, comprising: a drive resonator and a drive feedback; the detection charge amplifier, the phase shifter, the filter and the rectifier are sequentially connected in series; a first input end of the proportional-micro-integral controller is connected with an output end of the rectifier, and a second input end of the proportional-micro-integral controller is connected with a reference voltage; the first input end of the comparator is connected with the output end of the proportional-micro-integral controller, and the second input end of the comparator is connected with the inverted sawtooth wave signal; the input end of the charge pump is connected with the input end of the comparator; the input end of the phase-locked loop is connected with the output end of the filter; and the first input end of the driver is connected with the output end of the charge pump, the second input end of the driver is connected with the output end of the phase-locked loop, and the output end of the driver is connected with the driving resonator so as to provide a driving signal for the driving resonator.
Description
[ technical field ] A method for producing a semiconductor device
The invention relates to the technical field of MEMS (Micro-Electro-Mechanical System), in particular to an MEMS automatic gain control loop.
[ background of the invention ]
The MEMS device may include at least an accelerometer, a gyroscope, a magnetic sensor, a pressure sensor, an inertial sensor, and the like. In a vehicle, accelerometers and gyroscopes are used to deploy airbags and trigger dynamic stability control functions, respectively. MEMS gyroscopes can also be used in image stabilization systems for video and cameras, and in automatic steering systems for aircraft and torpedoes.
CMOS technology has become the dominant fabrication technology for Integrated Circuits (ICs), while MEMS devices continue to rely on traditional process technologies. IC and MEMS are actually involved in various types of environmental interactions, and techniques for improving the operation of integrated circuit devices and MEMS devices are needed. Although MEMS technology has developed rapidly over the years, there is still a great need for techniques to improve the cooperative operation of integrated circuit IC devices and MEMS.
For example, a MEMS gyroscope has a driving element that needs to resonate continuously at a desired frequency and amplitude. To maintain such oscillation of the MEMS device, an automatic gain control loop (AGC) needs to be formed to provide signal gain for the desired oscillation frequency. Thus, the automatic gain control loop AGC generates a drive signal from the feedback voltage signal and drives the resonator to maintain a desired frequency and amplitude. However, the existing agc loop structures are generally complex, have low response speed, and the like.
Therefore, a new technical solution is needed to solve the above problems.
[ summary of the invention ]
One of the objectives of the present invention is to provide an MEMS agc loop with simple structure and fast response speed.
According to one aspect of the invention, there is provided a MEMS automatic gain control loop comprising: a MEMS inertial sensing portion, comprising: a drive resonator and a drive feedback; the input end of the detection charge amplifier is connected with the output end of the driving feedback device; the input end of the phase shifter is connected with the output end of the detection charge amplifier; the input end of the filter is connected with the output end of the phase shifter; the input end of the rectifier is connected with the output end of the filter; a first input end of the proportional-micro-integral controller is connected with an output end of the rectifier, and a second input end of the proportional-micro-integral controller is connected with a reference voltage; the first input end of the comparator is connected with the output end of the proportional-micro-integral controller, and the second input end of the comparator is connected with the inverted sawtooth wave signal; the input end of the charge pump is connected with the input end of the comparator; the input end of the phase-locked loop is connected with the output end of the filter; and the first input end of the driver is connected with the output end of the charge pump, the second input end of the driver is connected with the output end of the phase-locked loop, and the output end of the driver is connected with the driving resonator so as to provide a driving signal for the driving resonator.
Compared with the prior art, the invention utilizes the charge pump to determine the amplitude of the driving signal output by the driver, utilizes the phase-locked loop to determine the frequency of the driving signal output by the driver, and has simple structure and high response speed.
[ description of the drawings ]
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise. Wherein:
fig. 1 is a schematic diagram of a MEMS automatic gain control loop in accordance with an embodiment of the present invention.
[ detailed description ] embodiments
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.
Reference herein to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic may be included in at least one implementation of the invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Unless otherwise specified, the terms connected, and connected as used herein mean electrically connected, directly or indirectly.
In the present invention, the terms "connected," "coupled," and the like are to be construed broadly unless otherwise explicitly specified or limited; for example, they may be connected directly or indirectly through an intermediate. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.
Fig. 1 is a schematic diagram of a MEMS automatic gain control loop 100 in accordance with an embodiment of the present invention. As shown in fig. 1, the MEMS automatic gain control loop comprises: the MEMS inertial sensing part 110, the detection charge amplifier 120, the phase shifter 130, the filter 140, the rectifier 150, the proportional-micro-integral controller 160, the comparator 170, the charge pump 180, the driver 190 and the phase-locked loop 145.
The MEMS inertial sensing section 110 includes: a drive resonator 111 and a drive feedback 112. The input of the sense charge amplifier 120 is connected to the output of the drive feedback 112. An input terminal of the phase shifter 130 is connected to an output terminal of the detection charge amplifier 120. An input of the filter 130 is connected to an output of the phase shifter 130. The input of the rectifier 150 is connected to the output of the filter 140. The proportional-micro-integral controller PID160 has a first input connected to the output of the rectifier 150 and a second input connected to a reference voltage Vref. A first input terminal of the comparator 170 is connected to the output terminal of the proportional-integral-derivative controller 160, and a second input terminal thereof is connected to the inverted sawtooth signal. An input of the charge pump 180 is connected to an input of the comparator 170. The input of the phase locked loop PLL is connected to the output of the filter 140. The driver 190 has a first input coupled to the output of the charge pump 180, a second input coupled to the output of the phase locked loop PLL, and an output coupled to the driving resonator 111 to provide a driving signal to the driving resonator 111.
As shown in fig. 1, the MEMS automatic gain control loop 100 further comprises: a power generator 195. The output of the power generator 195 is coupled to the input of the drive feedback 112 to provide a predetermined power supply voltage, such as 12V, to the drive feedback 112.
The driving feedback device 112 includes a driving feedback capacitor bank, and the driving feedback capacitor bank 112 includes a first driving feedback capacitor and a second driving feedback capacitor. One end of the first driving feedback capacitor and one end of the second driving feedback capacitor are respectively connected to the output end of the power generator 195. The other ends of the first driving feedback capacitor and the second driving feedback capacitor are respectively connected to two input/output ends of the detection charge amplifier 120.
The driving resonator 111 includes a driving capacitor bank including a first driving capacitor and a second driving capacitor. The driver 190 provides a driving signal to one end of each of the first driving capacitor and the second driving capacitor, so as to drive the mass block corresponding to the driving capacitor bank to perform simple harmonic motion (resonance), and the simple harmonic motion of the mass block can change the capacitance values of the first driving feedback capacitor and the second driving feedback capacitor.
The detection charge amplifier 120 senses the capacitance change of the first and second driving feedback capacitances and converts it into a voltage feedback signal. The phase shifter 130 phase shifts the voltage feedback signal by 90 degrees. The filter 140 is used for filtering the voltage feedback signal phase-shifted by 90 degrees, for example, the filter 140 is an anti-aliasing filter.
The rectifier 150 rectifies the filtered voltage feedback signal to provide a mean envelope trend of the detected voltage feedback signal.
The rectified voltage feedback signal is compared with a reference voltage Vref in the proportional micro-integral controller 160, and an error amplification signal is output. The comparator 170 compares the error amplification signal output by the proportional-micro-integral controller with a triangular wave signal to obtain a pulse width modulation pulse signal PWM. The charge pump 180 outputs a driving voltage based on the pulse width modulation pulse signal, and determines the magnitude of the driving voltage based on the duty ratio of the pulse width modulation pulse signal. The phase-locked loop 145 is configured to compare the frequency of the filtered voltage feedback signal with a reference frequency fref to generate a phase-locked clock signal, and the frequency of the filtered voltage feedback signal after loop stabilization is in the same frequency and phase as the reference frequency fref. The driver 190 generates a driving signal of a predetermined frequency and a predetermined amplitude according to the driving voltage and the phase-locked clock signal.
In one embodiment, there are multiple reference frequencies fref, one reference frequency fref being selected as an input to the phase locked loop. A plurality of reference frequencies fref may be stored in advance.
In one embodiment, the proportional micro integral controller 160 compares the average amplitude of the rectified voltage feedback signal with the amplitude provided by the reference signal Vref, if the output of the proportional micro integral controller 160 is at a desired value, the comparator 170 outputs a PWM pulse signal to maintain the output of the charge pump 180 at the desired value, if the output of the proportional micro integral controller 160 is lower than the desired value, the duty cycle of the PWM pulse signal is effectively increased, and if the output of the proportional micro integral controller 160 is higher than the desired value, the duty cycle of the PWM pulse signal is effectively decreased, the output of the charge pump is proportional to the PWM duty cycle.
The charge pump 180 supplies power to the driver 190 so that the amplitude of the driving signal output by the driver 190 is effectively controlled by the charge pump 180. If the driving voltage output by the charge pump 180 is high, the driver 190 will scale the driving signal to a higher amplitude, and if the driving voltage output by the charge pump 180 is low, the driver 190 will scale the driving signal to a lower amplitude, and the frequency of the driving signal output by the driver 190 is determined by the phase-locked clock signal.
When the amplitude of the signal generated by driving resonator 111 is below the desired amplitude, the automatic gain control loop AGC increases the amplitude of the driving signal to act in a manner that increases the force applied to the driving resonator, thereby increasing the feedback signal. On the other hand, when the amplitude of the signal generated by driving resonator 111 is greater than desired, the automatic gain control loop AGC will reduce the amplitude of the driving signal and need to act in a manner that reduces the force acting on the driving resonator, which in turn reduces the feedback signal. The driven resonator resonates at a predetermined amplitude and a predetermined frequency as adjusted by an automatic gain control loop AGC. The invention utilizes the charge pump to determine the amplitude of the driving signal output by the driver, utilizes the phase-locked loop to determine the frequency of the driving signal output by the driver, and has simple structure and high response speed.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example" or "some examples" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples described in this specification can be combined and combined by one skilled in the art.
While embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and not to be construed as limiting the present invention, and that changes, modifications and variations may be made therein by those of ordinary skill in the art within the scope of the present invention.
Claims (7)
1. A MEMS automatic gain control loop, comprising:
a MEMS inertial sensing portion, comprising: a drive resonator and a drive feedback;
the input end of the detection charge amplifier is connected with the output end of the driving feedback device;
the input end of the phase shifter is connected with the output end of the detection charge amplifier;
the input end of the filter is connected with the output end of the phase shifter;
the input end of the rectifier is connected with the output end of the filter;
a first input end of the proportional-micro-integral controller is connected with an output end of the rectifier, and a second input end of the proportional-micro-integral controller is connected with a reference voltage;
the first input end of the comparator is connected with the output end of the proportional-micro-integral controller, and the second input end of the comparator is connected with the inverted sawtooth wave signal;
the input end of the charge pump is connected with the input end of the comparator;
the input end of the phase-locked loop is connected with the output end of the filter;
and the first input end of the driver is connected with the output end of the charge pump, the second input end of the driver is connected with the output end of the phase-locked loop, and the output end of the driver is connected with the driving resonator so as to provide a driving signal for the driving resonator.
2. The MEMS automatic gain control loop of claim 1, further comprising:
and the output end of the power supply generator is connected with the input end of the driving feedback device so as to provide a preset power supply voltage for the driving feedback device.
3. The MEMS automatic gain control loop of claim 2,
the driving feedback device comprises a driving feedback capacitor bank, the driving feedback capacitor bank comprises a first driving feedback capacitor and a second driving feedback capacitor,
one end of the first driving feedback capacitor and one end of the second driving feedback capacitor are respectively connected with the output end of the power generator,
the other ends of the first driving feedback capacitor and the second driving feedback capacitor are respectively connected with two input and output ends of the detection charge amplifier.
4. The MEMS automatic gain control loop of claim 3,
the driving resonator comprises a driving capacitor group, the driving capacitor group comprises a first driving capacitor and a second driving capacitor, the driver provides driving signals for one end of the first driving capacitor and one end of the second driving capacitor respectively so as to drive a mass block corresponding to the driving capacitor group to do simple harmonic motion, and the capacitance values of the first driving feedback capacitor and the second driving feedback capacitor can be changed through the simple harmonic motion of the mass block.
5. The MEMS automatic gain control loop of claim 3,
the detection charge amplifier senses the capacitance change of the first drive feedback capacitor and the second drive feedback capacitor and converts the capacitance change into a voltage feedback signal,
the phase shifter phase shifts the voltage feedback signal by 90 degrees,
the filter is used for filtering the voltage feedback signal phase-shifted by 90 degrees,
the rectifier rectifies the filtered voltage feedback signal,
comparing the rectified voltage feedback signal with a reference voltage Vref in the proportional-micro-integral controller to output an error amplification signal,
the comparator compares the error amplification signal output by the proportional-micro-integral controller with a triangular wave signal to obtain a pulse width modulation pulse signal,
the charge pump outputting a driving voltage based on the pulse width modulated pulse signal, determining an amplitude of the driving voltage based on a duty ratio of the pulse width modulated pulse signal,
the phase-locked loop is used for comparing the frequency of the filtered voltage feedback signal with a reference frequency fref to generate a phase-locked clock signal, the frequency of the filtered voltage feedback signal after loop stabilization is in the same frequency and phase as the reference frequency fref,
the driver generates a driving signal of a predetermined frequency and a predetermined amplitude according to the driving voltage and the phase-locked clock signal.
6. The MEMS automatic gain control loop of claim 5, wherein there are a plurality of reference frequencies fref, one reference frequency fref is selected as an input to the phase locked loop.
7. The MEMS automatic gain control loop of claim 5,
the filter is an anti-aliasing filter and,
the proportional micro-integral controller compares the average amplitude of the rectified voltage feedback signal with the amplitude provided by the reference signal Vref, if the output of the proportional micro-integral controller is at a desired value, the output of the charge pump is maintained at the current period value by the pulse width modulation pulse signal output by the comparator, if the output of the proportional micro-integral controller is lower than the desired value, the duty ratio of the pulse width modulation pulse signal is effectively increased, if the output of the proportional micro-integral controller is higher than the desired value, the duty ratio of the pulse width modulation pulse signal is effectively reduced, and the output of the charge pump is proportional to the PWM duty ratio,
the charge pump supplies power to the driver so that the amplitude of the drive signal output by the driver is effectively controlled by the charge pump, if the drive voltage output by the charge pump is high, the driver will scale out a drive signal of higher amplitude, if the drive voltage output by the charge pump is low, the driver will scale out a drive signal of lower amplitude,
the frequency of the driving signal output by the driver is determined by the phase-locked clock signal.
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| CN202211677824.3A CN115800926A (en) | 2022-12-26 | 2022-12-26 | MEMS automatic gain control loop |
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| CN202211677824.3A CN115800926A (en) | 2022-12-26 | 2022-12-26 | MEMS automatic gain control loop |
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