Low-noise low-temperature-drift quartz resonant beam accelerometer driving circuit

Abstract

The invention discloses a quartz resonant beam accelerometer driving circuit with low noise and low temperature drift, which relates to the technical field of micro electro mechanical systems, and comprises a voltage-stabilized power supply module, a resonant circuit module, an output shaping circuit and a quartz resonant beam chip, the stabilized voltage supply module provides low-noise and stable working voltage for the resonance circuit module and the output shaping circuit; the resonance circuit module comprises a first-stage amplification circuit and a second-stage amplification circuit, the first-stage amplification circuit, the second-stage amplification circuit and the quartz resonance beam chip form a closed-loop series positive feedback resonance circuit, the quartz resonance beam chip serves as a meter head in the driving circuit, the first-stage amplification circuit receives output signals of the quartz resonance beam chip, and the second-stage amplification circuit receives the output signals of the quartz resonance beam chip. After being amplified, the signal is input into the second-stage amplification circuit, and the second-stage amplification circuit performs second-stage amplification on the signal and then outputs the signal to the quartz resonant beam chip; and the output shaping circuit adopts a hysteresis comparator to shape the signal output by the second-stage amplification circuit into a standard square wave signal and outputs the standard square wave signal outwards.

Description

Technical Field

[0001] The invention relates to the technical field of micro-electromechanical systems, and in particular to a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit. Background Art

[0002] The quartz resonant beam accelerometer is a digital micromechanical sensor made of MEMS technology based on the force-frequency characteristics of quartz crystals. It directly outputs frequency signals without AD conversion. It has the advantages of high precision, low cost, small size, and low power consumption. It can be widely used in inertial navigation, earthquake monitoring and other fields. The drive circuit is the core component of the accelerometer. The noise, temperature drift and other indicators of the drive circuit directly determine the zero bias stability, time jitter, Allan variance and temperature drift of the accelerometer.

[0003] At present, the driving circuit of the quartz resonant beam accelerometer (VIA) mainly adopts the series resonant circuit. Because its dynamic resistance is very large, there is no inductive interval in the entire frequency range, and the parallel resonant circuit in the passive quartz crystal oscillator circuit cannot be used. At present, the series resonant circuit widely adopts the multi-stage amplifier circuit. At the same time, in order to meet the phase balance condition of 2nπ, two-stage amplification is generally adopted. Since the dynamic resistance of VIA is very large, the circuit gain requirement is very high. The amplifier device generally adopts MOS tube, dual gate, triode, etc. Although the MOS tube has a high amplification factor, the noise is large. According to the Leeson formula, the noise of the resonant circuit determines the output phase noise of the oscillator, and the measured time jitter also reaches more than 100 nanoseconds (time jitter is the integral reflection of phase noise).

[0004] In the current design of quartz resonant beam accelerometer drive circuits, such as two-stage common emitter amplifier circuits, due to the Miller effect, the equivalent input capacitance Ci=Cbe+(1+Av)·Cbc, where Cbe is the base-emitter capacitance, Cbc is the base-collector capacitance, and Av is the voltage gain of the amplifier circuit, that is, the equivalent input capacitance is proportional to the voltage gain. Since the transistor has a temperature coefficient, the gain is different at different temperatures, so the equivalent input capacitance of the resonant circuit varies greatly with temperature, which in turn causes the circuit open-loop phase to vary greatly with temperature. Due to the frequency pulling effect, the phase jitter introduced into the loop will cause the oscillation frequency to change, and the frequency change is proportional to the phase change, which will cause the frequency change range of the accelerometer to expand. The measured resonant circuit will cause the output frequency change of the accelerometer at full temperature to expand by more than 10Hz compared to the resonant frequency change range of the quartz resonant beam chip (meter head), and the temperature drift performance will deteriorate by more than double. Furthermore, since the noise of the amplifier circuit determines the output phase noise of the resonant loop, and the lower the input noise of the low-noise JFET device, the larger the input capacitance, it is difficult to achieve both low noise and low temperature drift performance of the resonant circuit. Summary of the invention

[0005] The purpose of the present invention is to provide a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit to improve the frequency stability and temperature drift performance of the quartz resonant beam accelerometer.

[0006] The technical solution of the present invention is: to provide a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit, the driving circuit comprising: a voltage-stabilized power supply module, a resonant circuit module, an output shaping circuit and a quartz resonant beam chip;

[0007] The voltage-stabilized power supply module provides low-noise, stable operating voltage for the resonant circuit module and the output shaping circuit;

[0008] The resonant circuit module includes a first-stage amplifier circuit and a second-stage amplifier circuit. The first-stage amplifier circuit, the second-stage amplifier circuit and the quartz resonant beam chip form a closed-loop series positive feedback resonant circuit. The quartz resonant beam chip acts as a meter in the driving circuit. The first-stage amplifier circuit receives the output signal of the quartz resonant beam chip, and inputs it into the second-stage amplifier circuit after amplification. The second-stage amplifier circuit performs secondary amplification on the signal and then outputs it to the quartz resonant beam chip.

[0009] The output shaping circuit uses a hysteresis comparator to shape the signal output by the second-stage amplifier circuit into a standard square wave signal for external output.

[0010] In any of the above technical solutions, further, the voltage-stabilized power supply module includes a DC power supply, an LDO linear voltage-stabilized power supply chip and resistors R1 and R2;

[0011] The negative pole of the DC power supply is grounded, and the positive pole is connected to the VIN end of the LDO linear voltage regulator chip. The OUT end of the LDO linear voltage regulator chip is connected to the resistor R1. The OUT end outputs current at the same time. The resistors R1 and R2 are connected in series, and the resistor R2 is grounded. The FB end of the LDO linear voltage regulator chip is connected between the resistors R1 and R2. The voltage regulator module divides the output current through the resistors R1 and R2, and converts the input DC power Vin into the output voltage regulator Vcc. The conversion relationship is: V CC =(1+R1 / R2)·V in .

[0012] In any of the above technical solutions, further, the first-stage amplifier circuit includes: two parallel-connected JFET junction field effect transistors Q1 and Q2, and resistors R4, R5, R6, R7, and R8;

[0013] The gates of the JFET junction field effect transistors Q1 and Q2 both receive the output signal VIAout from the quartz resonant beam chip, the output Vcc of the voltage-stabilized power supply module is connected to resistors R4 and R7, the resistor R4 is connected to the drain of the JFET junction field effect transistor Q1, the resistor R7 is connected to the drain of the JFET junction field effect transistor Q2, the source of the JFET junction field effect transistor Q1 is grounded through the resistor R5, the source of the JFET junction field effect transistor Q2 is grounded through the resistor R8, the gate bias voltages of the JFET junction field effect transistors Q1 and Q2 are provided by the resistors R4 and R5 and the resistors R7 and R8, respectively, and are set to a zero temperature coefficient point; the drain signal of the JFET junction field effect transistor Q1 is combined with the drain signal of the JFET junction field effect transistor Q2 through the small resistance resistor R6 for output.

[0014] In any of the above technical solutions, further, the circuit gain A of the first-stage amplifier circuit is u1 For: A u1 =-g m ·R4, where g m The JFET junction field effect transistors Q1 and Q2 have the same transconductance.

[0015] In any of the above technical solutions, further, the second-stage amplifier circuit adopts a common-base Wolman circuit structure, and the second-stage amplifier circuit includes: NPN transistors Q3, Q4, resistors R9, R10, R11, and R12;

[0016] The output of the voltage-stabilized power supply module is connected to resistors R9 and R11, and the NPN transistors Q3 and Q4 obtain base voltages through voltage division by resistors R9, R10 and R11, R12 respectively. The base of the NPN transistor Q4 receives the output signal of the first-stage amplifier circuit, and the collector of the NPN transistor Q4 is connected to the emitter of the NPN transistor Q3. The collector of the NPN transistor Q3 outputs a signal VIAin to the quartz resonant beam chip.

[0017] In any of the above technical solutions, further, the output shaping circuit receives the output signal VIAin of the second-stage amplifier circuit, and the output shaping circuit includes: a hysteresis comparator, resistors R16 and R17;

[0018] The output Vcc of the voltage-stabilized power supply module is divided by resistors R16 and R17 to form a reference voltage Vref, which is input into the positive input of the hysteresis comparator. The reference voltage Vref is also used as a DC bias for the AC signal output by the oscillation loop. The output signal VIAin of the second-stage amplifier circuit is input into the negative input of the hysteresis comparator. The output Vcc of the voltage-stabilized power supply module supplies power to the hysteresis comparator, and the hysteresis comparator outputs a square wave signal backward.

[0019] The beneficial effects of the present invention are:

[0020] The first-stage amplifier circuit of the technical solution of the present invention utilizes two low-noise JFET devices in parallel to reduce the circuit voltage noise, thereby reducing the phase noise of the entire accelerometer and improving the instantaneous frequency stability of the accelerometer; at the same time, the JFET device has a zero temperature coefficient point and the second-stage amplifier circuit adopts a common-base Wolman circuit to reduce the phase temperature coefficient of the two-stage amplifier resonant circuit, reduce the frequency variation range of the quartz resonant beam accelerometer at full temperature, and achieve low noise and low temperature drift performance of the resonant circuit.

[0021] After testing and comparing the performance of a traditional dual MOS tube two-stage amplifier circuit with the resonant circuit described in the present invention in combination with a quartz resonant beam meter, the phase temperature coefficient of the resonant circuit provided by the present invention is optimized by 60%, the full-temperature output frequency variation range in combination with the quartz resonant beam chip (meter head) is reduced by 40%, and the time jitter noise of the output signal is reduced by 5 times, indicating that the resonant circuit provided by the present invention effectively reduces the noise of the accelerometer and improves the frequency stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The advantages of the above and additional aspects of the present invention will become apparent and easily understood in the description of the embodiments in conjunction with the following drawings, in which:

[0023] Figure 1 is an overall schematic diagram of a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit according to an embodiment of the present invention;

[0024] Figure 2 1 is a schematic diagram of a voltage-stabilized power supply module of a low-noise and low-temperature-drift quartz resonant beam accelerometer driving circuit according to an embodiment of the present invention;

[0025] Figure 3 1 is a schematic diagram of a first-stage amplifier circuit of a low-noise and low-temperature-drift quartz resonant beam accelerometer driving circuit according to an embodiment of the present invention;

[0026] Figure 4 1 is a schematic diagram of a second-stage amplifier circuit of a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit according to an embodiment of the present invention;

[0027] Figure 5 The diagram is a schematic diagram of an output shaping circuit of a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit according to an embodiment of the present invention. DETAILED DESCRIPTION

[0028] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0029] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0030] like Figure 1 As shown, this embodiment provides a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit, which includes: a voltage-stabilized power supply module 1, a resonant circuit module 2, an output shaping circuit 5 and a quartz resonant beam chip 6.

[0031] The voltage-stabilized power supply module 1 provides a low-noise power supply voltage to the overall circuit, and adopts an LDO linear voltage-stabilized power supply chip to suppress power supply noise, stabilize the static operating point of the two-stage amplifier circuit, and avoid the frequency pulling effect that causes the output frequency to be unstable.

[0032] The resonant circuit module 2 and the quartz resonant beam chip 6 form a closed-loop series positive feedback resonant circuit. The quartz resonant beam chip 6 acts as a meter in the circuit, outputs signals to the resonant circuit module 2, and also receives the output signal of the resonant circuit module 2.

[0033] The resonant circuit module 2 includes a first-stage amplifier circuit 3 and a second-stage amplifier circuit 4. The first-stage amplifier circuit 3 receives the output signal of the quartz resonant beam chip 6, and inputs it into the second-stage amplifier circuit 4 after amplification. The second-stage amplifier circuit 4 performs secondary amplification on the signal and outputs it to the quartz resonant beam chip 6.

[0034] The first-stage amplifier circuit 3 adopts a dual-JFET parallel common-source amplifier circuit, which utilizes the low-noise characteristics of JFET and further reduces the circuit voltage noise by connecting two JFETs in parallel; the input capacitor adopts a zero temperature coefficient bias point setting to reduce the input capacitance and gain changes caused by temperature changes.

[0035] The second-stage amplifier circuit 4 adopts a common-base Walman circuit, which is not affected by the Miller effect. The Miller effect refers to the fact that in some amplifier circuits, due to circuit design problems, the input capacitance changes with the gain, resulting in unstable circuit performance. The common-base Walman circuit avoids this problem through a unique design, further reducing the impact of temperature on circuit performance. The input capacitance does not change with the gain, reducing the phase temperature coefficient, and maintaining the stability and temperature stability of the accelerometer output signal.

[0036] The design idea of ​​the first-stage amplifier circuit 3 is as follows: the first-stage amplifier circuit 3 adopts a dual-JFET parallel common source amplifier circuit. According to the noise transfer theory of the cascade amplifier circuit, the total noise of the amplifier circuit is most affected by the first stage. Compared with the triode, the JFET tube has lower noise, but the amplification factor is lower, so it is placed in the first stage; according to the low-noise amplifier design theory, the amplifier parallel voltage noise can be reduced by half in theory, and because the input capacitance will increase by one time, the number of amplifiers in parallel cannot be increased indefinitely, and finally a solution of two JFET tubes in parallel is adopted. In addition, the gate bias voltage Vgs of the JFET tube is set to the zero temperature coefficient bias point, and the gain of the tested amplifier circuit basically does not change with temperature. In this way, even if there is a Miller effect, the equivalent input capacitance will not change with temperature, which ensures low noise while ensuring the low temperature drift performance of the circuit.

[0037] The design idea of ​​the second-stage amplifier circuit 4 is as follows: the second-stage amplifier circuit 4 adopts a common-base Walman circuit. Since the collector of the lower transistor Q4 is AC-grounded, it is equivalent to Av=0 of a common-emitter circuit, and the equivalent input capacitance Ci=Cbe+Cbc. Therefore, the Miller effect will not occur, and the equivalent input capacitance will not change with temperature. This can ensure the high gain of the two-stage amplifier resonant circuit, eliminate the influence of the Miller effect, and reduce the phase temperature coefficient.

[0038] The signal after the second-stage amplification in the second-stage amplifier circuit 4 is also output to the output shaping circuit 5 .

[0039] The output shaping circuit 5 uses a hysteresis comparator to shape the resonant signal into a standard square wave signal, which is convenient for frequency measurement. At the same time, the hysteresis comparator has an isolation buffering function to eliminate small pulse noise interference. The output shaping circuit 5 outputs a standard square wave signal for external use.

[0040] like Figure 2 As shown, the voltage-stabilized power supply module 1 includes a DC power supply, an LDO linear voltage-stabilized power supply chip and resistors R1 and R2. The negative pole of the DC power supply is grounded, and the positive pole is connected to the VIN terminal of the LDO linear voltage-stabilized power supply chip. The OUT terminal of the LDO linear voltage-stabilized power supply chip is connected to the resistor R1. The OUT terminal outputs current to the outside at the same time. The resistors R1 and R2 are connected in series, and the resistor R2 is grounded. The FB terminal of the LDO linear voltage-stabilized power supply chip is connected between the resistors R1 and R2. The voltage-stabilized power supply module 1 realizes the conversion of the input DC power supply Vin to the output voltage-stabilized power supply Vcc by dividing the output current through the resistors R1 and R2. The conversion relationship is: V CC =(1+R1 / R2)·V in .

[0041] like Figure 3As shown, the first-stage amplifier circuit 3 includes two parallel JFET junction field effect transistors Q1 and Q2, the gates of the JFET junction field effect transistors Q1 and Q2 both receive the output signal VIAout from the quartz resonant beam chip 6, the output of the voltage-stabilized power supply module 1 is connected to resistors R4 and R7, the resistor R4 is connected to the drain of the JFET junction field effect transistor Q1, the resistor R7 is connected to the drain of the JFET junction field effect transistor Q2, the source of the JFET junction field effect transistor Q1 is grounded through the resistor R5, the source of the JFET junction field effect transistor Q2 is grounded through the resistor R8, the gate bias voltages of the JFET junction field effect transistors Q1 and Q2 are provided by the resistors R4 and R5 and the resistors R7 and R8 respectively, and are set to a zero temperature coefficient point, so that the gain of the amplifier circuit does not change with temperature, and the oscillation phase drift caused by the input capacitance changing with temperature is avoided; the drain signal of the JFET junction field effect transistor Q1 is combined with the drain signal of the JFET junction field effect transistor Q2 through the small resistance resistor R6 for output.

[0042] In order to suppress the influence of power supply noise on the static operating point, a filter capacitor C4 is set in the circuit. The input capacitor C3 and the output capacitor C5 are used for DC isolation and signal transmission respectively. The high-capacitance capacitors C6 and C16 connect the source electrodes of Q1 and Q2 to AC ground respectively.

[0043] Since the dynamic resistance of the quartz resonant beam chip is at the MΩ level, in order to ensure that the loop meets the amplitude balance condition, the input resistance of the first-stage amplifier circuit cannot be too small. u1 For: A u1 =-g m ·R4, where g m The JFET junction field effect transistors Q1 and Q2 have the same transconductance.

[0044] like Figure 4 As shown, the second-stage amplifier circuit 4 adopts a common-base Wolman circuit structure, and the output of the voltage-stabilized power supply module 1 is connected to resistors R9 and R11.

[0045] NPN transistors Q3 and Q4 obtain base voltage through resistors R9, R10 and R11, R12 respectively. C12 and C13 make the collector of Q4 realize AC grounding, thus effectively reducing the equivalent input capacitance of the circuit. Input capacitor C8 and output capacitor C11 are used to block DC and pass AC. C7 is a power supply filter capacitor, which is used to suppress the influence of high-frequency noise on the amplifier circuit.

[0046] The base of the NPN transistor Q4 receives the output signal of the first-stage amplifier circuit 3 , the collector of the NPN transistor Q4 is connected to the emitter of the NPN transistor Q3 , and the collector of the NPN transistor Q3 outputs a signal VIAin to the quartz resonant beam chip 6 .

[0047] Since the base of Q3 is grounded by bypass capacitors C10 = 0.1uF and C9 = 10uF, there is no AC voltage between the base and emitter of Q3, which is equivalent to the gain of the Q4 common emitter amplifier circuit being 0. Therefore, the equivalent input capacitance Ci = Cbe + Cbc, and the input capacitance does not change with the change of the circuit gain. There is no Miller effect, and the phase temperature coefficient will be greatly reduced. Resistors R13 and R15 determine the gain of the Walman circuit. The circuit gain A u2 for:

[0048] The first-stage amplifier circuit 3, the second-stage amplifier circuit 4 and the quartz resonant beam chip 6 form a closed-loop series positive feedback resonant circuit. The signal enters the input end of the first-stage amplifier circuit 3 after passing through the quartz resonant beam chip 6 with a large reactance-frequency characteristic slope. The measured loop gain is 1.15>1, and the loop phase is 0°, which meets the amplitude starting condition and phase balance condition.

[0049] like Figure 5 As shown, the output signal VIAin of the second-stage amplifier circuit 4 is also input into the output shaping circuit 5. The output shaping circuit 5 uses a hysteresis comparator circuit to shape the input resonant signal and output a standard square wave signal, which is beneficial for other equipment to measure the frequency of the signal and can effectively eliminate abnormal small pulse interference caused by noise.

[0050] The output Vcc of the voltage-stabilized power supply module 1 is divided by resistors R16 and R17 to form a reference voltage Vref, which is input into the positive input terminal of the hysteresis comparator. The reference voltage Vref is also used as a DC bias for the AC signal output by the oscillation loop. The output signal VIAin of the second-stage amplifier circuit 4 is input into the negative input terminal of the hysteresis comparator. The output Vcc of the voltage-stabilized power supply module 1 is used to power the hysteresis comparator, and the hysteresis comparator outputs a square wave signal backward.

[0051] The filter capacitor C14 is connected in parallel across the resistor R17 to stabilize the power supply and eliminate the influence of high-frequency noise on signal shaping.

[0052] The threshold calculation formula of the square wave signal output by the output shaping circuit 5 is as follows:

[0053]

[0054] Among them, V H is the upper limit voltage, V L is the lower voltage limit.

[0055] In another embodiment of the present invention, a comparative test is conducted on the performance of a conventional dual MOS tube two-stage amplifier circuit and the resonant circuit of the present invention in combination with a quartz resonant beam meter, as shown in the following Table 1:

[0056] Table 1 Performance comparison of different resonant circuits

[0057]

[0058]

[0059] The test results show that the phase temperature coefficient of the resonant circuit provided by the present invention is optimized by 60%, the full-temperature output frequency variation range of the quartz resonant beam chip (meter head) is reduced by 40%, and the time jitter noise of the output signal is reduced by 5 times, indicating that the resonant circuit provided by the present invention effectively reduces the noise of the accelerometer and improves the frequency stability.

[0060] In summary, the present invention proposes a low-noise and low-temperature drift quartz resonant beam accelerometer driving circuit, the driving circuit comprising: a voltage-stabilized power supply module 1, a resonant circuit module 2, an output shaping circuit 5 and a quartz resonant beam chip 6;

[0061] The voltage-stabilized power supply module 1 provides a low-noise, stable operating voltage for the resonant circuit module 2 and the output shaping circuit 5;

[0062] The resonant circuit module 2 includes a first-stage amplifier circuit 3 and a second-stage amplifier circuit 4.

[0063] The first-stage amplifier circuit 3, the second-stage amplifier circuit 4 and the quartz resonant beam chip 6 form a closed-loop series positive feedback resonant circuit. The quartz resonant beam chip 6 acts as a meter in the driving circuit. The first-stage amplifier circuit 3 receives the output signal of the quartz resonant beam chip 6, and inputs it into the second-stage amplifier circuit 4 after amplification. The second-stage amplifier circuit 4 performs secondary amplification on the signal and outputs it to the quartz resonant beam chip 6; the output shaping circuit 5 uses a hysteresis comparator to shape the signal output by the second-stage amplifier circuit 4 into a standard square wave signal for external output.

[0064] The steps in the present invention can be adjusted in order, combined or deleted according to actual needs.

[0065] The units in the device of the present invention can be combined, divided and deleted according to actual needs.

[0066] Although the present invention is disclosed in detail with reference to the accompanying drawings, it should be understood that these descriptions are merely exemplary and are not intended to limit the application of the present invention. The scope of protection of the present invention is defined by the appended claims and may include various modifications, alterations and equivalents made to the invention without departing from the scope and spirit of the present invention.

Claims

1. A low noise and low temperature drift quartz resonant beam accelerometer driving circuit, characterized in that: The driving circuit comprises: a voltage-stabilized power supply module (1), a resonance circuit module (2), an output shaping circuit (5) and a quartz resonance beam chip (6); The voltage-stabilized power supply module (1) provides a low-noise, stable operating voltage for the resonant circuit module (2) and the output shaping circuit (5); The resonant circuit module (2) comprises a first-stage amplifier circuit (3) and a second-stage amplifier circuit (4); the first-stage amplifier circuit (3), the second-stage amplifier circuit (4) and a quartz resonant beam chip (6) form a closed-loop series positive feedback resonant circuit; the quartz resonant beam chip (6) acts as a meter in the driving circuit; the first-stage amplifier circuit (3) receives an output signal of the quartz resonant beam chip (6), amplifies the signal and inputs the signal to the second-stage amplifier circuit (4); the second-stage amplifier circuit (4) performs secondary amplification on the signal and outputs the signal to the quartz resonant beam chip (6); The output shaping circuit (5) uses a hysteresis comparator to shape the signal output by the second-stage amplification circuit (4) into a standard square wave signal for external output.

2. The low noise and low temperature drift quartz resonant beam accelerometer driving circuit according to claim 1, characterized in that: The voltage-stabilized power supply module (1) comprises a direct current power supply, an LDO linear voltage-stabilized power supply chip and resistors R1 and R2; The negative pole of the DC power supply is grounded, and the positive pole is connected to the VIN terminal of the LDO linear voltage regulator chip. The OUT terminal of the LDO linear voltage regulator chip is connected to the resistor R1. The OUT terminal outputs current to the outside at the same time. The resistors R1 and R2 are connected in series, and the resistor R2 is grounded. The FB terminal of the LDO linear voltage regulator chip is connected between the resistors R1 and R2. The voltage regulator module (1) divides the output current through the resistors R1 and R2, and converts the input DC power Vin into the output voltage regulator Vcc. The conversion relationship is: V CC =(1+R1 / R2)·V in .

3. The low noise and low temperature drift quartz resonant beam accelerometer driving circuit according to claim 1, characterized in that: The first-stage amplifier circuit (3) comprises: two parallel-connected JFET junction field effect transistors Q1 and Q2, and resistors R4, R5, R6, R7, and R8; The gates of the JFET junction field effect transistors Q1 and Q2 both receive an output signal VIAout from a quartz resonant beam chip (6); the output Vcc of the voltage-stabilized power supply module (1) is connected to resistors R4 and R7; the resistor R4 is connected to the drain of the JFET junction field effect transistor Q1; the resistor R7 is connected to the drain of the JFET junction field effect transistor Q2; the source of the JFET junction field effect transistor Q1 is grounded via a resistor R5; the source of the JFET junction field effect transistor Q2 is grounded via a resistor R8; the gate bias voltages of the JFET junction field effect transistors Q1 and Q2 are provided via resistors R4 and R5 and resistors R7 and R8, respectively, and are set to a zero temperature coefficient point; the drain signal of the JFET junction field effect transistor Q1 is combined with the drain signal of the JFET junction field effect transistor Q2 via a small resistance resistor R6 for output.

4. The low noise and low temperature drift quartz resonant beam accelerometer driving circuit according to claim 3, characterized in that: The circuit gain A of the first stage amplifier circuit (3) is u1 For: A u1 =-g m ·R4, where g m The JFET junction field effect transistors Q1 and Q2 have the same transconductance.

5. The low noise and low temperature drift quartz resonant beam accelerometer driving circuit according to claim 1, characterized in that: The second-stage amplifier circuit (4) adopts a common-base Wolman circuit structure, and the second-stage amplifier circuit (4) comprises: NPN transistors Q3, Q4, resistors R9, R10, R11, R12; The output of the voltage-stabilized power supply module (1) is connected to resistors R9 and R11, and the NPN transistors Q3 and Q4 obtain base voltages through voltage division through resistors R9 and R10 and R11 and R12 respectively. The base of the NPN transistor Q4 receives the output signal of the first-stage amplifier circuit (3), the collector of the NPN transistor Q4 is connected to the emitter of the NPN transistor Q3, and the collector of the NPN transistor Q3 outputs a signal VIAin to the quartz resonant beam chip (6).

6. The low noise and low temperature drift quartz resonant beam accelerometer driving circuit according to claim 1, characterized in that: The output shaping circuit (5) receives the output signal VIAin of the second-stage amplifier circuit (4), and the output shaping circuit (5) comprises: a hysteresis comparator, resistors R16 and R17; The output Vcc of the voltage-stabilized power supply module (1) is divided by resistors R16 and R17 to form a reference voltage Vref which is input into the positive input terminal of the hysteresis comparator. The reference voltage Vref is also used as a DC bias of the AC signal output by the oscillation loop. The output signal VIAin of the second-stage amplifier circuit (4) is input into the negative input terminal of the hysteresis comparator. The output Vcc of the voltage-stabilized power supply module (1) supplies power to the hysteresis comparator, which outputs a square wave signal backward.

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