CN103471765B - Underwater dynamic pressure sensor signal conditioning circuit - Google Patents

Abstract

The invention discloses an underwater dynamic pressure sensor signal conditioning circuit. The underwater dynamic pressure sensor signal conditioning circuit comprises a power circuit, an amplification and filter circuit and an output interface circuit; the power circuit provides a stable +15V power supply and a stable -15V power supply for the amplification and filter circuit and provides a stable +10V power supply for a sensitive element of a pressure sensor; the amplification and filter circuit comprises a zero position and full volume debugging circuit and an 8-order Butterworth lowpass filter circuit, wherein a positive output signal V+ and a negative output signal V- of the sensitive element of the pressure sensor are input into the zero position and full volume debugging circuit, a voltage output signal Vout2 of the zero position and full volume debugging circuit is input into the 8-order Butterworth lowpass filter circuit, and a voltage signal output by the 8-order Butterworth lowpass filter circuit is input into the output interface circuit. The underwater dynamic pressure sensor signal conditioning circuit is wide in frequency response range, high in reliability and safety, and capable of realizing measurement of underwater dynamic pressure signals with the frequency band ranging from 0 kHz to 5 kHz.

Description

A kind of underwater dynamic pressure sensor signal conditioning circuit

Technical field

The invention belongs to electronic measuring technology field, be specifically related to a kind of underwater dynamic pressure sensor signal conditioning circuit.

Background technology

In fields such as space flight, aviation, weapon, boats and ships, pressure transducer is widely used.Gradual pressure signal mainly measured by general space telemetry pressure transducer, and Hz-KHz mostly is below 100Hz.Under some special measurement environment, as bubble collapse pressure under water, this compression shock rise time is fast, and the duration is short, and surge pressure is high, and frequency response generally can reach thousand hertz, i.e. so-called high frequency dynamic pressure.The measurement effects on surface loading analysis of dynamic pressure signal and verify significant.

Summary of the invention

Technical matters to be solved by this invention is: provide a kind of reliability and the high underwater dynamic pressure sensor signal conditioning circuit of security, is used for coupling to adopt and be bordering on the thin film strain formula pressure-sensing device flushing installation; The dynamic pressure signal measurement under water of 0-5kHz frequency range can be realized.

Technical scheme of the present invention is:

A kind of underwater dynamic pressure sensor signal conditioning circuit, comprises power circuit, filtering and amplifying circuit and output interface circuit, and power circuit provides stable+15V and-15V power supply for filtering and amplifying circuit; The sensitive element that power circuit is pressure transducer provides stable+10V power supply; Filtering and amplifying circuit comprises zero-bit and completely measures debug circuit and 8 rank Butterworth low pass wave circuits, the positive output signal V of the sensitive element of pressure transducer ₊, negative output signal V _-input to zero-bit respectively and completely measure debug circuit, zero-bit and the voltage output signal Vout2 completely measuring debug circuit input to 8 rank Butterworth low pass wave circuits, and the filtered voltage signal that 8 rank Butterworth low pass wave circuits export inputs to described output interface circuit;

Power circuit comprises commutation diode V1-V2, resistance R1-R2, electric capacity C1-C8, three end reference source G1, + 15VIN the end of power supply is connected with the anode of commutation diode V1, the negative electrode of commutation diode V1 is connected with one end of resistance R1, the other end of resistance R1 respectively with the input end of three end reference source G1, one end of electric capacity C2, one end of electric capacity C3 is connected, by+15V the power supply of one end stable output of described electric capacity C3, hold with the GND of power supply after the other end of electric capacity C2 is connected with the other end of electric capacity C3 and be connected, the other end of electric capacity C2 is connected with one end of electric capacity C7, the other end of electric capacity C7 is connected with one end of resistance R2, the other end of electric capacity C3 is connected with one end of electric capacity C8, the other end of electric capacity C8 is connected with one end of resistance R2, by-15V the power supply of the other end stable output of described electric capacity C8, the other end of resistance R2 is connected with the anode of commutation diode V2, the negative electrode of commutation diode V2 is held with-the 15VIN of power supply and is connected, + 15VIN the end of power supply connects mechanically JXD by electric capacity C1,-15VIN the end of power supply connects mechanically JXD by electric capacity C6, the GND end of power supply connects mechanically JXD by electric capacity C5, by+10V the power supply of the output terminal stable output of three end reference source G1, the output terminal of three end reference source G1 is connected with the ground end of three end reference source G1 by electric capacity C4, the ground end of three end reference source G1 is held with the GND of power supply and is connected,

Zero-bit and completely amount debug circuit comprise the differential amplifier circuit debugged for zero-bit and the see-saw circuit of debugging for full amount, and wherein said differential amplifier circuit comprises resistance R3-R7, resistance R6T, amplifier N1A; Described see-saw circuit comprises resistance R8-R11, resistance R10T, electric capacity C9 and amplifier N1B; The negative output terminal V of sensitive element of pressure sensor _-be connected with the negative input end of amplifier N1A by resistance R3, simultaneously the negative input end of amplifier N1A be connected with the output terminal of amplifier N1A by resistance R5, the positive output end V of sensitive element ₊be connected with the positive input terminal of amplifier N1A by resistance R4, simultaneously the positive input terminal of amplifier N1A is connected with one end of resistance R6, and the other end of resistance R6 is connected with resistance R6T and R7 ground connection afterwards; The output terminal of amplifier N1A is connected with the positive input terminal of amplifier N1B by resistance R8, and the negative input end of amplifier N1B is connected with one end of resistance R9, the other end ground connection of resistance R9; The negative input end of amplifier N1B is connected with the output terminal of amplifier N1B by electric capacity C9; The output terminal of amplifier N1B is connected with one end of resistance R11, exports zero-bit and completely measure the output signal Vout2 of debug circuit by the other end of resistance R11; The negative input end of amplifier N1B is connected with one end of resistance R10, and the other end of resistance R10 is connected with one end of resistance R10T, and the other end of resistance R10T is connected with the other end of described resistance R11;

Described 8 rank Butterworth low pass wave circuits are in series by level Four 2 rank Butterworth LPF, the first to the third level 2 rank Butterworth LPF adopts second order unity gain voltage controlled voltage source type filtering circuit of the same type, and the fourth stage 2 rank Butterworth LPF increases the anti-self-excited circuit be made up of electric capacity C18 and resistance R20 on the basis of second order unity gain voltage controlled voltage source type filtering circuit; The negative input end of the amplifier N2D of the fourth stage 2 rank Butterworth LPF is connected with the output terminal of amplifier N2D by electric capacity C18, and the output terminal of amplifier N2D is by the voltage signal after resistance R20 output filtering;

Output interface circuit comprises voltage adjustment diode V3, silicon Schotty diode V4, current-limiting resistance R21 and electric capacity C19; The negative electrode of voltage adjustment diode V3, silicon Schotty diode V4 is connected with filtered voltage signal respectively, and the anode of voltage adjustment diode V3, silicon Schotty diode V4 connects the GND end of power supply respectively; One end of current-limiting resistance R21 is connected with filtered signal, and the other end of current-limiting resistance R21 is connected with one end of electric capacity C19, and the other end of electric capacity C19 meets mechanically JXD, and one end of wherein said electric capacity C19 is as the signal output part of signal conditioning circuit.

Electric capacity C1, C5, C6 are radioceramic Jie small capacitances; Electric capacity C2, C7 are tantalum electric capacity, and electric capacity C3, C8 are radioceramic Jie small capacitances, and electric capacity C19 is radioceramic Jie small capacitances.

The present invention's advantage is compared with prior art:

(1) Hz-KHz is wide.The present invention measures mainly for bubble collapse dynamic pressure signal.This pressure signal rise time is fast, and the duration is short, and surge pressure is high, and this just requires that signal conditioning circuit has higher Hz-KHz.Signal conditioning circuit of the present invention adopts 8 rank Butterworth low pass wave circuits, devises 5kHz low-pass filter circuit, and ensures the flatness in passband and attenuation outside a channel speed as far as possible.

(2) there is higher reliability and security.The present invention has taken into full account the environment service factor of circuit when designing.First carry out anti-reverse, current limliting, voltage stabilizing, decoupling equistability process to power supply, secondly operational amplifier adds anti-self-excited circuit, and at output terminal Finite Amplitude and isolation circuit.By these effective measures, improve reliability and the security of circuit.

Accompanying drawing explanation

Fig. 1 is underwater dynamic pressure sensor signal conditioning circuit theory diagram of the present invention;

Fig. 2 is power circuit schematic diagram;

Fig. 3 is zero-bit and completely measures debug circuit schematic diagram;

Fig. 4 is 8 rank Butterworth low pass wave circuit schematic diagram;

Fig. 5 is output interface circuit schematic diagram.

Embodiment

Just by reference to the accompanying drawings the present invention is described further below.

As shown in Figure 1, signal conditioning circuit of the present invention mainly comprises power circuit, filtering and amplifying circuit, output interface circuit.The ripple existed in power circuit suppression electric power system and interference, for signal conditioning circuit and sensitive element provide stable ± 15V and+10V power supply.Filtering and amplifying circuit adopt zero-bit and completely measure debug circuit, the output of voltage that the small-signal that sensitive element exports is nursed one's health into (0 ~ 5) V by 8 rank Butterworth low pass wave circuits, and there is amplitude-frequency and the phase-frequency characteristic of corresponding requirements.The security of system input interface that output interface circuit utilizes amplitude limiter circuit and isolation circuit to ensure that output interface circuit and match.

As shown in Figure 2, power circuit comprises commutation diode V1-V2, resistance R1-R2, electric capacity C1-C8, three end reference source G1, + 15VIN the end of power supply is connected with the anode of commutation diode V1, the negative electrode of commutation diode V1 is connected with one end of resistance R1, the other end of resistance R1 respectively with the input end of three end reference source G1, one end of electric capacity C2, one end of electric capacity C3 is connected, by+15V the power supply of one end stable output of described electric capacity C3, hold with the GND of power supply after the other end of electric capacity C2 is connected with the other end of electric capacity C3 and be connected, the other end of electric capacity C2 is connected with one end of electric capacity C7, the other end of electric capacity C7 is connected with one end of resistance R2, the other end of electric capacity C3 is connected with one end of electric capacity C8, the other end of electric capacity C8 is connected with one end of resistance R2, by-15V the power supply of the other end stable output of described electric capacity C8, the other end of resistance R2 is connected with the anode of commutation diode V2, the negative electrode of commutation diode V2 is held with-the 15VIN of power supply and is connected, + 15VIN the end of power supply connects mechanically JXD by electric capacity C1,-15VIN the end of power supply connects mechanically JXD by electric capacity C6, the GND end of power supply connects mechanically JXD by electric capacity C5, by+10V the power supply of the output terminal stable output of three end reference source G1, the output terminal of three end reference source G1 is connected with the ground end of three end reference source G1 by electric capacity C4, the ground end of three end reference source G1 is held with the GND of power supply and is connected.Wherein commutation diode V1 and V2, effectively can prevent the infringement that+15VIN and-15VIN reverse power connection bring circuit.And diode has the characteristic of one-way conduction, so V1 and V2 also has certain ability reducing power supply differential mode interference signal.+ the 15VIN ,-15VIN of power supply are connected mechanically JXD with GND by radioceramic Jie small capacitances C1, C5, C6, the high frequency interference that such method of attachment can exist in filter out power.Resistance R1 and R2 is current-limiting resistance, when there is instantaneous high pressure in circuit, can reduce the momentary current in circuit, can prevent big current in circuit from moving back in power supply simultaneously.Electric capacity C2, C3, C7, C8 have decoupling effect, and wherein C2, C7 are tantalum electric capacity, and C3, C8 are radioceramic Jie small capacitances.Radioceramic Jie small capacitances can absorb the high frequency interference of MHz magnitude, and tantalum electric capacity can absorb the undesired signal of kHz magnitude.Three end reference source G1 and decoupling capacitor C4 can provide+10V reference voltage source accurately for pressure-sensing device, and G1 such as can adopt the reference source chip AD581SH of ADI company.

As shown in Figure 3, zero-bit of the present invention and completely measure debug circuit, comprise the differential amplifier circuit for zero-bit debugging and the see-saw circuit of debugging for full amount, wherein said differential amplifier circuit comprises resistance R3-R7, resistance R6T, amplifier N1A; Described see-saw circuit comprises resistance R8-R11, resistance R10T, electric capacity C9 and amplifier N1B; The negative output terminal V of sensitive element of pressure sensor _-be connected with the negative input end of amplifier N1A by resistance R3, simultaneously the negative input end of amplifier N1A be connected with the output terminal of amplifier N1A by resistance R5, the positive output end V of sensitive element ₊be connected with the positive input terminal of amplifier N1A by resistance R4, simultaneously the positive input terminal of amplifier N1A is connected with one end of resistance R6, and the other end of resistance R6 is connected with resistance R6T and R7 ground connection afterwards; The output terminal of amplifier N1A is connected with the positive input terminal of amplifier N1B by resistance R8, and the negative input end of amplifier N1B is connected with one end of resistance R9, the other end ground connection of resistance R9; The negative input end of amplifier N1B is connected with the output terminal of amplifier N1B by electric capacity C9; The output terminal of amplifier N1B is connected with one end of resistance R11, exports zero-bit and completely measure the output signal Vout2 of debug circuit by the other end of resistance R11; The negative input end of amplifier N1B is connected with one end of resistance R10, and the other end of resistance R10 is connected with one end of resistance R10T, and the other end of resistance R10T is connected with the other end of described resistance R11.Output capacitor C9 and resistance R11 forms the phase compensation link of amplifying circuit, effectively can prevent the generation of amplifying circuit self-excitation phenomena.In circuit, Vout1, Vout2 computation process is:

$V_{\mathrm{out}1}=-\frac{R_5}{R_3}{V}_{-}+(1+\frac{R_5}{R_3})\frac{R_6+R_{6T}+R_7}{R_6+R_{6T}+R_7+R_4}{V}_{+}...\left(1\right)$

$V_{\mathrm{out}2}=(1+\frac{R_{10}+R_{10T}}{R_9})V_{\mathrm{out}1}...\left(2\right)$

R5=R7, R3=R4 in formula.R6, R6T, R10, R10T are adjusting resistance, can replace during adjustment with potentiometer.When circuit is input as the zero-bit of sensitive element or full amount exports, adjustment R6, R6T, R10, R10T make Vout2 meet the output requirement of zero-bit and full amount simultaneously.

As shown in Figure 4,8 rank Butterworth low pass wave circuits of the present invention are in series by level Four 2 rank Butterworth LPF, the first to the third level 2 rank Butterworth LPF adopts second order unity gain voltage controlled voltage source type filtering circuit of the same type, and each second order unity gain voltage controlled voltage source type filtering circuit is made up of two resistance, two electric capacity and an amplifier; The fourth stage 2 rank Butterworth LPF increases the anti-self-excited circuit be made up of electric capacity C18 and resistance R20 on the basis of second order unity gain voltage controlled voltage source type filtering circuit; The negative input end of the amplifier N2D of the fourth stage 2 rank Butterworth LPF is connected with the output terminal of amplifier N2D by electric capacity C18, and the output terminal of amplifier N2D is by the voltage signal after resistance R20 output filtering.For meeting the frequency response requirement of hydrodynamic pressure signal kHz rank, the filtering parameter account form of each low-pass filter circuit is identical, and first filtering circuit parameter calculation procedure is:

${\mathrm{\ω}}_0=\frac{1}{\sqrt{R_{12}{R}_{13}{C}_{10}{C}_{11}}}...\left(3\right)$

$Q=\frac{R_{12}{R}_{13}{C}_{10}}{R_{12}+R_{13}}*{\mathrm{\ω}}_0...\left(4\right)$

ω in formula ₀for natural frequency, Q is quality factor.In actual use, the size of nominal resistance, capacitance can be determined by Filter solutions filter circuit design software, Multisim circuit simulating software is utilized to carry out frequency response emulation, and come adjusting resistance, capacitance according to the amplitude versus frequency characte measured and phase-frequency characteristic, the amplitude-frequency of circuit and phase frequency parameter are met the demands.

The output terminal of the fourth stage 2 rank Butterworth LPF is made up of the phase compensation link of filtering circuit electric capacity C18 and resistance R20, effectively can prevent the generation of amplifying circuit self-excitation phenomena.

As shown in Figure 5, output interface circuit of the present invention comprises voltage adjustment diode V3, silicon Schotty diode V4, current-limiting resistance R21 and electric capacity C19; The negative electrode of voltage adjustment diode V3, silicon Schotty diode V4 is connected with filtered voltage signal respectively, and the anode of voltage adjustment diode V3, silicon Schotty diode V4 connects the GND end of power supply respectively; One end of current-limiting resistance R21 is connected with filtered signal, and the other end of current-limiting resistance R21 is connected with one end of electric capacity C19, and the other end of electric capacity C19 meets mechanically JXD, and one end of wherein said electric capacity C19 is as the signal output part of signal conditioning circuit.Voltage adjustment diode V3 and silicon Schotty diode V4 forms amplitude limiter circuit, and when exceeding specialized range when the abnormal saltus step of circuit output voltage, amplitude limiter circuit can, by its clamper within the scope of limiting voltage, avoid output voltage to exceed the magnitude of voltage of requirement.When in output interface circuit short circuit or misconnection during large voltage, current-limiting resistance R21 can absorb most electric current, prevents burning out of whole circuit.Electric capacity C19 is radioceramic Jie small capacitances C19, has decoupling effect, the high-frequency interferencing signal that can effectively exist in filtering output voltage.

The unspecified part of the present invention belongs to general knowledge as well known to those skilled in the art.

Claims (2)

1. a underwater dynamic pressure sensor signal conditioning circuit, it is characterized in that, modulate circuit comprises power circuit, filtering and amplifying circuit and output interface circuit, power circuit provides stable+15V and-15V power supply for filtering and amplifying circuit, and provides stable+10V power supply for the sensitive element of pressure transducer; Filtering and amplifying circuit comprises zero-bit and completely measures debug circuit and 8 rank Butterworth low pass wave circuits, the positive output signal V of the sensitive element of pressure transducer ₊, negative output signal V _-input to zero-bit and completely measure debug circuit, zero-bit and the voltage output signal Vout2 completely measuring debug circuit input to 8 rank Butterworth low pass wave circuits, and the voltage signal that 8 rank Butterworth low pass wave circuits export inputs to described output interface circuit;

Power circuit comprises commutation diode V1-V2, resistance R1-R2, electric capacity C1-C8, three end reference source G1, + 15VIN the end of power supply is connected with the anode of commutation diode V1, the negative electrode of commutation diode V1 is connected with one end of resistance R1, the other end of resistance R1 respectively with the input end of three end reference source G1, one end of electric capacity C2, one end of electric capacity C3 is connected, by+15V the power supply of one end stable output of described electric capacity C3, hold with the GND of power supply after the other end of electric capacity C2 is connected with the other end of electric capacity C3 and be connected, the other end of electric capacity C2 is connected with one end of electric capacity C7, the other end of electric capacity C7 is connected with one end of resistance R2, the other end of electric capacity C3 is connected with one end of electric capacity C8, the other end of electric capacity C8 is connected with one end of resistance R2, by-15V the power supply of the other end stable output of described electric capacity C8, the other end of resistance R2 is connected with the anode of commutation diode V2, the negative electrode of commutation diode V2 is held with-the 15VIN of power supply and is connected, + 15VIN the end of power supply connects mechanically JXD by electric capacity C1,-15VIN the end of power supply connects mechanically JXD by electric capacity C6, the GND end of power supply connects mechanically JXD by electric capacity C5, by+10V the power supply of the output terminal stable output of three end reference source G1, the output terminal of three end reference source G1 is connected with the ground end of three end reference source G1 by electric capacity C4, the ground end of three end reference source G1 is held with the GND of power supply and is connected,

Zero-bit and completely amount debug circuit comprise the differential amplifier circuit debugged for zero-bit and the see-saw circuit of debugging for full amount, and wherein said differential amplifier circuit comprises resistance R3-R7, resistance R6T, amplifier N1A; Described see-saw circuit comprises resistance R8-R11, resistance R10T, electric capacity C9 and amplifier N1B; The negative output signal V of sensitive element of pressure sensor _-be connected with the negative input end of amplifier N1A by resistance R3, simultaneously the negative input end of amplifier N1A be connected with the output terminal of amplifier N1A by resistance R5, the positive output signal V of sensitive element ₊be connected with the positive input terminal of amplifier N1A by resistance R4, simultaneously the positive input terminal of amplifier N1A is connected with one end of resistance R6, and the other end of resistance R6 connects power supply GND after connecting with resistance R6T and R7 holds; The output terminal of amplifier N1A is connected with the positive input terminal of amplifier N1B by resistance R8, and the negative input end of amplifier N1B is connected with one end of resistance R9, the GND end of another termination power supply of resistance R9; The negative input end of amplifier N1B is connected with the output terminal of amplifier N1B by electric capacity C9; The output terminal of amplifier N1B is connected with one end of resistance R11, exports zero-bit and completely measure the output signal Vout2 of debug circuit by the other end of resistance R11; The negative input end of amplifier N1B is connected with one end of resistance R10, and the other end of resistance R10 is connected with one end of resistance R10T, and the other end of resistance R10T is connected with the other end of described resistance R11;

Described 8 rank Butterworth low pass wave circuits are in series by level Four 2 rank Butterworth LPF, the first to the third level 2 rank Butterworth LPF adopts second order unity gain voltage controlled voltage source type filtering circuit of the same type, and the fourth stage 2 rank Butterworth LPF increases the anti-self-excited circuit be made up of electric capacity C18 and resistance R20 on the basis of second order unity gain voltage controlled voltage source type filtering circuit; The negative input end of the amplifier N2D of the fourth stage 2 rank Butterworth LPF is connected with the output terminal of amplifier N2D by electric capacity C18, and the output terminal of amplifier N2D is by the voltage signal after resistance R20 output filtering;

Output interface circuit comprises voltage adjustment diode V3, silicon Schotty diode V4, current-limiting resistance R21 and electric capacity C19; The negative electrode of voltage adjustment diode V3, silicon Schotty diode V4 is connected with filtered voltage signal respectively, and the anode of voltage adjustment diode V3, silicon Schotty diode V4 connects the GND end of power supply respectively; One end of current-limiting resistance R21 is connected with filtered signal, and the other end of current-limiting resistance R21 is connected with one end of electric capacity C19, and the other end of electric capacity C19 meets mechanically JXD, and one end of wherein said electric capacity C19 is as the signal output part of signal conditioning circuit.

2. a kind of underwater dynamic pressure sensor signal conditioning circuit according to claim 1, is characterized in that, electric capacity C1, C5, C6 are radioceramic Jie small capacitances; Electric capacity C2, C7 are tantalum electric capacity, and electric capacity C3, C8 are radioceramic Jie small capacitances, and electric capacity C19 is radioceramic Jie small capacitances.