Charge amplifier circuit with adjustable multiples

Abstract

The utility model belongs to the technical field of charge signal processing, and particularly relates to a multiple-adjustable charge amplifier circuit, which comprises a low-pass filter circuit, an integral negative feedback amplification circuit, a high-pass filter circuit, a voltage amplification circuit and a double-T-shaped wave trap circuit, wherein the low-pass filter circuit is used for filtering a high-frequency signal of a charge signal; the integral negative feedback amplification circuit is used for converting the charge signal into a charge voltage signal; the high-pass filter circuit is used for filtering low-frequency signals; the voltage amplifying circuit is used for amplifying the charge voltage signal; the double-T-shaped wave trap circuit is used for filtering power frequency interference. The charge amplifier solves the problems that the amplification factor of the charge amplifier is adjustable, the impedance of the charge amplifier is large, and the charge amplifier is easily interfered by power frequency radiation or other noises.

Description

Technical Field

[0001] This invention belongs to the field of charge signal processing technology, and particularly relates to a charge amplifier circuit with adjustable multiple. Background Technology

[0002] Since the discovery of materials with piezoelectric properties, the exploration of piezoelectric detection has never stopped. With the increasing requirements of sensing technology, more and more piezoelectric sensors have been applied in different fields, especially the rapid development of new energy, which has brought about a huge market.

[0003] Charge amplifiers are an essential component of piezoelectric ceramic sensors. When piezoelectric ceramics are subjected to changes in pressure, they release charges of varying magnitudes. These charge signals must ultimately be converted into voltage signals before they can be used by subsequent processors.

[0004] Traditional charge amplifier circuits are large, complex, expensive, and not universal; the same piezoelectric sensor can detect small forces in some applications but large forces in others, so charge amplifiers need to have adjustable amplification factor; charge amplifiers are highly susceptible to power frequency radiation interference or other noise due to their high impedance. Utility Model Content

[0005] Addressing the problems of existing technologies: This utility model solves the problems of adjustable amplification factor of charge amplifiers, high impedance of charge amplifiers, and susceptibility to power frequency radiation interference or other noise.

[0006] The technical solution adopted in this utility model is: a charge amplifier circuit with adjustable multiple, comprising: a low-pass filter circuit, an integral negative feedback amplifier circuit, a high-pass filter circuit, a voltage amplifier circuit, and a double-T notch filter circuit; wherein,

[0007] Low-pass filter circuits are used for high-frequency filtering of charge signals;

[0008] Integral negative feedback amplifier circuits are used to convert charge signals into charge voltage signals;

[0009] High-pass filter circuits are used for low-frequency filtering in charged voltage signals;

[0010] Voltage amplifier circuits are used to amplify low-frequency filtered load voltage signals;

[0011] A double-T notch filter circuit is used to filter out power frequency interference.

[0012] Furthermore, the low-pass filter circuit includes: resistor R5, capacitors C18 and C20, and bidirectional diode U3. The right end of R5 is connected to the left end of C18, and the right end of C18 is connected to the lower end of U3 and the upper end of C20, respectively.

[0013] Furthermore, the integral negative feedback amplifier circuit includes: operational amplifier U4A, capacitor C17, resistors R2 and R8. R2 and C17 are connected in parallel, and their two ends are connected to the inverting input and output of U4A, respectively. The non-inverting input of U4A is connected to the upper end of R8, and the lower end of R8 is connected to the lower end of C20.

[0014] Furthermore, the high-pass filter circuit includes: resistor R19 and C30, the right end of C30 is connected to the upper end of R19, the lower end of R19 is grounded, and the left end of C30 is connected to the output terminal of U4A.

[0015] Furthermore, the voltage amplifier circuit includes: resistors R3 and R6, adjustable resistor R4, capacitors C29 and C19, and operational amplifier U4B. The lower end of C29 is connected to the upper end of R3. The lower end of R3 is connected to the left end of R4 and the inverting input terminal of U4B. The output terminal of U4B is connected to the right end of R4 and the left end of R6. The right end of R6 is connected to the upper end of C19.

[0016] Furthermore, the double-T notch filter circuit includes: capacitors C22 to C25, adjustable resistors R11, R16, R17, R13, resistors R9, R14, R15, R20, operational amplifiers U5A and U5B. The left end of C22 is connected to the left end of R14, the right end of R14 is connected to the left end of R16, the right end of R16 is connected to the lower ends of C24 and C25, and the left end of R15, the right end of C22 is connected to the left end of C23, and the upper end of R9, and the lower end of R9 is connected to R11. The upper end of R11 is connected to the common upper end of C24 and C25, and the output of U5B. The right end of R15 is connected to the left end of R17. The right end of R17 is connected to the right end of C23 and the non-inverting input of U5A. The inverting input of U5A is connected to the output of U5A and the upper end of R10. The lower end of R10 is connected to the non-inverting input of U5B and the upper end of R20. The lower end of R20 is connected to the upper end of R13. The inverting input and output of U5B are connected.

[0017] Furthermore, the operational amplifier is model AD8616.

[0018] Furthermore, it also includes the power supply circuit.

[0019] Furthermore, the power supply circuit uses a voltage regulator chip VR2.

[0020] Furthermore, the output voltage of the power supply circuit is +9V and -9V.

[0021] The beneficial effects of this utility model are:

[0022] 1. The design integrates charge conversion, amplification speed adjustment, and filtering, resulting in a compact structure;

[0023] 2. The use of multi-turn precision adjustable resistors enables adjustable amplification, making the amplifier more widely applicable;

[0024] 3. An active double-T filter circuit was used, which increased the system's anti-interference capability. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the adjustable charge amplifier circuit system of this utility model;

[0026] Figure 2 This is the charge amplification circuit diagram of this utility model;

[0027] Figure 3 This is the circuit diagram of the double-T notch filter of this utility model;

[0028] Figure 4 This is the circuit diagram of the charge amplification power supply of this utility model. Detailed Implementation

[0029] The embodiments of this utility model will be further described in detail below with reference to the accompanying drawings:

[0030] like Figure 1 This utility model discloses a charge amplifier circuit with adjustable multiplier, comprising: a low-pass filter circuit, an integral negative feedback amplifier circuit, a high-pass filter circuit, a voltage amplifier circuit, and a dual-T notch filter circuit. The low-pass filter circuit is electrically connected sequentially to the integral negative feedback amplifier circuit, the high-pass filter circuit, the voltage amplifier circuit, and the dual-T notch filter circuit.

[0031] Low-pass filter circuits are used for high-frequency signal filtering of charge signals;

[0032] Integral negative feedback amplifier circuits are used to convert charge signals into charge voltage signals;

[0033] High-pass filter circuits are used to filter low-frequency signals;

[0034] Voltage amplifier circuits are used to amplify voltage-loaded signals;

[0035] A double-T notch filter circuit is used to filter out power frequency interference.

[0036] like Figure 2 The low-pass filter circuit includes: coaxial connector J1, capacitors C18 and C20, resistor R5, and bidirectional diode U3. The charge signal generated by the piezoelectric sensor is input through J1. One end of J1 is connected to R5 and C18 respectively. The right end of C18 is connected to one end of U3 and one end of C20 respectively. The upper end of U3 is connected to +9V and -9V voltages. The other end of C20 is connected to the COAX-P terminal of J1.

[0037] The integral negative feedback amplifier circuit includes: operational amplifier U4A, capacitor C17, resistor R2 and resistor R8. R2 and C17 are connected in parallel, and their two ends are connected to the inverting input terminal and the output terminal of U4A, respectively. The upper end of R8 is connected to the non-inverting input terminal of U4A, and the lower end of R8 is connected to the lower end of C20 and the COAX-F terminal of J1 and then grounded.

[0038] The high-pass filter circuit includes: capacitor C20 and resistor R19. The left end of C30 is connected to the output terminal of U4A, the right end of C20 is connected to the upper end of R19, and the lower end of R19 is grounded.

[0039] The voltage amplifier circuit includes: resistors R3 and R6, capacitors C29 and C19, adjustable resistor R4, and operational amplifier U4B. The right end of R19 is connected to the non-inverting input of U4B. The common terminal of R4 and R3 is connected to the inverting input of U4B. The upper end of R3 is connected to C29 and then grounded. The right end of R4 is connected to the output of U4B and the left end of R6. The right end of R6 is connected to the upper end of C19. The upper end of C19 is connected to a dual T-type notch filter circuit.

[0040] like Figure 3 The dual-T notch filter circuit includes: capacitors C22 to C25, adjustable resistors R11, R16, R17, R13, resistors R9, R14, R15, R20, operational amplifiers U5A and U5B, and coaxial connector J2. The left end of C22 is connected to the left end of R14, the right end of R14 is connected to the left end of R16, the right end of C22 is connected to the upper end of R9 and the left end of C23, the lower end of R9 is connected to the upper end of R11, the lower end of R11 is connected to the upper ends of C24 and C25, and the output terminal of U5B. C24 and The lower end of C25 is connected to the right end of R16 and the left end of R15. The right end of R15 is connected to the left end of R17. The right end of R17 is connected to the right end of C23 and the non-inverting input of U5A. The inverting input of U5A is connected to the output of U5A, the upper end of R10, and the input of J2. The lower end of R10 is connected to the non-inverting input of U5B and the upper end of R20. The lower end of R20 is connected to the upper end of R13. The lower end of R20 is connected to the upper end of R13. The lower end of R13 is connected to the COAXF terminal of J2.

[0041] The operational amplifiers U4 and U5 are model AD8616.

[0042] like Figure 4It also includes a power supply circuit that provides 9V to the charge amplifier circuit. The power supply circuit includes: polarized capacitors C15, C21, C27, C28, capacitors C26, C5, C6, C16, magnetic core inductor L1, voltage regulator chip VR2, resistors R7 and R18. The two ends of C15 are connected to the 2nd and 4th pins of VR2, respectively. The 7th pin of VR2 is connected to the upper end of C16 and the left end of R7, respectively. The lower ends of C16 and R7 are grounded. The 6th pin of VR2 is connected to R18 and outputs a +9V voltage. The 5th pin of VR2 is connected to the common terminal of C26, C21, and L1, respectively. The lower ends of C26 and C21 are connected to the lower ends of C27, C28, C5, and C6 and then grounded. The right end of L1 is connected to the common upper end of C27, C28, C5, and C6, and the output is -9V.

[0043] Working principle:

[0044] The charge signal enters the circuit through coaxial connector J1. R5, C18, and C20 form a low-pass filter to filter high-frequency signals. The signal flows into the negative input terminal of op-amp U4A. U4A, R2, C17, and R8 form an integrating negative feedback amplifier circuit. R2 is a 1G high-value resistor. After amplification by this stage, the charge signal is converted into a voltage signal. It then passes through a high-pass filter composed of C30 and R19 to filter low-frequency signals. The signal then enters the intermediate inverting proportional amplifier U4B to amplify the voltage signal. R4 is a multi-turn precision adjustable resistor, which allows for stepless adjustment of the voltage multiplier. The last stage of the circuit consists of an active double-T notch filter composed of U5A and U5B, with its center frequency set to 50Hz. This filter is mainly used to filter out power frequency interference. The final processed signal is output through coaxial connector J2.

[0045] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A charge amplifier circuit with adjustable multiple, characterized in that, include: The circuit includes a low-pass filter, an integral negative feedback amplifier, a high-pass filter, a voltage amplifier, and a double-T notch filter; among which, Low-pass filter circuits are used for high-frequency filtering of charge signals; Integral negative feedback amplifier circuits are used to convert charge signals into charge voltage signals; High-pass filter circuits are used for low-frequency filtering in charged voltage signals; Voltage amplifier circuits are used to amplify low-frequency filtered load voltage signals; A double-T notch filter circuit is used to filter out power frequency interference.

2. The charge amplifier circuit with adjustable multiple as described in claim 1, characterized in that, The voltage amplifier circuit includes: resistors R3 and R6, adjustable resistor R4, capacitors C29 and C19, and operational amplifier U4B. The lower end of C29 is connected to the upper end of R3. The lower end of R3 is connected to the left end of R4 and the inverting input terminal of U4B. The output terminal of U4B is connected to the right end of R4 and the left end of R6. The right end of R6 is connected to the upper end of C19.

3. The charge amplifier circuit with adjustable multiple as described in claim 1, characterized in that: The double-T notch filter circuit includes: capacitors C22 to C25, adjustable resistors R11, R16, R17, R13, resistors R9, R14, R15, R20, and operational amplifiers U5A and U5B. The left end of C22 is connected to the left end of R14, and the right end of R14 is connected to the left end of R16. The right end of R16 is connected to the lower ends of C24 and C25, and the left end of R15. The right end of C22 is connected to the left end of C23 and the upper end of R9. The lower end of R9 is connected to the upper end of R11. The lower end of R11 is connected to the common upper end of C24 and C25, and the output terminal of U5B. The right end of R15 is connected to the left end of R17. The right end of R17 is connected to the right end of C23 and the non-inverting input terminal of U5A. The inverting input terminal of U5A is connected to the output terminal of U5A and the upper end of R10. The lower end of R10 is connected to the non-inverting input terminal of U5B and the upper end of R20. The lower end of R20 is connected to the upper end of R13. The inverting input terminal and the output terminal of U5B are connected.

4. The charge amplifier circuit with adjustable multiple as described in claim 1, characterized in that, The low-pass filter circuit includes: resistor R5, capacitors C18 and C20, and bidirectional diode U3. The right end of R5 is connected to the left end of C18, and the right end of C18 is connected to the lower end of U3 and the upper end of C20.

5. The charge amplifier circuit with adjustable multiple as described in claim 1, characterized in that, The integral negative feedback amplifier circuit includes: operational amplifier U4A, capacitor C17, resistors R2 and R8. R2 and C17 are connected in parallel, and their two ends are connected to the inverting input and output of U4A, respectively. The non-inverting input of U4A is connected to the upper end of R8, and the lower end of R8 is connected to the lower end of C20.

6. The charge amplifier circuit with adjustable multiple as described in claim 1, characterized in that, The high-pass filter circuit includes: resistor R19 and C30. The right end of C30 is connected to the upper end of R19, the lower end of R19 is grounded, and the left end of C30 is connected to the output terminal of U4A.

7. The charge amplifier circuit with adjustable multiple as described in any one of claims 2, 3, and 5, characterized in that, The operational amplifier is model AD8616.

8. The charge amplifier circuit with adjustable multiple as described in claim 1, characterized in that, It also includes the power supply circuit.

9. The charge amplifier circuit with adjustable multiple as described in claim 8, characterized in that, The power supply circuit uses the VR2 voltage regulator chip.

10. The charge amplifier circuit with adjustable multiple as described in claim 9, characterized in that, The power supply circuit outputs +9V and -9V.

Images