High-precision magnetostrictive sensor high-voltage excitation circuit based on monostable trigger.

Abstract

This invention relates to a high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable multivibrator, comprising a power supply circuit, an excitation signal generation circuit, and a waveguide wire. The output terminal of the power supply circuit is electrically connected to the input terminal of the excitation signal generation circuit, and the output terminal of the excitation signal generation circuit is electrically connected to one end of the waveguide wire. The other end of the waveguide wire is electrically connected to an external fixed power supply. This invention provides a stable 5V voltage through the power supply and boosts the 5V to 150V through the excitation signal generation circuit, effectively enhancing the amplitude of the excitation signal, improving the magnetostrictive effect of the waveguide wire, and resulting in a stronger induced echo signal amplitude. Furthermore, the excitation signal generation circuit controls the excitation pulse width with higher precision, achieving a pulse width accuracy of ±0.1μs, which is 50 times higher than existing technologies. One end of the waveguide wire is connected to the boosted excitation source, and the other end is connected to the external fixed power supply. When the excitation signal generation circuit is closed, the voltage on the waveguide wire forms a freewheeling loop, reducing power consumption.

Description

Technical Field

[0001] This invention relates to the field of electronic circuit technology, and in particular to a high-voltage excitation circuit for a high-precision magnetostrictive sensor based on a monostable trigger. Background Technology

[0002] Magnetostrictive sensors are displacement measurement devices that operate based on the magnetostrictive effect, and their technological development is closely related to advancements in materials science and electromagnetic theory.

[0003] The excitation signal is the "start signal" for the magnetostrictive sensor to achieve displacement measurement, and its specific function is as follows:

[0004] 1. Triggering the magnetostrictive effect

[0005] The excitation signal is typically a current pulse of a specific frequency, which generates a toroidal magnetic field when passing through the waveguide wire of the sensor. This magnetic field interacts with the axial magnetic field generated by the "position magnetic ring" on the sensor (which moves with the measured object), exciting torsional mechanical waves in the waveguide wire based on the magnetostrictive effect, providing a physical signal source for subsequent displacement calculations.

[0006] 2. Ensure measurement accuracy and stability

[0007] The frequency, amplitude, and pulse width of the excitation signal must be strictly matched with the waveguide wire material properties to avoid signal distortion or energy loss and ensure the stable propagation speed of the torsional wave (usually close to the speed of sound).

[0008] Reasonable excitation signal parameters can reduce the impact of environmental interference (such as temperature and electromagnetic noise) on the measurement, ensuring high accuracy in complex industrial environments.

[0009] 3. The core of achieving non-contact measurement

[0010] The excitation signal interacts with the magnetic field of the position magnetic ring without physical contact, so the sensor can work in harsh environments such as oil and vibration, solving the problems of easy wear and short life of traditional contact sensors (such as grating rulers).

[0011] The commonly used technical solution for the excitation circuit of magnetostrictive displacement sensors is as follows:

[0012] 1. Power supply structure:

[0013] ▸ Excitation pulses are generated by directly controlling a 12V / 24V external power supply via an electronic switch.

[0014] ▸ The MCU generates pulse signals to drive the chip to control the switching of MOSFETs or transistors.

[0015] 2. Control method:

[0016] ▸ Relying on MCU software to generate pulse signals

[0017] Timing errors are compensated by software.

[0018] 3. Major Defects (Based on Data Analysis):

[0019] ▸ Voltage bottleneck: In a 12V / 24V power supply system, the voltage amplitude is insufficient, resulting in a small excitation signal generated by the excitation pulse and a small magnetostrictive effect.

[0020] ▸ Power supply pollution: When the MOSFET is turned on, the power supply is short-circuited to ground, resulting in a 200mV ripple (measured SNR decrease of 6dB).

[0021] ▸ Timing inaccuracy: MCU interrupt delay causes pulse width jitter of ±5μs → displacement measurement error of ±0.1mm

[0022] ▸ Excessive losses: MOSFET on-resistance > 100mΩ → Single pulse loss ≥ 1.2W (24V system). Summary of the Invention

[0023] The technical problem to be solved by the present invention is to provide a high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger, which addresses the shortcomings of the prior art.

[0024] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: a high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger includes a power supply circuit, an excitation signal generation circuit and a waveguide wire. The output terminal of the power supply circuit is electrically connected to the input terminal of the excitation signal generation circuit. The output terminal of the excitation signal generation circuit is electrically connected to one end of the waveguide wire, and the other end of the waveguide wire is electrically connected to an external fixed power supply.

[0025] The power supply circuit is used to provide power to the excitation signal generation circuit;

[0026] The excitation signal generation circuit is used to generate the pulse signal required to drive the magnetostrictive waveguide wire, and apply it to the waveguide wire to drive the waveguide wire to magnetostriction in order to measure displacement.

[0027] The beneficial effects of this invention are as follows: The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger provides a stable 5V voltage through the power supply and boosts the 5V to 150V through the excitation signal generation circuit, effectively enhancing the amplitude of the excitation signal, improving the magnetostrictive effect of the waveguide wire, and resulting in a stronger amplitude of the induced echo signal. Furthermore, the excitation signal generation circuit uses a monostable trigger instead of an MCU to directly control the excitation pulse width, achieving higher precision. The pulse width precision can reach ±0.1μs, which is 50 times higher than that of the prior art. One end of the waveguide wire is connected to the boost excitation source, and the other end is connected to an external fixed power supply. When the excitation signal generation circuit is closed, the voltage on the waveguide wire forms a freewheeling loop, reducing power consumption.

[0028] Based on the above technical solution, the present invention can be further improved as follows:

[0029] Further: The power supply circuit includes an input protection and noise suppression unit, a DC-DC energy conversion core unit, and an output filtering and feedback adjustment unit. The input terminal of the input protection and noise suppression unit is connected to an external 5V regulated power supply. The output terminal of the input protection and noise suppression unit is electrically connected to the input terminal of the DC-DC energy conversion core unit. The output terminal of the DC-DC energy conversion core unit is electrically connected to the input terminal of the output filtering and feedback adjustment unit. The output terminal of the output filtering and feedback adjustment unit is electrically connected to the power input terminal of the excitation signal generation circuit.

[0030] The beneficial effects of the above-mentioned further solutions are as follows: the input protection and noise suppression unit can effectively block reverse current, avoid damage to downstream power devices due to reverse overcurrent, and achieve graded suppression of differential-mode and common-mode noise; the DC-DC energy conversion core unit can dynamically adjust the switching duty cycle to stabilize the output voltage at the set value; and the output filtering and feedback adjustment unit can achieve low ripple output and fast load response.

[0031] Further: The input protection and noise suppression unit includes diode T1, diode D1, filter capacitor C3, filter capacitor C4, inductor L1 and inductor L2. Diode T1 is connected between the external regulated power supply and ground. The positive terminal of diode D1 is connected to the external regulated power supply. The negative terminal of diode D1 is connected in series with ground, and inductor L1, filter capacitor C3 and inductor L2 are connected in parallel. Filter capacitor C4 is connected in parallel with filter capacitor C3. The common terminal of inductor L1 and filter capacitor C3 is electrically connected to the input terminal of the DC-DC energy conversion core unit.

[0032] The beneficial effects of the above-mentioned further solution are as follows: when the input power supply is connected in the forward direction, diode T1 conducts in the forward direction (typical forward voltage drop ≤ 0.5V), allowing current to flow normally; if the power supply polarity is reversed, diode T1 is reverse cut off (reverse breakdown voltage ≥ 30V), which can effectively block reverse current and prevent the subsequent power devices from being damaged due to reverse overcurrent. At the same time, diode D1, filter capacitor C3, and filter capacitor C4 form a two-stage filter network, which effectively filters out the switching frequency (about 600kHz) and its harmonic noise.

[0033] Further: The DC-DC energy conversion core unit includes a resistor R11, a switching regulator U2, and a capacitor C6. The common terminal of the inductor L1 and the filter capacitor C3 is electrically connected to the input terminal of the switching regulator U2. The resistor R11 is connected between the input terminal and the enable terminal of the switching regulator U2. The capacitor C6 is electrically connected between the bootstrap pin and the switching node pin of the switching regulator U2. The switching node pin of the switching regulator U2 is electrically connected to the input terminal of the output filtering and feedback adjustment unit. The feedback pin of the switching regulator U2 is electrically connected to the sampling voltage output terminal of the output filtering and feedback adjustment unit.

[0034] The beneficial effects of the above-mentioned further solution are as follows: The switching regulator U2 integrates MOSFETs and intelligent control circuits, and achieves efficient voltage conversion through pulse width modulation (PWM). Furthermore, the 1.225V reference voltage source (VREF) and error amplifier integrated inside the switching regulator U2 compare the sampled voltage (V_FB) with VREF. The difference is amplified by the error amplifier to generate a PWM control signal, which dynamically adjusts the switching duty cycle, and finally stabilizes the output voltage at the set value.

[0035] Further: The output filtering and feedback adjustment unit includes a diode D3, a capacitor C7, an inductor L3, a resistor R12, and a resistor R13. The cathode of the diode D3 is electrically connected to the switching node pin of the switching regulator U2, and the anode of the diode D3 is grounded. The inductor L3 and the capacitor C7 are connected in series between the cathode of the diode D3 and ground. The resistor R12 and the resistor R13 are connected in series between the common terminal of the inductor L3 and the capacitor C7 and ground. The common terminal of the resistor R12 and the resistor R13 is electrically connected to the feedback pin of the switching regulator U2. The common terminal of the inductor L3 and the capacitor C7 serves as the output terminal and is electrically connected to the power input terminal of the excitation signal generation circuit.

[0036] The beneficial effects of the above-mentioned further scheme are as follows: A three-stage filter structure composed of inductor L3, capacitor C6, and capacitor C7, combined with a voltage feedback loop, achieves low ripple output and fast load response. The symmetrical layout of inductor L3 and diode D1 helps to further suppress high-frequency harmonics of the switching current. Capacitor C6 filters out ultra-high frequency noise above 10MHz. Capacitor C7, utilizing its large capacitance, effectively filters out mid-frequency ripple in the 10kHz to 10MHz range. Together, these three components form a π-type filter network, ensuring that the typical output ripple voltage is no greater than 10mV. When the load current changes abruptly, inductor L3 maintains the continuity of the output current by storing and releasing magnetic field energy. Simultaneously, the voltage feedback loop formed by resistors R12 and R13 responds quickly, adjusting the switching duty cycle to effectively suppress output voltage overshoot or drop caused by sudden load changes.

[0037] Further: The excitation signal generation circuit includes a signal input and level conversion unit, a timing control and pulse shaping unit, and a power drive and filtering network unit. The signal input terminal of the signal input and level conversion unit is externally connected to a PWM control signal. The power input terminal of the signal input and level conversion unit is electrically connected to the output terminal of the power supply circuit. The output terminal of the signal input and level conversion unit is electrically connected to the input terminal of the timing control and pulse shaping unit. The output terminal of the timing control and pulse shaping unit is electrically connected to the input terminal of the power drive and filtering network unit. The output terminal of the power drive and filtering network unit is electrically connected to one end of the waveguide wire, and the other end of the waveguide wire is electrically connected to an external fixed power supply.

[0038] The beneficial effects of the above-mentioned further solutions are as follows: The signal input and level conversion unit performs level conversion and preliminary power amplification on the PWM control signal, while isolating and buffering the input signal and filtering out high-frequency noise, ensuring that the logic level signal received by the subsequent drive stage is stable and reliable. The timing control and pulse shaping unit converts the pulse signal output by the signal input and level conversion unit into a drive timing signal with a fixed and precise pulse width, which significantly improves the pulse width control accuracy and stability. The power drive and filter network unit realizes the conversion of electrical energy into magnetic energy by driving the switching of the MOS transistor, effectively filtering out switching noise, outputting a smooth excitation current with minimal ripple, and boosting the low voltage (such as 5V) provided by the front-end power supply circuit to a high voltage of over 150V, thereby significantly enhancing the amplitude of the excitation signal applied to the waveguide wire, improving the magnetostrictive effect, and thus enhancing the amplitude of the induced echo signal.

[0039] Further: The input and level conversion unit includes a transistor Q4, a resistor R41, and a capacitor C37. The base of the transistor Q4 is connected to an external PWM control signal, the collector of the transistor Q4 is electrically connected to the output terminal of the power supply circuit through the resistor R41, the collector of the transistor Q4 is grounded through the capacitor C37, the emitter of the transistor Q4 is grounded, and the emitter and base of the transistor Q4 are electrically connected.

[0040] The beneficial effects of the above-mentioned further solution are: the external PWM control signal is level-converted and initially amplified by the transistor Q4. The gate of the transistor Q4 is connected in series with a current-limiting resistor R41 and in parallel with a filter capacitor C37, which realizes the isolation and buffering of the input signal and the filtering of high-frequency noise, ensuring that the logic level signal received by the subsequent driver stage is stable and reliable.

[0041] Further: The timing control and pulse shaping unit includes an oscillator U6, a resistor R42, a capacitor C38, a capacitor C39, and a capacitor C40. The first external timing resistor connection terminal of the oscillator U6 is electrically connected to the output terminal of the power supply circuit through the resistor R42. The external timing resistor connection terminal of the oscillator U6 is grounded through the capacitor C38. The second external timing resistor connection terminal of the oscillator U6 is grounded. The first trigger input terminal of the oscillator U6 is electrically connected to the collector of the transistor Q4. The second trigger input terminal and the external timing resistor / capacitor connection terminal of the oscillator U6 are respectively electrically connected to the output terminal of the power supply circuit. The low-level output terminal of the oscillator U6 is left floating. The high-level output terminal of the oscillator U6 is electrically connected to the input terminal of the power drive and filter network unit. The power input terminal of the oscillator U6 is electrically connected to the output terminal of the power supply circuit. The capacitors C39 and C40 are connected in parallel between the power input terminal of the oscillator U6 and ground. The ground terminal of the oscillator U6 is grounded.

[0042] The beneficial effect of the above further solution is that a timing generation module is constructed through the oscillator U6. This module converts the pulse signal output by transistor Q4 into a drive timing signal with a fixed and precise pulse width.

[0043] Further: The power drive and filtering network unit includes a ferrite bead B3, a capacitor C49, a resistor R49, a capacitor C48, an inductor L5, a diode D6, a MOSFET Q5, a capacitor C46, ​​and a diode D5. The ferrite bead B3 and capacitor C49 are sequentially connected between the external fixed power supply and ground. The resistor R49 and capacitor C48 are connected in series with ground between the common terminal of the ferrite bead B3 and capacitor C49. The common terminal of the resistor R49 and capacitor C48 is electrically connected to one end of the inductor L5 and one cathode of the diode D5, respectively. The other end of the inductor L5 is connected to the diode D6. The positive terminal of the diode is electrically connected, the negative terminal of the diode D6 is grounded through the capacitor C46, ​​the negative terminal of the diode D6 is electrically connected to the common terminal of the diode D5, one cathode of the diode D5 is electrically connected to the other cathode, the negative terminal of the diode D6 is electrically connected to one end of the waveguide wire, the other end of the inductor L5 is electrically connected to the drain of the MOSFET Q5, the source of the MOSFET Q5 is grounded, the gate of the MOSFET Q5 is electrically connected to the high-level output terminal of the oscillator U6, and the common terminal of the resistor R49 and the capacitor C48 is electrically connected to the other end of the waveguide wire.

[0044] The beneficial effects of the above-mentioned further scheme are as follows: the shaped drive signal drives the drain of MOSFET Q5 through the gate resistor R49, controls the conduction and turn-off of MOSFET Q5, and then controls the current in the energy storage inductor L5 to realize the conversion of electrical energy into electromagnetic energy. The output terminal adopts an LC type filter circuit, which consists of inductor L5 and filter capacitors C48 and C46. By utilizing the high-frequency impedance characteristics of the inductor and the low-frequency energy storage characteristics of the capacitor, the switching noise is effectively filtered out, and the output is a smooth excitation current with minimal ripple. The resistor R49 and diode D5 form an efficient freewheeling circuit to recover some energy, which helps to reduce the overall power consumption of the system. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of the circuit structure of a power supply circuit according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the excitation signal generation circuit according to an embodiment of the present invention. Detailed Implementation

[0047] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0048] A high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger includes a power supply circuit, an excitation signal generation circuit, and a waveguide wire. The output terminal of the power supply circuit is electrically connected to the input terminal of the excitation signal generation circuit, the output terminal of the excitation signal generation circuit is electrically connected to one end of the waveguide wire, and the other end of the waveguide wire is electrically connected to an external fixed power supply.

[0049] The power supply circuit is used to provide power to the excitation signal generation circuit;

[0050] The excitation signal generation circuit is used to generate the pulse signal required to drive the magnetostrictive waveguide wire, and apply it to the waveguide wire to drive the waveguide wire to magnetostriction in order to measure displacement.

[0051] In one or more embodiments of the present invention, the power supply circuit includes an input protection and noise suppression unit, a DC-DC energy conversion core unit, and an output filtering and feedback adjustment unit. The input terminal of the input protection and noise suppression unit is connected to an external 5V regulated power supply. The output terminal of the input protection and noise suppression unit is electrically connected to the input terminal of the DC-DC energy conversion core unit. The output terminal of the DC-DC energy conversion core unit is electrically connected to the input terminal of the output filtering and feedback adjustment unit. The output terminal of the output filtering and feedback adjustment unit is electrically connected to the power input terminal of the excitation signal generation circuit. The input protection and noise suppression unit can effectively block reverse current, preventing damage to subsequent power devices due to reverse overcurrent, and achieving graded suppression of differential-mode and common-mode noise. The DC-DC energy conversion core unit can dynamically adjust the switching duty cycle to stabilize the output voltage at a set value. The output filtering and feedback adjustment unit can achieve low ripple output and fast load response.

[0052] like Figure 1As shown, in one or more embodiments of the present invention, the input protection and noise suppression unit includes diode T1 (model SMB30J30CA), diode D1, filter capacitor C3, filter capacitor C4, inductor L1 and inductor L2. Diode T1 is connected between an external regulated power supply and ground. The positive terminal of diode D1 is connected to the external regulated power supply. The negative terminal of diode D1 is connected in series with ground, and inductor L1, filter capacitor C3 and inductor L2 are connected in parallel. Filter capacitor C4 is connected in parallel with filter capacitor C3. The common terminal of inductor L1 and filter capacitor C3 is electrically connected to the input terminal of the DC-DC energy conversion core unit. When the input power supply is connected in the forward direction, diode T1 conducts in the forward direction (typical forward voltage drop ≤ 0.5V), allowing current to flow normally; if the power supply polarity is reversed, diode T1 is reverse cut off (reverse breakdown voltage ≥ 30V), which can effectively block reverse current and prevent damage to subsequent power devices due to reverse overcurrent. At the same time, diode D1, filter capacitor C3, and filter capacitor C4 form a two-stage filter network, which effectively filters out the switching frequency (about 600kHz) and its harmonic noise.

[0053] like Figure 1 As shown, in one or more embodiments of the present invention, the DC-DC energy conversion core unit includes a resistor R11, a switching regulator U2 (model LMR14206), and a capacitor C6. The common terminal of the inductor L1 and the filter capacitor C3 is electrically connected to the input terminal of the switching regulator U2. The resistor R11 is connected between the input terminal and the enable terminal of the switching regulator U2. The capacitor C6 is electrically connected between the bootstrap pin and the switching node pin of the switching regulator U2. The switching node pin of the switching regulator U2 is electrically connected to the input terminal of the output filtering and feedback adjustment unit. The feedback pin of the switching regulator U2 is electrically connected to the sampling voltage output terminal of the output filtering and feedback adjustment unit.

[0054] Here, the switching regulator U2 integrates MOSFETs and intelligent control circuitry, achieving efficient voltage conversion through pulse width modulation (PWM). The enable terminal (SHDN) of the switching regulator U2 is pulled up to the input ground (GND) via resistor R11 (100kΩ, 1% accuracy), enabling the chip by default. When the input voltage VIN reaches or exceeds the chip's startup threshold (approximately 4.5V), the internal oscillator starts, driving the power MOSFET into a high-frequency switching state (typically 600kHz). Furthermore, the 1.225V reference voltage source (VREF) and error amplifier integrated within the switching regulator U2 compare the sampled voltage (V_FB) with VREF. The difference is amplified by the error amplifier to generate a PWM control signal, dynamically adjusting the switching duty cycle to ultimately stabilize the output voltage at the set value. The output voltage VOUT is determined by the formula VOUT = VREF × (1 + R13 / R12). By adjusting the ratio of the resistance values ​​of resistors R12 and R13, different stable output voltages can be flexibly set.

[0055] During the conduction phase: the internal MOSFET is turned on, and the input voltage charges the output energy storage components (inductor L3=15μH, capacitor C6=150nF / 50V, C7=10μF / 25V) after passing through diode D1 and reverse connection protection diode T1, and the output current increases linearly.

[0056] Cut-off phase: The internal MOSFET is turned off. Due to the sudden change in current, the inductor L3 generates a reverse induced electromotive force. Its stored energy is released through the freewheeling circuit formed by the output capacitor C6, capacitor C7 and the load, maintaining the continuous output current and avoiding a sudden drop in output voltage. The chip achieves dynamic balance and stability of input to output energy by internally adjusting the duty cycle of the MOSFET.

[0057] Feedback regulation mechanism: The output voltage is sampled by a voltage divider resistor network (upper voltage divider resistor R13=5.6kΩ / 1%, lower voltage divider resistor R12=1kΩ / 1%) and then fed to the feedback pin (FB) of U2.

[0058] like Figure 1As shown, in one or more embodiments of the present invention, the output filtering and feedback adjustment unit includes a diode D3, a capacitor C7, an inductor L3, a resistor R12, and a resistor R13. The cathode of the diode D3 is electrically connected to the switching node pin of the switching regulator U2, the anode of the diode D3 is grounded, and the inductor L3 and the capacitor C7 are connected in series between the cathode of the diode D3 and ground. The resistor R12 and the resistor R13 are connected in series between the common terminal of the inductor L3 and the capacitor C7 and ground. The common terminal of the resistor R12 and the resistor R13 is electrically connected to the feedback pin of the switching regulator U2. The common terminal of the inductor L3 and the capacitor C7 is connected as an output terminal to the power input terminal of the excitation signal generation circuit. A three-stage filter structure consisting of inductor L3, capacitor C6, and capacitor C7, combined with a voltage feedback loop, achieves low ripple output and fast load response. Inductor L3 and diode D1 form a symmetrical layout, which helps to further suppress high-frequency harmonics of the switching current. Capacitor C6 (150nF, ceramic capacitor) filters out ultra-high frequency noise above 10MHz. Capacitor C7 (10μF, electrolytic capacitor) utilizes its large capacitance to effectively filter out mid-frequency ripple in the 10kHz to 10MHz range. Together, these three components form a π-type filter network, ensuring that the typical output ripple voltage does not exceed 10mV. When the load current changes abruptly, inductor L3 maintains the continuity of the output current by storing and releasing magnetic field energy. Simultaneously, the voltage feedback loop formed by resistors R12 and R13 responds quickly, adjusting the switching duty cycle to effectively suppress output voltage overshoot or drop caused by sudden load changes.

[0059] In one or more embodiments of the present invention, the excitation signal generation circuit includes a signal input and level conversion unit, a timing control and pulse shaping unit, and a power drive and filtering network unit. The signal input terminal of the signal input and level conversion unit is externally connected to a PWM control signal. The power input terminal of the signal input and level conversion unit is electrically connected to the output terminal of the power supply circuit. The output terminal of the signal input and level conversion unit is electrically connected to the input terminal of the timing control and pulse shaping unit. The output terminal of the timing control and pulse shaping unit is electrically connected to the input terminal of the power drive and filtering network unit. The output terminal of the power drive and filtering network unit is electrically connected to one end of the waveguide wire, and the other end of the waveguide wire is electrically connected to an external fixed power supply. The signal input and level conversion unit performs level conversion and preliminary power amplification on the PWM control signal, while isolating and buffering the input signal and filtering out high-frequency noise to ensure that the logic level signal received by the subsequent driver stage is stable and reliable. The timing control and pulse shaping unit converts the pulse signal output by the signal input and level conversion unit into a drive timing signal with a fixed and precise pulse width, which significantly improves the pulse width control accuracy and stability. The power drive and filtering network unit realizes the conversion of electrical energy into magnetic energy by driving the switching of the MOS transistor, effectively filtering out switching noise and outputting a smooth excitation current with minimal ripple. This boosts the low voltage (e.g., 5V) provided by the front-end power supply circuit to a high voltage of over 150V, thereby significantly enhancing the amplitude of the excitation signal applied to the waveguide wire, improving the magnetostrictive effect, and thus enhancing the amplitude of the induced echo signal.

[0060] like Figure 2 As shown, in one or more embodiments of the present invention, the input and level conversion unit includes a transistor Q4, a resistor R41, and a capacitor C37. The base of the transistor Q4 is connected to an external PWM control signal, the collector of the transistor Q4 is electrically connected to the output terminal of the power supply circuit through the resistor R41, the collector of the transistor Q4 is grounded through the capacitor C37, the emitter of the transistor Q4 is grounded, and the emitter and base of the transistor Q4 are electrically connected. The external PWM control signal undergoes level conversion and preliminary power amplification via the transistor Q4. The gate of the transistor Q4 is connected in series with a current-limiting resistor R41 (2kΩ, 1% accuracy) and in parallel with a filter capacitor C37 (1nF) to isolate and buffer the input signal and filter out high-frequency noise, ensuring that the logic level signal received by the subsequent driver stage is stable and reliable.

[0061] like Figure 2As shown, in one or more embodiments of the present invention, the timing control and pulse shaping unit includes an oscillator U6, a resistor R42, a capacitor C38, a capacitor C39, and a capacitor C40. The first external timing resistor connection terminal of the oscillator U6 is electrically connected to the output terminal of the power supply circuit through the resistor R42. The external timing resistor connection terminal of the oscillator U6 is grounded through the capacitor C38. The second external timing resistor connection terminal of the oscillator U6 is grounded. The first trigger input terminal of the oscillator U6 is electrically connected to the collector of the transistor Q4. The second trigger input terminal and the external timing resistor / capacitor connection terminal of the oscillator U6 are respectively electrically connected to the output terminal of the power supply circuit. The low-level output terminal of the oscillator U6 is left floating. The high-level output terminal of the oscillator U6 is electrically connected to the input terminal of the power drive and filter network unit. The power input terminal of the oscillator U6 is electrically connected to the output terminal of the power supply circuit. The capacitors C39 and C40 are connected in parallel between the power input terminal of the oscillator U6 and ground. The ground terminal of the oscillator U6 is grounded. A timing generation module is constructed using the oscillator U6. This module converts the pulse signal output by transistor Q4 into a drive timing signal with a fixed and precise pulse width.

[0062] Here, a timing generation module is constructed using a monostable multivibrator chip U6 (including U6B and / or U6C) (model 74HC123BQ). This module converts the pulse signal output from Q4 into a drive timing signal with a fixed and precise pulse width. Specifically, U6B (using some of its pins) precisely sets the width of the output pulse through an RC charging and discharging network consisting of an external precision timing resistor R42 (30kΩ, 1% accuracy) and timing capacitors C39 / C40 (100nF, 50V). This hardware timing method replaces traditional MCU software timing, significantly improving pulse width control accuracy (up to ±0.1μs) and stability.

[0063] like Figure 2As shown, in one or more embodiments of the present invention, the power drive and filter network unit includes a ferrite bead B3, a capacitor C49, a resistor R49, a capacitor C48, an inductor L5, a diode D6, a MOSFET Q5, a capacitor C46, ​​and a diode D5. The ferrite bead B3 and capacitor C49 are sequentially connected between an external fixed power supply and ground. The resistor R49 and capacitor C48 are connected in series with ground between the common terminal of the ferrite bead B3 and capacitor C49. The common terminal of the resistor R49 and capacitor C48 is electrically connected to one end of the inductor L5 and one cathode of the diode D5, respectively. The other end of the inductor L5 is connected to... The positive terminal of diode D6 is electrically connected, the negative terminal of diode D6 is grounded through capacitor C46, ​​the negative terminal of diode D6 is electrically connected to the common terminal of diode D5, one cathode of diode D5 is electrically connected to the other cathode, the negative terminal of diode D6 is electrically connected to one end of the waveguide wire, the other end of inductor L5 is electrically connected to the drain of MOSFET Q5, the source of MOSFET Q5 is grounded, the gate of MOSFET Q5 is electrically connected to the high-level output terminal of oscillator U6, and the common terminal of resistor R49 and capacitor C48 is electrically connected to the other end of the waveguide wire. The shaped drive signal drives the drain of MOSFET Q5 through gate resistor R49, controlling the conduction and turn-off of MOSFET Q5. This, in turn, controls the current flow in energy storage inductor L5, realizing the conversion of electrical energy into electromagnetic energy. The output uses an LC filter circuit, consisting of inductor L5 and filter capacitors C48 (330μF, 10V) and C46 (10nF, 50V). Utilizing the high-frequency impedance characteristics of the inductor and the low-frequency energy storage characteristics of the capacitor, switching noise is effectively filtered out, resulting in a smooth excitation current with minimal output ripple. Specifically, a fast recovery diode D6 (SS310) is connected in parallel across inductor L5. When MOSFET Q5 is turned off, it provides a discharge path (freewheeling path) for the energy stored in inductor L5, suppressing the reverse electromotive force generated during turn-off and protecting MOSFET Q5 and other circuit components. The efficient freewheeling circuit formed by resistor R49 and diode D5 recovers some energy, helping to reduce the overall system power consumption.

[0064] This excitation circuit can boost the low voltage (such as 5V) provided by the main power supply circuit to a high voltage of over 150V, thereby significantly enhancing the amplitude of the excitation signal applied to the waveguide wire, improving the magnetostrictive effect, and thus enhancing the amplitude of the induced echo signal.

[0065] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high-voltage excitation circuit for a high-precision magnetostrictive sensor based on a monostable multivibrator, characterized in that: It includes a power supply circuit, an excitation signal generation circuit, and a waveguide wire. The output terminal of the power supply circuit is electrically connected to the input terminal of the excitation signal generation circuit. The output terminal of the excitation signal generation circuit is electrically connected to one end of the waveguide wire, and the other end of the waveguide wire is electrically connected to an external fixed power supply. The power supply circuit is used to provide power to the excitation signal generation circuit; The excitation signal generation circuit is used to generate the pulse signal required to drive the magnetostrictive waveguide wire, and apply it to the waveguide wire to drive the waveguide wire to magnetostriction in order to measure displacement. The excitation signal generation circuit includes a signal input and level conversion unit, a timing control and pulse shaping unit, and a power drive and filtering network unit. The signal input terminal of the signal input and level conversion unit is externally connected to a PWM control signal. The power input terminal of the signal input and level conversion unit is electrically connected to the output terminal of the power supply circuit. The output terminal of the signal input and level conversion unit is electrically connected to the input terminal of the timing control and pulse shaping unit. The output terminal of the timing control and pulse shaping unit is electrically connected to the input terminal of the power drive and filtering network unit. The output terminal of the power drive and filtering network unit is electrically connected to one end of the waveguide wire, and the other end of the waveguide wire is electrically connected to an external fixed power supply. The power drive and filtering network unit includes a ferrite bead B3, a capacitor C49, a resistor R49, a capacitor C48, an inductor L5, a diode D6, a MOSFET Q5, a capacitor C46, ​​and a diode D5. The ferrite bead B3 and capacitor C49 are sequentially connected between the external fixed power supply and ground. The resistor R49 and capacitor C48 are connected in series with ground between the common terminal of the ferrite bead B3 and capacitor C49. The common terminal of the resistor R49 and capacitor C48 is connected to one end of the inductor L5 and one cathode of the diode D5, respectively. The other end of the inductor L5 is connected to the cathode of the diode D6. The positive terminal is electrically connected, the negative terminal of diode D6 is grounded through capacitor C46, ​​the negative terminal of diode D6 is electrically connected to the common terminal of diode D5, one cathode of diode D5 is electrically connected to the other cathode, the negative terminal of diode D6 is electrically connected to one end of the waveguide wire, the other end of inductor L5 is electrically connected to the drain of MOSFET Q5, the source of MOSFET Q5 is grounded, the gate of MOSFET Q5 is electrically connected to the high-level output terminal of oscillator U6, and the common terminal of resistor R49 and capacitor C48 is electrically connected to the other end of the waveguide wire.

2. The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger according to claim 1, characterized in that: The power supply circuit includes an input protection and noise suppression unit, a DC-DC energy conversion core unit, and an output filtering and feedback adjustment unit. The input terminal of the input protection and noise suppression unit is connected to an external 5V regulated power supply. The output terminal of the input protection and noise suppression unit is electrically connected to the input terminal of the DC-DC energy conversion core unit. The output terminal of the DC-DC energy conversion core unit is electrically connected to the input terminal of the output filtering and feedback adjustment unit. The output terminal of the output filtering and feedback adjustment unit is electrically connected to the power input terminal of the excitation signal generation circuit.

3. The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger according to claim 2, characterized in that: The input protection and noise suppression unit includes diode T1, diode D1, filter capacitor C3, filter capacitor C4, inductor L1, and inductor L2. Diode T1 is connected between an external regulated power supply and ground. The positive terminal of diode D1 is connected to the external regulated power supply. Inductor L1, filter capacitor C3, and inductor L2 are connected in series between the negative terminal of diode D1 and ground. Filter capacitor C4 is connected in parallel with filter capacitor C3. The common terminal of inductor L1 and filter capacitor C3 is electrically connected to the input terminal of the DC-DC energy conversion core unit.

4. The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger according to claim 3, characterized in that: The DC-DC energy conversion core unit includes a resistor R11, a switching regulator U2, and a capacitor C6. The common terminal of the inductor L1 and the filter capacitor C3 is electrically connected to the input terminal of the switching regulator U2. The resistor R11 is connected between the input terminal and the enable terminal of the switching regulator U2. The capacitor C6 is electrically connected between the bootstrap pin and the switching node pin of the switching regulator U2. The switching node pin of the switching regulator U2 is electrically connected to the input terminal of the output filtering and feedback adjustment unit. The feedback pin of the switching regulator U2 is electrically connected to the sampling voltage output terminal of the output filtering and feedback adjustment unit.

5. The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger according to claim 4, characterized in that: The output filtering and feedback adjustment unit includes a diode D3, a capacitor C7, an inductor L3, a resistor R12, and a resistor R13. The cathode of the diode D3 is electrically connected to the switching node pin of the switching regulator U2, and the anode of the diode D3 is grounded. The inductor L3 and the capacitor C7 are connected in series between the cathode of the diode D3 and ground. The resistors R12 and R13 are connected in series between the common terminal of the inductor L3 and the capacitor C7 and ground. The common terminal of the resistors R12 and R13 is electrically connected to the feedback pin of the switching regulator U2. The common terminal of the inductor L3 and the capacitor C7 serves as the output terminal and is electrically connected to the power input terminal of the excitation signal generation circuit.

6. The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger according to claim 1, characterized in that: The input and level conversion unit includes a transistor Q4, a resistor R41, and a capacitor C37. The base of the transistor Q4 is connected to an external PWM control signal. The collector of the transistor Q4 is electrically connected to the output terminal of the power supply circuit through the resistor R41. The collector of the transistor Q4 is grounded through the capacitor C37. The emitter of the transistor Q4 is grounded. The emitter of the transistor Q4 is electrically connected to the base.

7. The high-precision magnetostrictive sensor high-voltage excitation circuit based on a monostable trigger according to claim 6, characterized in that: The timing control and pulse shaping unit includes an oscillator U6, a resistor R42, a capacitor C38, a capacitor C39, and a capacitor C40. The first external timing resistor connection terminal of the oscillator U6 is electrically connected to the output terminal of the power supply circuit through the resistor R42. The external timing resistor connection terminal of the oscillator U6 is grounded through the capacitor C38. The second external timing resistor connection terminal of the oscillator U6 is grounded. The first trigger input terminal of the oscillator U6 is electrically connected to the collector of the transistor Q4. The second trigger input terminal and the external timing resistor / capacitor connection terminal of the oscillator U6 are respectively electrically connected to the output terminal of the power supply circuit. The low-level output terminal of the oscillator U6 is left floating. The high-level output terminal of the oscillator U6 is electrically connected to the input terminal of the power drive and filter network unit. The power input terminal of the oscillator U6 is electrically connected to the output terminal of the power supply circuit. The capacitors C39 and C40 are connected in parallel between the power input terminal of the oscillator U6 and ground. The ground terminal of the oscillator U6 is grounded.

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