Variable high-voltage emission waveform excitation device of wide-range ultrasonic snow depth instrument

Abstract

A variable high-voltage emission waveform excitation device of a wide-range ultrasonic snow depth instrument comprises an MCU (Microprogrammed Control Unit) controller and an ultrasonic converter, and is characterized by further comprising a DC (Direct Current)-DC chip which is used for driving the ultrasonic converter; the input module is in circuit connection with the DC-DC chip and used for providing input voltage for the DC-DC chip, and the input circuit comprises a TVS tube D8, an absorption circuit and an anti-reverse-connection circuit; a variable resistor R1 of the potentiometer module is electrically connected with the output end of the DC-DC chip, the other end of the variable resistor R1 is grounded, and the potentiometer is connected with the MCU controller and used for adjusting the resistance value of the variable resistor R1. The excitation device provided by the utility model can generate high-voltage driving pulses with variable voltage, can directly drive various ultrasonic transducers, and realizes the functions of receiving and transmitting isolation and receiving circuit protection by utilizing the unidirectional conduction and clamping characteristics of the diodes in the circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of snow depth measurement, in particular to a variable high-voltage emission waveform excitation device for a large-range ultrasonic snow depth meter. Background Art

[0002] Snow depth detection not only provides meteorological data but is also closely related to people's daily lives. Snow disasters cause significant losses in my country every year, such as heavy snowfalls that crush trees and crops, traffic jams and travel disruptions caused by heavy snowfall, and damage to homes in mountainous areas, all of which pose a serious threat to the safety of people and their property. Therefore, snow depth measurement can effectively monitor snowfall levels and enable preemptive response plans, thereby reducing losses.

[0003] Ultrasonic technology is currently widely used in snow depth detection technology, enabling relatively accurate snow depth detection. By recording a fixed voltage square wave on an ultrasonic transducer, the ultrasonic wave is emitted and the echo signal is processed to detect the snow depth. However, because snow depth meters typically operate in harsh environments with low operating temperatures, coupled with increasing requirements for detection range, the traditional fixed voltage square wave excitation method is no longer able to meet current detection requirements.

[0004] Therefore, there is an urgent need for an ultrasonic transducer to realize a large-scale variable high-voltage transmission waveform excitation device. Utility Model Content

[0005] The purpose of this utility model is to provide a variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter. In order to solve the above technical problems, this utility model adopts the following technical solutions:

[0006] A variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter includes an MCU controller and an ultrasonic converter, and also includes

[0007] A DC-DC chip, wherein the DC-DC chip is used to drive the ultrasonic transducer;

[0008] An input module is connected to the DC-DC chip circuit to provide an input voltage to the DC-DC chip. The input circuit includes a TVS tube D8, an absorption circuit, and an anti-reverse connection circuit.

[0009] A potentiometer module, wherein the variable resistor R1 of the potentiometer module is electrically connected to the output end of the DC DC chip, the other end of the variable resistor R1 is grounded, and the potentiometer is connected to the MCU controller to adjust the resistance value of the variable resistor R1.

[0010] Furthermore, the absorption circuit includes a resistor R16 and a capacitor C27 connected in series. One end of the capacitor C27 is connected to the resistor R16, and the other end is grounded.

[0011] Furthermore, the anti-reverse connection circuit includes a PMOS tube Q2, a resistor R18 and a voltage regulator Z1. The drain of the PMOS tube is connected to the absorption circuit, the gate of the PMOS tube Q2 is connected to the resistor R18 and one end of the voltage regulator Z1 respectively, the other end of the resistor R18 is grounded, and the source of the PMOS tube Q2 and the other end of the voltage regulator Z1 are electrically connected to the DCDC chip.

[0012] Furthermore, the TVS tube D8 is provided in multiple numbers connected in parallel.

[0013] Furthermore, a boost module is included, which is electrically connected to the output pin of the DC DC chip to boost the output voltage of the DC DC chip again. The boost module includes a boost transformer T1, and the first primary pin of the boost transformer T1 is connected to an NMOS tube Q1. The source of the NMOS tube Q1 is connected to the first primary pin of the boost transformer T1, the drain of the NMOS tube Q1 is grounded, and the gate of the NMOS tube Q1 is electrically connected to the MCU controller to receive control pulses. The second primary pin of the boost transformer T1 is connected to the output voltage of the DC DC chip, and a storage capacitor C12 is provided in parallel. The secondary output pin of the boost transformer T1 is electrically connected to the ultrasonic converter to emit an excitation waveform.

[0014] Furthermore, the secondary side of the step-up transformer T1 is further connected to diodes D2 and D3 connected in series, with the cathode of diode D3 connected to the ultrasonic transducer; diodes D4 and D5 are further connected in series, and the diodes D4 and D5 form a parallel circuit with the diodes D2 and D3, and the anode of diode D5 is connected to the ultrasonic transducer; the step-up transformer T1 is further connected to diodes D6 and D7 connected in parallel and a resistor R5 forming a series circuit with the parallel diodes D6 and D7, with one end of the resistor R5 connected to the ultrasonic transducer and the other end connected to the parallel diodes D6 and D7.

[0015] The beneficial effects produced by the utility model are as follows:

[0016] The variable high-voltage transmit waveform excitation device provided in this embodiment uses a high-precision digital potentiometer to control the feedback loop of the DC-DC step-down chip, thereby accurately controlling the DC-DC chip's output voltage. Combined with a gate driver chip, an NMOS switch, and a step-up transformer, it generates variable-voltage high-voltage drive pulses that can directly drive various ultrasonic transducers. The circuit utilizes the unidirectional conduction and clamping characteristics of the diode to achieve transmit-receive isolation and receive circuit protection. The board integrates a high-performance DC-DC converter, supports a wide input voltage range, and provides surge and reverse polarity protection for the input power supply, ensuring smooth EMI testing. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural diagram of the present utility model.

[0018] Figure 2 This is the circuit diagram of the input module in the present utility model.

[0019] Figure 3 This is the circuit diagram of the potentiometer module in this utility model.

[0020] Figure 4 This is the circuit diagram of the boost module in this utility model. DETAILED DESCRIPTION

[0021] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings. The contents mentioned in the embodiments are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0022] The embodiment of the utility model provides a variable high-voltage transmission waveform excitation device for a large-scale ultrasonic snow depth meter, which has multiple numerical control gears and can select different transmission voltages and waveform styles according to the actual working environment to ensure that the receiving device can receive an echo signal with sufficient signal-to-noise ratio and appropriate amplitude, thereby completing accurate snow depth detection. This device has a high-performance DC-DC chip, supports a wide voltage range input, and has anti-surge and anti-reverse connection functions for the input power supply, which can successfully pass EMI testing. Figure 1-4As shown, an embodiment of the utility model provides a variable high-voltage transmitting waveform excitation device for a large-range ultrasonic snow depth meter, which is provided with an MCU controller and an ultrasonic converter for detection, and is also provided with a DC DC chip, an input module and a potentiometer module, wherein the DC DC chip is used to drive the ultrasonic converter; the input module is connected to the DC DC chip circuit to provide input voltage to the DC DC chip, and the input circuit includes a TVS tube D8, an absorption circuit and an anti-reverse connection circuit; the variable resistor R1 of the potentiometer module is electrically connected to the output end of the DC DC chip, and the other end of the variable resistor R1 is grounded, and the potentiometer is connected to the MCU controller to adjust the resistance value of the variable resistor R1.

[0023] VCCIN is the input voltage of the circuit board. The input voltage range is determined by the tolerance voltage range of the DC-DC chip on the board, and has a wide voltage input capability. Taking the domestic SCT2630 as an example, its maximum input voltage can reach 60V. According to the 80% derating design, the maximum input voltage range can still be guaranteed to be no less than 48V. The minimum voltage is determined by the maximum output voltage Vadj of the DC-DC chip plus a certain margin. In this embodiment, the maximum voltage of Vadj is typically 20V. The input voltage on the board only needs to be within the range of 24-48V to ensure its normal operation.

[0024] A single TVS diode, D8, can be used to suppress abnormal signals such as input surges and pulse train interference. To maximize the suppression effect, a large-volume SMC package should be selected, and the TVS diode's VBR voltage should be as low as possible within the product's normal operating range. For example, if the product's actual supply voltage is 36V, the SMCJ36CA is a suitable choice, with a VBR value between 40-44V and a peak pulse current exceeding 26A. In actual applications, a grounded gas discharge tube can be selectively added depending on whether the product is grounded. Alternatively, multiple TVS diodes, D8, can be connected in parallel to further enhance surge and pulse train suppression.

[0025] The FB pin of the DC-DC chip is connected to one end of the variable resistor of the digital potentiometer, and the other end of the variable resistor of the potentiometer is grounded. The digital potentiometer is a special integrated circuit that can adjust its resistance through digital control. The main manufacturers are ADI, TI, NS, etc.; let the current resistance of the digital potentiometer be Radj. According to the buck principle, the output voltage of the DC-DC is Vadj = VFB * (1 + R1 / Radj); select the appropriate digital potentiometer model according to the actual voltage range to be adjusted and the interface form of the digital potentiometer. Usually, a digital potentiometer with a resistance of 10-100K can meet the needs. The more gears a digital potentiometer has, the finer the variable voltage control. Figure 3Taking IC1 in the figure as an example, the MCU can achieve 256-level resistance control through the three control ports of the digital potentiometer, "digital potentiometer Ctr1", "digital potentiometer Ctr2" and "digital potentiometer Ctr3". The adjustment range is 0-50K and the minimum step is 195 ohms. At this time, the DC DC output voltage Vadj can be adjusted in the range of 6.2V~Vin.

[0026] In an embodiment, the absorption circuit includes a resistor R16 and a capacitor C27 connected in series. One end of the capacitor C27 is connected to the resistor R16, and the other end is grounded.

[0027] R16 and C27 form a typical Snubber absorption circuit, which can absorb the spike pulse of input voltage to a certain extent. The parameters of R16 and C27 should be selected appropriately, and typical values ​​can be obtained through actual experiments.

[0028] In this embodiment, the anti-reverse connection circuit includes a PMOS transistor Q2, a resistor R18 and a voltage regulator Z1. The drain of the PMOS transistor is connected to the absorption circuit, the gate of the PMOS transistor Q2 is connected to the resistor R18 and one end of the voltage regulator Z1 respectively, the other end of the resistor R18 is grounded, and the source of the PMOS transistor Q2 and the other end of the voltage regulator Z1 are electrically connected to the DC-DC chip.

[0029] The PMOS transistor Q2, R18, and Zener diode Z1 together form a PMOS-based reverse connection protection circuit, which has lower power loss than the traditional series diode reverse connection protection circuit. Its working principle is: when the voltage is connected in a positive direction, Q2's body diode is turned on, causing its source voltage to rise to (VCCIN-0.7V). At this time, the initial value of the gate voltage is still 0V, but due to the presence of Zener diode Z1, Q2's Vgs voltage is clamped to about -7.5V, which is significantly higher than Q2's threshold voltage, causing Q2 to turn on and the source voltage to further rise to VCCIN. Q2's body diode is cut off, and the circuit operates normally. Because Q2's on-resistance is extremely small, adding this circuit does not affect the power consumption of the entire device. When the voltage is reversed, Q2 and its body diode are always in the cut-off state, and the circuit cannot conduct. Vin is the voltage of the input DC voltage VCCIN after the reverse connection protection process. This voltage is stabilized and decoupled by capacitors C6, C7, and C8 before reaching a DC The DC chip U1 generates Vadj. To reduce power consumption, the enable of the DC chip is controlled by VpowEnaBuf. The DC is enabled only during transmission. The selection of DC is very flexible. A small SOT chip power supply or a high-power power supply can be selected according to the actual situation. Usually, a SOT23-6 package BUCK power supply can be selected.

[0030] In order to further increase the ultrasonic emission voltage, a boost module is also included. The boost module is electrically connected to the output pin of the DC DC chip to further boost the output voltage of the DC DC chip. The boost module includes a boost transformer T1. The first primary pin of the boost transformer T1 is connected to an NMOS transistor Q1, wherein the source of the NMOS transistor Q1 is connected to the first primary pin of the boost transformer T1, the drain of the NMOS transistor Q1 is grounded, and the gate of the NMOS transistor Q1 is electrically connected to the MCU controller to receive control pulses. The second primary pin of the boost transformer T1 is connected to the output voltage of the DC DC chip, and a storage capacitor C12 is provided in parallel. The secondary output pin of the boost transformer T1 is electrically connected to the ultrasonic converter to emit an excitation waveform. The secondary side of the step-up transformer T1 is further connected to diodes D2 and D3 connected in series, with the cathode of diode D3 connected to the ultrasonic transducer. It is also connected to diodes D4 and D5 connected in series, with diodes D4 and D5 forming a parallel circuit with diodes D2 and D3, and the anode of diode D5 connected to the ultrasonic transducer. The step-up transformer T1 is further connected to diodes D6 and D7 connected in parallel, and a resistor R5 forming a series circuit with the parallel diodes D6 and D7. One end of the resistor R5 is connected to the ultrasonic transducer, and the other end is connected to the parallel diodes D6 and D7.

[0031] A step-up transformer T1 is introduced to further boost Vadj, with a transformation ratio of 1:M. Note that in practical applications, the transformer's operating frequency must be consistent with the transducer frequency, and the boosted voltage must not exceed its calibrated maximum operating voltage. This circuit receives transmit control pulses generated by the MCU or FPGA via the pulseCtr pin. This pulse reaches the G terminal of the NMOS device Q1 through the gate control chip. When the pulse is high, Q1 turns on, and pin 1 of the step-up transformer is grounded. At this time, because pin 2 of the step-up transformer is connected to energy storage capacitor C12, pin 2 can still maintain a voltage near Vadj. This generates an alternating pulse train with a Vpp of Vadj on the primary side of the step-up transformer T1, and further generates a high-voltage pulse train with a Vpp of M*Vadj on the secondary side. In practical applications, 5-10 pulse trains are sufficient to generate an echo with sufficient energy. The high-voltage pulse train reaches the transducer end through diodes D2 and D3, completing the transmission waveform excitation. D4 and D5 are used to isolate the transmit and receive echo signals. D6 and D7 can clamp the echo signal within the range of +-0.7V, which helps to maintain the subsequent receiving and amplifying circuits.

[0032] The variable high-voltage transmit waveform excitation device provided in this embodiment uses a high-precision digital potentiometer to control the feedback loop of the DC-DC step-down chip, thereby accurately controlling the DC-DC chip's output voltage. Combined with a gate driver chip, an NMOS switch, and a step-up transformer, it generates variable-voltage high-voltage drive pulses that can directly drive various ultrasonic transducers. The circuit utilizes the unidirectional conduction and clamping characteristics of the diode to achieve transmit-receive isolation and receive circuit protection. The board integrates a high-performance DC-DC converter, supports a wide input voltage range, and provides surge and reverse polarity protection for the input power supply, ensuring smooth EMI testing.

[0033] The above are only preferred embodiments of the present invention and are not intended to limit the present invention in any form. Although the present invention is disclosed as above in terms of preferred embodiments, they are not intended to limit the present invention. Any technician familiar with the profession can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to equivalent embodiments using the technical content disclosed above. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technology of the present invention, which do not depart from the content of the technical solution of the present invention, are within the scope of the technical solution of the present invention.

Claims

1. A variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter, comprising an MCU controller and an ultrasonic converter, characterized in that: Also includes A DC-DC chip, wherein the DC-DC chip is used to drive the ultrasonic transducer; An input module is connected to the DC-DC chip circuit to provide an input voltage to the DC-DC chip. The input circuit includes a TVS tube D8, an absorption circuit, and an anti-reverse connection circuit. A potentiometer module, wherein the variable resistor R1 of the potentiometer module is electrically connected to the output end of the DC DC chip, the other end of the variable resistor R1 is grounded, and the potentiometer is connected to the MCU controller to adjust the resistance value of the variable resistor R1.

2. The variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter according to claim 1 is characterized in that: The absorption circuit includes a resistor R16 and a capacitor C27 connected in series. One end of the capacitor C27 is connected to the resistor R16, and the other end is grounded.

3. The variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter according to claim 2, characterized in that: The anti-reverse connection circuit includes a PMOS transistor Q2, a resistor R18 and a voltage regulator Z1. The drain of the PMOS transistor is connected to the absorption circuit, the gate of the PMOS transistor Q2 is connected to the resistor R18 and one end of the voltage regulator Z1 respectively, the other end of the resistor R18 is grounded, and the source of the PMOS transistor Q2 and the other end of the voltage regulator Z1 are electrically connected to the DC-DC chip.

4. The variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter according to claim 1 is characterized in that: The TVS tube D8 is provided in multiple parallel connections.

5. The variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter according to claim 1 is characterized in that: It also includes a boost module, which is electrically connected to the output pin of the DC DC chip to further boost the output voltage of the DC DC chip. The boost module includes a boost transformer T1. The first primary pin of the boost transformer T1 is connected to an NMOS transistor Q1. The source of the NMOS transistor Q1 is connected to the first primary pin of the boost transformer T1, the drain of the NMOS transistor Q1 is grounded, and the gate of the NMOS transistor Q1 is electrically connected to the MCU controller to receive control pulses. The second primary pin of the boost transformer T1 is connected to the output voltage of the DC DC chip, and a storage capacitor C12 is provided in parallel. The secondary output pin of the boost transformer T1 is electrically connected to the ultrasonic transducer to emit an excitation waveform.

6. The variable high-voltage transmission waveform excitation device for a large-range ultrasonic snow depth meter according to claim 5, characterized in that: The secondary side of the step-up transformer T1 is further connected to diodes D2 and D3 connected in series, with the cathode of diode D3 connected to the ultrasonic transducer. It is also connected to diodes D4 and D5 connected in series, with diodes D4 and D5 forming a parallel circuit with diodes D2 and D3, and the anode of diode D5 connected to the ultrasonic transducer. The step-up transformer T1 is further connected to diodes D6 and D7 connected in parallel, and a resistor R5 forming a series circuit with the parallel diodes D6 and D7. One end of the resistor R5 is connected to the ultrasonic transducer, and the other end is connected to the parallel diodes D6 and D7.

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