Ultrasonic detection circuit for rain and water level integrated machine

Abstract

The utility model provides an ultrasonic detection circuit for rain and water level integrated machine, provides high pressure excitation pulse signal to the transmitting and receiving integrated rain ultrasonic probe and water level ultrasonic probe, it includes a controller of providing PWM1 and PWM2 signal, still includes: half bridge inverter circuit is used to the direct current voltage VDC input to half bridge drive chip U1 is inverted into square wave voltage PowSW, voltage dividing transformer circuit produces high voltage pulse signal HvSig, excitation pulse generation circuit is used to produce high voltage excitation pulse signal TransducerSig, and is connected water level ultrasonic probe JP1 and rain ultrasonic probe JP2. Through the technical scheme provided by the utility model embodiment, two probes can be simultaneously driven through a circuit, thereby realizing the detection of rain and water level, through the technical scheme, the depth multiplexing and integration of the two are realized from the circuit structure, and the measurement of rain intensity and rain is realized by directly using the rain gauge cylinder scheme, and the volume is greatly reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of integrated water level and rainfall detection equipment, and in particular to an ultrasonic detection circuit for an integrated rainfall and water level detection machine. Background Technology

[0002] Traditional rain gauges mostly use mechanical tipping bucket measuring cylinders to measure rainfall. In recent years, some rain gauges have also used ultrasonic probes instead of weighing sensors to measure the water level in the measuring cylinder, thereby achieving higher measurement accuracy. However, this solution still requires the rain measuring cylinder to collect rainwater and requires a special structural design to avoid large fluctuations in the liquid level.

[0003] Water level gauges typically use ultrasonic or radar probes to measure the distance to the water surface, thereby indirectly obtaining the water level height.

[0004] Currently, many unmanned weather stations typically require separate rain gauges and water level gauges to measure rainfall and water level, respectively. These are completely independent instruments in terms of structure and circuitry, which not only increase their size but also increase the overall cost and wiring complexity of the system.

[0005] Therefore, in the pursuit of integrated design in some unmanned weather stations, it is necessary to integrate rain gauges and water level gauges to simultaneously detect both rainfall and water level. However, while some rain gauges and water level gauges can be structurally combined, there are significant challenges in integrating their independent circuits.

[0006] Therefore, a new technical solution is urgently needed to solve the above-mentioned technical problems. Utility Model Content

[0007] The purpose of this utility model is to provide an ultrasonic detection circuit for an integrated rain gauge and water level meter. To solve the above-mentioned technical problems, this utility model adopts the following technical solution:

[0008] An ultrasonic detection circuit for an integrated rain gauge and water level meter is provided to provide high-voltage excitation pulse signals to an integrated transceiver ultrasonic rain gauge probe and a ultrasonic water level probe. It includes a controller providing PWM1 and PWM2 signals, and further includes:

[0009] A half-bridge inverter circuit includes a half-bridge driver chip U1 and two NMOS transistors Q1 and Q2. PWM1 and PWM2 are respectively connected to the two input ports of the half-bridge driver chip U1, and the two NMOS transistors Q1 and Q2 are respectively connected to the output ports of the half-bridge driver chip U1. When the two NMOS transistors Q1 and Q2 are alternately turned on, the DC voltage VDC input to the half-bridge driver chip U1 is inverted into a square wave voltage PowSW.

[0010] The voltage divider transformer circuit includes two capacitors C4 and C6 connected in series with the DC voltage VDC, and capacitor C6 is grounded. The DC voltage VDC is divided to generate a voltage divider voltage Vmid3. The voltage divider transformer circuit also includes a step-up transformer T1. The voltage divider voltage Vmid3 and the square wave voltage PowSW form the primary coil of the half-bridge inverter circuit and are connected to the input terminal of the step-up transformer T1, so that the step-up transformer T1 boosts the voltage to generate a high-voltage pulse signal HvSig.

[0011] An excitation pulse generation circuit includes four diodes D2, D3, D4, and D5 arranged in an array with their positive and negative terminals connected sequentially and connected at the center. The high-voltage pulse signal HvSig is connected to the input terminal of the excitation pulse generation circuit, and the excitation pulse generation circuit generates a high-voltage excitation pulse signal TransducerSig. The high-voltage excitation pulse signal TransducerSig is connected to the water level ultrasonic probe JP1 and the rainfall ultrasonic probe JP2 respectively through two parallel relays K1 and K2.

[0012] The controller is connected to relays K1 and K2 respectively, and is used to control the on and off of relays K1 and K2 respectively, so as to connect the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2.

[0013] Furthermore, it also includes an amplification circuit, which is connected to the output of the excitation pulse generation circuit to receive and amplify the echo signal from the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2. The first-stage amplification output Sig1 and the second-stage amplification output Sig2 of the amplification circuit are respectively connected to the digital-to-analog converter (ADC).

[0014] Furthermore, the amplification circuit is composed of a dual-channel integrated operational amplifier chip IC1, and the input terminal of the dual-channel integrated operational amplifier chip IC1 is connected to the output terminal of the excitation pulse generation circuit.

[0015] Furthermore, the amplification circuit also includes resistors R10, R8, R13, and R11. The positive and negative terminals of resistor R10 are connected to the output terminal of the excitation pulse generation circuit and the input terminal of the dual-channel integrated operational amplifier chip IC1, respectively. The positive and negative terminals of resistor R8 are connected to the first-stage amplification output terminal of the dual-channel integrated operational amplifier chip IC1, respectively. The positive and negative terminals of resistor R13 are connected to the input interface of the dual-channel integrated operational amplifier chip IC1 and ground, respectively. The positive and negative terminals of resistor R11 are connected to the positive terminal of resistor R13 and the headphone discharge output terminal of the dual-channel integrated operational amplifier chip, respectively.

[0016] Furthermore, the ultrasonic measuring motor is also provided with a transceiver isolation circuit located at the front end of the amplifier circuit and the output end of the excitation pulse generation circuit, which is used to isolate the transmitting voltage and receiving voltage of the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2. The transceiver isolation circuit includes a series resistor R9 and two diodes D6 and D7 connected in parallel and grounded in opposite directions.

[0017] Furthermore, the half-bridge inverter circuit is also provided with a bootstrap power supply circuit to power the high-side drive of the half-bridge driver chip U1. The bootstrap power supply circuit includes a resistor R1, a diode D1 and a capacitor C5 connected in series. The resistor R1 is connected to the power supply voltage VCC of the half-bridge driver chip U1, and the capacitor C5 is connected to the source of NMOS transistor Q1 and the drain of NMOS transistor Q2.

[0018] Furthermore, the half-bridge inverter circuit is also equipped with impedance matching resistors to avoid fluctuations in the rise and fall times of the output square wave. The impedance matching resistors include resistor R3 connected to the circuit of PWM1 signal and half-bridge driver chip U1, resistor R4 connected to the circuit of PWM2 signal and half-bridge driver chip U1, resistor R2 connected to the circuit of half-bridge driver chip U1 and NMOS transistor Q1, and resistor R5 connected to the circuit of half-bridge driver chip and NMOS transistor Q2.

[0019] Furthermore, an overshoot oscillation circuit is also configured on the half-bridge inverter circuit to suppress overshoot and oscillation of the square wave voltage PowSW inverted by the half-bridge inverter circuit. The overshoot oscillation circuit includes a resistor R7 and a capacitor C7 connected in parallel at the output terminal of the half-bridge inverter circuit, and the capacitor C7 is grounded.

[0020] The beneficial effects of this utility model are as follows:

[0021] In this embodiment, an ultrasonic detection circuit for an integrated rain gauge and water level meter is provided. This circuit provides high-voltage excitation pulse signals to the integrated ultrasonic probes for rain measurement and water level measurement, enabling the integration of a rain gauge and a water level meter into a single device. Furthermore, the technical solution provided by this embodiment allows for simultaneous driving of both probes through a single circuit, thereby achieving the detection of both rainfall and water level. This technical solution achieves deep reuse and integration of the two devices from a circuit structure perspective. It also directly utilizes a rainless measuring cylinder to measure rainfall intensity and amount, significantly reducing the size of the device. A complete ultrasonic transceiver circuit for both rain measurement and water level measurement is implemented on the same circuit board. Only two ultrasonic probes are needed: one facing downwards to measure water level and the other facing upwards to measure rainfall intensity, thus achieving complete rainfall and water level measurement functionality. Attached Figure Description

[0022] Figure 1 This is a circuit diagram of the half-bridge inverter circuit in this utility model.

[0023] Figure 2 This is a circuit diagram of the voltage divider transformer circuit in this utility model.

[0024] Figure 3 This is a circuit diagram of the excitation pulse generation circuit and the amplification circuit in this utility model.

[0025] Figure 4 This is a circuit diagram showing the connection between this utility model and the ultrasonic rain gauge probe and the ultrasonic water level probe. Detailed Implementation

[0026] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention. The present invention will be described in detail below with reference to the accompanying drawings.

[0027] In this embodiment, an ultrasonic detection circuit for an integrated rain gauge and water level meter is provided. This circuit provides high-voltage excitation pulse signals to the integrated ultrasonic probes for rain measurement and water level measurement, enabling the integration of a rain gauge and a water level meter into a single device. Furthermore, the technical solution provided by this embodiment allows for simultaneous driving of both probes through a single circuit, thereby achieving the detection of both rainfall and water level. This technical solution achieves deep reuse and integration of the two devices from a circuit structure perspective. It also directly utilizes a rainless measuring cylinder to measure rainfall intensity and amount, significantly reducing the size of the device. A complete ultrasonic transceiver circuit for both rain measurement and water level measurement is implemented on the same circuit board. Only two ultrasonic probes are needed: one facing downwards to measure water level and the other facing upwards to measure rainfall intensity, thus achieving complete rainfall and water level measurement functionality.

[0028] Specifically, such as Figure 1-4As shown in the figure, this utility model provides an ultrasonic detection circuit for an integrated rain gauge and water level detector, used to provide high-voltage excitation pulse signals to the integrated rain gauge ultrasonic probe and water level ultrasonic probe. It includes a controller providing PWM1 and PWM2 signals, and also includes a half-bridge inverter circuit, a wind pressure transformer circuit, and an excitation pulse generation circuit. The half-bridge inverter circuit includes a half-bridge driver chip U1 and two NMOS transistors Q1 and Q2. PWM1 and PWM2 are respectively connected to the two input ports of the half-bridge driver chip U1, and the two NMOS transistors Q1 and Q2 are respectively connected to the output ports of the half-bridge driver chip U1. When the two NMOS transistors Q1 and Q2 are alternately turned on, the DC voltage VDC input to the half-bridge driver chip U1 is inverted into a square wave voltage PowSW. The voltage divider transformer circuit includes two capacitors C4 and C6 connected in series with the DC voltage VDC. The capacitor C6 is grounded, and the DC voltage VDC is divided to generate a voltage divider voltage Vmid3. The voltage divider transformer circuit also includes a step-up transformer T1. The voltage divider voltage Vmid3 and the square wave voltage PowSW constitute the primary coil of the half-bridge inverter circuit and are connected to the input terminal of the step-up transformer T1, so that the step-up transformer T1 boosts the voltage to generate a high-voltage pulse signal HvSig. The excitation pulse generation circuit includes four diodes D2, D3, D4, and D5 arranged in an array with their positive and negative terminals connected in sequence and connected in the center. The high-voltage pulse signal HvSig is connected to the input terminal of the excitation pulse generation circuit, and the excitation pulse generation circuit generates a high-voltage excitation pulse signal TransducerSig. The high-voltage excitation pulse signal TransducerSig is connected to the water level ultrasonic probe JP1 and the rainfall ultrasonic probe JP2 respectively through two parallel relays K1 and K2.

[0029] The controller is connected to relays K1 and K2 respectively to control the on / off state of relays K1 and K2, so as to connect the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2.

[0030] During the detection of rainfall and water level, this detection circuit generates high-voltage excitation pulse signals to the two probes, enabling the two probes to simultaneously emit and receive ultrasonic signals to complete the detection of rainfall and water level.

[0031] In this technical solution, the controller provides PWM1 and PWM2 signals to the amplifier circuit. Under the control of the half-bridge driver chip UI, the NMOS transistors Q1 and Q2 are alternately turned on, thereby inverting the external input voltage VDC into a square wave voltage PowSW. At the same time, capacitors C4 and C6 divide the DC voltage to generate Vmid3, which, together with the square wave voltage PowSW, forms the primary coil input of the step-up transformer T1 located on the half-bridge inverter circuit side. The step-up transformer T1 boosts the voltage to generate a high-voltage pulse signal HvSig. It should be noted that the specific boost ratio can be reasonably selected according to the tolerance voltage and measurement range of the actual ultrasonic transducer. The high-voltage pulse signal HvSig is passed through the diode array of D2, D3, D4, and D5 to generate the high-voltage excitation pulse TransducerSig of the transducer. This signal is selected by two relays K1 and K2 and then connected to the water level ultrasonic probe JP1 and the rainfall ultrasonic probe JP2 respectively. At the same time, the controller can control which ultrasonic probe is currently selected through relayCtr and relayCtr2 respectively, thereby realizing the transmission control of two different ultrasonic probes by the same circuit.

[0032] In this embodiment, as Figure 3 As shown, the excitation pulse generation circuit includes four diodes D2, D3, D4, and D5 arranged in an array with their positive and negative terminals connected sequentially and centrally. In the specific circuit connection, diodes D2, D3, D4, and D5 are in the same direction in one loop, and their positive and negative terminals are connected to each other sequentially. At the same time, a connecting loop is also provided to connect the four diodes D2, D3, D4, and D5 in the middle. Specifically, the negative terminal of diode D2 is connected to the positive terminal of D3 and D4, and the negative terminal of diode D2 is connected to the negative terminal of diode D5, thereby forming a structure in which the four diodes D2, D3, D4, and D5 are connected in the middle, which is used to convert the high-voltage pulse signal HvSig into the high-voltage excitation pulse TransducerSig of the ultrasonic probe.

[0033] This technical solution provides an ultrasonic measurement circuit that generates a high-voltage excitation pulse signal to simultaneously drive two transceiver ultrasonic probes for detection. This allows for the integration of rainfall and water level detection into a single device, achieving deep reuse and integration of the two technologies through circuit structure. Furthermore, it directly utilizes a rainless measuring cylinder solution to measure rainfall intensity and amount, making it more suitable for the needs of integrated weather stations.

[0034] This embodiment also includes an amplification circuit to amplify the echo signal from the ultrasonic probe, thereby enabling the controller to calculate rainfall and water level. Figure 3As shown, the amplification circuit is connected to the output of the excitation pulse generation circuit to receive and amplify the echo signal from the ultrasonic water level probe JP1 or the ultrasonic rainfall probe JP2. The first-stage amplification output Sig1 and the second-stage amplification output Sig2 of the amplification circuit are respectively connected to the digital-to-analog converter (ADC). In practical applications, the dynamic range of the ultrasonic echo signal is very large as the measurement distance changes. Therefore, the first-stage amplification output sig_1 and the second-stage amplification output sig_2 of IC1 are selected using a 2:1 analog switch. The MCU can flexibly use GPIO to control the analog switch to sample sig_1 or sig_2 from the ADC. This approach can be further extended to achieve digital reception within a wider dynamic range.

[0035] In this embodiment, the amplification circuit is composed of a dual-channel integrated operational amplifier chip IC1, and the input terminal of the dual-channel integrated operational amplifier chip IC1 is connected to the output terminal of the excitation pulse generation circuit to receive and amplify the echo signal from the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2.

[0036] Meanwhile, the amplification circuit also includes resistors R10, R8, R13, and R11. The positive and negative terminals of resistor R10 are connected to the output terminal of the excitation pulse generation circuit and the input terminal of the dual-channel integrated operational amplifier chip IC1, respectively. The positive and negative terminals of resistor R8 are connected to the first-stage amplification output terminal of the dual-channel integrated operational amplifier chip IC1, respectively. The positive and negative terminals of resistor R13 are connected to the input interface of the dual-channel integrated operational amplifier chip IC1 and ground, respectively. The positive and negative terminals of resistor R11 are connected to the positive terminal of resistor R13 and the headphone discharge output terminal of the dual-channel integrated operational amplifier chip, respectively.

[0037] To reduce system complexity and hardware costs, a two-stage inverting amplifier circuit was implemented using a single-supply operational amplifier IC1. The amplification gain can be adjusted by changing the ratio between R10, R8, R13, and R11 to suit different application scenarios.

[0038] The ultrasonic measuring motor is also equipped with a transceiver isolation circuit located at the front end of the amplifier circuit and the output end of the excitation pulse generation circuit, which is used to isolate the transmitting voltage and receiving voltage of the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2. The transceiver isolation circuit includes a series resistor R9 and two diodes D6 and D7 connected in parallel and grounded in opposite directions.

[0039] In this embodiment, both ultrasonic probes are integrated transceiver structures, meaning that the transmission and reception share the same signal. However, with this structure, the transmission voltage and reception voltage differ significantly—the former can reach hundreds of V, while the latter may be less than 1 mV. Therefore, effective transmission-reception isolation measures are designed in the circuit. The TransducerSig is grounded through a series resistor R9 and two parallel diodes D6 and D7 in opposite directions. This ensures that even when the transducer is in a high-voltage transmission state, the clamping effect of the diodes prevents the voltage level reaching C12 from exceeding 0.7 V. When the ultrasonic probe is in receiving mode, its echo energy is only on the order of mV. At this time, the two parallel diodes D6 and D7 are in the cutoff state, so the echo signal can smoothly pass through the series resistor R9, the DC blocking capacitor C12, and then through resistor R10 to reach the front end of the receiving amplifier circuit.

[0040] In this embodiment, the high-side drive of the half-bridge driver chip U1 adopts bootstrap power supply. The bootstrap power supply circuit includes a resistor R1, a diode D1 and a capacitor C5 connected in series. The resistor R1 is connected to the power supply voltage VCC of the half-bridge driver chip U1, and the capacitor C5 is connected to the source of NMOS transistor Q1 and the drain of NMOS transistor Q2.

[0041] When Q2 is turned on, VCC charges C5 through R1 and D1. When Q2 is turned off and Q1 is turned on, the voltage stored in C5 ensures that the VGs voltage of Q1 exceeds its threshold voltage, thus enabling Q1 to be continuously turned on. With bootstrap power supply, there is no need for a dedicated isolation power supply to achieve the alternating turn-on of the two NMOS devices Q1 and Q2, converting the VDC DC voltage into a square wave voltage PowSW.

[0042] In this embodiment, in order to adjust the rise and fall times of the output square wave, an impedance matching resistor is also provided in the half-bridge inverter circuit to avoid fluctuations in the rise and fall times of the output square wave. The impedance matching resistor includes a resistor R3 connected to the circuit of PWM1 signal and the half-bridge driver chip U1, a resistor R4 connected to the circuit of PWM2 signal and the half-bridge driver chip U1, a resistor R2 connected to the circuit of the half-bridge driver chip U1 and the NMOS transistor Q1, and a resistor R5 connected to the circuit of the half-bridge driver chip and the NMOS transistor Q2.

[0043] In this embodiment, an overshoot oscillation circuit is also configured above the half-bridge inverter circuit to suppress overshoot and oscillation of the square wave voltage PowSW inverted by the half-bridge inverter circuit. The overshoot oscillation circuit includes a resistor R7 and a capacitor C7 connected in parallel at the output terminal of the half-bridge inverter circuit, with capacitor C7 grounded. By suppressing overshoot and oscillation of the square wave voltage PowSW through the R7 and C7 grounded circuit, the waveform of PowSW is made closer to the ideal square wave. The resistance value of R7 and the capacitance value of C7 can be selected according to the PRF frequency and the actual oscillation waveform.

[0044] In the process of calculating the water level after measurement, an ADC chip or the ADC inside the MCU is used to perform analog-to-digital conversion on the amplified ultrasonic probe echo signal. The MCU's internal timer is used to record the transmission time from the start of transmission to the receipt of the echo signal. Then, the speed of sound is calculated based on the current temperature using the formula: V = 331.45 × sqrt(1 + T / 273), where sqrt is the square root operation and T is the sensed temperature data. First, the current speed of sound is calculated based on the temperature. Thus, as long as the ultrasonic transmission time can be measured, t*V is the ultrasonic propagation distance, which can then be used to calculate the water level. In reality, ultrasonic waves travel a two-way distance, so dividing by 2 gives the distance.

[0045] In the process of calculating rainfall intensity after measuring rainfall, an ultrasonic probe periodically emits short-duration ultrasonic signals into the sky, and an ADC samples the echo signals within a specific receiving window. When a rainfall event occurs, raindrops scatter and reflect the ultrasonic waves. The MCU directly counts the amount of echo energy within the receiving window to intuitively represent the current rainfall intensity. The rainfall intensity is accumulated to obtain the rainfall amount per unit time.

[0046] The correspondence between echo signals and rainfall intensity was determined in advance using a simulated rainfall device to obtain a fitting curve. The cumulative rainfall intensity is the amount of rainfall, and rainfall intensity multiplied by time can be considered as the amount of rainfall.

[0047] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model in any way. Although the present utility model has been disclosed above with preferred embodiments, it is not intended to limit the present utility model. Any person skilled in the art can make some changes or modifications to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present utility model. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the present utility model without departing from the scope of the present utility model shall fall within the scope of the present utility model.

Claims

1. An ultrasonic detection circuit for a rain gauge and water level integrated meter, used to provide high-voltage excitation pulse signals to a transceiver-integrated rain gauge ultrasonic probe and a water level ultrasonic probe, comprising a controller providing PWM1 and PWM2 signals, characterized in that, It also includes: A half-bridge inverter circuit includes a half-bridge driver chip U1 and two NMOS transistors Q1 and Q2. PWM1 and PWM2 are respectively connected to the two input ports of the half-bridge driver chip U1, and the two NMOS transistors Q1 and Q2 are respectively connected to the output ports of the half-bridge driver chip U1. When the two NMOS transistors Q1 and Q2 are alternately turned on, the DC voltage VDC input to the half-bridge driver chip U1 is inverted into a square wave voltage PowSW. The voltage divider transformer circuit includes two capacitors C4 and C6 connected in series with the DC voltage VDC, and capacitor C6 is grounded. The DC voltage VDC is divided to generate a voltage divider voltage Vmid3. The voltage divider transformer circuit also includes a step-up transformer T1. The voltage divider voltage Vmid3 and the square wave voltage PowSW form the primary coil of the half-bridge inverter circuit and are connected to the input terminal of the step-up transformer T1, so that the step-up transformer T1 boosts the voltage to generate a high-voltage pulse signal HvSig. An excitation pulse generation circuit includes four diodes D2, D3, D4, and D5 arranged in an array with their positive and negative terminals connected sequentially and connected at the center. The high-voltage pulse signal HvSig is connected to the input terminal of the excitation pulse generation circuit, and the excitation pulse generation circuit generates a high-voltage excitation pulse signal TransducerSig. The high-voltage excitation pulse signal TransducerSig is connected to the water level ultrasonic probe JP1 and the rainfall ultrasonic probe JP2 respectively through two parallel relays K1 and K2. The controller is connected to relays K1 and K2 respectively, and is used to control the on and off of relays K1 and K2 respectively, so as to connect the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2.

2. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 1, characterized in that, It also includes an amplifier circuit, which is connected to the output of the excitation pulse generation circuit to receive and amplify the echo signal of the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2. The first-stage amplification output Sig1 and the second-stage amplification output Sig2 of the amplifier circuit are respectively connected to the digital-to-analog converter (ADC).

3. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 2, characterized in that, The amplifier circuit is composed of a dual-channel integrated operational amplifier chip IC1, and the input terminal of the dual-channel integrated operational amplifier chip IC1 is connected to the output terminal of the excitation pulse generation circuit.

4. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 3, characterized in that, The amplification circuit also includes resistors R10, R8, R13, and R11. The positive and negative terminals of resistor R10 are connected to the output terminal of the excitation pulse generation circuit and the input terminal of the dual-channel integrated operational amplifier chip IC1, respectively. The positive and negative terminals of resistor R8 are connected to the first-stage amplification output terminal of the dual-channel integrated operational amplifier chip IC1, respectively. The positive and negative terminals of resistor R13 are connected to the input interface of the dual-channel integrated operational amplifier chip IC1 and ground, respectively. The positive and negative terminals of resistor R11 are connected to the positive terminal of resistor R13 and the headphone discharge output terminal of the dual-channel integrated operational amplifier chip, respectively.

5. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 2, characterized in that, The ultrasonic measuring motor is also equipped with a transceiver isolation circuit located at the front end of the amplifier circuit and the output end of the excitation pulse generation circuit, which is used to isolate the transmitting voltage and receiving voltage of the water level ultrasonic probe JP1 or the rainfall ultrasonic probe JP2. The transceiver isolation circuit includes a series resistor R9 and two diodes D6 and D7 connected in parallel and grounded in opposite directions.

6. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 1, characterized in that, The half-bridge inverter circuit is also provided with a bootstrap power supply circuit to power the high-side drive of the half-bridge driver chip U1. The bootstrap power supply circuit includes a resistor R1, a diode D1 and a capacitor C5 connected in series. The resistor R1 is connected to the power supply voltage VCC of the half-bridge driver chip U1, and the capacitor C5 is connected to the source of NMOS transistor Q1 and the drain of NMOS transistor Q2.

7. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 1, characterized in that, The half-bridge inverter circuit is also equipped with impedance matching resistors to avoid the rise and fall time of the output square wave. The impedance matching resistors include resistor R3 in the circuit connecting the PWM1 signal and the half-bridge driver chip U1, resistor R4 in the circuit connecting the PWM2 signal and the half-bridge driver chip U1, resistor R2 in the circuit connecting the half-bridge driver chip U1 and the NMOS transistor Q1, and resistor R5 in the circuit connecting the half-bridge driver chip and the NMOS transistor Q2.

8. The ultrasonic detection circuit for an integrated rain gauge and water level meter according to claim 1, characterized in that, An overshoot oscillation circuit is also configured on the half-bridge inverter circuit to suppress overshoot and oscillation of the square wave voltage PowSW inverted by the half-bridge inverter circuit. The overshoot oscillation circuit includes a resistor R7 and a capacitor C7 connected in parallel at the output terminal of the half-bridge inverter circuit, and the capacitor C7 is grounded.

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