Single probe ultrasonic ranging circuit and device

Abstract

The application provides a single-probe ultrasonic ranging circuit and device, comprising a transmitting drive circuit and a pre-receiving circuit; the transmitting drive circuit comprises an H-bridge drive circuit and an isolation diode, the H-bridge drive circuit is electrically connected with the positive and negative poles of an ultrasonic probe S1, and the isolation diode is connected in series between the H-bridge drive circuit and the positive and negative poles of the ultrasonic probe S1; the positive pole of the H-bridge drive circuit is connected with a drive voltage, the negative pole of the H-bridge drive circuit is grounded, and the ultrasonic probe S1 is grounded through the negative pole of the H-bridge drive circuit when the transmission pulse ends; and the pre-receiving circuit is electrically connected with the positive and negative poles of the ultrasonic probe S1. The H-bridge drive circuit provided by the application can perfectly overcome the influence of the transmission high voltage on the high-sensitivity receiving circuit, so that the single-probe transmission and reception multiplexing ranging function is realized, the number of components and the space are saved compared with the circuit with separate transmission and reception, the complexity of the circuit is reduced, and the cost is also saved.

Description

Technical Field

[0001] This invention relates to the technical field of ultrasonic ranging circuits, and more specifically, to a single-probe ultrasonic ranging circuit and device. Background Technology

[0002] Traditional ultrasonic ranging modules come in single-probe and dual-probe configurations. For example, the US-015 ultrasonic ranging module uses two ultrasonic probes (one for transmitting and the other for receiving) and a separation element. Dual-probe configurations generally cannot directly output the measured distance; they can only output a digital signal, requiring an external MCU to convert the digital signal into a distance value. Furthermore, using two ultrasonic probes is costly, the circuitry is complex, and the circuit board integrating the probes and separation element must be long enough to accommodate both probes; the circuit board size cannot be reduced.

[0003] Single-probe solutions offer advantages such as low hardware cost, high integration, and simple deployment, leading to an increasing market share. However, the hardware design of single-probe solutions is relatively complex. Seamless switching between transmission and reception is crucial in single-probe measurement circuits. When transmitting ultrasonic pulses, the voltage amplitude on the probe reaches hundreds of volts, while the amplitude of the echo signal during reception is very small. Therefore, the gain of the amplifier circuit is extremely high. Since ultrasonic probes typically have parasitic capacitances of several thousand pF, if the signal immediately switches to receiving mode after transmission, the high-voltage charge on the probe requires a long time to discharge. During this period, residual charge on the probe will be superimposed on the input of the differential amplifier in a mixed manner of common-mode and differential-mode. This not only causes the differential amplifier to remain in saturation for an extended period but also severely degrades its common-mode rejection ratio (CMRR). Failure to quickly release the residual high voltage from the transmission will seriously affect the signal amplitude, baseline recovery time, and CMRR performance of the differential amplifier output. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a single-probe ultrasonic ranging circuit and device.

[0005] A single-probe ultrasonic ranging circuit according to the present invention includes: a transmitting drive circuit and a front-end receiving circuit;

[0006] The transmission drive circuit includes an H-bridge drive circuit and an isolation diode. The H-bridge drive circuit is electrically connected to the positive and negative terminals of the ultrasonic probe S1, and the isolation diode is connected in series between the H-bridge drive circuit and the positive and negative terminals of the ultrasonic probe S1.

[0007] The positive terminal of the H-bridge drive circuit is connected to the drive voltage, and the negative terminal of the H-bridge drive circuit is grounded. When the ultrasonic probe S1 finishes emitting a pulse, it is grounded through the negative terminal of the H-bridge drive circuit.

[0008] The pre-receiving circuit is electrically connected to the positive and negative terminals of the ultrasonic probe S1.

[0009] Preferably, the H-bridge drive circuit includes MOSFETs Q1, Q2, Q3, and Q4;

[0010] The MOS transistors Q1 and Q2 are connected in series. The drain of the MOS transistor Q1 is connected to the driving voltage, and the source of the MOS transistor Q2 is grounded. The source of the MOS transistor Q1 and the drain of the MOS transistor Q2 are electrically connected to the positive / negative terminal of the ultrasonic probe S1 through an isolation diode.

[0011] The MOS transistors Q3 and Q4 are connected in series. The drain of the MOS transistor Q3 is connected to the driving voltage, and the source of the MOS transistor Q4 is grounded. The source of the MOS transistor Q3 and the drain of the MOS transistor Q4 are electrically connected to the negative / positive terminal of the ultrasonic probe S1 through an isolation diode.

[0012] When the ultrasonic probe S1 finishes emitting a pulse, the MOS transistors Q2 and Q4 are turned on, and the positive and negative terminals of the ultrasonic probe S1 are grounded through the isolation diode.

[0013] Preferably, it further includes an H-bridge controller, which is electrically connected to the gates of MOSFET Q1, MOSFET Q2, MOSFET Q3, and MOSFET Q4.

[0014] Preferably, the H-bridge controller uses an IR2101STRPBF chip. The HIN and LIN ports of the H-bridge controller acquire control signals. The VCC port of the H-bridge controller is connected to VCC. The COM port of the H-bridge controller is grounded. A capacitor C2 is connected in series between the VCC port and the COM port. The HO port of the H-bridge controller is connected to the gate of MOSFET Q1. A diode D2 is connected in series between the VB port and the VCC port of the H-bridge controller, and the anode of the diode D2 is connected to the VCC port. The VS port of the H-bridge controller is connected to the source of MOSFET Q1. A capacitor C1 is connected in series between the VB port and the VS port. The LO port of the H-bridge controller is connected to the gate of MOSFET Q2.

[0015] Preferably, the front-end receiving circuit includes an RC circuit, which is connected to the ultrasonic probe S1 and the differential amplifier circuit respectively;

[0016] The RC circuit includes capacitor C1, capacitor C2, resistor R1, and resistor R2;

[0017] The capacitor C1 is connected in series with the resistor R1, and the other end of the capacitor C1 is connected to the positive / negative terminal of the ultrasonic probe S1;

[0018] The capacitor C2 and the resistor R2 are connected in series, and the other end of the capacitor C2 is connected to the negative / positive terminal of the ultrasonic probe S1;

[0019] The other end of resistor R1 and the other end of resistor R2 are connected to a differential amplifier circuit.

[0020] Preferably, a clamping diode D3 is connected in series between the other end of the resistor R1 and the other end of the resistor R2.

[0021] Preferably, it also includes a protective resistor R3, the two ends of which are respectively connected to the positive and negative terminals of the ultrasonic probe S1.

[0022] This invention discloses a single-probe ultrasonic ranging device, including the single-probe ultrasonic ranging circuit described above.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] 1. This invention provides a circuit for H-bridge direct drive of ultrasonic probe transceiver switching, which can perfectly overcome the influence of high-voltage transmission on high-sensitivity receiving circuit, thereby realizing the ranging function of single probe transceiver multiplexing. Compared with the separate transceiver circuit, it saves the number of components and space, reduces the complexity of the circuit, and also saves costs.

[0025] 2. The single-probe ultrasonic ranging device provided by the present invention reduces the three-dimensional spatial size of the ultrasonic radiation path, enabling measurement tasks to be completed even in narrower scenarios.

[0026] Other beneficial effects of the present invention will be explained in detail through the introduction of specific technical features and technical solutions in specific embodiments. Those skilled in the art should be able to understand the beneficial technical effects brought about by these technical features and technical solutions through the introduction of these technical features and technical solutions. Attached Figure Description

[0027] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings:

[0028] Figure 1 This is a structural diagram of the single-probe ultrasonic ranging circuit of the present invention;

[0029] Figure 2 This is the equivalent circuit diagram of the single-probe ultrasonic ranging circuit of the present invention during state switching;

[0030] Figure 3 This is a structural diagram of a single-probe ultrasonic ranging device in one embodiment of the present invention;

[0031] Figure 4This is a timing diagram of the control of the single-probe ultrasonic ranging circuit of the present invention. Detailed Implementation

[0032] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make several changes and improvements without departing from the concept of the present invention. These all fall within the protection scope of the present invention.

[0033] This invention provides a single-probe ultrasonic ranging circuit, referring to... Figure 1 and Figure 2 As shown, the system includes a transmitting drive circuit and a pre-receiving circuit. The transmitting drive circuit includes an H-bridge drive circuit and an isolation diode. The H-bridge drive circuit is electrically connected to the positive and negative terminals of the ultrasonic probe S1. The isolation diode is connected in series between the H-bridge drive circuit and the positive and negative terminals of the ultrasonic probe S1. The positive terminal of the H-bridge drive circuit is connected to the driving voltage, and the negative terminal is grounded. When the ultrasonic probe S1 finishes transmitting a pulse, it is grounded through the negative terminal of the H-bridge drive circuit. The pre-receiving circuit is electrically connected to the positive and negative terminals of the ultrasonic probe S1.

[0034] The transmitting drive circuit uses an H-bridge driver, and the pre-receiving circuit uses a differential amplifier U1 for pre-amplification. The probe's transmitting and receiving are physically separated by an isolation diode. At the moment of switching from transmitting to receiving, the two low-side MOS transistors of the H-bridge are short-circuited to ground to form a rapid discharge to the probe, thereby ensuring seamless connection of ultrasonic pulses during the transmission and reception switching process.

[0035] In a preferred embodiment, the H-bridge drive circuit includes MOSFETs Q1, Q2, Q3, and Q4.

[0036] The MOS transistors Q1 and Q2 are connected in series. The drain of the MOS transistor Q1 is connected to the driving voltage, and the source of the MOS transistor Q2 is grounded. The source of the MOS transistor Q1 and the drain of the MOS transistor Q2 are electrically connected to the positive or negative terminal of the ultrasonic probe S1 through the isolation diode D1.

[0037] The MOS transistors Q3 and Q4 are connected in series. The drain of the MOS transistor Q3 is connected to the driving voltage, and the source of the MOS transistor Q4 is grounded. The source of the MOS transistor Q3 and the drain of the MOS transistor Q4 are electrically connected to the negative or positive terminal of the ultrasonic probe S1 through the isolation diode D2.

[0038] The pre-receiving circuit includes an RC circuit, which is connected to the ultrasonic probe S1 and the differential amplifier circuit. The RC circuit includes capacitors C1 and C2, resistors R1 and R2.

[0039] The capacitor C1 is connected in series with the resistor R1, and the other end of the capacitor C1 is connected to the positive / negative terminal of the ultrasonic probe S1; the capacitor C2 is connected in series with the resistor R2, and the other end of the capacitor C2 is connected to the negative / positive terminal of the ultrasonic probe S1; the other ends of the resistor R1 and the other ends of the resistor R2 are connected to the differential amplifier circuit.

[0040] A clamping diode D3 is connected in series between the other end of resistor R1 and the other end of resistor R2.

[0041] When transmitting an ultrasonic pulse, the ultrasonic probe S11 is driven by the pulse power of Q1, Q2, Q3, Q4 of the H-bridge drive circuit and the isolation diodes D1 and D2, exciting it to transmit ultrasonic pulse waves. When receiving the echo, the echo signal sensed by the probe is coupled to the differential amplifier U1 for differential amplification through the high-impedance RC network of C1, C2, R1, R2 and the clamping circuit of D3. When the ultrasonic probe S1 finishes transmitting the pulse, the two low-side MOSFETs Q2 and Q4 of the H-bridge drive circuit are immediately forced to conduct, and their equivalent diagram is shown in Figure 1. Figure 2 The residual charge on the ultrasonic probe S1 is rapidly discharged to ground through MOSFETs Q2 and Q4. In this way, the residual high voltage on the ultrasonic probe S1 is rapidly discharged through isolation diodes D1 and D2. Since the isolation diodes have a forward voltage drop of several hundred millivolts, this voltage drop plays a good role in isolating the echo signal. For weak echo signals in the range of μV or several mV, the amplitude is much lower than the forward voltage drop of D1 and D2. Therefore, D1 and D2 are high impedance to the echo signal and cannot be attenuated by short-circuiting Q2 and Q4. In this way, seamless switching of single probe transmission and reception is perfectly achieved.

[0042] Upon encountering an echo signal, the ultrasonic probe S1 generates a weak voltage in the mV range. This voltage is much smaller than the forward voltage drop of isolation diodes D1 and D2, thus the diodes act as isolation devices. The weak echo voltage can only flow through the RC circuit of the pre-amplifier circuit into the input terminal of the differential amplifier circuit for amplification. Clamping diode D3 provides protection, limiting the input voltage to a maximum of 0.7V to prevent the hundreds of volts of high voltage from the transmitting circuit from damaging the amplifier input terminal.

[0043] The driving voltage of the H-bridge drive circuit comes from the output of the programmable high-voltage adjustable power supply. Its voltage can be adjusted as needed. The maximum voltage is determined according to the user's requirements and the parameters of the ultrasonic probe S1. In this example, the driving voltage range is between 0 and 200V.

[0044] In a preferred embodiment, the single-probe ultrasonic ranging circuit further includes an H-bridge controller, which is electrically connected to the gates of MOS transistors Q1, Q2, Q3, and Q4.

[0045] Reference Figure 3 As shown, the H-bridge controller uses the IR2101STRPBF chip. H-bridge controller U2 is connected to the gates of MOSFETs Q1 and Q2, and H-bridge controller U3 is connected to the gates of MOSFETs Q3 and Q4. The HIN and LIN ports of the H-bridge controller acquire control signals. The VCC port of the H-bridge controller is connected to VCC, and the COM port of the H-bridge controller is grounded. A capacitor is connected in series between the VCC port and the COM port. The HO port of the H-bridge controller is connected to the gate of MOSFET Q1. Bootstrap diodes D4 and D5 are connected between the VB port and the VCC port of the H-bridge controller, with the anode of the bootstrap diode connected to the VCC port. The VS port of the H-bridge controller is connected to the source of MOSFET Q1. Bootstrap capacitors C3 and C4 are connected in series between the VB port and the VS port. The LO port of the H-bridge controller is connected to the gate of MOSFET Q2.

[0046] The TTL timing control signal from the control unit provides control signals to the H-bridge controllers U1 and U2 through the four input terminals H1, H2, L1, and L2. The output level of the H-bridge controller is passed through the bootstrap diode and bootstrap capacitor to obtain the drive level of the high-side MOS transistor of the H-bridge, thereby realizing level matching and driving of the drive bridge composed of MOS transistors.

[0047] See Figure 4 The logic control timing for forced blanking is as follows: after the ultrasonic pulse is emitted, the control unit provides a high level to L1 and L2 and a low level to H1 and H2, which turns on the two low-side MOSFETs Q2 and Q4 and turns off the high-side MOSFETs Q1 and Q3. In this way, the residual charge on the ultrasonic probe S1 is discharged instantaneously by Q2 and Q4, achieving the effect of forced blanking.

[0048] In a preferred embodiment, a protective resistor R3 is connected to the positive and negative terminals of the ultrasonic probe S1.

[0049] The present invention also discloses a single-probe ultrasonic ranging device, which employs the above-mentioned single-probe ultrasonic ranging circuit.

[0050] Specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various changes or modifications within the scope of the claims, which do not affect the essence of the present invention. Unless otherwise specified, the embodiments and features described in this application can be arbitrarily combined with each other.

Claims

1. A single-probe ultrasonic ranging circuit, characterized in that, include: Transmitter drive circuit and pre-receiver circuit; The transmission drive circuit includes an H-bridge drive circuit and an isolation diode. The H-bridge drive circuit is electrically connected to the positive and negative terminals of the ultrasonic probe S1, and the isolation diode is connected in series between the H-bridge drive circuit and the positive and negative terminals of the ultrasonic probe S1. The positive terminal of the H-bridge drive circuit is connected to the drive voltage, and the negative terminal of the H-bridge drive circuit is grounded. When the ultrasonic probe S1 finishes emitting a pulse, it is grounded through the negative terminal of the H-bridge drive circuit. The pre-receiving circuit is electrically connected to the positive and negative terminals of the ultrasonic probe S1. The H-bridge drive circuit includes MOSFETs Q1, Q2, Q3, and Q4; The MOS transistors Q1 and Q2 are connected in series. The drain of the MOS transistor Q1 is connected to the driving voltage, and the source of the MOS transistor Q2 is grounded. The source of the MOS transistor Q1 and the drain of the MOS transistor Q2 are electrically connected to the positive / negative terminal of the ultrasonic probe S1 through an isolation diode. The MOS transistors Q3 and Q4 are connected in series. The drain of the MOS transistor Q3 is connected to the driving voltage, and the source of the MOS transistor Q4 is grounded. The source of the MOS transistor Q3 and the drain of the MOS transistor Q4 are electrically connected to the negative / positive terminal of the ultrasonic probe S1 through an isolation diode. When the ultrasonic probe S1 finishes emitting a pulse, the MOS transistors Q2 and Q4 are turned on, and the positive and negative terminals of the ultrasonic probe S1 are grounded through the isolation diode. The front-end receiving circuit includes an RC circuit, which is connected to the ultrasonic probe S1 and the differential amplifier circuit respectively. The RC circuit includes capacitor C1, capacitor C2, resistor R1, and resistor R2; The capacitor C1 is connected in series with the resistor R1, and the other end of the capacitor C1 is connected to the positive / negative terminal of the ultrasonic probe S1; The capacitor C2 and the resistor R2 are connected in series, and the other end of the capacitor C2 is connected to the negative / positive terminal of the ultrasonic probe S1; The other end of resistor R1 and the other end of resistor R2 are connected to a differential amplifier circuit; The residual charge on the ultrasonic probe S1 is rapidly discharged to ground through MOSFETs Q2 and Q4, causing the residual high voltage on the ultrasonic probe S1 to discharge rapidly through the isolation diode. Since the isolation diode has a forward voltage drop of several hundred millivolts, the voltage drop isolates the echo signal. For weak echo signals in the range of μV or several mV, the amplitude is lower than the forward voltage drop of the isolation diode. The isolation diode presents a high impedance to the echo signal and cannot be attenuated by short-circuiting Q2 and Q4. When the ultrasonic probe S1 encounters an echo signal, it generates a weak voltage in the mV range. This voltage is less than the forward voltage drop of the isolation diode, which acts as an isolation device. The weak echo voltage can only flow into the input terminal of the differential amplifier circuit through the RC circuit of the pre-receiving circuit for amplification.

2. The single-probe ultrasonic ranging circuit according to claim 1, characterized in that, It also includes an H-bridge controller, which is electrically connected to the gates of MOSFET Q1, MOSFET Q2, MOSFET Q3 and MOSFET Q4.

3. The single-probe ultrasonic ranging circuit according to claim 2, characterized in that, The H-bridge controller uses an IR2101STRPBF chip. Control signals are acquired through the HIN and LIN ports of the H-bridge controller. The VCC port of the H-bridge controller is connected to VCC. The COM port of the H-bridge controller is grounded. A capacitor C2 is connected in series between the VCC port and the COM port. The HO port of the H-bridge controller is connected to the gate of MOSFET Q1. A diode D2 is connected in series between the VB port and the VCC port of the H-bridge controller, with the anode of diode D2 connected to the VCC port. The VS port of the H-bridge controller is connected to the source of MOSFET Q1. A capacitor C1 is connected in series between the VB port and the VS port. The LO port of the H-bridge controller is connected to the gate of MOSFET Q2.

4. The single-probe ultrasonic ranging circuit according to claim 1, characterized in that, A clamping diode D3 is connected in series between the other end of resistor R1 and the other end of resistor R2.

5. The single-probe ultrasonic ranging circuit according to claim 1, characterized in that, It also includes a protective resistor R3, the two ends of which are connected to the positive and negative terminals of the ultrasonic probe S1, respectively.

6. A single-probe ultrasonic ranging device, characterized in that, Includes the single-probe ultrasonic ranging circuit according to any one of claims 1-5.

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