Ultrasonic drive circuit, ultrasonic radar, and vehicle

Abstract

The present application provides an ultrasonic drive circuit, an ultrasonic radar, and a vehicle, relating to the technical field of ultrasonic apparatuses. The circuit comprises: a capacitor and a power supply module. The capacitor is connected to the power supply module, and the capacitor is further configured to connect an ultrasonic transducer. The power supply module is configured to charge the capacitor. The capacitor is configured to provide a positive pressure drive signal and / or a negative pressure drive signal to the ultrasonic transducer. Detection ranges of ultrasonic waves emitted by the ultrasonic transducer under the drive of the positive pressure drive signal and the negative pressure drive signal are different. According to the present application, detection distances of the ultrasonic waves emitted by the ultrasonic transducer can be increased without increasing the integrated area of the entire ultrasonic drive circuit.

Description

Ultrasonic driving circuit, ultrasonic radar and vehicle

[0001] The present application claims priority to the Chinese patent application No. 202411053416.X, filed on August 01, 2024, entitled "Ultrasonic driving circuit, ultrasonic radar and vehicle", the whole content of which is incorporated herein by reference. TECHNICAL FIELD

[0002] The present application relates to the technical field of ultrasonic device, in particular to an ultrasonic driving circuit, an ultrasonic radar and a vehicle. BACKGROUND

[0003] The ultrasonic driving circuit is used to amplify the input signal of the signal source, so as to drive the ultrasonic transducer to generate the ultrasonic signal. The transmitting pulse level range of the ultrasonic driving circuit directly determines the maximum detectable distance of the ultrasonic signal generated by the ultrasonic transducer. The maximum detectable distance of the ultrasonic signal transmitted by the ultrasonic transducer can be expanded to twice of that of the unipolar pulse level by the bipolar pulse level.

[0004] At present, one way is to use a transformer to generate a bipolar pulse level, but in this way, an off-chip inductor is needed, and the cost of the off-chip inductor is high. Another way is to increase a negative high-voltage power supply on the basis of a traditional single positive high-voltage power supply, so as to provide a positive and negative high-voltage dual power supply rail for the ultrasonic driving circuit, but this way will increase the integrated area of the whole ultrasonic driving circuit. SUMMARY

[0005] The present application provides an ultrasonic driving circuit, an ultrasonic radar and a vehicle, which can increase the corresponding detection distance of the ultrasonic signal transmitted by the ultrasonic transducer without increasing the integrated area of the whole ultrasonic driving circuit.

[0006] The present application provides an ultrasonic driving circuit for driving an ultrasonic transducer, comprising: a capacitor and a power supply module.

[0007] The capacitor is connected with the power supply module, and the capacitor is further used to connect the ultrasonic transducer.

[0008] The power supply module is used to charge the capacitor.

[0009] The capacitor is used to provide a positive voltage driving signal and / or a negative voltage driving signal to the ultrasonic transducer, and the detection range of the ultrasonic signal transmitted by the ultrasonic transducer driven by the positive voltage driving signal and the negative voltage driving signal is different.

[0010] In an optional embodiment, the capacitor comprises a first electrode plate and a second electrode plate.

[0011] When the capacitor provides a positive pressure driving signal to the ultrasonic transducer, the first plate is connected to the ultrasonic transducer, and the second plate is grounded.

[0012] An optional embodiment, when the capacitor provides a negative pressure driving signal to the ultrasonic transducer, the first plate is grounded, and the second plate is connected to the ultrasonic transducer.

[0013] An optional embodiment, the ultrasonic driving circuit further comprises a switching module.

[0014] The switching module is connected to the capacitor, and is configured to form a corresponding driving path when the capacitor provides the positive pressure driving signal or the negative pressure driving signal to the ultrasonic transducer.

[0015] An optional embodiment, the switching module comprises a first switching circuit and a second switching circuit.

[0016] The first switching circuit is connected between the capacitor and the ultrasonic transducer, and is configured to connect the first plate to the ultrasonic transducer when the capacitor provides a positive pressure driving signal to the ultrasonic transducer, and is configured to connect the second plate to the ultrasonic transducer when the capacitor provides a negative pressure driving signal to the ultrasonic transducer.

[0017] The second switching circuit is connected between the capacitor and a ground terminal, and is configured to ground the second plate when the capacitor provides a positive pressure driving signal to the ultrasonic transducer, and is configured to ground the first plate when the capacitor provides a negative pressure driving signal to the ultrasonic transducer.

[0018] An optional embodiment, the first switching circuit comprises a first switch tube, and the second switching circuit comprises a fourth switch tube.

[0019] The first switch tube is connected between the first plate and the ultrasonic transducer, and is configured to be turned on when the capacitor provides a positive pressure driving signal to the ultrasonic transducer.

[0020] The fourth switch tube is connected between the second plate and the ground terminal, and is configured to be turned on when the capacitor provides a positive pressure driving signal to the ultrasonic transducer.

[0021] An optional embodiment, the first switching circuit comprises a second switch tube, and the second switching circuit comprises a third switch tube.

[0022] The second switch tube is connected between the second plate and the ultrasonic transducer, and is used to be turned on when the capacitor provides a negative voltage driving signal to the ultrasonic transducer.

[0023] The third switch tube is connected between the first plate and the ground terminal, and is used to be turned on when the capacitor provides a negative voltage driving signal to the ultrasonic transducer.

[0024] In an optional implementation, the switch module further comprises a first driving circuit, wherein the first driving circuit is connected to the driving end of the first switch tube, and is used to drive the first switch tube to be turned on when the capacitor provides a positive voltage driving signal to the ultrasonic transducer.

[0025] In an optional implementation, the first driving circuit comprises a driving voltage generation sub-circuit and a driving voltage reset sub-circuit.

[0026] The first end of the driving voltage generation sub-circuit is connected to the first plate of the capacitor, the second end is connected to a first power supply terminal, and the third end is connected to the driving end of the first switch tube, and is used to provide a first driving voltage to the driving end of the first switch tube.

[0027] The first end of the driving voltage reset sub-circuit is connected to the first plate of the capacitor, the second end is grounded, and the third end is connected to the driving end of the first switch tube, and is used to provide a reset voltage to the driving end of the first switch tube.

[0028] In an optional implementation, the driving voltage generation sub-circuit comprises:

[0029] A first Zener diode, whose first end is connected to the first plate of the capacitor.

[0030] A first capacitor, whose first plate is connected to the second end of the first voltage stabilizing element.

[0031] A first inverter, one end of which is connected to the second plate of the first capacitor, and the other end of which is connected to the first power supply terminal.

[0032] The first plate of the first capacitor is further connected to the driving end of the first switch tube, and is used to provide the first driving voltage to the driving end of the first switch tube.

[0033] In an optional implementation, the driving voltage reset sub-circuit comprises a first current mirror, a second current mirror, a first control tube, a second control tube, and a bias voltage source.

[0034] The bias voltage source is connected with the first end of the first current mirror through the first control tube, the second end of the first current mirror is connected with the first end of the second current mirror through the second control tube, the third end of the first current mirror is grounded, and the second end of the second current mirror is connected with the first plate of the capacitor.

[0035] The output end of the first control tube is connected with the control end of the first current mirror, the output end of the second control tube is connected with the control end of the second current mirror, and the control end of the first control tube and the control end of the second control tube are used for connecting a reset signal end.

[0036] The third end of the second current mirror is connected with the driving end of the first switch tube, and used for providing the reset voltage to the driving end of the first switch tube.

[0037] An optional implementation, the switch module further comprises a fourth drive circuit; the fourth drive circuit is connected with the driving end of the fourth switch tube, and used for driving the first switch tube to be turned on in the case that the capacitor provides a positive voltage driving signal to the ultrasonic transducer.

[0038] An optional implementation, the fourth drive circuit comprises: a fourth inverter, one end of which is connected with a fourth power supply end.

[0039] A third capacitor, a first plate of which is connected with the other end of the fourth inverter.

[0040] A third Zener tube, a first end of which is connected with the second plate of the third capacitor, and a second end of which is grounded.

[0041] The second plate of the third capacitor is further connected with the driving end of the fourth switch tube, and used for providing a fourth drive voltage to the driving end of the fourth switch tube.

[0042] An optional implementation, the switch module further comprises a second drive circuit; the second drive circuit is connected with the driving end of the second switch tube, and used for driving the second switch tube to be turned on in the case that the capacitor provides a negative voltage driving signal to the ultrasonic transducer.

[0043] An optional implementation, the second drive circuit comprises:

[0044] A second Zener tube, a first end of which is connected with the second plate of the capacitor.

[0045] A second capacitor, a first plate of which is connected with the second end of the second voltage stabilizing element.

[0046] A second inverter, one end of which is connected with the second plate of the second capacitor, and the other end of which is connected with a second power supply end.

[0047] The first plate of the second capacitor is also connected to the driving end of the second switch tube, for providing a second driving voltage to the driving end of the second switch tube.

[0048] In an alternative embodiment, the switch module further comprises a third driving circuit; the third driving circuit is connected to the driving end of the third switch tube, for driving the third switch tube to be turned on when the capacitor provides a negative voltage driving signal to the ultrasonic transducer.

[0049] In an alternative embodiment, the third driving circuit comprises:

[0050] a third inverter, one end of which is connected to the third power supply end, and the other end of which is connected to the driving end of the third switch tube, for providing a third driving voltage to the driving end of the third switch tube.

[0051] In an alternative embodiment, the power supply module comprises a power supply and a fifth switch tube.

[0052] The power supply is connected to the first end of the fifth switch tube, and the second end of the fifth switch tube is connected to the first plate of the capacitor, and the power supply is used to charge the capacitor.

[0053] The switch module is also connected to the driving end of the fifth switch tube, for driving the fifth switch tube to be turned on when the capacitor is charging.

[0054] In an alternative embodiment, the switch module further comprises a fifth driving circuit, and the fifth driving circuit is connected to the driving end of the fifth switch tube, for driving the fifth switch tube to be turned on when the capacitor is charging.

[0055] In an alternative embodiment, the fifth driving circuit comprises:

[0056] a first resistor, one end of which is connected to the power supply.

[0057] a fourth Zener diode, which is connected across the first resistor.

[0058] a sixth switch tube, the first end of which is connected to the other end of the first resistor, and the driving end of which is connected to a fifth power supply end.

[0059] and a current source, one end of which is connected to the second end of the sixth switch tube, and the other end of which is grounded.

[0060] The first end of the sixth switch tube is also connected to the driving end of the fifth switch tube, for providing a fifth driving voltage to the fifth switch tube.

[0061] The application further provides an ultrasonic radar, comprising an ultrasonic transducer, a controller and the ultrasonic drive circuit in the application.

[0062] The controller is connected with the first end of the ultrasonic drive circuit, and the second end of the ultrasonic drive circuit is connected with the ultrasonic transducer.

[0063] The controller is used for controlling the ultrasonic drive circuit to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges through the ultrasonic drive circuit.

[0064] The application further provides a vehicle comprising the ultrasonic radar in the application.

[0065] The technical scheme provided by the application can emit multiple drive signals based on the single charging of the capacitor before the ultrasonic transducer emits ultrasonic signals, and the capacitor can provide positive and negative drive signals for the ultrasonic transducer when the ultrasonic transducer is in the emission stage based on the structure of the capacitor itself, and the ultrasonic waves emitted by the ultrasonic transducer have different detection ranges under the drive of the positive and negative drive signals.

[0066] In addition, the capacitor can be integrated outside the chip where the ultrasonic drive circuit is located, and the number of power modules used in the application is one, so the area of the chip occupied by the power module is basically the same as that when a single high-voltage power supply is used, and therefore the technical scheme of the application will not increase the integrated area of the entire ultrasonic drive circuit. BRIEF DESCRIPTION OF DRAWINGS

[0067] The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments consistent with the application and, together with the description, serve to explain the principles of the application.

[0068] FIG. 1 is an equivalent model of a transducer provided by an embodiment of the application;

[0069] FIG. 2 is a schematic diagram of a unipolar pulse (top) and a bipolar pulse (top) provided by an embodiment of the application;

[0070] FIG. 3 is a structural schematic diagram of an ultrasonic drive circuit provided by an embodiment of the application;

[0071] FIG. 4 is a structural schematic diagram of another ultrasonic drive circuit provided by an embodiment of the application;

[0072] FIG. 5 is a structural schematic diagram of a first drive circuit provided by an embodiment of the application;

[0073] Fig. 6 is a structural schematic diagram of a second drive circuit according to an embodiment of the present application;

[0074] Fig. 7 is a structural schematic diagram of a third drive circuit according to an embodiment of the present application;

[0075] Fig. 8 is a structural schematic diagram of a fourth drive circuit according to an embodiment of the present application;

[0076] Fig. 9 is a structural schematic diagram of a fifth drive circuit according to an embodiment of the present application;

[0077] Fig. 10 is a structural schematic diagram of an ultrasonic drive circuit according to an embodiment of the present application;

[0078] Fig. 11 is a structural schematic diagram of an ultrasonic drive circuit according to an embodiment of the present application;

[0079] Fig. 12 is a timing chart of an ultrasonic drive circuit according to an embodiment of the present application;

[0080] Fig. 13 is a schematic block diagram of an ultrasonic radar according to an embodiment of the present application;

[0081] Fig. 14 is a schematic diagram of a vehicle according to an embodiment of the present application.

[0082] Reference Signs: 10: capacitor; 30: power supply module; 11: first electrode plate; 12: second electrode plate; 21: first switching circuit; 22: second switching circuit; 231: first drive circuit; 232: second drive circuit; 233: third drive circuit; 234: fourth drive circuit; 301: power supply; 40: ultrasonic radar; 41: controller; 50: vehicle.

[0083] The specific embodiments of the present application have been shown and described in the above-described drawings and specification, and the following detailed description is made in reference thereto. These drawings and detailed description are not intended to limit the scope of the inventive concept in any way, but rather to illustrate the inventive concept by reference to specific embodiments. DETAILED DESCRIPTION

[0084] The exemplary embodiments will be described in detail herein below with reference to the drawings. In the following description, the same drawings reference numbers are used to denote like or similar elements. The embodiments described in the following exemplary embodiments are not representative of all embodiments consistent with the present application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of the present application, as detailed in the appended claims.

[0085] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for describing particular embodiments only and is not intended to be limiting of the application. It is to be understood that the use of "first", "second", etc. herein does not denote any order, quantity, or importance, but rather is used to distinguish one element from another. For example, a first action can be termed a second action, and similarly, a second action can be termed a first action, without departing from the scope of the present application, without departing from the scope of the application.

[0086] First, the terms involved in the present application are explained:

[0087] Ultrasonic drive circuit: is used to drive the ultrasonic transducer electronic circuit, can be converted into a low frequency or direct current signal into a high frequency alternating current signal, so that the ultrasonic transducer produces ultrasonic waves.

[0088] Ultrasonic transducer: is a kind of device that converts electrical energy into ultrasonic energy, or converts ultrasonic energy into electrical energy.

[0089] Ultrasonic radar: is a kind of device that uses ultrasonic waves to detect and measure distance. It determines the position, distance and speed of the target object by emitting ultrasonic signals and receiving the reflected echo signals. Ultrasonic radar is widely used in car reversing radar, robot navigation, liquid level measurement, obstacle detection and other fields.

[0090] Before introducing the content of the present application, the technology involved in the present application is introduced as follows:

[0091] Ultrasonic wave refers to the sound wave beyond the highest threshold (20 kHz) that human ear can hear, which has strong directivity and is almost not affected by light, dust, smoke and electromagnetic interference. The ultrasonic drive circuit in ultrasonic radar is one of the important components of the whole radar system. The ultrasonic drive circuit is usually a power amplifier, which is used to amplify the input signal of the signal source, so as to drive the ultrasonic transducer to generate ultrasonic signal. The ultrasonic transducer can be equivalent to R-L-C series-parallel resonance model formed by resistance-inductance-capacitance, as shown in figure 1.

[0092] The transmitting pulse level range of the ultrasonic wave driving circuit directly determines the maximum detectable distance of the ultrasonic wave radar. Generally, the input voltage of the chip is small, and therefore, the high-voltage power supply needs to be generated by the on-chip integrated boost circuit. Taking the common on-chip boost circuit charge pump as an example, in order to improve the output voltage, more charge pump stages are needed, and the area of the charge pump will increase significantly, and the energy loss will also increase with the increase of the number of stages. As shown in FIG. 2, the bipolar level pulse can expand the ultrasonic wave radar transmitting pulse level to twice of the unipolar level, and more importantly, the average direct current voltage of the transducer driven by the bipolar pulse is zero when working, which can avoid the leakage of even order harmonics, and the round-trip signal-to-noise ratio is higher. That is, the detection distance of the bipolar level pulse is farther, and the energy loss is lower.

[0093] At present, the bipolar ultrasonic wave driving circuit mainly includes the following modes:

[0094] One mode is to use a transformer to generate a bipolar pulse level, but in this mode, an off-chip inductor needs to be set, and the cost of the off-chip inductor is high.

[0095] Another mode is to increase a negative high-voltage power supply on the basis of a traditional single positive high-voltage power supply, so as to provide a positive and negative high-voltage double power supply rail for the ultrasonic wave driving circuit, but this mode will increase the integrated area of the entire ultrasonic wave driving circuit.

[0096] Based on this, the embodiment of the present application provides a technical solution capable of increasing the corresponding detection distance of the ultrasonic wave transmitted by the ultrasonic wave transducer without increasing the integrated area of the entire ultrasonic wave driving circuit.

[0097] The technical solution of the present application and how the technical solution of the present application solves the above technical problems will be described in detail in the following specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes can not be described in detail in some embodiments. The embodiments of the present application will be described below with reference to the accompanying drawings.

[0098] In a first aspect, referring to FIG. 3, the present application provides an ultrasonic wave driving circuit for driving the ultrasonic wave transducer; which can include: a capacitor 10 and a power supply module 30;

[0099] The capacitor 10 is connected with the power supply module 30, and the capacitor 10 is also used to connect the ultrasonic wave transducer.

[0100] The power supply module 30 is used to charge the capacitor 10.

[0101] The capacitor 10 is used to provide a positive voltage driving signal and / or a negative voltage driving signal to the ultrasonic transducer; wherein the positive voltage driving signal and the negative voltage driving signal drive the ultrasonic transducer to emit ultrasonic waves with different detection ranges.

[0102] The capacitor 10 is used to store electrical energy and release the energy when driving the ultrasonic transducer to emit ultrasonic waves. The power supply module 30 provides stable electrical energy to the capacitor 10 to charge the capacitor 10.

[0103] Optionally, the capacitor can be a super capacitor. Since the super capacitor has the advantages of high power density, long cycle life and fast charging and discharging, the super capacitor can be used in the embodiment and can drive the ultrasonic transducer to complete multiple emission cycles after a single charging.

[0104] Based on the above structure and description, the embodiment of the application can emit multiple driving signals based on the fast charging of the capacitor and the characteristic of storing electrical energy before the ultrasonic transducer emits ultrasonic signals. Based on the structure of the capacitor itself, the capacitor can provide a positive voltage driving signal and a negative voltage driving signal to the ultrasonic transducer when the ultrasonic transducer is in the emission stage. Under the driving of the positive voltage driving signal and the negative voltage driving signal, the ultrasonic waves emitted by the ultrasonic transducer have different detection ranges. Based on this, the detection distance of the ultrasonic waves emitted by the ultrasonic transducer can be increased.

[0105] In addition, the capacitor can be integrated outside the chip where the ultrasonic driving circuit is located. The number of power supply modules used in the application is one. Therefore, the area of the chip occupied by the power supply module is basically the same as that when a single high-voltage power supply is used in the traditional way. Therefore, the technical solution of the application will not increase the integrated area of the entire ultrasonic driving circuit.

[0106] Optionally, the capacitor 10 includes a first electrode plate 11 and a second electrode plate 12; when the capacitor 10 provides a positive voltage driving signal and a negative voltage driving signal to the ultrasonic transducer, the connection relationship between the capacitor and the ultrasonic transducer is different.

[0107] For example, when the capacitor 10 provides a positive voltage driving signal to the ultrasonic transducer, the first electrode plate 11 is connected to the ultrasonic transducer, and the second electrode plate 12 is grounded.

[0108] For another example, when the capacitor 10 provides a negative voltage driving signal to the ultrasonic transducer, the first electrode plate 11 is grounded, and the second electrode plate 12 is connected to the ultrasonic transducer.

[0109] In an alternative embodiment, the ultrasonic driving circuit can further comprise a switch module; the switch module is connected with the capacitor 10, and is used to form a corresponding driving path when the capacitor 10 provides the positive voltage driving signal or the negative voltage driving signal to the ultrasonic transducer.

[0110] Further, the switch module can be used to control the charging process of the capacitor.

[0111] According to different stages of the capacitor, the working process of the above ultrasonic driving circuit can be divided into a pre-charging stage and a driving stage.

[0112] In the pre-charging stage, the capacitor 10 is connected with the power module 30, and is used to provide electric energy for the capacitor 10.

[0113] Referring to FIG. 3, in this stage, the first plate 11 of the capacitor 10 is connected with the power module 30, so as to charge the capacitor 10.

[0114] In the driving stage, the ultrasonic transducer is driven to generate ultrasonic signals with different detection ranges by different connection modes of the capacitor 10 and the switch module. Alternatively, referring to FIG. 3, the first plate 11 of the capacitor 10 is connected with the switch module, and the second plate 12 is grounded through the switch module; the first plate 11 of the capacitor 10 is used to provide a positive voltage driving signal to the ultrasonic transducer through the switch module.

[0115] Referring to FIG. 3, the first plate 11 of the capacitor 10 is also used to be grounded through the switch module; at this time, the second plate 12 is a negative voltage; the second plate 12 of the capacitor 10 is used to provide a negative voltage driving signal to the ultrasonic transducer through the switch module. The positive voltage driving signal and the negative voltage driving signal correspond to different detection ranges of the ultrasonic signals emitted by the ultrasonic transducer.

[0116] In this embodiment, the capacitor can be used to realize efficient energy storage and rapid release, so as to drive the ultrasonic transducer. The switch module can realize accurate control of the energy release process of the capacitor, thereby improving the working efficiency and stability of the ultrasonic transducer.

[0117] The above embodiment describes the overall structure of the ultrasonic driving circuit, and the following embodiment focuses on the specific structure and function of the switch module.

[0118] Alternatively, referring to FIG. 4, the switch module can comprise a first switch circuit 21 and a second switch circuit 22.

[0119] The first switch circuit 21 is connected between the capacitor 10 and the ultrasonic transducer, and is used to connect the first plate 11 to the ultrasonic transducer when the capacitor 10 provides a positive voltage driving signal to the ultrasonic transducer, and is used to connect the second plate 12 to the ultrasonic transducer when the capacitor 10 provides a negative voltage driving signal to the ultrasonic transducer.

[0120] The second switch circuit 22 is connected between the capacitor 10 and the ground terminal, and is used to ground the second plate 12 when the capacitor 10 provides a positive voltage driving signal to the ultrasonic transducer, and is used to ground the first plate 11 when the capacitor 10 provides a negative voltage driving signal to the ultrasonic transducer.

[0121] In the embodiment, the first switch circuit 21 and the second switch circuit 22 are used to turn on the driving path between the first plate 11 or the second plate 12 of the capacitor 10 and the ultrasonic transducer, so as to provide a positive voltage driving signal or a negative voltage driving signal to the ultrasonic transducer.

[0122] In the positive voltage driving signal, the ultrasonic transducer can emit ultrasonic signals of a first detection range. In the negative voltage driving signal, the ultrasonic transducer can emit ultrasonic signals of a second detection range.

[0123] Based on the above description, the embodiment can control the first switch circuit and the second switch circuit through the driving circuit, so that the capacitor can provide a positive voltage driving signal and a negative voltage driving signal to the ultrasonic transducer, so as to make the ultrasonic transducer emit ultrasonic signals of a first detection range and ultrasonic signals of a second detection range, thereby providing an implementable solution for improving the detection range of the ultrasonic transducer.

[0124] The above describes the structure and function of the switch module, and the following describes the structure and function of the first switch circuit and the second switch circuit in more detail.

[0125] In an example, the first switch circuit 21 includes a first switch tube, and the second switch circuit 22 includes a fourth switch tube. The first switch tube is connected between the first plate 11 and the ultrasonic transducer, and is used to be turned on when the capacitor 10 provides a positive voltage driving signal to the ultrasonic transducer. The fourth switch tube is connected between the second plate 12 and the ground terminal, and is used to be turned on when the capacitor 10 provides a positive voltage driving signal to the ultrasonic transducer.

[0126] In another example, the first switch circuit 21 comprises a second switch tube, and the second switch circuit 22 comprises a third switch tube; the second switch tube is connected between the second plate 12 and the ultrasonic transducer, and is used to be turned on when the capacitor 10 provides a negative voltage driving signal to the ultrasonic transducer; the third switch tube is connected between the first plate 11 and the ground, and is used to be turned on when the capacitor 10 provides a negative voltage driving signal to the ultrasonic transducer.

[0127] The above two examples describe the structure of the first switch circuit and the second switch circuit from the perspective of providing a positive voltage driving signal or a negative voltage driving signal from the capacitor to the ultrasonic transducer. The following describes the first switch circuit and the second switch circuit from the perspective of the overall structure.

[0128] In one example, referring to FIG. 4, the first switch circuit 21 comprises a first switch tube M1 and a second switch tube M2, and the second switch circuit 22 comprises a third switch tube M3 and a fourth switch tube M4.

[0129] Referring to FIG. 4, the first end of the first switch tube M1 is connected with the first plate 11, the second end is connected with the first end of the second switch tube M2 and is used to be connected with the ultrasonic transducer, the first switch tube M1 is turned on when the first plate 11 provides a positive voltage driving signal to the ultrasonic transducer, and is turned off when the second plate 12 provides a negative voltage driving signal to the ultrasonic transducer.

[0130] The second end of the second switch tube M2 is connected with the second plate 12, the first switch tube M1 and the second switch tube M2 are turned off when the first plate 11 provides a positive voltage driving signal to the ultrasonic transducer, and are turned on when the second plate 12 provides a negative voltage driving signal to the ultrasonic transducer.

[0131] The first end of the third switch tube M3 is connected with the first plate 11, the second end is connected with the first end of the fourth switch tube M4 and is grounded, the third switch tube M3 is turned off when the first plate 11 provides a positive voltage driving signal to the ultrasonic transducer, and is turned on when the second plate 12 provides a negative voltage driving signal to the ultrasonic transducer.

[0132] The second end of the fourth switch tube M4 is connected with the second plate 12, the fourth switch tube M4 is turned on when the first plate 11 provides a positive voltage driving signal to the ultrasonic transducer, and is turned off when the second plate 12 provides a negative voltage driving signal to the ultrasonic transducer.

[0133] In some embodiments, the first plate 11 can be the positive plate of the capacitor 10, and the second plate 12 can be the negative plate of the capacitor 10, based on which the first plate 11 can provide a positive voltage driving signal to the ultrasonic transducer, and the second plate 12 can provide a negative voltage driving signal to the ultrasonic transducer.

[0134] Based on the above description, in the driving stage, the first switch M1 is driven to be turned on, the second switch M2 is turned off, the third switch M3 is turned off, and the fourth switch M4 is turned on. At this time, the second plate 12 of the capacitor 10 is grounded, the first plate 11 is connected to the first end of the ultrasonic transducer through the first switch M1, and the second end of the ultrasonic transducer is grounded. The first plate 11 provides a positive voltage driving signal for the ultrasonic transducer, so as to drive the ultrasonic transducer to emit ultrasonic waves in the first detection range.

[0135] Then, the first switch M1 is driven to be turned off, the third switch M3 is turned on, and the fourth switch M4 is turned off. The first plate 11 of the capacitor 10 is grounded, and the voltage of the first plate 11 is set to 0. At this time, the voltage of the second plate 12 is negative, the second switch M2 is driven to be turned on, and the second plate 12 of the capacitor is connected to the first end of the ultrasonic transducer through the second switch M2. The second end of the ultrasonic transducer is grounded, and the second plate 12 provides a negative voltage driving signal for the ultrasonic transducer, so as to drive the ultrasonic transducer to emit ultrasonic waves in the second detection range.

[0136] It is worth noting that then, the second plate can be grounded again by the above-mentioned method, and the voltage of the second plate is set to 0. At this time, the voltage of the first plate 11 is positive, and the ultrasonic transducer can be provided with a positive voltage driving signal again. By repeating the above process, the ultrasonic transducer can be provided with alternating positive voltage driving signals and negative voltage driving signals.

[0137] The first switch, the second switch, the third switch, and the fourth switch can be any switch element with appropriate function and structure, and the embodiment does not make specific limitations.

[0138] For example, the first switch, the second switch, the third switch, and the fourth switch can be MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or IGBT (Insulated Gate Bipolar Transistor).

[0139] The above part describes the structure of the first switch circuit and the second switch circuit in the switch module, and the following part describes the driving circuit in the switch module.

[0140] Referring to FIG. 4, the switch module can further include a first driving circuit 231, a second driving circuit 232, a third driving circuit 233, and a fourth driving circuit 234.

[0141] The first driving circuit 231 is connected with the driving end of the first switch tube M1, and is used for controlling the first switch tube M1 to be turned on or turned off. Optionally, when the first polar plate 11 provides a positive voltage driving signal to the ultrasonic transducer, the first driving circuit is used for driving the first switch tube M1 to be turned on, and when the second polar plate 12 provides a negative voltage driving signal to the ultrasonic transducer, the first driving circuit is used for driving the first switch tube M1 to be turned off.

[0142] The second driving circuit 232 is connected with the third end of the second switch tube M2, and is used for controlling the second switch tube M2 to be turned on or turned off; optionally, when the first polar plate 11 provides a positive voltage driving signal to the ultrasonic transducer, the second driving circuit is used for driving the second switch tube M2 to be turned off, and when the second polar plate 12 provides a negative voltage driving signal to the ultrasonic transducer, the second driving circuit is used for driving the second switch tube M2 to be turned on.

[0143] The third driving circuit 233 is connected with the driving end of the third switch tube M3, and is used for controlling the third switch tube M3 to be turned on or turned off; optionally, when the first polar plate 11 provides a positive voltage driving signal to the ultrasonic transducer, the third driving circuit is used for driving the third switch tube M3 to be turned off, and when the second polar plate 12 provides a negative voltage driving signal to the ultrasonic transducer, the third driving circuit is used for driving the second switch tube M3 to be turned on.

[0144] The fourth driving circuit 234 is connected with the driving end of the fourth switch tube M4, and is used for controlling the fourth switch tube M4 to be turned on or turned off; optionally, when the first polar plate 11 provides a positive voltage driving signal to the ultrasonic transducer, the fourth driving circuit is used for driving the fourth switch tube M4 to be turned on, and when the second polar plate 12 provides a negative voltage driving signal to the ultrasonic transducer, the fourth driving circuit is used for driving the fourth switch tube M4 to be turned off.

[0145] In this embodiment, the driving circuit is divided into the first driving circuit 231, the second driving circuit 232, the third driving circuit 233 and the fourth driving circuit 234, based on which, the first switch tube M1, the second switch tube M2, the third switch tube M3 and the fourth switch tube M4 can be controlled separately, which not only can simplify the control logic and structure of the driving circuit, but also can realize more accurate and reliable control of the first switch tube M1, the second switch tube M2, the third switch tube M3 and the fourth switch tube M4, thereby further providing strong support for the capacitor to provide positive voltage driving signals and negative voltage driving signals to the ultrasonic transducer.

[0146] It should be understood that the above-mentioned first driving circuit can select any unit that can realize its driving logic, and the present embodiment does not make special limitation thereto.

[0147] For example, the first switch tube is a first transistor, and the first transistor is a P-type transistor. Referring to FIG. 5, the first driving circuit includes:

[0148] a driving voltage generation sub-circuit and a driving voltage reset sub-circuit;

[0149] The first end of the driving voltage generation sub-circuit is connected with the first plate 11 of the capacitor 10, the second end is connected with the first power supply end, and the third end is connected with the driving end of the first switch tube, so as to provide the first driving voltage to the driving end of the first switch tube.

[0150] The first end of the driving voltage reset sub-circuit is connected with the first plate 11 of the capacitor 10, the second end is grounded, and the third end is connected with the driving end of the first switch tube, so as to provide the reset voltage to the driving end of the first switch tube.

[0151] The driving voltage generation sub-circuit includes:

[0152] A first Zener tube Z1, the first end of which is connected with the first plate of the capacitor. The Zener tube works like a common diode when it is forward biased, but when it is reverse biased, it will conduct and maintain this voltage stable when the voltage reaches its breakdown voltage.

[0153] A first capacitor C1, the first plate of which is connected with the second end of the first voltage stabilizing element Z1.

[0154] A first inverter, one end of which is connected with the second plate of the first capacitor C1, and the other end is connected with the first power supply end VEN1.

[0155] The first plate of the first capacitor C1 is also connected with the third end of the first switch tube, so as to provide the first driving voltage to the third end of the first switch tube. The first driving voltage can include a first turn-off voltage for turning off the first switch tube and a first turn-on voltage for turning on the first switch tube.

[0156] The driving voltage reset sub-circuit includes:

[0157] A first current mirror (composed of M14 and M16), a second current mirror (composed of M11 and M12), a first control tube M15, a second control tube M13, and a bias voltage source;

[0158] The bias voltage source is connected with the first end of the first current mirror through the first control tube M15, the second end of the first current mirror is connected with the first end of the second current mirror through the second control tube M13, the third end of the first current mirror is grounded, and the second end of the second current mirror is connected with the first plate 11 of the capacitor 10;

[0159] The output end of the first control tube M15 is connected with the control end of the first current mirror, the output end of the second control tube M13 is connected with the control end of the second current mirror, the control end of the first control tube M15 and the control end of the second control tube M13 are used for connecting a reset signal end VRST; the third end of the second current mirror is connected with the driving end of the first switch tube, and is used for providing the reset voltage to the driving end of the first switch tube.

[0160] Based on the structure of the first driving circuit and the condition that the gate-source voltage of the first transistor is 5V, the working process of the first driving circuit is described.

[0161] In a complete transmitting cycle of the ultrasonic transducer, the first transistor experiences once conduction before the capacitor flips, once off, and once off after the capacitor flips. The source end of the first transistor is connected with the positive plate of the capacitor, so the voltage of the source end changes with the capacitor. In the off state, the first driving circuit ensures that the gate-source voltage of the first transistor is 0V, and in the on state, the first driving circuit ensures that the gate-source voltage of the first transistor is 5V. The gate voltage change process of the first transistor is HVVDD-5V, HVVDD, 0, -5V. The conventional high voltage level converter is difficult to realize this control function, so the capacitive high voltage level converter needs to be used. HVVDD is the first plate voltage of the capacitor, CFP is the first plate of the capacitor, which is connected with the cathode of the Zener tube Z1, the anode of the Zener tube Z1 is connected with the upper plate of the capacitor C1, and the gate control voltage is generated. The lower plate of the capacitor C1 is connected with the inverter. When VEN1 is 5V, the voltage of VGATE_CTRL1 is equal to the first plate voltage of the capacitor.

[0162] When VEN1 is 0V, the VGATE_CTRL1 voltage is equal to CFP-5V. When the first plate voltage of the capacitor is HVVDD and the second plate is 0V, the VGATE_CTRL1 switches between HVVDD to HVVDD-5V; when the first plate of the capacitor is 0V and the second plate voltage is HVVSS, the VGATE_CTRL1 switches between 0V to -5V, which can meet the requirements of the zeroing sequence. The static power consumption of the capacitive high voltage level converter is 0, and the output signal higher or lower than the voltage rail can be generated. Since the state of the ultrasonic transducer before the transmission stage is unknown due to the direct current isolation of the first capacitor C1, the driving voltage reset sub-circuit is needed. The driving voltage reset sub-circuit includes transistors M11-M16. The high voltage transistor M11 and the high voltage transistor M12 form a high voltage current mirror to release the charge on C1. The high voltage transistor M13 controls the off of the M12 current path, and at the same time, isolates the high voltage domain and the low voltage domain from each other. The low voltage transistor M14 and the low voltage transistor M16 form a low voltage current mirror to copy the current from the low voltage power supply. The low voltage transistor M15 controls the off of the M16 current path. When VRST is high, the VGATE_CTRL1 is reset to HVVSS; when VRST is low, the reset circuit current path is all off, and there is no static current.

[0163] Based on the above description, the third end voltage of the first switch tube can be reset before the ultrasonic transducer is in the transmission stage, so as to avoid damage to the first switch tube caused by the excessively high gate-source voltage of the first switch tube. When the ultrasonic transducer is in the transmission stage, the first switch tube is controlled to be turned on or turned off, so as to provide an executable solution for the capacitor to provide positive voltage driving signals and negative voltage driving signals to the ultrasonic transducer.

[0164] The above describes the process of driving the first transistor by the first driving circuit, and the structure and function of the second driving circuit will be described below.

[0165] It should be understood that the above-mentioned second driving circuit can select any unit that can realize the above-mentioned driving logic, and the present embodiment does not specially limit this.

[0166] Optionally, the above-mentioned second switch tube can be a second transistor, and the second transistor can be an N-type transistor. Referring to FIG. 6, the second driving circuit includes:

[0167] A second Zener diode Z2, a first end of which is connected with the second plate CPN of the capacitor. The Zener diode works like a normal diode when it is forward biased, but when it is reverse biased, it will conduct and maintain this voltage stable when the voltage reaches its breakdown voltage.

[0168] A second capacitor C2, a first plate of which is connected with the second end of the second voltage stabilizing element Z2.

[0169] The second inverter has one end connected to the second plate of the second capacitor C2 and the other end connected to the second power supply terminal VEN2.

[0170] The first plate of the second capacitor C2 is also connected to the third terminal VGATE_CTRL2 of the second switch tube, for providing a second driving voltage to the third terminal VGATE_CTRL2 of the second switch tube. The second driving voltage includes a second turn-on voltage for turning on the second switch tube and a second turn-off voltage for turning off the second switch tube.

[0171] Optionally, the second switch tube is a second transistor, and the gate-source voltage of the second transistor can be 5V. In the case of using the above structure for the second driving circuit, the process of driving the turn-on and turn-off of the second switch tube by the second driving circuit is as follows:

[0172] In a complete transmitting cycle of the ultrasonic transducer, the second transistor will be turned on and turned off once after the capacitor is flipped. The source terminal of the second transistor is connected to the negative plate of the capacitor, so the voltage of the source terminal will change with the flipping of the capacitor. In the turn-off state of the second transistor, the second driving circuit is used to ensure that the gate-source voltage of the second transistor is 0V, and in the turn-on state of the second transistor, the second driving circuit is used to ensure that the gate-source voltage of the second transistor is 5V. Based on the above circuit structure of the second driving circuit, when it is needed to control the turn-off of the second transistor, the second driving circuit is used to provide a second turn-off voltage to the gate of the second switch tube through the second power supply terminal VEN2, the inverter and the second capacitor, and the turn-off voltage is used to ensure that the voltage difference between the first plate of the second capacitor C2 and the second plate of the capacitor is 0V, so as to ensure that the gate-source voltage of the second transistor is 0V. When it is needed to control the turn-on of the second transistor, the second driving circuit is used to provide a second turn-on voltage to the gate of the second transistor through the second power supply terminal VEN2, the inverter and the second capacitor, and the turn-on voltage is used to ensure that the voltage difference between the first plate of the second capacitor C2 and the second plate of the capacitor is 5V, so as to ensure that the gate-source voltage of the second transistor is 5V.

[0173] It should be understood that the above third driving circuit can also select any unit that can realize its driving logic, and the present embodiment does not specially limit this.

[0174] Optionally, the third switch tube can be a third transistor, and the third transistor can be an N-type transistor. Referring to FIG. 7, the third driving circuit includes:

[0175] A third inverter is connected at one end to the third power supply terminal VEN3 and at the other end to the third terminal of the third switch tube, for providing a third driving voltage to the third terminal of the third switch tube. The third driving voltage includes a third on voltage for driving the third switch tube to be on, and a third off voltage for driving the third switch tube to be off.

[0176] Optionally, the gate-source voltage of the third transistor can be 5V. In the case of the third driving circuit adopting the above structure, the process of driving the third switch tube to be on and off by the third driving circuit is as follows:

[0177] During a complete transmitting cycle of the ultrasonic transducer, the third transistor will be on once when the capacitor is reversed, and will be off once when the capacitor is reversed again. The drain of the third transistor is connected to the negative plate of the capacitor, and the source is grounded, so the voltage of the source will not change with the reversal of the capacitor. In the off state of the third transistor, the third driving circuit is used to ensure that the gate-source voltage of the third transistor is 0V, and in the on state of the third transistor, the third driving circuit is used to ensure that the gate-source voltage of the third transistor is 5V. Based on the above circuit structure of the third driving circuit, when it is needed to control the third transistor to be off, the third driving circuit is used to provide a third off voltage of 0V to the gate of the third transistor through the third power supply terminal VEN3 and the inverter, so as to ensure that the gate-source voltage of the third transistor is 0V. When it is needed to control the third transistor to be on, the third driving circuit is used to provide a third on voltage of 5V to the gate of the third transistor through the third power supply terminal VEN3 and the third inverter, so as to ensure that the gate-source voltage of the third transistor is 5V.

[0178] In the embodiment, since the source of the third transistor is grounded, the third driving circuit including only the inverter can be used to generate a voltage of 0V or 5V to realize the off and on of the third transistor, which is simple in structure and easy to implement.

[0179] It should be understood that the above gate-source voltage of the third switch tube is only an example, and the embodiment is not specially limited.

[0180] It should be understood that the above fourth driving circuit can also select any unit that can realize the above driving logic, and the embodiment is not specially limited.

[0181] Optionally, the above fourth switch tube can be a fourth transistor, which can be a P-type transistor. Referring to FIG. 8, the fourth driving circuit includes:

[0182] A fourth inverter is connected at one end to the fourth power supply terminal VEN4.

[0183] A third capacitor C3 is connected at one end to the other end of the fourth inverter.

[0184] a third Zener diode Z3, a first end of which is connected to the second plate of the third capacitor C3, and a second end of which is grounded; wherein the Zener diode works like a normal diode when it is forward biased, but when it is reversely biased, it will conduct and keep the voltage stable when the voltage reaches its breakdown voltage.

[0185] The second plate of the third capacitor C3 is also connected to a third end VGATE_CTRL4 of the fourth switch tube, for providing a fourth driving voltage to the third end VGATE_CTRL4 of the fourth switch tube. The fourth driving voltage includes a fourth turn-on voltage for turning on the fourth switch tube, and a fourth turn-off voltage for turning off the fourth switch tube.

[0186] Optionally, the gate-source voltage of the fourth transistor can be 5V. In the case that the fourth driving circuit adopts the above structure, the process of the fourth driving circuit driving the turn-on and turn-off of the fourth switch tube is as follows:

[0187] In a complete transmitting cycle of the ultrasonic transducer, the fourth transistor will undergo turn-on and turn-off once before the capacitor flips. The source end of the fourth transistor is connected to the negative plate of the capacitor, so the voltage of the source end will change with the flipping of the capacitor. In the turn-off state of the fourth switch tube, the fourth driving circuit is used to ensure that the gate-source voltage of the fourth transistor is 0V, and in the turn-on state of the fourth switch tube, the fourth driving circuit is used to ensure that the gate-source voltage of the fourth transistor is 5V. Based on the above circuit structure of the fourth driving circuit, when it is needed to control the fourth switch tube to turn off, the fourth driving circuit is used to provide a fourth turn-off voltage to the gate of the fourth switch tube through the fourth power supply end VEN4, the fourth inverter and the third capacitor, and the turn-off voltage is used to ensure that the voltage difference between the second plate of the third capacitor C3 and the second plate of the capacitor is 0V, so as to ensure that the gate-source voltage of the fourth transistor is 0V. When it is needed to control the fourth switch tube to turn on, the fourth driving circuit is used to provide a fourth turn-on voltage to the gate of the fourth switch tube through the fourth power supply end VEN4, the fourth inverter and the third capacitor, and the turn-on voltage is used to ensure that the voltage difference between the second plate of the third capacitor C3 and the second plate of the capacitor is 5V, so as to ensure that the gate-source voltage of the fourth transistor is 5V.

[0188] The following part describes the power supply module in the embodiment of the present application.

[0189] Referring to FIG. 4, the power supply module 30 includes a power supply 301 and a fifth switch tube M5.

[0190] The power supply 301 is connected to the first end of the fifth switch tube M5, the second end of the fifth switch tube is connected to the first plate 11 of the capacitor 10, and the second plate 12 of the capacitor 10 is connected to the ground through the second switch circuit 22. The power supply charges the capacitor 10.

[0191] The driving circuit is also connected to the third end of the fifth switch tube M5.

[0192] In this embodiment, the driving circuit is used to drive the fifth switch tube M5. When the capacitor 10 needs to be charged, the fifth switch tube M5 is turned on. After the capacitor 10 completes a charging, the fifth switch tube M5 is turned off.

[0193] Through the above structure and control mode, the power supply module 30 and the driving circuit of the embodiment can effectively manage the charging process of the capacitor 10, ensure that it can be charged in time when needed, and be turned off in time after charging is completed, so as to avoid overcharging or unnecessary energy consumption.

[0194] Optionally, on the basis that the power supply module includes the fifth switch tube, the driving circuit can also include a fifth driving circuit for driving the fifth switch tube to turn on and turn off.

[0195] In this embodiment, the above-mentioned fifth driving circuit can select any unit that can realize its driving logic, and this embodiment does not make special limitation.

[0196] For example, the above-mentioned fifth switch tube can be a fifth transistor, which can be a P-type transistor. Referring to FIG. 9, the fifth driving circuit includes:

[0197] A first resistor R1 is connected to the power supply at one end.

[0198] A fourth voltage stabilizing element Z4 is connected to both ends of the first resistor R1. The fourth voltage stabilizing element can use any element that can realize the voltage stabilizing function and is suitable for the present scheme, and this embodiment does not make special limitation.

[0199] For example, the fourth voltage stabilizing element can use a Zener diode. The Zener diode works like an ordinary diode when it is forward biased, but when it is reverse biased, it will conduct and maintain this voltage stable when the voltage reaches its breakdown voltage. Based on this, a Zener diode can be selected as a voltage stabilizing element in this embodiment.

[0200] A sixth switch tube M17 is connected to the other end of the first resistor R1 at the first end, and the driving end is connected to the fifth power supply end VEN5.

[0201] And a current source is connected to the second end of the sixth switch at one end and grounded at the other end.

[0202] The first end of the sixth switch M17 is connected with the third end VGATE_CTRL5 of the fifth switch, for providing the fifth driving voltage to the fifth switch.

[0203] Optionally, the gate-source voltage of the fifth transistor can be 5V. In the case of the fifth driving circuit adopting the above structure, the process of the fifth driving circuit driving the turn-on and turn-off of the fifth transistor is as follows:

[0204] In one cycle of charging the capacitor, the fifth transistor will experience turn-on and turn-off once.

[0205] The source end of the fifth transistor is connected with the power supply, and thus the voltage of the source end is fixed. In the turn-off state of the fifth switch, the fifth driving circuit is used to ensure that the gate-source voltage of the fifth transistor is 0V, and in the turn-on state of the fifth switch, the fifth driving circuit is used to ensure that the gate-source voltage of the fifth transistor is 5V. Based on the above circuit structure of the fifth driving circuit, when it is required to control the turn-off of the fifth switch, the fifth driving circuit is used to open the sixth switch M17 through the fifth power supply end VEN5, so that the difference between the source voltage of the sixth switch M17 and the power supply voltage is 0V. When it is required to control the turn-off of the fifth switch, the fifth driving circuit is used to control the sixth switch M17 through the fifth power supply end VEN5, so that the difference between the source voltage of the sixth switch M17 and the power supply voltage is 5V. The current source is used to reset the source voltage of the sixth switch M17 when the sixth switch M17 is turned on, so as to meet the above requirement. Referring to FIG. 9, the current source can be realized by adopting the structure of a low-voltage power supply and a current mirror.

[0206] The above contents are used to describe the structure, function, and structure and function of each module, circuit, sub-circuit and element of the ultrasonic driving circuit provided by the application embodiment as a whole. The following describes an application embodiment of the ultrasonic driving circuit provided by the application embodiment by taking a specific embodiment as an example:

[0207] In this embodiment, referring to Fig. 10, the ultrasonic driving circuit can include two switching bridge circuits and a gate control circuit, and the capacitor can be a flying capacitor. The first high-voltage transistor S1 and the second high-voltage transistor S2 constitute a switching bridge 1, and the third high-voltage transistor S3 and the fourth high-voltage transistor S4 constitute a switching bridge 2. The source of the first high-voltage transistor is connected to the drain of the third high-voltage transistor and the upper plate of the flying capacitor. The drain of the first high-voltage transistor, the drain of the second high-voltage transistor, and one pin of the ultrasonic transducer are connected, and the other pin of the ultrasonic transducer is grounded. The source of the second high-voltage transistor is connected to the lower plate of the flying capacitor. The source of the third high-voltage transistor and the source of the fourth high-voltage transistor are connected to the ground. The drain of the fourth high-voltage transistor is connected to the lower plate of the flying capacitor. Among them, the upper plate of the flying capacitor can correspond to the first plate of the capacitor, and the lower plate of the flying capacitor can correspond to the second plate of the capacitor.

[0208] The ultrasonic driving circuit of the embodiment has the characteristics of not requiring an expensive off-chip inductor or an on-chip negative high-voltage power supply. Only some control logic and off-chip flying capacitor need to be added. The cost is lower, and only a single charging before the ultrasonic transducer emits is required to emit multiple pulses. Bipolar pulses have a longer detection distance and a higher round-trip signal-to-noise ratio than unipolar pulses. The zero-returning sequence not only improves the linearity of the emitted pulses, but also reduces the voltage withstand requirement of the high-voltage transistors, further reducing the circuit cost.

[0209] Referring to Fig. 11, the output of the gate control circuit 1 is connected to the gate of the first high-voltage transistor M1 and the second high-voltage transistor M2. The gate control circuit 1 includes two corresponding control circuits and a non-overlapping clock generator. The gate control circuit of the first high-voltage transistor M1 and the second high-voltage transistor M2 is generated by two capacitive high-voltage level converters. The non-overlapping clock circuit is used to realize the function of the zero-returning sequence.

[0210] Optionally, the gate control circuit 1 uses a capacitive high-voltage level converter, which has no static power consumption. By using the characteristics of the capacitor, a control signal higher or lower than the power rail can be generated, thereby realizing the zero-returning sequence. The zero-returning sequence can avoid the situation that the source and drain of the first high-voltage transistor M1 and the second high-voltage transistor M2 in the switching bridge 1 are not twice the power supply, thereby relaxing the voltage withstand requirement of the two high-voltage transistors. The bipolar emission pulse with zero-returning logic is closer to the three-level pulse of positive high voltage-zero-negative high voltage, and has higher linearity.

[0211] The switching bridge circuit 2 uses a push-pull structure of upper PMOS and lower NMOS. This structure not only has the function of flying capacitor flip control, but also the optimized gate control circuit 2 only needs to generate 5V and -5V signals, and does not need to work in the high-voltage domain, thereby reducing the difficulty of circuit implementation.

[0212] The negative high-voltage capacitor generated by the fly capacitor replaces the original off-chip inductor, and compared with the existing off-chip inductor circuit, the overall cost is significantly reduced. Compared with the existing additional on-chip high-voltage power supply circuit, the chip area occupied by the high-voltage power supply remains unchanged, and a large amount of on-chip area resources is saved.

[0213] The embodiment can realize a bipolar ultrasonic drive circuit with a zero-return function in the case of using a low-cost fly capacitor.

[0214] As shown in FIG. 10, the bipolar ultrasonic drive circuit includes a fly capacitor, a switch bridge 1 and a switch bridge 2, and a driven ultrasonic transducer. The switch bridge 1 is the main circuit of the ultrasonic drive for driving the ultrasonic transducer to generate an ultrasonic signal. When S1 is closed and S2 is turned off, the ultrasonic transducer is driven by the upper plate of the fly capacitor; when S1 is turned off and S2 is closed, the ultrasonic transducer is driven by the lower plate of the fly capacitor. The switch bridge 2 is an auxiliary circuit for controlling the fly capacitor. When S3 is closed and S4 is turned off, the upper plate of the fly capacitor is ground, and the lower plate is a negative high-voltage signal; when S3 is turned off and S4 is closed, the lower plate of the fly capacitor is ground, and the upper plate is a positive high-voltage signal. Only one fly capacitor is needed to generate positive and negative high-voltage power supplies.

[0215] It is worth noting that the fly capacitor in the embodiment is an off-chip capacitor integrated outside the chip where the switch bridge 1 and the switch bridge 2 are located.

[0216] It should be understood that the capacitor in the embodiment of the application can not only use a fly capacitor, but also use other off-chip capacitors that can be integrated outside the chip where the switch bridge 1 and the switch bridge 2 are located, and can realize the above functions.

[0217] As shown in Figure 11, it is a specific scheme of ultrasonic drive circuit. The source of the fifth high voltage transistor M5 is connected to the positive high voltage power supply, and the drain is connected to the upper plate CFP of the flying capacitor C1. Before the transmitting stage, the gate control circuit 2 controls the fifth high voltage transistor M5 and the fourth high voltage transistor M4 to be closed, the upper plate CFP of the flying capacitor C1 is connected to the positive high voltage power supply, and the lower plate CFN is connected to the ground. The charge is accumulated on the upper plate to pre-charge the flying capacitor C1. One end of the ultrasonic transducer is connected to the output of the switch bridge one, and the other end is connected to the ground, which is driven by the switch bridge one. The high side switch of the switch bridge one is the P-type high voltage transistor M1, and the low side switch is the N-type high voltage transistor M2, which forms a complementary ultrasonic drive circuit. Compared with the double N-type ultrasonic drive circuit, the complementary ultrasonic drive circuit does not need to use a complex gate control circuit scheme, which helps to simplify the circuit and is suitable for low-speed ultrasonic applications. The source of the first high voltage transistor M1 is connected to the upper plate of the flying capacitor C1, and when it is closed, the upper plate of the flying capacitor C1 is connected to the ultrasonic transducer. The source of the second high voltage transistor M2 is connected to the lower plate of the flying capacitor C1, and when it is closed, the lower plate of the flying capacitor C1 is connected to the ultrasonic transducer. When the gate control circuit 1 inputs a period control signal, the corresponding gate control signal can be generated to control the first high voltage transistor M1 and the second high voltage transistor M2 to be opened and closed alternately, thereby generating a period ultrasonic drive signal. The high side switch of the switch bridge two is the N-type high voltage transistor M3 and the P-type high voltage transistor M4. The drain of the third high voltage transistor M3 is connected to the upper plate of the flying capacitor C1, and the source is connected to the ground. The drain of the fourth high voltage transistor M4 is connected to the upper plate of the flying capacitor C1, and the source is connected to the ground. When the third high voltage transistor M3 is closed and the fourth high voltage transistor M4 is turned off, the upper plate of the flying capacitor C1 can be set to zero, and the lower plate of the flying capacitor C1 is floating at this time. Since the voltage across the capacitor cannot change abruptly, a negative high voltage signal will be generated on the lower plate. The switch bridge two is different from the switch bridge one, which is a push-pull structure, and the sources of the third high voltage transistor M3 and the fourth high voltage transistor are connected to the ground. The drain of the third high voltage transistor M3 and the drain of the fourth high voltage transistor M4 are connected to the high voltage. Such a structure not only improves the reliability of the circuit, but also reduces the difficulty of circuit design. First, the high voltage voltage domain is separated, the voltage domain of the third high voltage transistor M3 is from the ground to the positive high voltage, and the voltage domain of the fourth high voltage transistor M4 is from the negative high voltage to the ground. Both transistors only need single voltage resistance, and the extreme voltage resistance condition of one end being negative high voltage and the other end being positive high voltage will not occur. Second, the parasitic source-drain diode of the third high voltage transistor M3 and the fourth high voltage transistor M4 will not be forward biased, which will cause energy leakage. Finally, the gate control circuit 2 only needs to generate 5V and -5V signals to control the closing and opening of the third high voltage transistor M3 and the fourth high voltage transistor M4, respectively, without the need to work in the high voltage domain, which reduces the difficulty of circuit implementation and improves the reliability of the circuit.

[0218] In order to avoid the switch bridge at the same time caused by energy leakage power switch, gate control circuit 1 and gate control circuit 2 with non-intersecting clock circuit, ensure that the gate control signal will not overlap, for switch bridge switching leave enough dead time.

[0219] As shown in Figure 12 is the corresponding timing of the above embodiments. TX / RX is the enable signal of the ultrasonic wave transmission, high TX effective is the transmission phase, low RX effective is the receiving phase. Switch S1, S2, S3, S4 corresponds to the first high voltage transistor M1, the second high voltage transistor M2, the third high voltage transistor M3, the fourth high voltage transistor M4 in the second embodiment. Pull-up is the pull-up enable, controlled by the first switch S1; Pull-down is the pull-down enable, controlled by the second switch S2; Fly is the fly capacitor flip enable by the third switch S3 and the fourth switch S4. VDRV is the ultrasonic wave drive output signal, driving the ultrasonic transducer.

[0220] In the transmitting stage, the first switch S1 is closed, the second switch S2 is turned off, and a pull-up signal is generated. The upper plate of the flying capacitor is connected to the ultrasonic transducer. At this time, the third switch S3 is turned off, and the fourth switch S4 is closed. The upper plate of the flying capacitor is at a positive high voltage, the lower plate is at a low voltage, and the ultrasonic drive output VDRV is at a positive high voltage. Then, the first switch S1 is turned off, the second switch S2 is closed, and a pull-down signal is generated. The upper plate of the flying capacitor is connected to the ultrasonic transducer. At this time, the third switch S3 is closed, and the fourth switch S4 is turned off. The upper plate of the flying capacitor is at a low voltage, the lower plate is at a negative high voltage, and the ultrasonic drive output VDRV is at a negative high voltage. The pull-up and pull-down signals form a complete cycle of transmission. However, the above timing still has a problem. The drain-source voltage drop on the first switch S1 and the second switch S2 can reach double the voltage drop (the positive high voltage minus the negative high voltage). Using a high-voltage transistor with higher voltage resistance will increase the cost of the circuit. Therefore, the embodiment further optimizes the transmission timing. The fourth switch S4 is slightly delayed, and the delay time is t2. The fourth switch S4 and the second switch S2 have a certain overlap. t1 is the non-overlapping time of the first switch S1 and the second switch S2. When the first switch S1 is turned off, the ultrasonic transducer is temporarily floating, and the potential remains at a positive high voltage (HVVDD). The fourth switch S4 is not turned off due to the delay, the upper plate of the flying capacitor is at a positive high voltage, and the lower plate is at ground. Then, the second switch S2 is closed. At this time, the flying capacitor is not flipped, and the lower plate is still at ground. Therefore, the ultrasonic drive output VDRV is pulled down from a positive high voltage (HVVDD) to ground, instead of being directly pulled down to a negative high voltage (HVVSS). When the ultrasonic drive output VDRV is completely at ground, the fourth switch S4 is turned off, the third switch S3 is turned on, and the flying capacitor is flipped. The upper plate is at ground, and the lower plate is at a negative high voltage. In this process, the second switch S2 remains closed, the third switch S3 remains turned off, and the ultrasonic drive output VDRV follows the lower plate of the flying capacitor and is pulled to a negative high voltage (HVVSS).

[0221] The zeroing timing only needs to slightly modify the control timing and is easy to implement. In the case of a bipolar pulse, the zeroing timing effectively reduces the voltage resistance requirement of the high-voltage transistor of the ultrasonic drive circuit, does not require a high-voltage transistor with a higher voltage resistance level, and reduces the actual cost of the circuit. The bipolar transmission pulse with zeroing logic is closer to a three-level pulse of a positive high voltage-zero-negative high voltage, and has higher linearity.

[0222] In a second aspect, the embodiment of the present application also provides an ultrasonic radar 40, as shown in FIG. 13, which includes an ultrasonic transducer, a controller 41, and the ultrasonic drive circuit in the first aspect.

[0223] The controller 41 is connected to the first end of the ultrasonic drive circuit, and the second end of the ultrasonic drive circuit is connected to the ultrasonic transducer.

[0224] The controller 41 is configured to control the ultrasonic drive circuit to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges.

[0225] In this embodiment, the controller 41 is configured to control the ultrasonic drive circuit to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges; the specific structure of the ultrasonic drive circuit can refer to the structure of the ultrasonic drive circuit of any of the foregoing examples. Through the above structure, the ultrasonic radar 40 of this embodiment can adjust the detection range of the ultrasonic waves as needed, thereby achieving effective detection of targets at different distances.

[0226] In a third aspect, the embodiments of the present application also provide a vehicle 50, as shown in FIG. 14, comprising the ultrasonic radar 40 of the second aspect.

[0227] In this embodiment, the vehicle 50 can realize real-time monitoring of the surrounding environment by integrating the ultrasonic radar 40, thereby improving driving safety. For example, when reversing, the ultrasonic radar 40 can detect obstacles behind the vehicle and issue a warning to the driver, thereby avoiding collision accidents. In addition, the ultrasonic radar 40 can also be used for an automatic parking system to help the vehicle automatically complete the parking operation.

[0228] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An ultrasonic driving circuit, wherein, Used to drive an ultrasonic transducer; includes: a capacitor (10) and a power supply module (30); The capacitor (10) is connected to the power module (30), and the capacitor (10) is also used to connect the ultrasonic transducer; The power module (30) is used to charge the capacitor (10); The capacitor (10) is used to provide at least one of a positive pressure drive signal and a negative pressure drive signal to the ultrasonic transducer; wherein the detection range of the ultrasonic waves emitted by the ultrasonic transducer driven by the positive pressure drive signal and the negative pressure drive signal are different.

2. The ultrasonic driving circuit according to claim 1, wherein, The capacitor (10) includes a first plate (11) and a second plate (12); When the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer, the first electrode plate (11) is connected to the ultrasonic transducer, and the second electrode plate (12) is grounded.

3. The ultrasonic driving circuit according to claim 2, wherein, When the capacitor (10) provides a negative pressure drive signal to the ultrasonic transducer, the first electrode plate (11) is grounded and the second electrode plate (12) is connected to the ultrasonic transducer.

4. The ultrasonic driving circuit according to claim 3, wherein, The ultrasonic driving circuit also includes a switching module; The switching module is connected to the capacitor (10) and is used to form a corresponding driving path when the capacitor (10) provides the positive pressure driving signal or the negative pressure driving signal to the ultrasonic transducer.

5. The ultrasonic driving circuit according to claim 4, wherein, The switching module includes a first switching circuit (21) and a second switching circuit (22); The first switching circuit (21) is connected between the capacitor (10) and the ultrasonic transducer. It is used to connect the first electrode plate (11) to the ultrasonic transducer when the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer, and to connect the second electrode plate (12) to the ultrasonic transducer when the capacitor (10) provides a negative pressure drive signal to the ultrasonic transducer. The second switching circuit (22) is connected between the capacitor (10) and the ground terminal. It is used to ground the second electrode plate (12) when the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer, and to ground the first electrode plate (11) when the capacitor (10) provides a negative pressure drive signal to the ultrasonic transducer.

6. The ultrasonic driving circuit according to claim 5, wherein, The first switching circuit (21) includes a first switching transistor, and the second switching circuit (22) includes a fourth switching transistor; The first switch is connected between the first electrode plate (11) and the ultrasonic transducer, and is used to turn on when the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer; The fourth switch is connected between the second electrode plate (12) and the ground terminal, and is used to turn on when the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer.

7. The ultrasonic driving circuit according to claim 5, wherein, The first switching circuit (21) includes a second switching transistor, and the second switching circuit (22) includes a third switching transistor; The second switch is connected between the second electrode plate (12) and the ultrasonic transducer, and is used to turn on when the capacitor (10) provides a negative pressure drive signal to the ultrasonic transducer; The third switch is connected between the first electrode plate (11) and the ground terminal, and is used to turn on when the capacitor (10) provides a negative pressure drive signal to the ultrasonic transducer.

8. The ultrasonic driving circuit according to claim 6, wherein, The switching module further includes a first driving circuit (231); the first driving circuit (231) is connected to the driving end of the first switching transistor and is used to drive the first switching transistor to conduct when the capacitor (10) provides a positive pressure driving signal to the ultrasonic transducer.

9. The ultrasonic driving circuit according to claim 8, wherein, The first driving circuit (231) includes: a driving voltage generation sub-circuit and a driving voltage reset sub-circuit; The first end of the driving voltage generating sub-circuit is connected to the first plate (11) of the capacitor (10), the second end is connected to the first power supply end, and the third end is connected to the driving end of the first switching transistor, for providing a first driving voltage to the driving end of the first switching transistor. The drive voltage reset sub-circuit has a first end connected to the first plate (11) of the capacitor (10), a second end grounded, and a third end connected to the drive end of the first switch transistor, for providing a reset voltage to the drive end of the first switch transistor.

10. The ultrasonic driving circuit according to claim 9, wherein, The driving voltage generation sub-circuit includes: The first Zener diode has its first end connected to the first plate (11) of the capacitor (10); The first capacitor has its first plate connected to the second end of the first voltage regulator element. The first inverter has one end connected to the second plate of the first capacitor and the other end connected to the first power supply terminal; The first plate of the first capacitor is also connected to the driving terminal of the first switching transistor, for providing the first driving voltage to the driving terminal of the first switching transistor.

11. The ultrasonic driving circuit according to claim 9 or 10, wherein, The drive voltage reset sub-circuit includes: a first current mirror, a second current mirror, a first control transistor, a second control transistor, and a bias voltage source; The bias voltage source is connected to the first end of the first current mirror through the first control transistor, the second end of the first current mirror is connected to the first end of the second current mirror through the second control transistor, the third end of the first current mirror is grounded, and the second end of the second current mirror is connected to the first plate (11) of the capacitor (10). The output terminal of the first control transistor is connected to the control terminal of the first current mirror, and the output terminal of the second control transistor is connected to the control terminal of the second current mirror. The control terminals of the first control transistor and the second control transistor are used to connect to the reset signal terminal. The third end of the second current mirror is connected to the driving end of the first switching transistor, and is used to provide the reset voltage to the driving end of the first switching transistor.

12. The ultrasonic driving circuit according to claim 6 or any one of claims 8-11, wherein, The switching module further includes a fourth driving circuit (234); the fourth driving circuit (234) is connected to the driving terminal of the fourth switching transistor and is used to drive the first switching transistor to conduct when the capacitor (10) provides a positive pressure driving signal to the ultrasonic transducer.

13. The ultrasonic driving circuit according to claim 12, wherein, The fourth driving circuit (234) includes: a fourth inverter, one end of which is connected to a fourth power supply terminal; The third capacitor has its first plate connected to the other end of the fourth inverter. The third Zener diode has its first end connected to the second plate of the third capacitor, and its second end grounded. The second plate of the third capacitor is also connected to the driving terminal of the fourth switch, for providing a fourth driving voltage to the driving terminal of the fourth switch.

14. The ultrasonic driving circuit according to claim 7, wherein, The switching module further includes a second driving circuit (232); the second driving circuit (232) is connected to the driving end of the second switching tube and is used to drive the second switching tube to conduct when the capacitor (10) provides a negative pressure driving signal to the ultrasonic transducer.

15. The ultrasonic driving circuit according to claim 14, wherein, The second driving circuit (232) includes: The second Zener diode has its first end connected to the second plate (12) of the capacitor (10); The second capacitor has its first plate connected to the second terminal of the second voltage regulator element. The second inverter has one end connected to the second plate of the second capacitor and the other end connected to the second power supply terminal; The first plate of the second capacitor is also connected to the driving terminal of the second switching transistor to provide a second driving voltage to the driving terminal of the second switching transistor.

16. The ultrasonic driving circuit according to claim 7, wherein, The switching module further includes a third driving circuit (233); the third driving circuit (233) is connected to the driving terminal of the third switching tube and is used to drive the third switching tube to conduct when the capacitor (10) provides a negative pressure driving signal to the ultrasonic transducer.

17. The ultrasonic driving circuit according to claim 16, wherein, The third driving circuit (233) includes: The third inverter has one end connected to the third power supply terminal and the other end connected to the driving terminal of the third switching transistor, and is used to provide a third driving voltage to the driving terminal of the third switching transistor.

18. The ultrasonic driving circuit according to any one of claims 4-17, wherein, The power module (30) includes a power supply (301) and a fifth switching transistor; The power supply (301) is connected to the first end of the fifth switching transistor, and the second end of the fifth switching transistor is connected to the first plate (11) of the capacitor (10). The power supply (301) is used to charge the capacitor. The switching module is also connected to the driving terminal of the fifth switching transistor, and is used to drive the fifth switching transistor to conduct when the capacitor is charging.

19. The ultrasonic driving circuit according to claim 18, wherein, The switching module further includes a fifth driving circuit (235), which is connected to the driving terminal of the fifth switching transistor and is used to drive the fifth switching transistor to conduct when the capacitor (10) is charging.

20. The ultrasonic driving circuit according to claim 19, wherein, The fifth driving circuit (235) includes: The first resistor has one end connected to the power supply; The fourth Zener diode is connected across the first resistor; The sixth switching transistor has its first terminal connected to the other end of the first resistor, and its driving terminal connected to the fifth power supply terminal. And a current source, one end of which is connected to the second terminal of the sixth switch, and the other end is grounded; The first terminal of the sixth switch is also connected to the driving terminal of the fifth switch, for providing a fifth driving voltage to the fifth switch.

21. An ultrasonic radar (40), wherein, Includes an ultrasonic transducer, a controller (41), and an ultrasonic drive circuit as described in any one of claims 1-20; The controller (41) is connected to the first end of the ultrasonic drive circuit, and the second end of the ultrasonic drive circuit is connected to the ultrasonic transducer. The controller (41) is used to control the ultrasonic drive circuit to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges.

22. A vehicle (50), wherein, Includes the ultrasonic radar (40) as described in claim 21.

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