Ultrasonic drive circuit, ultrasonic radar and vehicle

Abstract

The invention provides an ultrasonic driving circuit, an ultrasonic radar and a vehicle, and relates to the technical field of ultrasonic devices. The capacitor is connected with the power supply module, and the capacitor is also used for being connected with the ultrasonic transducer; the power supply module is used for charging the capacitor; the capacitor is used for providing a positive pressure driving signal and / or a negative pressure driving signal for the ultrasonic transducer; wherein the detection ranges of ultrasonic waves emitted by the ultrasonic transducer driven by the positive pressure driving signal and the negative pressure driving signal are different. According to the invention, the detection distance of the ultrasonic wave emitted by the ultrasonic transducer can be increased, and the integration area of the whole ultrasonic drive circuit is not increased.

Description

Technical Field

[0001] The present application relates to the technical field of ultrasonic devices, and in particular to ultrasonic drive circuits, ultrasonic radars and vehicles. Background Art

[0002] The ultrasonic drive circuit is used to amplify the input signal of the signal source, thereby driving the ultrasonic transducer to generate an ultrasonic signal. The emission pulse level range of the ultrasonic drive circuit directly determines the maximum detectable distance of the ultrasonic signal generated by the ultrasonic transducer. The bipolar pulse level can extend the maximum detectable distance of the ultrasonic signal emitted by the ultrasonic transducer to twice that of the unipolar pulse level.

[0003] Currently, one way is to use a transformer to generate a bipolar pulse level, but this method requires an off-chip inductor, which is expensive. Another way is to add a negative high-voltage power supply to the traditional single positive high-voltage power supply, thereby providing a positive and negative high-voltage dual power supply rail for the ultrasonic drive circuit, but this method will increase the integration area of ​​the entire ultrasonic drive circuit. Summary of the invention

[0004] The present application provides an ultrasonic drive circuit, an ultrasonic radar and a vehicle, which are used to provide a technical solution that can increase the corresponding detection distance of the ultrasonic wave emitted by the ultrasonic transducer without increasing the integration area of ​​the entire ultrasonic drive circuit.

[0005] In a first aspect, the present application provides an ultrasonic driving circuit for driving an ultrasonic transducer; comprising: a capacitor and a power module.

[0006] The capacitor is connected to the power module, and the capacitor is also used to connect to the ultrasonic transducer.

[0007] The power supply module is used to charge the capacitor.

[0008] The capacitor is used to provide a positive pressure driving signal and / or a negative pressure driving signal to the ultrasonic transducer; wherein the detection range of the ultrasonic wave emitted by the ultrasonic transducer driven by the positive pressure driving signal and the negative pressure driving signal is different.

[0009] In an optional implementation manner, the capacitor includes a first electrode plate and a second electrode plate.

[0010] When the capacitor provides a positive voltage driving signal to the ultrasonic transducer, the first electrode plate is connected to the ultrasonic transducer, and the second electrode plate is grounded.

[0011] In an optional implementation manner, when the capacitor provides a negative pressure driving signal to the ultrasonic transducer, the first electrode plate is grounded, and the second electrode plate is connected to the ultrasonic transducer.

[0012] In an optional implementation manner, the ultrasonic drive circuit further includes a switch module.

[0013] The switch module is connected to the capacitor and is used 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.

[0014] In an optional implementation manner, the switch module includes a first switch circuit and a second switch circuit.

[0015] The first switching circuit is connected between the capacitor and the ultrasonic transducer, and is used to connect the first electrode plate to the ultrasonic transducer when the capacitor provides a positive pressure driving signal to the ultrasonic transducer, and is also used to connect the second electrode plate to the ultrasonic transducer when the capacitor provides a negative pressure driving signal to the ultrasonic transducer.

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

[0017] In an optional implementation manner, the first switch circuit includes a first switch tube, and the second switch circuit includes a fourth switch tube.

[0018] The first switch tube is connected between the first electrode plate and the ultrasonic transducer, and is used for being turned on when the capacitor provides a positive voltage driving signal to the ultrasonic transducer.

[0019] The fourth switch tube is connected between the second electrode plate and the ground terminal, and is used for being turned on when the capacitor provides a positive voltage driving signal to the ultrasonic transducer.

[0020] In an optional implementation manner, the first switch circuit includes a second switch tube, and the second switch circuit includes a third switch tube.

[0021] The second switch tube is connected between the second electrode plate and the ultrasonic transducer, and is configured to be turned on when the capacitor provides a negative pressure driving signal to the ultrasonic transducer.

[0022] The third switch tube is connected between the first electrode plate and the ground terminal, and is used for being turned on when the capacitor provides a negative pressure driving signal to the ultrasonic transducer.

[0023] In an optional embodiment, the switch module also includes a first drive circuit; the first drive circuit is connected to the drive end of the first switch tube, and is used to drive the first switch tube to turn on when the capacitor provides a positive pressure drive signal to the ultrasonic transducer.

[0024] In an optional implementation manner, the first driving circuit includes: a driving voltage generating subcircuit and a driving voltage resetting subcircuit.

[0025] The first end of the drive voltage generating subcircuit is connected to the first plate of the capacitor, the second end is connected to the first power supply end, and the third end is connected to the drive end of the first switch tube, for providing a first drive voltage to the drive end of the first switch tube.

[0026] The driving voltage reset subcircuit has a first end connected to the first plate of the capacitor, a second end connected to the ground, and a third end 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.

[0027] In an optional implementation manner, the driving voltage generating subcircuit includes:

[0028] A first Zener tube has a first end connected to the first electrode plate of the capacitor.

[0029] A first capacitor, a first electrode plate is connected to the second end of the first voltage stabilizing element.

[0030] 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 end.

[0031] The first electrode plate of the first capacitor is also 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.

[0032] In an optional implementation manner, the driving voltage resetting subcircuit includes a first current mirror, a second current mirror, a first control tube, a second control tube and a bias voltage source.

[0033] The bias voltage source is connected to the first end of the first current mirror through the first control tube, the second end of the first current mirror is connected to 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 to the first plate of the capacitor.

[0034] The output end of the first control tube is connected to the control end of the first current mirror, the output end of the second control tube is connected to 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 to connect to the reset signal end.

[0035] The third terminal of the second current mirror is connected to the driving terminal of the first switch tube, and is used to provide the reset voltage to the driving terminal of the first switch tube.

[0036] In an optional embodiment, the switch module also includes a fourth drive circuit; the fourth drive circuit is connected to the drive end of the fourth switch tube, and is used to drive the first switch tube to turn on when the capacitor provides a positive pressure drive signal to the ultrasonic transducer.

[0037] In an optional implementation manner, the fourth driving circuit includes: a fourth inverter, one end of which is connected to a fourth power supply end.

[0038] A first electrode plate of the third capacitor is connected to the other end of the fourth inverter.

[0039] The third Zener tube has a first end connected to the second electrode plate of the third capacitor and a second end connected to the ground.

[0040] The second electrode plate of the third capacitor is also connected to the driving end of the fourth switch tube, and is used to provide a fourth driving voltage to the driving end of the fourth switch tube.

[0041] In an optional embodiment, the switch module also includes a second drive circuit; the second drive circuit is connected to the drive end of the second switch tube, and is used to drive the second switch tube to turn on when the capacitor provides a negative pressure drive signal to the ultrasonic transducer.

[0042] In an optional implementation manner, the second driving circuit includes:

[0043] A second Zener tube has a first end connected to the second electrode plate of the capacitor.

[0044] The second capacitor has a first electrode plate connected to the second end of the second voltage stabilizing element.

[0045] 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 end.

[0046] The first electrode plate of the second capacitor is also connected to the driving end of the second switch tube, and is used to provide a second driving voltage to the driving end of the second switch tube.

[0047] In an optional embodiment, the switch module also includes a third drive circuit; the third drive circuit is connected to the drive end of the third switch tube, and is used to drive the third switch tube to turn on when the capacitor provides a negative pressure drive signal to the ultrasonic transducer.

[0048] In an optional implementation manner, the third driving circuit includes:

[0049] The third inverter has one end connected to the third power supply end and the other end connected to the driving end of the third switch tube, and is used to provide a third driving voltage to the driving end of the third switch tube.

[0050] In an optional implementation, the power module includes a power supply and a fifth switching tube.

[0051] The power source is connected to the first end of the fifth switch tube, the second end of the fifth switch tube is connected to the first electrode plate of the capacitor, and the power source is used to charge the capacitor.

[0052] The switch module is also connected to the driving end of the fifth switch tube, and is used to drive the fifth switch tube to conduct when the capacitor is charged.

[0053] In an optional implementation manner, the switch module further includes a fifth drive circuit, which is connected to a drive end of the fifth switch tube and is used to drive the fifth switch tube to be turned on when the capacitor is charged.

[0054] In an optional implementation manner, the fifth driving circuit includes:

[0055] A first resistor has one end connected to the power supply.

[0056] The fourth Zener diode is connected to two ends of the first resistor.

[0057] A sixth switch tube has a first end connected to the other end of the first resistor, and a driving end connected to the fifth power supply end.

[0058] and a current source, one end of which is connected to the second end of the sixth switch and the other end of which is grounded.

[0059] The first end of the sixth switch tube is also connected to the driving end of the fifth switch tube, and is used to provide a fifth driving voltage to the fifth switch tube.

[0060] In a second aspect, the present application further provides an ultrasonic radar, comprising an ultrasonic transducer, a controller, and the ultrasonic driving circuit in the first aspect;

[0061] The controller is connected to a first end of the ultrasonic drive circuit, and a second end of the ultrasonic drive circuit is connected to the ultrasonic transducer;

[0062] The controller is used to control the ultrasonic driving circuit so as to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges through the ultrasonic driving circuit.

[0063] In a third aspect, the present application also provides a vehicle, comprising the ultrasonic radar in the second aspect.

[0064] The technical solution provided by the present application is based on the fast charging and electrical energy storage characteristics of the capacitor. Before the ultrasonic transducer transmits an ultrasonic signal, a single charge of the capacitor is required to transmit multiple drive signals. Moreover, based on the structure of the capacitor itself, when the ultrasonic transducer is driven in the transmitting stage, the capacitor can provide the ultrasonic transducer with a positive pressure drive signal and a negative pressure drive signal. Driven by the positive pressure drive signal and the negative pressure drive signal, the ultrasonic wave emitted by the ultrasonic transducer has a different detection range. Based on this, the detection distance of the ultrasonic wave emitted by the ultrasonic transducer can be increased.

[0065] Moreover, the present application can integrate the capacitor outside the chip where the ultrasonic drive circuit is located. The number of power supply modules used in the present application is one, so the area of ​​the chip occupied by the power supply module is basically the same as the area of ​​the chip occupied when a single high-voltage power supply is used in the traditional way. Therefore, the technical solution of the present application will not increase the integration area of ​​the entire ultrasonic drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0067] Figure 1 A transducer equivalent model provided in an embodiment of the present application;

[0068] Figure 2 A schematic diagram of a unipolar pulse (above) and a bipolar pulse (above) provided in an embodiment of the present application;

[0069] Figure 3 A schematic diagram of the structure of an ultrasonic drive circuit provided in an embodiment of the present application;

[0070] Figure 4 A schematic diagram of the structure of another ultrasonic driving circuit provided in an embodiment of the present application;

[0071] Figure 5 A schematic diagram of the structure of a first driving circuit provided in an embodiment of the present application;

[0072] Figure 6 A schematic diagram of the structure of a second driving circuit provided in an embodiment of the present application;

[0073] Figure 7 A schematic diagram of the structure of a third driving circuit provided in an embodiment of the present application;

[0074] Figure 8 A schematic diagram of the structure of a fourth driving circuit provided in an embodiment of the present application;

[0075] Fig. 9 A schematic diagram of the structure of a fifth driving circuit provided in an embodiment of the present application;

[0076] Fig.10 A schematic diagram of the structure of an ultrasonic drive circuit provided in an embodiment of the present application;

[0077] Fig.11 A schematic diagram of a specific structure of an ultrasonic drive circuit provided in an embodiment of the present application;

[0078] Fig.12 A timing diagram of an ultrasonic drive circuit provided in an embodiment of the present application.

[0079] Reference numerals:

[0080] 10: capacitor; 30: power module; 11: first electrode plate; 12: second electrode plate; 21: first switch circuit; 22: second switch circuit; 231: first drive circuit; 232: second drive circuit; 233: third drive circuit; 234: fourth drive circuit; 301: power supply.

[0081] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0082] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The implementations described in the following exemplary embodiments do not represent all implementations consistent with the present application. Instead, they are merely examples of devices and methods consistent with some aspects of the present application as detailed in the appended claims.

[0083] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which the present application belongs. The terms used herein in the specification of the present application are only for the purpose of describing specific embodiments and are not intended to limit the present application. It is understood that the terms "first", "second", etc. used in the present application can be used to describe various information or data in this article, but these elements are not limited by these terms. These terms are only used to distinguish the first information from another information. For example, without departing from the scope of the present application, the first action information can be referred to as the second action information, and similarly, the second action information can be referred to as the first action information. Both the first action information and the second action information are action information, but they are not the same action information.

[0084] First, the terms involved in this application are explained:

[0085] Ultrasonic drive circuit: It is an electronic circuit used to drive the ultrasonic transducer, which can convert low-frequency or DC signals into high-frequency AC signals, thereby enabling the ultrasonic transducer to generate ultrasonic waves.

[0086] Ultrasonic transducer: A device that converts electrical energy into ultrasonic energy, or converts ultrasonic energy into electrical energy.

[0087] Ultrasonic radar: a device that uses ultrasonic waves for detection and ranging. 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 automobile reversing radar, robot navigation, liquid level measurement, obstacle detection and other fields.

[0088] Before introducing the content of this application, the following is an introduction to the technology involved in this application:

[0089] Ultrasonic waves refer to sound waves that exceed the highest threshold (20kHz) that can be heard by human ears. They are highly directional and are almost unaffected by light, dust, smoke, and electromagnetic interference. The ultrasonic drive circuit in ultrasonic radar is one of the important components of the entire radar system. The ultrasonic drive circuit is usually a power amplifier, which is used to amplify the input signal of the signal source to drive the ultrasonic transducer to generate an ultrasonic signal. The ultrasonic transducer can be equivalent to an RLC series-parallel resonant model formed by resistance-inductance-capacitance, such as Figure 1 shown.

[0090] The range of the ultrasonic drive circuit's emission pulse level directly determines the maximum detectable distance of the ultrasonic radar. Usually, the chip's input voltage is small, so the high-voltage power supply needs to be generated by the integrated boost circuit on the chip. Taking the common on-chip boost circuit charge pump as an example, in order to increase its output voltage, more charge pump stages are required, and the area of ​​the charge pump will increase significantly. At the same time, the energy loss will also increase with the increase in the number of stages. Figure 2 As shown in the figure, bipolar level pulses can expand the ultrasonic radar transmission pulse level to twice that of unipolar pulses. More importantly, the average DC voltage of the transducer driven by the bipolar pulse is zero during operation, which can avoid even-order harmonic leakage and increase the round-trip signal-to-noise ratio. In other words, the detection distance of bipolar level pulses is longer and the energy loss is lower.

[0091] At present, bipolar ultrasonic drive circuits are mainly divided into the following types:

[0092] One method is to use a transformer to generate a bipolar pulse level, but this method requires an off-chip inductor, which has a high cost.

[0093] Another way is to add a negative high-voltage power supply on the basis of the traditional single positive high-voltage power supply, thereby providing a positive and negative high-voltage dual power supply rail for the ultrasonic drive circuit, but this way will increase the integration area of ​​the entire ultrasonic drive circuit.

[0094] Based on this, the embodiment of the present application provides a technical solution that can increase the corresponding detection distance of the ultrasonic wave emitted by the ultrasonic transducer without increasing the integration area of ​​the entire ultrasonic drive circuit.

[0095] The technical solution of the present application and how the technical solution of the present application solves the above-mentioned technical problems are described in detail below with specific embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the present application will be described below in conjunction with the accompanying drawings.

[0096] First, refer to Figure 3 , the present application provides an ultrasonic driving circuit for driving the ultrasonic transducer as described above; it may include: a capacitor 10 and a power module 30;

[0097] The capacitor 10 is connected to the power module 30 , and the capacitor 10 is also used to connect to the ultrasonic transducer.

[0098] The power module 30 is used to charge the capacitor 10;

[0099] The capacitor 10 is used to provide a positive pressure driving signal and / or a negative pressure driving signal to the ultrasonic transducer; wherein the detection range of the ultrasonic wave emitted by the ultrasonic transducer driven by the positive pressure driving signal and the negative pressure driving signal is different.

[0100] The capacitor 10 is used to store electrical energy and release energy when driving the ultrasonic transducer to emit ultrasonic waves. The power module 30 provides stable electrical energy to the capacitor 10 to charge the capacitor 10 .

[0101] Optionally, the capacitor may be a supercapacitor. Since supercapacitors have the advantages of high power density, long cycle life, and fast charging and discharging, supercapacitors may be used in this embodiment, and after one charge, they may drive the ultrasonic transducer to complete multiple emission cycles.

[0102] Based on the above structure and description, the embodiments of the present application can be based on the fast charging of the capacitor and the characteristics of being able to store electrical energy. Before the ultrasonic transducer transmits an ultrasonic signal, the capacitor can be charged once to transmit multiple drive signals. Based on the structure of the capacitor itself, when the ultrasonic transducer is driven in the transmitting stage, the capacitor can provide the ultrasonic transducer with a positive pressure drive signal and a negative pressure drive signal. Driven by the positive pressure drive signal and the negative pressure drive signal, the ultrasonic wave emitted by the ultrasonic transducer has a different detection range. Based on this, the detection distance of the ultrasonic wave emitted by the ultrasonic transducer can be increased.

[0103] Moreover, the present application can integrate the capacitor outside the chip where the ultrasonic drive circuit is located. The number of power supply modules used in the present application is one, so the area of ​​the chip occupied by the power supply module is basically the same as the area of ​​the chip occupied when a single high-voltage power supply is used in the traditional way. Therefore, the technical solution of the present application will not increase the integration area of ​​the entire ultrasonic drive circuit.

[0104] Optionally, the capacitor 10 includes a first electrode plate 11 and a second electrode plate 12; when the capacitor 10 provides a positive pressure driving signal and a negative pressure driving signal to the ultrasonic transducer, the connection relationship between the capacitor and the ultrasonic transducer is different.

[0105] For example, when the capacitor 10 provides a positive voltage driving signal to the ultrasonic transducer, the first electrode 11 is connected to the ultrasonic transducer, and the second electrode 12 is grounded.

[0106] 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.

[0107] In an optional embodiment, the ultrasonic driving circuit may further include 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.

[0108] Furthermore, the switch module can also be used to control the charging process of the capacitor.

[0109] According to the different stages of the capacitor, the working process of the ultrasonic driving circuit can be divided into a pre-charging stage and a driving stage in this embodiment.

[0110] In the pre-charging stage, the capacitor 10 is connected to the power module 30 to provide electrical energy to the capacitor 10 .

[0111] Reference Figure 3 In this stage, the first electrode plate 11 of the capacitor 10 is connected to the power module 30 to charge the capacitor 10 .

[0112] In the driving stage, the ultrasonic transducer is driven to generate ultrasonic signals with different detection ranges through different connection modes between the capacitor 10 and the switch module. Figure 3 The first plate 11 of the capacitor 10 is connected to 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 pressure driving signal to the ultrasonic transducer through the switch module.

[0113] Reference Figure 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, and the second plate 12 of the capacitor 10 is used to provide a negative pressure driving signal to the ultrasonic transducer through the switch module. The positive pressure driving signal and the negative pressure driving signal drive the ultrasonic transducer to emit ultrasonic waves with different detection ranges.

[0114] In this embodiment, the capacitor can be used to achieve efficient energy storage and rapid release to drive the ultrasonic transducer. The switch module can achieve precise control of the capacitor energy release process, thereby improving the working efficiency and stability of the ultrasonic transducer.

[0115] The above embodiments describe the overall structure of the ultrasonic drive circuit, and the following embodiments focus on the specific structure and function of the switch module.

[0116] Optional, see Figure 4 , the switch module may include a first switch circuit 21 and a second switch circuit 22 .

[0117] The first switching circuit 21 is connected between the capacitor 10 and the ultrasonic transducer, and is used to connect the first electrode 11 to the ultrasonic transducer when the capacitor 10 provides a positive pressure driving signal to the ultrasonic transducer, and is also used to connect the second electrode 12 to the ultrasonic transducer when the capacitor 10 provides a negative pressure driving signal to the ultrasonic transducer.

[0118] The second switch circuit 22 is connected between the capacitor 10 and the ground terminal; it is used to ground the second electrode 12 when the capacitor 10 provides a positive pressure driving signal to the ultrasonic transducer, and is also used to ground the first electrode 11 when the capacitor 10 provides a negative pressure driving signal to the ultrasonic transducer.

[0119] In this embodiment, the first switch circuit 21 and the second switch circuit 22 are used to conduct the driving path between the first plate 11 or the second plate 12 of the capacitor 10 and the ultrasonic transducer to provide a positive pressure driving signal or a negative pressure driving signal to the ultrasonic transducer.

[0120] Wherein, under a positive pressure driving signal, the ultrasonic transducer can emit an ultrasonic signal within a first detection range, and under a negative pressure driving signal, the ultrasonic transducer can emit an ultrasonic signal within a second detection range.

[0121] Based on the above description, this embodiment can control the first switching circuit and the second switching circuit through the driving circuit, so that the capacitor can provide a positive pressure driving signal and a negative pressure driving signal for the ultrasonic transducer, so that the ultrasonic transducer can generate an ultrasonic signal within the first detection range and an ultrasonic signal within the second detection range, providing an implementable solution for improving the detection range of the ultrasonic transducer.

[0122] The above content introduces the structure and function of the switch module, and the following content introduces the structure and function of the first switch circuit and the second switch circuit in more detail.

[0123] 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 electrode plate 11 and the ultrasonic transducer, and is used to be turned on when the capacitor 10 provides a positive voltage drive signal to the ultrasonic transducer. The fourth switch tube is connected between the second electrode plate 12 and the ground terminal, and is used to be turned on when the capacitor 10 provides a positive voltage drive signal to the ultrasonic transducer.

[0124] In another example, the first switching circuit 21 includes a second switching tube, and the second switching circuit 22 includes a third switching tube; the second switching tube is connected between the second electrode plate 12 and the ultrasonic transducer, and is used to be turned on when the capacitor 10 provides a negative pressure driving signal to the ultrasonic transducer; the third switching tube is connected between the first electrode plate 11 and the ground terminal, and is used to be turned on when the capacitor 10 provides a negative pressure driving signal to the ultrasonic transducer.

[0125] The above two examples describe the structure of the first switch circuit and the second switch circuit based on the capacitor providing a positive pressure drive signal or a negative pressure drive signal to the ultrasonic transducer. The following describes the first switch circuit and the second switch circuit based on their overall structure.

[0126] In one example, referring to Figure 4 The first switch circuit 21 includes a first switch tube M1 and a second switch tube M2, and the second switch circuit 22 includes a third switch tube M3 and a fourth switch tube M4.

[0127] Reference Figure 4 The first end of the first switch tube M1 is connected to the first electrode plate 11, and the second end is connected to the first end of the second switch tube M2 and is used to connect the ultrasonic transducer. The first switch tube M1 is turned on when the first electrode plate 11 provides a positive pressure driving signal to the ultrasonic transducer, and is turned off when the second electrode plate 12 provides a negative pressure driving signal to the ultrasonic transducer.

[0128] The second end of the second switch tube M2 is connected to the second electrode plate 12. The first switch tube M1 and the second switch tube M2 are turned off when the first electrode plate 11 provides a positive pressure driving signal to the ultrasonic transducer, and are turned on when the second electrode plate 12 provides a negative pressure driving signal to the ultrasonic transducer.

[0129] The first end of the third switch tube M3 is connected to the first electrode plate 11, and the second end is connected to the first end of the fourth switch tube M4 and grounded. The third switch tube M3 is turned off when the first electrode plate 11 provides a positive pressure driving signal to the ultrasonic transducer, and is turned on when the second electrode plate 12 provides a negative pressure driving signal to the ultrasonic transducer.

[0130] The second end of the fourth switch tube M4 is connected to the second electrode plate 12 . The fourth switch tube M4 is turned on when the first electrode plate 11 provides a positive pressure driving signal to the ultrasonic transducer, and is turned off when the second electrode plate 12 provides a negative pressure driving signal to the ultrasonic transducer.

[0131] In some embodiments, the first electrode 11 can be the positive electrode of the capacitor 10, and the second electrode 12 can be the negative electrode of the capacitor 10. Based on this, the first electrode 11 can provide a positive pressure driving signal to the ultrasonic transducer, and the second electrode 12 can provide a negative pressure driving signal to the ultrasonic transducer.

[0132] Based on the above description, in the driving stage, the first switch tube M1 is first driven to be turned on, the second switch tube M2 is turned off, the third switch tube M3 is turned off, and the fourth switch tube 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 tube M1, the second end of the ultrasonic transducer is grounded, and the first plate 11 provides a positive voltage driving signal for the ultrasonic transducer, thereby driving the ultrasonic transducer to emit ultrasonic waves in the first detection range.

[0133] Afterwards, the first switch tube M1 is driven to turn off, the third switch tube M3 is turned on, and the fourth switch tube 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 a negative voltage, and the second switch tube M2 is driven to turn on. The second plate 12 of the capacitor is connected to the first end of the ultrasonic transducer through the second switch tube M2, and the second end of the ultrasonic transducer is grounded. The second plate 12 provides a negative pressure driving signal for the ultrasonic transducer, thereby driving the ultrasonic transducer to emit ultrasonic waves in the second detection range.

[0134] It is worth noting that, after that, the second electrode plate can be grounded again in the above manner, and the voltage of the second electrode plate can be set to 0. At this time, the voltage of the first electrode plate 11 is positive, and at this time, a positive voltage driving signal can be provided to the ultrasonic transducer again. Repeating this process can provide the ultrasonic transducer with alternating positive and negative voltage driving signals.

[0135] The first switch tube, the second switch tube, the third switch tube and the fourth switch tube may be any switch element with suitable function and structure, and this embodiment does not make any specific limitation on this.

[0136] For example, the first switch tube, the second switch tube, the third switch tube and the fourth switch tube can be selected from MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) or IGBT (Insulated Gate Bipolar Transistor).

[0137] The above part describes the structures of the first switch circuit and the second switch circuit in the switch module, and the following part describes the drive circuit in the switch module.

[0138] Reference Figure 4 The switch module may further include a first drive circuit 231 , a second drive circuit 232 , a third drive circuit 233 and a fourth drive circuit 234 .

[0139] The first drive circuit 231 is connected to the drive end of the first switch tube M1, and is used to control the first switch tube M1 to be turned on or off. Optionally, when the first electrode plate 11 provides a positive pressure drive signal to the ultrasonic transducer, the first drive circuit is used to drive the first switch tube M1 to be turned on, and when the second electrode plate 12 provides a negative pressure drive signal to the ultrasonic transducer, the first drive circuit is used to drive the first switch tube M1 to be turned off.

[0140] The second drive circuit 232 is connected to the third end of the second switch tube M2, and is used to control the second switch tube M2 to be turned on or off; optionally, when the first electrode plate 11 provides a positive pressure drive signal to the ultrasonic transducer, the second drive circuit is used to drive the second switch tube M2 to be turned off, and when the second electrode plate 12 provides a negative pressure drive signal to the ultrasonic transducer, the second drive circuit is used to drive the second switch tube M2 to be turned on.

[0141] The third drive circuit 233 is connected to the drive end of the third switch tube M3, and is used to control the third switch tube M3 to be turned on or off; optionally, when the first electrode plate 11 provides a positive pressure drive signal to the ultrasonic transducer, the third drive circuit is used to drive the third switch tube M3 to be turned off, and when the second electrode plate 12 provides a negative pressure drive signal to the ultrasonic transducer, the third drive circuit is used to drive the second switch tube M3 to be turned on.

[0142] The fourth drive circuit 234 is connected to the drive end of the fourth switch tube M4, and is used to control the fourth switch tube M4 to be turned on or off; optionally, when the first electrode plate 11 provides a positive pressure drive signal to the ultrasonic transducer, the fourth drive circuit is used to drive the fourth switch tube M4 to be turned on, and when the second electrode plate 12 provides a negative pressure drive signal to the ultrasonic transducer, the fourth drive circuit is used to drive the fourth switch tube M4 to be turned off.

[0143] In this embodiment, the driving circuit is divided into a first driving circuit 231, a second driving circuit 232, a third driving circuit 233 and a fourth driving circuit 234. Based on this, 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 simplifies the control logic and structure of the driving circuit, but also realizes more precise 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 pressure driving signals and negative pressure driving signals to the ultrasonic transducer.

[0144] It should be understood that the first driving circuit may select any unit that can implement its driving logic, and this embodiment does not impose any special limitation on this.

[0145] For example, the first switch tube is a first transistor, and the first transistor is a P-type transistor. Figure 5 , the first driving circuit comprises:

[0146] a driving voltage generating subcircuit and a driving voltage resetting subcircuit;

[0147] The first end of the drive voltage generating subcircuit is connected to the first electrode 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 drive end of the first switch tube, for providing a first drive voltage to the drive end of the first switch tube.

[0148] The driving voltage reset subcircuit has a first end connected to the first electrode plate 11 of the capacitor 10, a second end connected to the ground, and a third end 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.

[0149] Wherein, the driving voltage generating subcircuit comprises:

[0150] The first Zener diode Z1 has a first end connected to the first plate of the capacitor, wherein the Zener diode works like a common diode when forward biased, but when reverse biased, when the voltage reaches its breakdown voltage, it will conduct and keep this voltage stable.

[0151] The first capacitor C1 has a first electrode connected to the second end of the first voltage stabilizing element Z1.

[0152] A first inverter has one end connected to the second plate of the first capacitor C1 and the other end connected to the first power supply terminal V EN1 connect.

[0153] The first electrode of the first capacitor C1 is also connected to the third end of the first switch tube, for providing a first driving voltage to the third end of the first switch tube, wherein the first driving voltage may 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.

[0154] The driving voltage resetting subcircuit comprises:

[0155] 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;

[0156] The bias voltage source is connected to the first end of the first current mirror through the first control tube M15, the second end of the first current mirror is connected to 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 to the first electrode plate 11 of the capacitor 10;

[0157] The output end of the first control tube M15 is connected to the control end of the first current mirror, the output end of the second control tube M13 is connected to the control end of the second current mirror, and the control end of the first control tube M15 and the control end of the second control tube M13 are used to connect to the reset signal end V RST ; The third end of the second current mirror is connected to the driving end of the first switch tube, and is used to provide the reset voltage to the driving end of the first switch tube.

[0158] Based on the above structure of the first driving circuit and the case where the gate-source voltage of the first transistor is 5V, the working process of the first driving circuit is described.

[0159] In a complete transmission cycle of the ultrasonic transducer, the first transistor will experience a turn-on and turn-off before the capacitor flips, and a turn-off and turn-on after the capacitor flips. The source terminal of the first transistor is connected to the positive plate of the capacitor, so the voltage of the source terminal will change with the flipping of the capacitor. In the off state, the first drive circuit must ensure that the gate-source voltage of the first transistor is at 0V, and in the on state, the first drive circuit must ensure that the gate-source voltage of the first transistor is at 5V. The gate voltage change process of the first transistor is HVVDD-5V, HVVDD, 0, -5V. Conventional high-voltage level converters are difficult to achieve this control function, so a capacitive high-voltage level converter is required. HVVDD is the first plate voltage of the capacitor, CFP is the first plate of the capacitor, and is connected to the cathode of the Zener Z1. The anode of the Zener Z1 is connected to the upper plate of the capacitor C1 and generates a gate control voltage. The lower plate of the capacitor C1 is connected to the inverter. When VEN1 is 5V, V GATE _ CTRL1 The voltage is equal to the first plate voltage of the capacitor.

[0160] When VEN1 is 0V, V GATE_CTRL1 The voltage is equal to CFP-5V. When the voltage of the first plate of the capacitor is HVVDD and the voltage of the second plate is 0V, V GATE_CTRL1 Switch between HVVDD and HVVDD-5V; when the first plate of the capacitor is 0V and the second plate voltage is HVVSS, V GATE _ CTRL1Switching between 0V and -5V can meet the requirements of zero return timing. The static power consumption of the capacitive high voltage level converter is 0, and it can generate output signals higher or lower than the voltage rail. Due to the DC isolation effect of the first capacitor C1, V GATE_CTRL1 The state of the ultrasonic transducer before it is in the transmitting phase is unknown, so a driving voltage reset subcircuit is required. The driving voltage reset subcircuit includes transistors M11 to M16. High-voltage transistor M11 and high-voltage transistor M12 form a high-voltage current mirror to release the charge on C1. High-voltage transistor M13 controls the shutdown of the M12 current path and isolates the high-voltage domain and the low-voltage domain from each other. Low-voltage transistor M14 and low-voltage transistor M16 form a low-voltage current mirror to copy the current from the low-voltage power supply. Low-voltage transistor M15 controls the shutdown of the M16 current path. When VRST is high, V GATE_CTRL1 is reset to HVVSS; when VRST is low, the reset circuit current paths are all cut off and there is no quiescent current.

[0161] Based on the above description, this embodiment can reset the voltage of the third terminal of the first switch tube before the ultrasonic transducer is in the transmitting stage to avoid damage to the first switch tube caused by excessive gate-source voltage. When the ultrasonic transducer is in the transmitting stage, the first switch tube is controlled to be turned on or off, providing a feasible solution for the capacitor to provide positive voltage driving signals and negative voltage driving signals to the ultrasonic transducer.

[0162] The above content is used to describe the process of the first driving circuit driving the first transistor. The following will describe the structure and function of the second driving circuit.

[0163] It should be understood that the second driving circuit may select any unit that can implement the driving logic, and this embodiment does not impose any special limitation on this.

[0164] Optionally, the second switch tube may be a second transistor, and the second transistor may be an N-type transistor. Figure 6 , the second driving circuit comprises:

[0165] The second Zener diode Z2 has a first end connected to the second plate CPN of the capacitor, wherein the Zener diode works like a common diode when forward biased, but when reverse biased, when the voltage reaches its breakdown voltage, it will conduct and keep this voltage stable.

[0166] The first electrode plate of the second capacitor C2 is connected to the second end of the second voltage stabilizing element Z2.

[0167] 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.

[0168] The first electrode plate of the second capacitor C2 is also connected to the third terminal VGATE_CTRL2 connected to the third terminal V of the second switch tube GATE_CTRL2 A second driving voltage is provided, wherein the second driving voltage includes a second on-voltage for turning on the second switch tube and a second off-voltage for turning off the second switch tube.

[0169] Optionally, the second switch tube is a second transistor, and the gate-source voltage of the second transistor may be 5V. When the second drive circuit adopts the above structure, the process of the second drive circuit driving the second switch tube to be turned on and off is as follows:

[0170] In a complete transmission cycle of the ultrasonic transducer, the second transistor will be turned on and off once after the capacitor flips. 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. When the second transistor is turned off, the second drive circuit is used to ensure that the gate-source voltage of the second transistor is at 0V, and when the second transistor is turned on, the second drive circuit must ensure that the gate-source voltage of the second transistor is at 5V. Based on the circuit structure of the second drive circuit above, when it is necessary to control the second transistor to turn off, the second drive circuit is used to control the second transistor to turn off through V EN2 , the inverter and the second capacitor provide a second turn-off voltage to the gate of the second switch tube, 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 at 0V. When it is necessary to control the second transistor to be turned on, 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 at 5V.

[0171] It should be understood that the third driving circuit may also select any unit that can implement its driving logic, and this embodiment does not impose any special limitation on this.

[0172] Optionally, the third switch tube may be a third transistor, and the third transistor may be an N-type transistor. Figure 7 , the third driving circuit comprises:

[0173] The third inverter has one end connected to the third power supply end VEN3 and the other end connected to the third end of the third switch tube, and is used to provide a third driving voltage to the third end of the third switch tube. The third driving voltage includes a third on-voltage for driving the third switch tube to turn on, and a third off-voltage for driving the third switch tube to turn off.

[0174] Optionally, the gate-source voltage of the third transistor may be 5V. When the third driving circuit adopts the above structure, the process of the third driving circuit driving the third switch tube to be turned on and off is as follows:

[0175] In a complete transmission cycle of the ultrasonic transducer, the third transistor will be turned on once when the capacitor flips, and turned off once when the capacitor flips again. The drain terminal of the third transistor is connected to the negative plate of the capacitor, and the source terminal is grounded, so the voltage of the source terminal does not change with the flipping of the capacitor. When the third transistor is in the off state, the third drive circuit is used to ensure that the gate-source voltage of the third transistor is at 0V, and when the third transistor is in the on state, the third drive circuit must ensure that the gate-source voltage of the third transistor is at 5V. Based on the circuit structure of the third drive circuit above, when it is necessary to control the third transistor to turn off, the third drive circuit is used to control the third transistor to turn off through V EN3 The inverter provides a third off-voltage to the gate of the third transistor, and the off-voltage is 0V to ensure that the gate-source voltage of the third transistor is at 0V. When the third transistor needs to be turned on, the third driving circuit is used to control the third transistor to turn on through the third power supply terminal V EN3 The third inverter provides a third on-voltage to the gate of the third transistor, and the third on-voltage is 5V to ensure that the gate-source voltage of the third transistor is at 5V.

[0176] In this embodiment, since the source terminal of the third transistor is grounded, the third transistor can be turned off and on by generating a voltage of 0V or 5V through a third driving circuit including only an inverter, which has a simple structure and is easy to implement.

[0177] It should be understood that the gate-source voltage of the third switch tube is only an example and is not particularly limited in this embodiment.

[0178] It should be understood that the fourth driving circuit may also select any unit that can implement the driving logic, and this embodiment does not impose any special limitation on this.

[0179] Optionally, the fourth switch tube may be a fourth transistor, and the fourth transistor may be a P-type transistor. Figure 8 , the fourth driving circuit comprises:

[0180] A fourth inverter has one end connected to a fourth power supply end V EN4 connect.

[0181] A third capacitor C3, a first plate of which is connected to the other end of the fourth inverter;

[0182] The third Zener diode Z3 has a first end connected to the second plate of the third capacitor C3 and a second end grounded; the Zener diode works like a common diode when forward biased, but when reverse biased, when the voltage reaches its breakdown voltage, it will conduct and keep this voltage stable.

[0183] The second electrode plate of the third capacitor C3 is also connected to the third terminal V GATE_CTRL4 connected to the third terminal V of the fourth switch tube GATE_CTRL4 A fourth driving voltage is provided, wherein the fourth driving voltage includes a fourth on-voltage for turning on the fourth switch tube and a fourth off-voltage for turning off the fourth switch tube.

[0184] Optionally, the gate-source voltage of the fourth transistor may be 5V. When the fourth driving circuit adopts the above structure, the process of the fourth driving circuit driving the fourth switch tube to be turned on and off is as follows:

[0185] In a complete transmission cycle of the ultrasonic transducer, the fourth transistor will be turned on and off once before the capacitor flips. The source terminal of the fourth 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. When the fourth switch tube is turned off, the fourth drive circuit is used to ensure that the gate-source voltage of the fourth transistor is at 0V, and when the fourth switch tube is turned on, the fourth drive circuit must ensure that the gate-source voltage of the fourth transistor is at 5V. Based on the circuit structure of the fourth drive circuit above, when it is necessary to control the fourth switch tube to turn off, the fourth drive circuit is used to control the fourth power supply terminal V EN4 , the fourth inverter and the third capacitor provide a fourth turn-off voltage to the gate of the fourth switch tube, 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 at 0V. When it is necessary to control the fourth switch tube to be turned 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 terminal 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 at 5V.

[0186] The following section describes the power module in the embodiment of the present application.

[0187] Reference Figure 4 The power module 30 includes a power supply 301 and a fifth switch tube M5.

[0188] 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 , the second plate 12 of the capacitor 10 is grounded through the second switch circuit 22 , and the power supply charges the capacitor 10 .

[0189] The driving circuit is also connected to the third end of the fifth switch tube M5.

[0190] 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 is charged once, the fifth switch tube M5 is turned off.

[0191] Through the above structure and control method, the power module 30 and the drive circuit of this embodiment can effectively manage the charging process of the capacitor 10, ensuring that it can be charged in time when needed and disconnected in time after charging is completed to avoid overcharging or unnecessary energy consumption.

[0192] Optionally, on the basis that the power module includes the fifth switch tube, the drive circuit may further include a fifth drive circuit, and the fifth drive circuit is used to drive the fifth switch tube to be turned on and off.

[0193] In this embodiment, the fifth driving circuit may select any unit that can implement its driving logic, and this embodiment does not impose any special limitation on this.

[0194] For example, the fifth switch tube may be a fifth transistor, and the fifth transistor may be a P-type transistor. Fig. 9 , the fifth driving circuit comprises:

[0195] One end of the first resistor R1 is connected to the power supply.

[0196] The fourth voltage stabilizing element Z4 is connected to both ends of the first resistor R1; the fourth voltage stabilizing element may be any element that can realize the voltage stabilizing function and is applicable to the present solution, and this embodiment does not specifically limit this.

[0197] For example, the fourth voltage stabilizing element may be a Zener diode, which works like a common diode when forward biased, but when reverse biased, when the voltage reaches its breakdown voltage, it will conduct and keep the voltage stable. Based on this, the Zener diode can be selected as the voltage stabilizing element in this embodiment.

[0198] The sixth switch tube M17 has a first end connected to the other end of the first resistor R1, and a driving end connected to the fifth power supply end V EN5 connect.

[0199] and a current source, one end of which is connected to the second end of the sixth switch and the other end of which is grounded.

[0200] The first end of the sixth switch M17 and the third end V GATE_CTRL5 connected, and used to provide a fifth driving voltage to the fifth switch tube.

[0201] Optionally, the gate-source voltage of the fifth transistor may be 5V. When the fifth driving circuit adopts the above structure, the process of the fifth driving circuit driving the fifth transistor to be turned on and off is as follows:

[0202] In one cycle of charging the capacitor, the fifth transistor undergoes one on and one off.

[0203] The source terminal of the fifth transistor is connected to the power supply, so the voltage of the source terminal is fixed. When the fifth switch tube is in the off state, the fifth drive circuit is used to ensure that the gate-source voltage of the fifth transistor is at 0V, and when the fifth switch tube is in the on state, the fifth drive circuit must ensure that the gate-source voltage of the fifth transistor is at 5V. Based on the circuit structure of the above fifth drive circuit, when it is necessary to control the fifth switch tube to be turned off, the fifth drive circuit is used to turn on the sixth switch tube M17 through the fifth power supply terminal VEN5, so that the difference between the source voltage of the sixth switch tube M17 and the power supply voltage is 0V. When it is necessary to control the fifth switch tube to be turned off, the fifth drive circuit is used to control the sixth switch M17 through the fifth power supply terminal VEN5, so that the difference between the source voltage of the sixth switch M17 and the power supply voltage is 5V. Among them, 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 requirements. Refer to Fig. 9 , the current source can be implemented by using a low voltage power supply and a current mirror structure.

[0204] The above content is used as a whole to describe the structure, function and structure and function of each module, circuit, sub-circuit and component of the ultrasonic driving circuit provided in the embodiment of the application. The ultrasonic driving circuit provided in the embodiment of the application is described below with a specific embodiment:

[0205] In this embodiment, refer to Fig.10, the ultrasonic drive circuit may include two switch bridge circuits and a gate control circuit, and the above-mentioned capacitor may be a flying capacitor. The first high-voltage transistor S1 and the second high-voltage transistor S2 constitute a switch bridge 1, and the third high-voltage transistor S3 and the fourth high-voltage transistor S4 constitute a switch 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 and the drain of the second high-voltage transistor are connected to a pin of the ultrasonic transducer, 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.

[0206] The ultrasonic drive circuit of this embodiment is characterized in that it does not require expensive off-chip inductors or on-chip negative high-voltage power supplies. Only some control logic and off-chip flying capacitors need to be added. The cost is lower, and multiple pulses can be emitted by only charging the ultrasonic transducer once before emission. Bipolar pulses have a longer detection distance and a higher round-trip signal-to-noise ratio than unipolar pulses. The zeroing timing can not only improve the linearity of the emission pulse, but also reduce the withstand voltage requirements for high-voltage transistors to further reduce the circuit cost.

[0207] Reference Fig.11 The output end of the gate control circuit 1 is connected to the gates 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 non-overlapping clock generation. The gate control circuits of the first high-voltage transistor M1 and the second high-voltage transistor M2 are generated by two capacitive high-voltage level converters. The non-overlapping clock circuit is to achieve the function of the return to zero timing.

[0208] Optionally, the gate control circuit 1 uses a capacitive high-voltage level converter with no static power consumption. By utilizing the characteristics of the capacitor, a control signal higher or lower than the power rail can be generated, thereby achieving a return-to-zero timing. The return-to-zero timing can avoid the situation where the source and drain of the first high-voltage transistor M1 and the second high-voltage transistor M2 on the switch bridge 1 do not have twice the power supply, thereby relaxing the withstand voltage requirements of the two high-voltage transistors. The bipolar emission pulse with return-to-zero logic is closer to a three-level pulse of positive high voltage-zero-negative high voltage, and has higher linearity.

[0209] The switch bridge circuit 2 adopts a push-pull structure with upper PMOS and lower NMOS. This structure can not only realize the flip control function of the flying capacitor, 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, which reduces the difficulty of circuit implementation.

[0210] The negative high-voltage capacitor generated by the flying capacitor replaces the original off-chip inductor, and the overall cost is significantly reduced compared with the existing circuit with off-chip inductor. Compared with the existing circuit with additional on-chip high-voltage power supply, the chip area occupied by the high-voltage power supply remains unchanged, saving a lot of on-chip area resources.

[0211] This embodiment can realize a bipolar ultrasonic driving circuit with a zeroing function by using a low-cost flying capacitor.

[0212] like Fig.10 The bipolar ultrasonic driving circuit shown includes a flying capacitor, switch bridge 1 and switch bridge 2, and a driven ultrasonic transducer. Switch bridge 1 is the main circuit of the ultrasonic drive and is used to drive 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 flying capacitor; when S1 is turned off and S2 is closed, the ultrasonic transducer is driven by the lower plate of the flying capacitor. Switch bridge 2 is an auxiliary circuit used to control the flying capacitor. When S3 is closed and S4 is turned off, the upper plate of the flying 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 flying capacitor is ground and the upper plate is a positive high-voltage signal. Only one flying capacitor is needed to generate positive and negative high-voltage power supplies.

[0213] It should be noted that the flying capacitor in this embodiment is an off-chip capacitor, which is integrated outside the chip where the switch bridge 1 and the switch bridge 2 are located.

[0214] It should be understood that the capacitor in the embodiment of the present application can not only adopt the flying capacitor, but also adopt 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 achieve the above functions.

[0215] like Fig.11As shown, it is a specific scheme of the 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 emission stage, the gate control circuit 2 controls the fifth high-voltage transistor M5 and the fourth high-voltage transistor M4 to close, the upper plate CFP of the flying capacitor C1 is connected to the positive high-voltage power supply, and the lower plate CFN is grounded. The charge accumulates 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 grounded, and is driven by the switch bridge one. The high-side switch of the switch bridge one is a P-type high-voltage transistor M1, and the low-side switch is an N-type high-voltage transistor M2, which constitutes a complementary ultrasonic drive circuit. Compared with the dual N-type ultrasonic drive circuit, the complementary ultrasonic drive circuit does not need to adopt a complex gate control circuit solution, 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. 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 periodic control signal, a corresponding gate control signal can be generated to control the first high-voltage transistor M1 and the second high-voltage transistor M2 to be alternately turned on and off, thereby generating a periodic ultrasonic drive signal. The second high-side switch of the switch bridge is an N-type high-voltage transistor M3 and a 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 grounded. The drain of the fourth high-voltage transistor M4 is connected to the upper plate of the flying capacitor C1, and the source is grounded. 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 two ends of the capacitor will not suddenly change, the lower plate will generate a negative high-voltage signal. The switch bridge 2 is different from the switch bridge 1. It is a push-pull structure, and the sources of the third high-voltage transistor M3 and the fourth high-voltage transistor are grounded, and the drain of the third high-voltage transistor M3 and the drain of the fourth high-voltage transistor M4 are connected to high voltage. Such a structure can not only improve the circuit reliability, but also reduce 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 ground to positive high voltage, and the voltage domain of the fourth high-voltage transistor M4 is from negative high voltage to ground. Both transistors only need a single withstand voltage, and there will be no extreme withstand voltage situation where one end is negative high voltage and the other end is positive high voltage. Secondly, the parasitic source-drain diodes of the third high-voltage transistor M3 and the fourth high-voltage transistor M4 will not be forward-conducted, resulting in energy leakage. Finally, the gate control circuit 2 only needs to generate 5V and -5V signals to control the closing and closing of the third high-voltage transistor M3 and the fourth high-voltage transistor M4, respectively, and does not need to work in the high-voltage domain, which reduces the difficulty of circuit implementation and improves the reliability of the circuit.

[0216] In order to avoid power supply energy leakage caused by simultaneous conduction of the switch bridges, both the gate control circuit 1 and the gate control circuit 2 are equipped with non-overlapping clock circuits to ensure that the gate control signals do not overlap, leaving sufficient dead time for the switching of the switch bridges.

[0217] like Fig.12 The corresponding timing of the above embodiment is shown. TX / RX is the enable signal for ultrasonic transmission. When TX is set high, it is valid for the transmission stage, and when RX is set low, it is valid for the reception stage. Switches S1, S2, S3, and S4 correspond to the first high-voltage transistor M1, the second high-voltage transistor M2, the third high-voltage transistor M3, and the fourth high-voltage transistor M4 in the second specific implementation method, respectively. Pull-up is the pull-up enable, which is controlled by the first switch S1; Pull-down is the pull-down enable, which is controlled by the second switch S2; Fly is the flying capacitor flip enable controlled by the third switch S3 and the fourth switch S4. VDRV is the ultrasonic drive output signal, which drives the ultrasonic transducer.

[0218] In the emission phase, the first switch S1 is closed and the second switch S2 is turned off, generating a pull-up signal (Pull-up, 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 a positive high voltage, the lower plate is low, and the ultrasonic drive output VDRV is a positive high voltage. After that, the first switch S1 is turned off and the second switch S2 is closed, generating a pull-down signal (Pull-down, the lower 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 low, the lower plate is a negative high voltage, and the ultrasonic drive output VDRV is a negative high voltage. The pull-up and pull-down signals form a complete emission cycle. However, there is still a problem with the above timing. The drain-source voltage drop on the first switch S1 and the second switch S2 can reach up to double the voltage drop (positive high voltage minus negative high voltage), and the use of high-voltage transistors with higher withstand voltage will increase the cost of the circuit. Therefore, this embodiment further optimizes this emission timing by changing the fourth The conduction phase of switch S4 is slightly delayed, and the delay time is t2, which overlaps with the conduction phase of the second switch S2. 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 floats briefly, and the potential remains at the positive high voltage (HVVDD. Due to the delay, the fourth switch S4 does not flip, and the upper plate of the flying capacitor is a positive high voltage, and the lower plate is ground. Then the second switch S2 is closed. At this time, the flying capacitor has not flipped, and the lower plate is still ground. Therefore, the ultrasonic drive output VDRV is pulled down from the positive high voltage (HVVDD) to the ground, instead of being directly pulled to the negative high voltage (HVVSS). When the ultrasonic drive output VDRV is completely grounded, the fourth switch S4 will be turned off, and the third switch S3 will be turned on. The flying capacitor flips, the upper plate is ground, and the lower plate is negative high voltage. In this process, the second switch S2 remains closed, and the third switch S3 remains turned off. The ultrasonic drive output VDRV follows the lower plate of the flying capacitor and is pulled to the negative high voltage (HVVSS.

[0219] This zeroing timing only requires a slight modification of the control timing and is easy to implement. In the case of bipolar pulses, the zeroing timing effectively reduces the withstand voltage requirements of the high-voltage transistors in the ultrasonic drive circuit, and does not require high-voltage transistors with higher withstand voltage levels, reducing the actual cost of the circuit. The bipolar transmit pulse with zeroing logic is closer to a three-level pulse of positive high voltage-zero-negative high voltage, and has higher linearity.

[0220] In a second aspect, an embodiment of the present application further provides an ultrasonic radar, including an ultrasonic transducer, a controller, and the ultrasonic driving circuit in the first aspect.

[0221] The controller is connected to a first end of the ultrasonic drive circuit, and a second end of the ultrasonic drive circuit is connected to the ultrasonic transducer.

[0222] The controller is used to control the ultrasonic driving circuit so as to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges through the ultrasonic driving circuit.

[0223] In this embodiment, the controller is used to control the ultrasonic drive circuit to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges through the ultrasonic drive circuit. Through the above structure, the ultrasonic radar of this embodiment can adjust the detection range of ultrasonic waves as needed, thereby achieving effective detection of targets at different distances.

[0224] In a third aspect, an embodiment of the present application further provides a vehicle, comprising the ultrasonic radar of the second aspect.

[0225] In this embodiment, the vehicle can monitor the surrounding environment in real time and improve driving safety by integrating ultrasonic radar. For example, when reversing, the ultrasonic radar can detect obstacles behind and warn the driver to avoid collision accidents. In addition, ultrasonic radar can also be used in automatic parking systems to help vehicles automatically complete parking operations.

[0226] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. An ultrasonic driving circuit, characterized in that: Used to drive an ultrasonic transducer; comprising: a capacitor (10) and a power module (30); The capacitor (10) is connected to the power module (30), and the capacitor (10) is also used to connect to the ultrasonic transducer; The power module (30) is used to charge the capacitor (10); The capacitor (10) is used to provide a positive pressure driving signal and / or a negative pressure driving signal to the ultrasonic transducer; wherein the detection range of the ultrasonic wave emitted by the ultrasonic transducer driven by the positive pressure driving signal and the negative pressure driving signal is different.

2. The ultrasonic driving circuit according to claim 1, characterized in that: The capacitor (10) comprises a first electrode plate (11) and a second electrode plate (12); 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.

3. The ultrasonic driving circuit according to claim 2, characterized in that: 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.

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

5. The ultrasonic driving circuit according to claim 4, characterized in that: The switch module comprises a first switch circuit (21) and a second switch circuit (22); The first switch circuit (21) is connected between the capacitor (10) and the ultrasonic transducer, and is used to connect the first electrode plate (11) to the ultrasonic transducer when the capacitor (10) provides a positive pressure driving signal to the ultrasonic transducer, and is also used to connect the second electrode plate (12) to the ultrasonic transducer when the capacitor (10) provides a negative pressure driving signal to the ultrasonic transducer; The second switch circuit (22) is connected between the capacitor (10) and a ground terminal, and is used to ground the second electrode plate (12) when the capacitor (10) provides a positive voltage driving signal to the ultrasonic transducer, and is also used to ground the first electrode plate (11) when the capacitor (10) provides a negative voltage driving signal to the ultrasonic transducer.

6. The ultrasonic driving circuit according to claim 5, characterized in that: The first switch circuit (21) comprises a first switch tube, and the second switch circuit (22) comprises a fourth switch tube; The first switch tube is connected between the first electrode plate (11) and the ultrasonic transducer, and is used for being 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 electrode plate (12) and the ground terminal, and is used for being turned on when the capacitor (10) provides a positive voltage driving signal to the ultrasonic transducer.

7. The ultrasonic driving circuit according to claim 5, characterized in that: The first switch circuit (21) includes a second switch tube, and the second switch circuit (22) includes a third switch tube; The second switch tube is connected between the second electrode plate (12) and the ultrasonic transducer, and is used for being turned on when the capacitor (10) provides a negative pressure driving signal to the ultrasonic transducer; The third switch tube is connected between the first electrode plate (11) and the ground terminal, and is used for being turned on when the capacitor (10) provides a negative pressure driving signal to the ultrasonic transducer.

8. The ultrasonic driving circuit according to claim 6, characterized in that: The switch module further comprises a first drive circuit (231); the first drive circuit (231) is connected to the drive end of the first switch tube and is used to drive the first switch tube to conduct when the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer.

9. The ultrasonic driving circuit according to claim 8, characterized in that: The first driving circuit (231) comprises: a driving voltage generating subcircuit and a driving voltage resetting subcircuit; The first end of the drive voltage generating subcircuit is connected to the first electrode 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 drive end of the first switch tube, and is used to provide a first drive voltage to the drive end of the first switch tube; The driving voltage resetting subcircuit has a first end connected to the first electrode plate (11) of the capacitor (10), a second end connected to the ground, and a third end connected to the driving end of the first switching tube, and is used to provide a reset voltage to the driving end of the first switching tube.

10. The ultrasonic driving circuit according to claim 9, characterized in that: The driving voltage generating subcircuit comprises: A first Zener tube, a first end of which is connected to a first electrode plate (11) of the capacitor (10); A first capacitor, a first plate connected to a second end of the first voltage stabilizing element; 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 end; The first electrode plate of the first capacitor is also 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.

11. The ultrasonic driving circuit according to claim 9, characterized in that: The driving voltage resetting subcircuit comprises: a first current mirror, a second current mirror, a first control tube, a second control tube and a bias voltage source; The bias voltage source is connected to the first end of the first current mirror through the first control tube, the second end of the first current mirror is connected to 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 to the first electrode plate (11) of the capacitor (10); The output end of the first control tube is connected to the control end of the first current mirror, the output end of the second control tube is connected to 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 to connect to a reset signal end; The third terminal of the second current mirror is connected to the driving terminal of the first switch tube, and is used to provide the reset voltage to the driving terminal of the first switch tube.

12. The ultrasonic driving circuit according to claim 6, characterized in that: The switch module further comprises a fourth drive circuit (234); the fourth drive circuit (234) is connected to the drive end of the fourth switch tube and is used to drive the first switch tube to conduct when the capacitor (10) provides a positive pressure drive signal to the ultrasonic transducer.

13. The ultrasonic driving circuit according to claim 12, characterized in that: The fourth driving circuit (234) comprises: a fourth inverter, one end of which is connected to a fourth power supply end; A third capacitor, a first plate of which is connected to the other end of the fourth inverter; A third Zener tube, a first end of which is connected to the second plate of the third capacitor and a second end of which is grounded; The second electrode plate of the third capacitor is also connected to the driving end of the fourth switch tube, and is used to provide a fourth driving voltage to the driving end of the fourth switch tube.

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

15. The ultrasonic driving circuit according to claim 14, characterized in that: The second driving circuit (232) comprises: A second Zener tube, a first end of which is connected to a second electrode plate (12) of the capacitor (10); A second capacitor, a first electrode plate connected to a second end of the second voltage stabilizing element; A second inverter, one end of which is connected to the second plate of the second capacitor, and the other end of which is connected to the second power supply end; The first electrode plate of the second capacitor is also connected to the driving end of the second switch tube, and is used to provide a second driving voltage to the driving end of the second switch tube.

16. The ultrasonic driving circuit according to claim 7, characterized in that: The switch module further comprises a third drive circuit (233); the third drive circuit (233) is connected to the drive end of the third switch tube and is used to drive the third switch tube to conduct when the capacitor (10) provides a negative pressure drive signal to the ultrasonic transducer.

17. The ultrasonic driving circuit according to claim 16, characterized in that: The third driving circuit (233) comprises: The third inverter has one end connected to the third power supply end and the other end connected to the driving end of the third switch tube, and is used to provide a third driving voltage to the driving end of the third switch tube.

18. The ultrasonic driving circuit according to any one of claims 4 to 17, characterized in that: The power module (30) comprises a power supply (301) and a fifth switch tube; The power source (301) is connected to the first end of the fifth switch tube, the second end of the fifth switch tube is connected to the first electrode plate (11) of the capacitor (10), and the power source (301) is used to charge the capacitor; The switch module is also connected to the driving end of the fifth switch tube, and is used to drive the fifth switch tube to be turned on when the capacitor is charged.

19. The ultrasonic driving circuit according to claim 18, characterized in that: The switch module further comprises a fifth drive circuit (235), the fifth drive circuit (235) being connected to the drive end of the fifth switch tube and being used for driving the fifth switch tube to conduct when the capacitor (10) is charged.

20. The ultrasonic driving circuit according to claim 19, characterized in that: The fifth driving circuit (235) comprises: A first resistor, one end of which is connected to the power supply; a fourth Zener diode connected to two ends of the first resistor; a sixth switch tube, a first end of which is connected to the other end of the first resistor, and a driving end of which is connected to the fifth power supply end; and a current source, one end of which is connected to the second end of the sixth switch and the other end of which is grounded; The first end of the sixth switch tube is also connected to the driving end of the fifth switch tube, and is used to provide a fifth driving voltage to the fifth switch tube.

21. An ultrasonic radar, characterized in that: It comprises an ultrasonic transducer, a controller and an ultrasonic driving circuit according to any one of claims 1 to 20; The controller is connected to a first end of the ultrasonic drive circuit, and a second end of the ultrasonic drive circuit is connected to the ultrasonic transducer; The controller is used to control the ultrasonic driving circuit so as to drive the ultrasonic transducer to generate ultrasonic waves with different detection ranges through the ultrasonic driving circuit.

22. A vehicle, characterized in that: Including the ultrasonic radar as described in claim 21.

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