Drive circuit and ultrasonic sensor
By using a drive circuit controlled by switching modules in the ultrasonic sensor, ultrasonic signals are emitted under series resonance and ultrasonic signals are received under parallel resonance, which solves the problem of poor sensitivity of received signals in traditional designs, and realizes miniaturization and high-sensitivity reception of ultrasonic sensors.
Patent Information
- Application Number
- CN202421483577.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-26
- Publication Date
- 2025-03-21
- Estimated Expiration
- 2034-06-26
AI Technical Summary
In traditional ultrasonic sensor design, when receiving ultrasonic signals through series resonant circuits, the sensitivity of the received ultrasonic signals will be poor, making it difficult to achieve miniaturization while improving the sensitivity of the received signal.
A driving circuit is adopted, including a switching module, a second inductor, an ultrasonic probe equivalent module and a controller. The switching module forms series resonance when transmitting ultrasonic signals, and parallel resonance when receiving ultrasonic signals, thereby enhancing the intensity of the transmitted signal and improving the sensitivity of the received signal.
The ultrasonic sensor is miniaturized, and the intensity of the transmitted signal and the sensitivity of the received signal are improved through the control of the switching module, which solves the problem of poor sensitivity of the received signal in traditional designs.
Smart Images
Figure CN222652257U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of ultrasonic technology, and in particular to a driving circuit and an ultrasonic sensor. Background Art
[0002] In the design of traditional ultrasonic sensors, the same ultrasonic element is usually used as both a transmitting element and a receiving element to achieve miniaturization. This design method requires the ultrasonic element to operate at its resonant frequency, and ultrasonic waves are transmitted and received by applying an electrical pulse signal of the resonant frequency to a series resonant circuit. However, receiving ultrasonic signals through a series resonant circuit will result in poor sensitivity in receiving ultrasonic signals. Therefore, how to miniaturize ultrasonic sensors while improving the sensitivity of receiving ultrasonic signals has become a technical problem that needs to be solved urgently. Utility Model Content
[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a driving circuit and an ultrasonic sensor, which solves the problem of poor sensitivity of receiving ultrasonic signals when the ultrasonic sensor is miniaturized.
[0004] In a first aspect, the present application proposes a driving circuit, which is applied to an ultrasonic sensor, and the driving circuit includes: a switching module, a second inductor, an ultrasonic probe equivalent module, and a controller;
[0005] The switching module is electrically connected to the controller;
[0006] A first end of the second inductor is connected to the switching module, and a second end of the second inductor is connected to the ultrasonic probe equivalent module;
[0007] When transmitting an ultrasonic signal, the controller controls the switching module to connect the first end of the second inductor to an AC power source, so that the second inductor and the ultrasonic probe equivalent module are connected in series to form a series resonance;
[0008] When receiving an ultrasonic signal, the controller controls the switching module to ground the first end of the second inductor, so that the second inductor and the ultrasonic probe equivalent module are connected in parallel to form parallel resonance.
[0009] In some embodiments, the switching module includes an AND gate, a first NOT gate, a second NOT gate, a first switch, a second switch, and a power supply;
[0010] The controller is connected to the first input terminal of the AND gate and the second input terminal of the AND gate respectively, the output terminal of the AND gate is connected to the input terminal of the first NOT gate and the input terminal of the second NOT gate respectively, the output terminal of the first NOT gate is connected to the first terminal of the first switch, the second terminal of the first switch is connected to the power supply, the third terminal of the first switch is connected to the second terminal of the second switch and the first terminal of the second inductor respectively, the first terminal of the second switch is connected to the output terminal of the second NOT gate, and the third terminal of the second switch is grounded;
[0011] The controller outputs a square wave signal to the first input terminal of the AND gate, and the controller outputs a level signal to the second input terminal of the AND gate; wherein the level signal includes a high level signal or a low level signal;
[0012] When the level signal is the high level signal, the first switch and the second switch are alternately turned on so that the first end of the second inductor is connected to the AC power supply. When the level signal is the low level signal, the first switch is turned off and the second switch is turned on so that the first end of the second inductor is grounded.
[0013] In some embodiments, the switching module includes a third switch and a fourth switch;
[0014] The controller is connected to the first end of the third switch and the first end of the fourth switch respectively, the second end of the third switch is connected to the second end of the fourth switch and the first end of the second inductor respectively, the third end of the third switch is connected to the power supply, and the third end of the fourth switch is grounded;
[0015] When the controller outputs a square wave signal to the first end of the third switch and the first end of the fourth switch, the third switch and the fourth switch are alternately turned on, so that the first end of the second inductor is connected to an AC power source;
[0016] When the controller outputs a low level signal to the first end of the third switch and the first end of the fourth switch, the third switch is turned off and the fourth switch is turned on, so that the first end of the second inductor is grounded.
[0017] In some embodiments, the driving circuit further includes a first filtering and amplifying module, a second filtering and amplifying module, a third filtering module and an inverting module;
[0018] The first end of the first filtering and amplifying module is connected to the second end of the second inductor, the second end of the first filtering and amplifying module is connected to the first end of the second filtering and amplifying module, the second end of the second filtering and amplifying module is connected to the first end of the inverting module, and the second end of the inverting module is respectively connected to the first end of the third filtering module and the controller;
[0019] The first filtering and amplifying module is used to perform primary filtering and primary amplification on the ultrasonic signal, the second filtering and amplifying module is used to perform secondary filtering and secondary amplification on the ultrasonic signal, the inverting module is used to flip the negative half-cycle signal into a positive half-cycle signal, and the third filtering module is used to perform third-stage filtering on the ultrasonic signal; wherein the ultrasonic signal includes a positive half-cycle signal and the negative half-cycle signal.
[0020] In some embodiments, the first filtering and amplifying module includes a first filtering submodule and a first amplifying submodule, the first filtering submodule includes a third resistor, a third inductor and a sixth capacitor, and the first amplifying submodule includes a fifth switch, a fourth resistor, a fifth resistor and a third capacitor;
[0021] The first end of the third resistor is connected to the second end of the second inductor, the second end of the third resistor is connected to the first end of the third inductor and the first end of the sixth capacitor respectively, and the second end of the third inductor and the second end of the sixth capacitor are grounded;
[0022] The first end of the fifth switch is connected to the second end of the third resistor, the third end of the fifth switch is connected to the first end of the fifth resistor, the second end of the fifth resistor is grounded, the second end of the fifth switch is respectively connected to the first end of the fourth resistor and the first end of the third capacitor, the second end of the fourth resistor is connected to a power supply, and the second end of the third capacitor is connected to the first end of the second filtering and amplifying module.
[0023] In some embodiments, the second filtering and amplifying module includes a second filtering submodule and a second amplifying submodule, the second filtering submodule includes a sixth resistor, a fourth inductor and a fourth capacitor, and the second amplifying submodule includes a first amplifier, a seventh resistor and an eighth resistor;
[0024] The first end of the sixth resistor is connected to the second end of the first filtering and amplifying module, the second end of the sixth resistor is connected to the first end of the fourth inductor and the first end of the fourth capacitor respectively, and the second end of the fourth inductor and the second end of the fourth capacitor are grounded;
[0025] The non-inverting input terminal of the first amplifier is connected to the second end of the sixth resistor, the inverting input terminal of the first amplifier is respectively connected to the first end of the seventh resistor and the first end of the eighth resistor, the second end of the seventh resistor is grounded, and the output terminal of the first amplifier is respectively connected to the second end of the eighth resistor and the first end of the inverting module.
[0026] In some embodiments, the inversion module includes a positive half-cycle detection submodule and a negative half-cycle detection submodule;
[0027] The first end of the positive half-cycle detection submodule is respectively connected to the second end of the second filtering and amplifying module and the first end of the negative half-cycle detection submodule, the second end of the positive half-cycle detection submodule is respectively connected to the second end of the negative half-cycle detection submodule, the third filtering module and the controller, the positive half-cycle detection submodule is used to allow the positive half-cycle signal to pass and cut off the negative half-cycle signal, the negative half-cycle detection submodule is used to flip the negative half-cycle signal into a positive half-cycle signal, the positive half-cycle signal is flipped into a negative half-cycle signal, and the flipped positive half-cycle signal is passed and the flipped negative half-cycle signal is cut off.
[0028] In some embodiments, the negative half-cycle detection submodule includes an inverting amplifier, a ninth resistor, a tenth resistor, and a second diode;
[0029] The first end of the ninth resistor is respectively connected to the second end of the second filtering and amplifying module and the first end of the negative half-cycle detection submodule, the second end of the ninth resistor is respectively connected to the inverting input end of the inverting amplifier and the first end of the tenth resistor, the non-inverting input end of the inverting amplifier is grounded, the output end of the inverting amplifier is respectively connected to the second end of the tenth resistor and the first end of the second diode, and the second end of the second diode is respectively connected to the second end of the positive half-cycle detection submodule, the third filtering module and the controller.
[0030] In some embodiments, the third filtering module includes a fifth capacitor and an eleventh resistor;
[0031] The first end of the fifth capacitor is respectively connected to the second end of the positive half-cycle detection submodule, the second end of the negative half-cycle detection submodule, the first end of the eleventh resistor and the controller, and the second end of the fifth capacitor and the second end of the eleventh resistor are grounded.
[0032] In a second aspect, an embodiment of the present application provides an ultrasonic sensor, comprising a driving circuit as described in the first aspect.
[0033] The driving circuit proposed in the embodiment of the present application includes a switching module, a second inductor, an ultrasonic probe equivalent module, and a controller. The switching module is electrically connected to the controller, the first end of the second inductor is connected to the switching module, and the second end of the second inductor is connected to the ultrasonic probe equivalent module. When transmitting an ultrasonic signal, the controller controls the switching module to connect the first end of the second inductor to an AC power supply so that the second inductor and the ultrasonic probe equivalent module are connected in series to form a series resonance. When receiving an ultrasonic signal, the controller controls the switching module to ground the first end of the second inductor so that the second inductor and the ultrasonic probe equivalent module are connected in parallel to form a parallel resonance. In the present application, the miniaturization of the ultrasonic sensor is achieved by using the same ultrasonic element as both a transmitting element and a receiving element. At the same time, the switching module is used to transmit ultrasonic signals under series resonance and receive ultrasonic signals under parallel resonance, thereby enhancing the intensity of the transmitted ultrasonic signal and improving the sensitivity of the received ultrasonic signal.
[0034] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:
[0036] Figure 1 is a schematic diagram of a driving circuit provided in a first embodiment of the present application;
[0037] Figure 2 This is a first circuit connection diagram of the switching module provided in an embodiment of the present application;
[0038] Figure 3 This is a second circuit connection diagram of the switching module provided in an embodiment of the present application;
[0039] Figure 4 is a module schematic diagram of a driving circuit provided in an embodiment of the present application;
[0040] Figure 5 It is a schematic diagram of a driving circuit provided in the second embodiment of the present application. DETAILED DESCRIPTION
[0041] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.
[0042] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0043] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0044] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0045] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0046] In the traditional ultrasonic sensor design, the same ultrasonic element is usually used as both a transmitting element and a receiving element to achieve miniaturization. This design method requires the ultrasonic element to work at its resonant frequency, and ultrasonic waves are transmitted and received by applying an electrical pulse signal of the resonant frequency to the series resonant circuit. However, receiving ultrasonic signals through a series resonant circuit will result in poor sensitivity in receiving ultrasonic signals.
[0047] Based on this, a driving circuit is provided in an embodiment of the present application, which is applied to an ultrasonic sensor and is specifically described in the following embodiments.
[0048] Figure 1 is a schematic diagram of a driving circuit provided in the first embodiment of the present application, such as Figure 1As shown, the driving circuit provided in the embodiment of the present application includes: a switching module 10, a second inductor L2, an ultrasonic probe equivalent module 11 (ultrasonic element), and a controller (not shown in the figure). The switching module 10 is electrically connected to the controller, the first end of the second inductor L2 is connected to the switching module 10, and the second end of the second inductor L2 is connected to the ultrasonic probe equivalent module 11. The ultrasonic probe equivalent module 11 is a piezoelectric ceramic equivalent circuit, and the piezoelectric ceramic equivalent circuit includes a first capacitor C1, a second capacitor C2, a first inductor L1 and a first resistor R1. The first capacitor C1, the first inductor L1 and the first resistor R1 are connected in series, and the second capacitor C2 is connected in parallel with the first capacitor C1, the first inductor L1 and the first resistor R1. The two ends of the piezoelectric ceramic equivalent circuit are respectively connected to the second end of the second inductor L2 and the ground.
[0049] like Figure 1 As shown, the driving circuit may further include a second resistor R2, a first end of the second resistor R2 is connected to a second end of the second inductor L2, and a second end of the second resistor R2 is grounded. When the total impedance of the ultrasonic probe equivalent module 11 is equal to the impedance of the second resistor R2, the voltage signal generated by the ultrasonic signal received by the ultrasonic probe is output at maximum power, so that the energy transmission is maximized.
[0050] When transmitting an ultrasonic signal, the controller controls the switching module 10 to connect the first end of the second inductor L2 to the AC power supply V1, so that the second inductor L2 and the ultrasonic probe equivalent module 11 are connected in series to form a series resonance. When receiving an ultrasonic signal, the controller controls the switching module 10 to ground the first end of the second inductor L2, so that the second inductor L2 and the ultrasonic probe equivalent module 11 are connected in parallel to form a parallel resonance. By using the same ultrasonic element as both a transmitting element and a receiving element, the miniaturization of the ultrasonic sensor is achieved. At the same time, the switching module 10 realizes the transmission of ultrasonic signals under series resonance and the reception of ultrasonic signals under parallel resonance, thereby enhancing the strength of the transmitted ultrasonic signal and improving the sensitivity of the received ultrasonic signal.
[0051] In one example, the switching module 10 includes an electronic switch S1. When transmitting an ultrasonic signal, after the controller controls the first end of the electronic switch S1 to be connected to the second end of the electronic switch S1, the first end of the second inductor L2 can be connected to the AC power supply V1. At this time, the second inductor L2 and the ultrasonic probe equivalent module 11 form a series resonance. Transmitting an ultrasonic signal under series resonance can enhance the intensity of the transmitted ultrasonic signal. When receiving an ultrasonic signal, after the controller controls the first end of the electronic switch S1 to be connected to the third end of the electronic switch S1, the first end of the second inductor L2 is grounded. At this time, the second inductor L2 and the ultrasonic probe equivalent module 11 form a parallel resonance. Receiving an ultrasonic signal under parallel resonance can improve the sensitivity of receiving an ultrasonic signal.
[0052] The driving circuit proposed in the embodiment of the present application includes a switching module 10, a second inductor L2, an ultrasonic probe equivalent module 11, and a controller. The switching module 10 is electrically connected to the controller, the first end of the second inductor L2 is connected to the switching module 10, and the second end of the second inductor L2 is connected to the ultrasonic probe equivalent module 11. When transmitting an ultrasonic signal, the controller controls the switching module 10 to connect the first end of the second inductor L2 to an AC power supply so that the second inductor L2 and the ultrasonic probe equivalent module 11 are connected in series to form a series resonance. When receiving an ultrasonic signal, the controller controls the switching module 10 to ground the first end of the second inductor L2 so that the second inductor L2 and the ultrasonic probe equivalent module 11 are connected in parallel to form a parallel resonance. In the present application, the miniaturization of the ultrasonic sensor is achieved by using the same ultrasonic element as both a transmitting element and a receiving element. At the same time, the switching module 10 is used to transmit ultrasonic signals under series resonance and receive ultrasonic signals under parallel resonance, thereby enhancing the intensity of the transmitted ultrasonic signal and improving the sensitivity of the received ultrasonic signal.
[0053] In some embodiments, Figure 2 As shown, the switching module 10 includes an AND gate A, a first NOT gate N1, a second NOT gate N2, a first switch Q1, a second switch Q2 and a power source VCC; wherein the first switch Q1 may be a PMOS tube, and the second switch Q2 may be an NMOS tube.
[0054] The controller is connected to the first input terminal of the AND gate A and the second input terminal of the AND gate A respectively, the output terminal of the AND gate A is connected to the input terminal of the first NOT gate N1 and the input terminal of the second NOT gate N2 respectively, the output terminal of the first NOT gate N1 is connected to the gate of the PMOS tube Q1, the source of the PMOS tube Q1 is connected to the power supply VCC, the drain of the PMOS tube Q1 is connected to the drain of the NMOS tube Q2 and the first terminal of the second inductor L2 respectively, the gate of the NMOS tube Q2 is connected to the output terminal of the second NOT gate N2, and the source of the NMOS tube Q2 is grounded. When all the inputs of the AND gate A are high level, the output is high level, otherwise, the output is low level. The input of the NOT gate is opposite to the output, and when the input of the NOT gate is high level, the output is low level.
[0055] The controller outputs a square wave signal to the first input terminal of the AND gate A, and the controller outputs a level signal to the second input terminal of the AND gate A; wherein the level signal includes a high level signal or a low level signal; when the level signal is a high level signal, the PMOS tube Q1 and the NMOS tube Q2 are alternately turned on, so that the first end of the second inductor L2 is connected to the AC power supply V1, and when the level signal is a low level signal, the PMOS tube Q1 is turned off, and the NMOS tube Q2 is turned on, so that the first end of the second inductor L2 is grounded. Specifically, the square wave signal is a periodic waveform signal, and its voltage alternately switches between high and low levels. In this embodiment, the magnitude of the high level is VCC, and the magnitude of the low level is 0.
[0056] It should be noted that when the level signal is a high level signal, if the square wave signal is a high level, the output of the AND gate A is a high level, and if the square wave signal is a low level, the output of the AND gate A is a low level. Therefore, the signal output by the AND gate A is consistent with the square wave signal. When the output of the AND gate A is a high level, the first NOT gate N1 and the second NOT gate N2 both output a low level, at which time the PMOS tube Q1 is turned off and the NMOS tube Q2 is turned on. When the output of the AND gate A is a low level, the first NOT gate N1 and the second NOT gate N2 both output a high level, at which time the PMOS tube Q1 is turned on and the NMOS tube Q2 is turned off. Therefore, when the level signal is a high level signal, the PMOS tube Q1 and the NMOS tube Q2 are alternately turned on, and the first end of the second inductor L2 is equivalent to connecting the AC power supply V1, so that the second inductor L2 and the ultrasonic probe equivalent module 11 form a series resonance.
[0057] When the level signal is a low level signal, no matter the square wave signal is high level or low level, the AND gate A outputs a low level, and the first NOT gate N1 and the second NOT gate N2 output a high level. At this time, the PMOS tube Q1 is turned off, the NMOS tube Q2 is turned on, and the first end of the second inductor L2 is grounded, so that the second inductor L2 and the ultrasonic probe equivalent module 11 form a parallel resonance.
[0058] The switching module 10 is implemented by a MOS tube, which has the advantage that the MOS tube has no voltage drop, but has the disadvantage that the gates of the MOS tube cannot be directly connected together and must be controlled independently. Therefore, in some embodiments, in order to simplify the circuit, the switching module 10 can also be implemented by a triode.
[0059] like Figure 3 As shown, the switching module 10 includes a third switch Q3 and a fourth switch Q4, the third switch Q3 may be an NPN tube, and the third switch Q4 may be a PNP tube. The controller is connected to the base of the NPN tube Q3 and the base of the PNP tube Q4 respectively, the emitter of the NPN tube Q3 is connected to the emitter of the PNP tube Q4 and the first end of the second inductor L2 respectively, the collector of the NPN tube Q3 is connected to the power supply VCC, and the collector of the PNP tube Q4 is grounded.
[0060] When the output terminal IN of the controller outputs a square wave signal to the base of the NPN tube Q3 and the base of the PNP tube Q4, the NPN tube Q3 and the PNP tube Q4 are alternately turned on so that the first end of the second inductor L2 is connected to the AC power supply V1. Specifically, when the square wave signal is a high-level signal, the NPN tube Q3 is turned on, the PNP tube Q4 is turned off, and the emitter of the NPN tube Q3 is a high level. When the square wave signal is a low-level signal, the NPN tube Q3 is turned off, the PNP tube Q4 is turned on, and the emitter of the NPN tube Q3 is a low level. Therefore, when the output terminal IN of the controller outputs a square wave signal, the NPN tube Q3 and the PNP tube Q4 are alternately turned on, and the first end of the second inductor L2 is equivalent to connecting the AC power supply V1, so that the second inductor L2 and the ultrasonic probe equivalent module 11 form a series resonance.
[0061] When the output terminal IN of the controller outputs a low-level signal to the base of the NPN tube Q3 and the base of the PNP tube Q4, the NPN tube Q3 is turned off, the PNP tube Q4 is turned on, and the emitter of the PNP tube Q4 is grounded, that is, the first end of the second inductor L2 is grounded, so that the second inductor L2 and the ultrasonic probe equivalent module 11 form a parallel resonance.
[0062] After the ultrasonic sensor receives the ultrasonic signal, it needs to filter, amplify and smooth the ultrasonic signal before inputting it into the controller so that the controller can perform data analysis on the ultrasonic signal. Figure 4 As shown, the driving circuit further includes a first filtering and amplifying module 12 , a second filtering and amplifying module 13 , a third filtering module 15 and an inverting module 14 .
[0063] The first end of the first filtering and amplifying module 12 is connected to the second end of the second inductor L2, the second end of the first filtering and amplifying module 12 is connected to the first end of the second filtering and amplifying module 13, the second end of the second filtering and amplifying module 13 is connected to the first end of the inverting module 14, and the second end of the inverting module 14 is respectively connected to the first end of the third filtering module 15 and a controller (not shown in the figure).
[0064] The first filter-amplifier module 12 is used to perform primary filtering and primary amplification on the ultrasonic signal, and the second filter-amplifier module 13 is used to perform secondary filtering and secondary amplification on the ultrasonic signal. The inversion module 14 is used to flip the negative half-cycle signal into a positive half-cycle signal, and combine it with the original positive half-cycle signal, so as to achieve smoothing of the ultrasonic signal. The third filter module 15 is used to perform a third-stage filtering on the smoothed ultrasonic signal, and the ultrasonic signal after the third-stage filtering is then input into the controller for data analysis and processing. Among them, the ultrasonic signal is usually a pulse signal composed of a sine wave, including a positive half-cycle signal and a negative half-cycle signal.
[0065] Through this embodiment, multi-stage filtering and multi-stage amplification of the received ultrasonic signal are achieved. And there is no need to use a high-cost high-performance controller to perform complex Fourier transform processing on the ultrasonic signal, so as to achieve smooth processing of the ultrasonic signal. Instead, the ultrasonic signal is smoothed by the inverting module 14, which is low in cost.
[0066] In some embodiments, Figure 5 As shown, the first filtering and amplifying module 12 includes a first filtering submodule and a first amplifying submodule, the first filtering submodule includes a third resistor R3, a third inductor L3 and a sixth capacitor C6, and the first amplifying submodule includes a fifth switch Q5, a fourth resistor R4, a fifth resistor R5 and a third capacitor C3. Among them, the fifth switch Q5 is an NPN transistor Q5.
[0067] The first end of the third resistor R3 is connected to the second end of the second inductor L2, the second end of the third resistor R3 is connected to the first end of the third inductor L3 and the first end of the sixth capacitor C6 respectively, and the second end of the third inductor L3 and the second end of the sixth capacitor C6 are grounded. The base of the NPN transistor Q5 is connected to the second end of the third resistor R3, the emitter of the NPN transistor Q5 is connected to the first end of the fifth resistor R5, the second end of the fifth resistor R5 is grounded, the collector of the NPN transistor Q5 is connected to the first end of the fourth resistor R4 and the first end of the third capacitor C3 respectively, the second end of the fourth resistor R4 is connected to the power supply VCC, and the second end of the third capacitor C3 is connected to the first end of the second filtering and amplifying module 13.
[0068] In some embodiments, Figure 5 As shown, the second filtering and amplifying module 13 includes a second filtering submodule and a second amplifying submodule, the second filtering submodule includes a sixth resistor R6, a fourth inductor L4 and a fourth capacitor C4, and the second amplifying submodule includes a first amplifier U1, a seventh resistor R7 and an eighth resistor R8.
[0069] The first end of the sixth resistor R6 is connected to the second end of the first filtering and amplifying module 12, the second end of the sixth resistor R6 is connected to the first end of the fourth inductor L4 and the first end of the fourth capacitor C4 respectively, and the second end of the fourth inductor L4 and the second end of the fourth capacitor C4 are grounded. The non-inverting input end of the first amplifier U1 is connected to the second end of the sixth resistor R6, the inverting input end of the first amplifier U1 is connected to the first end of the seventh resistor R7 and the first end of the eighth resistor R8 respectively, the second end of the seventh resistor R7 is grounded, and the output end of the first amplifier U1 is connected to the second end of the eighth resistor R8 and the first end of the inverting module 14 respectively.
[0070] In some embodiments, Figure 5As shown, the inverting module 14 includes a positive half-cycle detection submodule and a negative half-cycle detection submodule. The positive half-cycle detection submodule includes a first diode D1.
[0071] The first end of the first diode D1 is respectively connected to the second end of the second filtering and amplifying module 13 and the first end of the negative half-cycle detection submodule, and the second end of the first diode D1 is respectively connected to the second end of the negative half-cycle detection submodule, the third filtering module 15 and the input end I / 0 of the controller. The first diode D1 is used to allow the positive half-cycle signal in the ultrasonic signal to pass through and to cut off the negative half-cycle signal in the ultrasonic signal. The negative half-cycle detection submodule is used to flip the negative half-cycle signal in the ultrasonic signal into a positive half-cycle signal, flip the positive half-cycle signal in the ultrasonic signal into a negative half-cycle signal, and allow the flipped positive half-cycle signal to pass through and cut off the flipped negative half-cycle signal, thereby achieving smooth processing of the ultrasonic signal.
[0072] In some embodiments, Figure 5 As shown, the negative half-cycle detection submodule includes an inverting amplifier U2, a ninth resistor R9, a tenth resistor R10, and a second diode D2. The first end of the ninth resistor R9 is respectively connected to the second end of the second filter amplifier module 13 and the first end of the first diode D1, the second end of the ninth resistor R9 is respectively connected to the inverting input end of the inverting amplifier U2 and the first end of the tenth resistor R10, the non-inverting input end of the inverting amplifier U2 is grounded, the output end of the inverting amplifier U2 is respectively connected to the second end of the tenth resistor R10 and the first end of the second diode D2, and the second end of the second diode D2 is respectively connected to the second end of the first diode D1, the third filter module 15, and the input end I / 0 of the controller.
[0073] It should be noted that the inverting amplifier U2 is used to convert the positive half-cycle signal in the ultrasonic signal into the negative half-cycle signal, and to convert the negative half-cycle signal in the ultrasonic signal into the positive half-cycle signal. The second diode D2 allows the positive half-cycle signal to pass and cuts off the negative half-cycle signal, thereby achieving smooth processing of the ultrasonic signal.
[0074] In some embodiments, Figure 5 As shown, the third filtering module 15 includes a fifth capacitor C5 and an eleventh resistor R11;
[0075] The first end of the fifth capacitor C5 is respectively connected to the second end of the positive half-cycle detection submodule, the second end of the negative half-cycle detection submodule, the first end of the eleventh resistor R11 and the controller, and the second end of the fifth capacitor C5 and the second end of the eleventh resistor R11 are grounded. The smoothed ultrasonic signal is filtered by the third filtering module 15 and then input into the controller for digital analysis and processing.
[0076] The embodiments of the utility model are described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.
Claims
1. A driving circuit, characterized in that: Applied to an ultrasonic sensor, the driving circuit comprises: a switching module, a second inductor, an ultrasonic probe equivalent module and a controller; The switching module is electrically connected to the controller; A first end of the second inductor is connected to the switching module, and a second end of the second inductor is connected to the ultrasonic probe equivalent module; When transmitting an ultrasonic signal, the controller controls the switching module to connect the first end of the second inductor to an AC power source, so that the second inductor and the ultrasonic probe equivalent module are connected in series to form a series resonance; When receiving an ultrasonic signal, the controller controls the switching module to ground the first end of the second inductor, so that the second inductor and the ultrasonic probe equivalent module are connected in parallel to form parallel resonance.
2. The driving circuit according to claim 1, characterized in that: The switching module includes an AND gate, a first NOT gate, a second NOT gate, a first switch, a second switch and a power supply; The controller is connected to the first input terminal of the AND gate and the second input terminal of the AND gate respectively, the output terminal of the AND gate is connected to the input terminal of the first NOT gate and the input terminal of the second NOT gate respectively, the output terminal of the first NOT gate is connected to the first terminal of the first switch, the second terminal of the first switch is connected to the power supply, the third terminal of the first switch is connected to the second terminal of the second switch and the first terminal of the second inductor respectively, the first terminal of the second switch is connected to the output terminal of the second NOT gate, and the third terminal of the second switch is grounded; The controller outputs a square wave signal to the first input terminal of the AND gate, and the controller outputs a level signal to the second input terminal of the AND gate; wherein the level signal includes a high level signal or a low level signal; When the level signal is the high level signal, the first switch and the second switch are alternately turned on so that the first end of the second inductor is connected to the AC power supply. When the level signal is the low level signal, the first switch is turned off and the second switch is turned on so that the first end of the second inductor is grounded.
3. The driving circuit according to claim 1, characterized in that: The switching module includes a third switch and a fourth switch; The controller is connected to the first end of the third switch and the first end of the fourth switch respectively, the second end of the third switch is connected to the second end of the fourth switch and the first end of the second inductor respectively, the third end of the third switch is connected to the power supply, and the third end of the fourth switch is grounded; When the controller outputs a square wave signal to the first end of the third switch and the first end of the fourth switch, the third switch and the fourth switch are alternately turned on, so that the first end of the second inductor is connected to an AC power source; When the controller outputs a low level signal to the first end of the third switch and the first end of the fourth switch, the third switch is turned off and the fourth switch is turned on, so that the first end of the second inductor is grounded.
4. The driving circuit according to claim 1, characterized in that: The driving circuit also includes a first filtering and amplifying module, a second filtering and amplifying module, a third filtering module and an inverting module; The first end of the first filtering and amplifying module is connected to the second end of the second inductor, the second end of the first filtering and amplifying module is connected to the first end of the second filtering and amplifying module, the second end of the second filtering and amplifying module is connected to the first end of the inverting module, and the second end of the inverting module is respectively connected to the first end of the third filtering module and the controller; The first filtering and amplifying module is used to perform primary filtering and primary amplification on the ultrasonic signal, the second filtering and amplifying module is used to perform secondary filtering and secondary amplification on the ultrasonic signal, the inverting module is used to flip the negative half-cycle signal into a positive half-cycle signal, and the third filtering module is used to perform third-stage filtering on the ultrasonic signal; wherein the ultrasonic signal includes a positive half-cycle signal and the negative half-cycle signal.
5. The driving circuit according to claim 4, characterized in that: The first filtering and amplifying module includes a first filtering submodule and a first amplifying submodule, the first filtering submodule includes a third resistor, a third inductor and a sixth capacitor, and the first amplifying submodule includes a fifth switch, a fourth resistor, a fifth resistor and a third capacitor; The first end of the third resistor is connected to the second end of the second inductor, the second end of the third resistor is connected to the first end of the third inductor and the first end of the sixth capacitor respectively, and the second end of the third inductor and the second end of the sixth capacitor are grounded; The first end of the fifth switch is connected to the second end of the third resistor, the third end of the fifth switch is connected to the first end of the fifth resistor, the second end of the fifth resistor is grounded, the second end of the fifth switch is respectively connected to the first end of the fourth resistor and the first end of the third capacitor, the second end of the fourth resistor is connected to a power supply, and the second end of the third capacitor is connected to the first end of the second filtering and amplifying module.
6. The driving circuit according to claim 4, characterized in that: The second filtering and amplifying module includes a second filtering submodule and a second amplifying submodule, the second filtering submodule includes a sixth resistor, a fourth inductor and a fourth capacitor, and the second amplifying submodule includes a first amplifier, a seventh resistor and an eighth resistor; The first end of the sixth resistor is connected to the second end of the first filtering and amplifying module, the second end of the sixth resistor is connected to the first end of the fourth inductor and the first end of the fourth capacitor respectively, and the second end of the fourth inductor and the second end of the fourth capacitor are grounded; The non-inverting input terminal of the first amplifier is connected to the second end of the sixth resistor, the inverting input terminal of the first amplifier is respectively connected to the first end of the seventh resistor and the first end of the eighth resistor, the second end of the seventh resistor is grounded, and the output terminal of the first amplifier is respectively connected to the second end of the eighth resistor and the first end of the inverting module.
7. The driving circuit according to claim 4, characterized in that: The inversion module includes a positive half-cycle detection submodule and a negative half-cycle detection submodule; The first end of the positive half-cycle detection submodule is respectively connected to the second end of the second filtering and amplifying module and the first end of the negative half-cycle detection submodule, the second end of the positive half-cycle detection submodule is respectively connected to the second end of the negative half-cycle detection submodule, the third filtering module and the controller, the positive half-cycle detection submodule is used to allow the positive half-cycle signal to pass and cut off the negative half-cycle signal, the negative half-cycle detection submodule is used to flip the negative half-cycle signal into a positive half-cycle signal, the positive half-cycle signal is flipped into a negative half-cycle signal, and the flipped positive half-cycle signal is passed and the flipped negative half-cycle signal is cut off.
8. The driving circuit according to claim 7, characterized in that: The negative half-cycle detection submodule includes an inverting amplifier, a ninth resistor, a tenth resistor, and a second diode; The first end of the ninth resistor is respectively connected to the second end of the second filtering and amplifying module and the first end of the negative half-cycle detection submodule, the second end of the ninth resistor is respectively connected to the inverting input end of the inverting amplifier and the first end of the tenth resistor, the non-inverting input end of the inverting amplifier is grounded, the output end of the inverting amplifier is respectively connected to the second end of the tenth resistor and the first end of the second diode, and the second end of the second diode is respectively connected to the second end of the positive half-cycle detection submodule, the third filtering module and the controller.
9. The driving circuit according to claim 7, characterized in that: The third filtering module includes a fifth capacitor and an eleventh resistor; The first end of the fifth capacitor is respectively connected to the second end of the positive half-cycle detection submodule, the second end of the negative half-cycle detection submodule, the first end of the eleventh resistor and the controller, and the second end of the fifth capacitor and the second end of the eleventh resistor are grounded.
10. An ultrasonic sensor, characterized in that: The invention comprises a driving circuit as claimed in any one of claims 1 to 9.