Ultrasonic signal generation apparatus

Abstract

The embodiments of the present application relate to the field of ultrasonic technology, and in particular relate to an ultrasonic signal generation apparatus. The ultrasonic signal generation apparatus comprises a pulse generation circuit, a resonance circuit and an ultrasonic sensor chip, wherein the pulse generation circuit is used for outputting a pulse voltage signal; the resonance circuit is connected to the pulse generation circuit, and is used for receiving the pulse voltage signal and outputting a driving signal which is generated on the basis of the pulse voltage signal; and the ultrasonic sensor chip is connected to the resonance circuit, and is used for receiving the driving signal and outputting an ultrasonic signal which is generated on the basis of the driving signal. Therefore, the solution improves the quality of work of processing work, such as performing fingerprint detection on the basis of an ultrasonic signal.

Description

[0001] Ultrasonic Signal Generator This application claims priority to Chinese Utility Model Patent Application No. 202420247436.X, filed January 31, 2024, and entitled "Ultrasonic Signal Generator," the entire contents of which are incorporated herein by reference. Technical Field: Embodiments of this application relate to the field of ultrasonic technology, and more particularly, to an ultrasonic signal generator. Background: Ultrasonic technology utilizes ultrasonic waves for detection, measurement, or imaging. For example, ultrasonic technology can be used to perform fingerprint detection and other processing tasks in devices to which it is applied. Currently, when performing fingerprint detection and other processing tasks based on ultrasonic technology, a sinusoidal signal is typically generated from a pulsed voltage signal, and the sinusoidal signal is used as a drive signal to generate an ultrasonic signal. This ultrasonic signal can then be used to perform fingerprint detection and other processing tasks. However, pulse voltage signals include high-frequency components. When generating a sine wave signal from the pulse voltage signal, at least some of the high-frequency components of the pulse voltage signal are transferred to the sine wave signal, resulting in significant electromagnetic interference (EMI) in the sine wave signal. This EMI further leads to poor quality of the generated ultrasonic signal, resulting in poor operating quality of equipment using ultrasonic technology. In view of this, embodiments of the present application provide an ultrasonic signal generating device to at least partially address the aforementioned issues. Embodiments of the present application provide an ultrasonic signal generating device comprising: a pulse generating circuit, a resonant circuit, and an ultrasonic sensor chip. The pulse generating circuit is configured to output a pulse voltage signal. The resonant circuit is connected to the pulse generating circuit, configured to receive the pulse voltage signal and output a drive signal generated based on the pulse voltage signal. The resonant circuit includes a high-frequency blocking component, configured to block the high-frequency components of the pulse voltage signal from being transferred to the drive signal. The ultrasonic sensor chip is connected to the resonant circuit, configured to receive the drive signal and output an ultrasonic signal generated based on the drive signal. In one possible implementation, the pulse generating circuit includes a first pulse output terminal and a second pulse output terminal; the first pulse output terminal is used to output a first pulse voltage signal, and the second pulse output terminal is used to output a second pulse voltage signal, and the first pulse voltage signal and the second pulse voltage signal have opposite phases; the resonant circuit is connected to the first pulse output terminal and the second pulse output terminal, and the resonant circuit is used to generate the drive signal according to the first pulse voltage signal and the second pulse voltage signal, wherein the waveform of the drive signal is a sine wave.In one possible implementation, the resonant circuit includes a first inductor and a first capacitor; one end of the first inductor is connected to the first pulse output terminal, one end of the first capacitor is connected to the second pulse output terminal, the other end of the first inductor and the other end of the first capacitor are both connected to one end of the high-frequency blocking component, and the other end of the high-frequency blocking component is connected to the ultrasonic sensor chip. In one possible implementation, the resonant circuit includes a second inductor and a second capacitor; one end of the second inductor is connected to the first pulse output terminal, the high-frequency blocking component is connected between the second pulse output terminal and one end of the second capacitor, and the other end of the second inductor and the other end of the second capacitor are both connected to the ultrasonic sensor chip. In one possible implementation, the resonant circuit includes a third inductor and a third capacitor; one end of the third inductor is connected to the first pulse output terminal, the third capacitor is connected between the second pulse output terminal and one end of the high-frequency blocking component, and the other end of the third inductor and the other end of the high-frequency blocking component are both connected to the ultrasonic sensor chip. In one possible implementation, the high-frequency blocking component includes a ferrite bead. In one possible implementation, the high-frequency blocking component includes an inductor. In one possible implementation, the impedance of the high-frequency blocking component in the 100 MHz frequency band is 10 ohms to 91 ohms. In one possible implementation, the resonant circuit includes a damping resistor; one end of the damping resistor is connected to the first pulse output terminal, and the other end of the damping resistor is grounded. In one possible implementation, the ultrasonic signal generating device also includes a main control module; the main control module includes a power supply for powering the pulse generating circuit and the ultrasonic sensor chip. In one possible implementation, the main control module includes a serial peripheral interface; the serial peripheral interface is used for communication between the main control module and the ultrasonic sensor chip. According to the above technical solution, the ultrasonic signal generating device includes a pulse generating circuit, a resonant circuit, and an ultrasonic sensor chip. The pulse generating circuit outputs a pulse voltage signal to the resonant circuit, causing the resonant circuit to generate and output a drive signal. The ultrasonic sensor chip can generate an ultrasonic signal based on the drive signal. The high-frequency blocking component blocks the high-frequency component included in the pulse voltage signal. As a result, the high-frequency blocking component blocks the high-frequency components, so that the drive signal output by the resonant circuit contains almost no high-frequency components, thereby reducing the electromagnetic interference of the drive signal. This can further improve the quality of the ultrasonic signal generated by the ultrasonic signal generating device, thereby improving the quality of fingerprint detection and other processing based on the ultrasonic signal.To more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the following briefly describes the drawings required for use in the embodiments or prior art descriptions. Obviously, the drawings described below only represent some of the embodiments described in the present application. Those skilled in the art can also derive other drawings based on these drawings. Figure 1 is a schematic diagram of an ultrasonic signal generating device according to one embodiment of the present application; Figure 2 is a schematic diagram of an ultrasonic signal generating device according to another embodiment of the present application; Figure 3 is a schematic diagram of an ultrasonic signal generating device according to yet another embodiment of the present application; Figure 4 is a physical diagram of a resonant circuit according to one embodiment of the present application; Figure 5 is a physical diagram of a resonant circuit according to a related art of the present application; and Figure 6 is a schematic diagram of electromagnetic radiation interference according to one embodiment of the present application. Explanation of the Figures:

[0002] 1. Pulse generating circuit; 2. Resonant circuit; 3. Ultrasonic sensor chip; 31. Control module; 32. Ultrasonic transducer; 33. Pixel array; 34. Readout module; 35. Analog-to-digital conversion module; 36. Interface module; 4. Main control module. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First, some nouns or terms used in the description of the embodiments of this application are subject to the following explanations. Ferrite beads: Ferrite beads are passive components used to suppress high-frequency noise in circuits. They are also a special type of choke, mostly made of ferrite. They suppress high-frequency noise by dissipating heat generated by high-frequency currents. Although ferrite beads are inductors, their specifications differ from those of general inductors because they consider the impedance characteristics of a specific frequency band. Ferrite beads are specified based on the impedance (in ohms) at a specific frequency. For example, 22ohm@100MHz means an impedance of 22 ohms at a frequency of 100MHz. The impedance characteristics of ferrite beads in different frequency bands are generally listed in the data sheet. To help those skilled in the art better understand the technical solutions in the embodiments of this application, the following will be a clear and complete description of the technical solutions in the embodiments of this application, in conjunction with the accompanying drawings. Obviously, the described embodiments are only some of the embodiments of this application, and not all of them. All other embodiments derived by those skilled in the art based on the embodiments of this application should fall within the scope of protection of the embodiments of this application. When performing fingerprint detection and other processing tasks based on ultrasonic technology, a sinusoidal signal is typically generated from a pulsed voltage signal. This sinusoidal signal is then used as a driving signal to generate an ultrasonic signal, thereby enabling fingerprint detection and other processing tasks. However, because the pulsed voltage signal includes high-frequency components, at least some of these high-frequency components can cause the sinusoidal signal to have significant electromagnetic interference (EMI). This EMI further results in poor quality of the generated ultrasonic signal and, consequently, poor operating quality of the equipment using ultrasonic technology. To address these issues, an embodiment of the present application provides an ultrasonic signal generating device, which is described in detail below with reference to the accompanying drawings. Figure 1 is a schematic diagram of an ultrasonic signal generating device according to one embodiment of the present application. As shown in Figure 1, the ultrasonic signal generating device provided in this embodiment of the present application includes a pulse generating circuit 1, a resonant circuit 2, and an ultrasonic sensor chip 3.The pulse generating circuit 1 is configured to output a pulse voltage signal. For example, the pulse generating circuit 1 is configured to receive a control signal output by the ultrasonic sensor chip 3 and output a pulse voltage signal generated based on the control signal. The pulse generating circuit 1 can be a circuit within the pulse generating chip or a circuit composed of discrete components, which is not limited in this embodiment of the present application. A resonant circuit 2 is connected to the pulse generating circuit 1. The resonant circuit 2 is configured to receive the pulse voltage signal and output a drive signal generated based on the pulse voltage signal. The resonant circuit 2 includes a high-frequency blocking component B1, which has a high-frequency blocking characteristic. Specifically, the high-frequency blocking component B1 is configured to block the high-frequency component included in the pulse voltage signal from being transmitted to the drive signal. The ultrasonic sensor chip 3 is connected to the resonant circuit 2, configured to receive the drive signal and output an ultrasonic signal generated based on the drive signal. In one embodiment, as shown in FIG1 , the ultrasonic sensor chip 3 may include a control module 31 for sending a control signal to the pulse generating circuit 1. Upon receiving the control signal, the pulse generating circuit 1 outputs a pulse voltage signal generated based on the control signal to the resonant circuit 2. The pulse voltage signal causes the resonant circuit 2 to resonate, and the high-frequency blocking component B1 included in the resonant circuit 2 blocks the high-frequency components of the pulse voltage signal. As a result, the resonant circuit 2 can output a drive signal containing almost no high-frequency components to the ultrasonic sensor chip 3. Based on the received drive signal, the ultrasonic sensor chip 3 generates an ultrasonic signal for performing fingerprint detection and other processing tasks, thereby converting electrical energy into mechanical energy. In this embodiment of the present application, the ultrasonic signal generating device includes the pulse generating circuit 1, the resonant circuit 2, and the ultrasonic sensor chip 3. The pulse generating circuit 1 outputs a pulse voltage signal to the resonant circuit 2, causing the resonant circuit 2 to generate and output a drive signal. The ultrasonic sensor chip 3 can generate an ultrasonic signal based on the drive signal. The high-frequency blocking component B1 blocks the high-frequency components of the pulse voltage signal. As a result, the high-frequency blocking component B1 blocks the high-frequency components, so that the drive signal output by the resonant circuit 2 contains almost no high-frequency components, thereby reducing the electromagnetic interference of the drive signal. This can further improve the quality of the ultrasonic signal generated by the ultrasonic signal generating device, thereby improving the quality of fingerprint detection and other processing based on the ultrasonic signal.For example, if the ultrasonic signal is used for fingerprint detection in a smartphone to implement a fingerprint unlocking function, the high-frequency blocking component B1 reduces electromagnetic interference in the drive signal, thereby improving the quality of the ultrasonic signal generated based on the drive signal. This results in more accurate fingerprint detection results, thereby enhancing the fingerprint unlocking function of the smartphone and improving the operating quality of the smartphone. In one possible implementation, as shown in Figure 1, the pulse generating circuit 1 includes a first pulse output terminal and a second pulse output terminal. The first pulse output terminal is used to output a first pulse voltage signal, and the second pulse output terminal is used to output a second pulse voltage signal. The first pulse voltage signal and the second pulse voltage signal have opposite phases. For example, based on the pulse voltage signal generated by the pulse generating circuit 1 based on the control signal output by the ultrasonic sensor chip 3, the control signal may include a first pulse control signal and a second pulse control signal. The pulse generating circuit 1 may generate and output the first pulse voltage signal and the second pulse voltage signal with opposite phases based on the first pulse control signal and the pulse control signal. The resonant circuit 2 is connected to the first pulse output terminal and the second pulse output terminal. The resonant circuit 2 is configured to receive the first pulse voltage signal and the second pulse voltage signal and generate a drive signal based on the first pulse voltage signal and the second pulse voltage signal. The drive signal waveform is a sine wave, and the drive signal waveform can be a sine waveform, a cosine waveform, or the like. For example, the drive signal is a high-voltage sinusoidal pulse signal. In the embodiment of the present application, the resonant circuit 2 resonates under the action of the first pulse voltage signal and the second pulse voltage signal to generate the drive signal. As a result, compared to generating the drive signal based on a single pulse voltage signal, the drive signal in the embodiment of the present application has a doubled voltage value, thereby eliminating the need for complex voltage boosting operations to obtain a drive signal with a higher voltage value. This not only eliminates the need for complex circuitry to boost the drive signal, but also reduces the possibility of poor driving performance due to a low drive signal voltage value, making the circuit structure simple and easy to implement. Furthermore, the good voltage boosting effect of the drive signal improves the quality of the ultrasonic signal. In one possible implementation, as shown in Figure 1 , the first pulse output terminal is connected to the control module 31. Therefore, the first pulse output terminal is also used to send a synchronization signal for the drive signal to the control module 31. Specifically, the first pulse voltage signal can be input as a synchronization signal to the ultrasonic sensor chip 3 to synchronize the drive signal. The specific circuit structure of the resonant circuit 2 can be implemented in the following ways: In one possible implementation, as shown in Figure 1 , the resonant circuit 2 also includes a first inductor L1 and a first capacitor C1.One end of the first inductor L1 is connected to the first pulse output terminal, and one end of the first capacitor C1 is connected to the second pulse output terminal. The other ends of the first inductor L1 and the first capacitor C1 are both connected to one end of a high-frequency blocking component B1. This ensures that the first inductor L1 and the first capacitor C1 are connected in parallel and connected to one end of the high-frequency blocking component B1. The other end of the high-frequency blocking component B1 is connected to the ultrasonic sensor chip 3. Because the inductor has the characteristic of "blocking high frequencies" and the first inductor L1 is connected between the first pulse output terminal and the ultrasonic sensor chip 3, the first inductor L1 can block the high-frequency component of the first pulse voltage signal. That is, the first pulse voltage signal output from the first pulse output terminal will not be transmitted to the high-frequency blocking component B1. Furthermore, because the capacitor has the characteristic of "passing high frequencies", the high-frequency component of the second pulse voltage signal output from the second pulse output terminal will be transmitted to the high-frequency blocking component B1. Therefore, the high-frequency blocking component B1 is used to block the high-frequency component of the second pulse voltage signal from being transmitted to the drive signal. Specifically, under the influence of the first pulse voltage signal and the second pulse voltage signal in opposite phases, the first inductor L1 and the first capacitor C1 can resonate to generate a signal. The aforementioned drive signal is the signal generated by this resonance after passing through the high-frequency blocking component B1. In the embodiment of the present application, by connecting the first inductor L1 and the first capacitor C1 in parallel and then to the high-frequency blocking component B1, the high-frequency blocking component B1 can block the high-frequency component in the signal generated by the resonance of the first inductor L1 and the first capacitor C1, thereby achieving a drive signal with almost no high-frequency component. This can reduce electromagnetic interference in the drive signal and improve the quality of the ultrasonic signal. In another possible implementation, as shown in FIG2 , the resonant circuit 2 further includes a second inductor L2 and a second capacitor C2. One end of the second inductor L2 is connected to the first pulse output end, the high-frequency blocking component B1 is connected between the second pulse output end and one end of the second capacitor C2, and the other end of the second inductor L2 and the other end of the second capacitor C2 are both connected to the ultrasonic sensor chip 3, so that the high-frequency blocking component B1 and the second capacitor C2 are connected in series and then in parallel with the second inductor L2, and the high-frequency blocking component B1 is connected between the second pulse output end and the second capacitor C2.Because the inductor has the characteristic of "blocking high frequencies," and the second inductor L2 is connected between the first pulse output terminal and the ultrasonic sensor chip 3, the second inductor L2 can block the high-frequency component of the first pulse voltage signal. Specifically, the first pulse voltage signal output by the first pulse output terminal is not transmitted to the ultrasonic sensor chip 3. Furthermore, because the high-frequency blocking component B1 also has the characteristic of "blocking high frequencies," and the high-frequency blocking component B1 and the second capacitor C2 are connected in series between the second pulse output terminal and the ultrasonic sensor chip 3, the high-frequency blocking component B1 can block the high-frequency component of the second pulse voltage signal. Specifically, the high-frequency blocking component B1 is used to prevent the high-frequency component of the second pulse voltage signal from being transmitted to the drive signal. Specifically, the second inductor L2 and the second capacitor C2, under the influence of the first pulse voltage signal and the signal generated after the second pulse voltage signal passes through the high-frequency blocking component B1, resonate to generate a signal. The drive signal is the signal generated by this resonance. In the embodiment of the present application, by connecting a high-frequency blocking component B1 in series with a second capacitor C2 and then in parallel with a second inductor L2, and by connecting the high-frequency blocking component B1 between the second pulse output terminal and the second capacitor C2, the high-frequency blocking component B1 can directly block the high-frequency components in the second pulse voltage signal. Furthermore, since the high-frequency components in the first pulse voltage signal can be blocked by the second inductor L2, the drive signal generated by the resonance circuit 2 can be virtually free of high-frequency components, thereby reducing electromagnetic interference in the drive signal and improving the quality of the ultrasonic signal. Furthermore, as shown in Figures 1 and 2, compared to the scheme in which the first inductor L1 and the first capacitor C1 are connected in parallel and then connected to the high-frequency blocking component B1, the scheme in which the high-frequency blocking component B1 is connected in series with the second capacitor C2 and then in parallel with the second inductor L2 allows the high-frequency blocking component B1 to be directly added between the second pulse output terminal and the second capacitor C2. This scheme requires fewer components to be connected to the high-frequency blocking component B1, making it easier to add the high-frequency blocking component B1 to a circuit that does not already have the high-frequency blocking component B1. In yet another possible implementation, as shown in FIG3 , the resonant circuit 2 further includes a third inductor L3 and a third capacitor C3. OOne end of the third inductor L3 is connected to the first pulse output end, and the third capacitor C3 is connected between the second pulse output end and one end of the high-frequency blocking component B1. The other ends of the third inductor L3 and the other end of the high-frequency blocking component B1 are both connected to the ultrasonic sensor chip 3, so that the high-frequency blocking component B1 and the third capacitor C3 are connected in series and then in parallel with the third inductor L3, and the high-frequency blocking component B1 is connected between the third capacitor C3 and the ultrasonic sensor chip 3. Because inductors have the characteristic of "blocking high frequencies" and the third inductor L3 is connected between the first pulse output end and the ultrasonic sensor chip 3, the third inductor L3 can block the high-frequency component of the first pulse voltage signal. That is, the first pulse voltage signal output by the first pulse output end is not transmitted to the ultrasonic sensor chip 3. Furthermore, because the high-frequency blocking component B1 has the characteristic of "blocking high frequencies" and the high-frequency blocking component B1 and the third capacitor C3 are connected in series between the second pulse output end and the ultrasonic sensor chip 3, the high-frequency blocking component B1 can block the high-frequency component of the signal obtained after the second pulse voltage signal passes through the third capacitor C3. Based on this, the high-frequency blocking component B1 is used to block the high-frequency component of the second pulse voltage signal from being transmitted to the drive signal. Specifically, the third inductor L3 and the third capacitor C3 can resonate under the influence of the first pulse voltage signal and the second pulse voltage signal in anti-phase. The drive signal is the signal generated by the resonance of the third capacitor C3, which passes through the high-frequency blocking component B1 and then the signal generated by the resonance of the third inductor L3. In this embodiment of the present application, by connecting the high-frequency blocking component B1 in series with the third capacitor C3 and then in parallel with the third inductor L3, and connecting the high-frequency blocking component B1 between the third capacitor C3 and the ultrasonic sensor chip 3, the high-frequency blocking component B1 can block the high-frequency component in the signal generated by the resonance of the third capacitor C3. Since the high-frequency component in the first pulse voltage signal can be blocked by the third inductor L3, the drive signal generated by the resonance of the resonant circuit 2 is almost free of high-frequency components, thereby reducing electromagnetic interference in the drive signal and improving the quality of the ultrasonic signal.1 and 3 , compared to a solution in which the first inductor L1 and the first capacitor C1 are connected in parallel and then connected to the high-frequency blocking component B1, a solution in which the high-frequency blocking component B1 is connected in series with the third capacitor C3 and then connected in parallel to the third inductor L3 allows the high-frequency blocking component B1 to be directly added between the third capacitor C3 and the ultrasonic sensor chip 3. The high-frequency blocking component B1 connects to fewer components, making it easier to add the high-frequency blocking component B1 to a circuit that does not already have the high-frequency blocking component B1. In one possible implementation, the high-frequency blocking component B1 includes a magnetic bead. For example, the high-frequency blocking component B1 can be a magnetic bead. In the embodiment of the present application, the high-frequency blocking component B1 uses a magnetic bead, which not only effectively reduces electromagnetic interference in the drive signal, but also minimizes the size of the high-frequency blocking component B1, thereby significantly reducing the size benefit of the high-frequency blocking component B1 in reducing electromagnetic interference. Furthermore, using a magnetic bead in the high-frequency blocking component B1 can also reduce the cost of the high-frequency blocking component B1. In addition, because the magnetic bead is a component that can suppress high-frequency noise by dissipating heat generated by its high-frequency current and has low impedance to low-frequency signals, the high-frequency blocking component B1 can have almost no impact on the normal operation of the drive signal. For example, as shown in FIG4 , the high-frequency blocking component B1 in one embodiment of the present application may be a ferrite bead with a 0201 package size (0.6*0.3*0.3 mm), which costs approximately 0.2 yuan per bead. As shown in FIG5 , the high-frequency blocking component LL in the related art uses an inductor with a 0603 package size (1.6*0.8*0.8 mm), which has an inductance of approximately 220 nanohenries and costs approximately 1.4 yuan per bead. Comparing the high-frequency blocking component B1 in FIG4 with the high-frequency blocking component LL in FIG5 , it can be clearly seen that the high-frequency blocking component B1 in FIG4 is smaller in size and lower in cost. Therefore, using a ferrite bead as the high-frequency blocking component B1 can make the high-frequency blocking component B1 smaller in size and lower in cost.Based on the above example, the test results of the high-frequency blocking component B1 (i.e., B1 in FIG. 4 ) in one embodiment of the present application are as follows: If the high-frequency blocking component B1 is removed from the ultrasonic signal generating device, as shown in the left half of FIG. 6 , the peak electromagnetic radiation interference generated is -66.8 dBm. However, for the ultrasonic signal generating device including the high-frequency blocking component B1, the peak electromagnetic radiation interference generated is -70.6 dBm, as shown in the right half of FIG. This test result clearly shows that the electromagnetic radiation interference generated by the ultrasonic signal generating device with the high-frequency blocking component B1 is reduced by 4 dBm. Therefore, using a magnetic bead as the high-frequency blocking component B1 can effectively reduce electromagnetic interference in the drive signal. In another possible implementation, the high-frequency blocking component B1 includes an inductor. For example, the high-frequency blocking component B1 can also be an inductor, or an interconnected inductor and magnetic bead, etc., which is not limited in this embodiment of the present application. In one possible implementation, the impedance of high-frequency blocking component B1 in the 100 MHz frequency band is 10 ohms to 91 ohms. In the embodiment of the present application, high-frequency blocking component B1 with an impedance of 10 ohms to 91 ohms not only effectively blocks the high-frequency components of the pulse voltage signal, thereby effectively reducing electromagnetic interference in the drive signal, but is also relatively small and low-cost. Therefore, the size and cost-effectiveness of high-frequency blocking component B1 are both high in terms of electromagnetic interference mitigation. When resonant circuit 2 stops outputting the drive signal, the oscillating energy of resonant circuit 2 cannot immediately dissipate, resulting in residual vibration. To minimize the occurrence of this residual vibration, in one possible implementation, as shown in Figures 1, 2, and 3, resonant circuit 2 further includes a damping resistor R1. One end of damping resistor R1 is connected to the first pulse output end, and the other end of damping resistor R1 is grounded. Specifically, the resistance value of the damping resistor R1 is related to the characteristic impedance Z of the resonant circuit 2. To achieve a better effect of avoiding the occurrence of residual vibration, in one possible implementation, the resistance value of the damping resistor R1 can be between 0.8*Z and 2*Z. For example, the resistance value of the damping resistor R1 includes but is not limited to 1.4*Z. Wherein, the characteristic impedance Z satisfies the following formula (1): z=Vii7cT (1) Corresponding to the various implementations of the resonant circuit 2 described above, the specific definitions of l1 and cl can have the following three cases:

[0003] 11 is the inductance of the first inductor L1 in the resonant circuit 2, and c1 is the capacitance of the first capacitor C1 in the resonant circuit 2; alternatively, 11 is the inductance of the second inductor L2 in the resonant circuit 2, and c1 is the capacitance of the second capacitor C2 in the resonant circuit 2; alternatively, 11 is the inductance of the third inductor L3 in the resonant circuit 2, and c1 is the capacitance of the third capacitor C3 in the resonant circuit 2. In this embodiment of the present application, a damping resistor R1 is added to the resonant circuit 2 so that when the resonant circuit 2 stops outputting a drive signal, the damping resistor R1 can absorb excess signal energy generated by the resonant circuit 2. This can reduce residual vibration after the resonant circuit 2 stops outputting the drive signal and improve the quality of the drive signal. In one possible implementation, as shown in Figures 1, 2, and 3, the ultrasonic sensor chip 3 may include an ultrasonic transducer 32. The ultrasonic transducer 32 is capable of generating an ultrasonic signal in response to the drive signal output by the resonant circuit 2. For example, when the ultrasonic signal generating device is used for fingerprint detection, the ultrasonic transducer 32 can generate an ultrasonic signal under the action of a driving signal and can receive an echo signal reflected by the user's finger to generate an electrical signal. This electrical signal can then be detected by other detection circuits in the ultrasonic sensor chip 3, such as an echo detection circuit, to achieve fingerprint detection. Since the ultrasonic transducer is a capacitive load, assuming its capacitance value is cO, cO and the above-mentioned capacitance value cI can satisfy cI>cO to obtain a driving signal with a better voltage amplitude. At the same time, the pulse frequency f of the driving signal satisfies the following formula (2): f= — / ] (2)

[0004] In one possible implementation, as shown in FIG1 , FIG2 , and FIG3 , the ultrasonic sensor chip 3 may further include a pixel array 33 (Pixel Array). The pixel array 33 is composed of a plurality of pixel cells (Pixel Cells). The pixel array 33 is connected to the control module 31. When the ultrasonic signal generating device is used for fingerprint detection, the pixel array 33 is used to perform ultrasonic fingerprint imaging. In one possible implementation, as shown in Figures 1, 2, and 3, the ultrasonic sensor chip 3 may further include a readout module 34, an analog-to-digital conversion module 35, and an interface module 36. The readout module 34 is connected to the pixel array 33, the analog-to-digital conversion module 35 is connected to the readout module 34, and the interface module 36 is connected to the analog-to-digital conversion module 35. The readout module 34 may obtain the accumulated amplitude value of multiple electrical signals generated by the ultrasonic signal and read the accumulated amplitude value to the analog-to-digital conversion module 35. The analog-to-digital conversion module 35 converts the accumulated amplitude value into a digital signal and outputs the digital signal to the interface module 36. The interface module 36 may transmit the digital signal to an external device so that the digital signal is averaged to implement corresponding related functions. Optionally, the readout module 34 may be a reader, the analog-to-digital conversion module 35 may be an analog-to-digital converter (ADC), and the interface module 36 includes, but is not limited to, a serial peripheral interface (SPI). In one possible implementation, as shown in Figures 1, 2, and 3, the ultrasonic signal generating device further includes a main control module 4, which includes a power supply VDD. The power supply VDD is used to power the pulse generating circuit 1 and the ultrasonic sensor chip 3. In a specific embodiment, the main control module 4 may include a control chip of an electronic device equipped with the ultrasonic signal generating device. The electronic device may be a terminal device such as a mobile phone or a tablet computer. The power supply VDD included in the main control module 4 may be the power supply of the electronic device, thereby eliminating the need for an additional power supply and reducing the overall power consumption of the ultrasonic signal generating device.In one possible implementation, as shown in Figures 1, 2, and 3, the main control module 4 also includes a serial peripheral interface (the API interface included in the main control module 4 in Figures 1, 2, and 3). This serial peripheral interface is used for communication between the main control module 4 and the ultrasonic sensor chip 3. For example, this serial peripheral interface is used for communication between the main control module 4 and the interface module 36 described above. It should be noted that, in this document, relational terms such as first and second are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Furthermore, the terms "comprise," "include," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. Without further restriction, elements defined by the phrase "comprising a..." do not preclude the presence of other identical elements in the process, method, article, or device comprising the elements. Not all steps and modules in the above-mentioned processes and system structure diagrams are required; certain steps or modules may be omitted based on actual needs. The order of execution of the steps is not fixed and may be adjusted as needed. The system structures described in the above-mentioned embodiments may be physical or logical. That is, some modules may be implemented by the same physical entity, or some modules may be implemented by multiple physical entities, or they may be implemented jointly by certain components in multiple independent devices. In the above-mentioned embodiments, hardware modules may be implemented mechanically or electrically. For example, a hardware module may include permanent, dedicated circuits or logic (such as a dedicated processor, FPGA, or ASIC) to perform corresponding operations. A hardware module may also include programmable logic or circuits (such as a general-purpose processor or other programmable processor) that can be temporarily configured by software to perform corresponding operations. The specific implementation method (mechanical method, dedicated permanent circuit, or temporary circuit) can be determined based on cost and time considerations.

Claims

Claims 1. An ultrasonic signal generating device, characterized in that: include: Pulse generating circuit, resonant circuit and ultrasonic sensor chip; The pulse generating circuit is used to output a pulse voltage signal; The resonant circuit is connected to the pulse generating circuit, and is used to receive the pulse voltage signal and output a driving signal generated according to the pulse voltage signal. The resonant circuit includes a high-frequency blocking component, and the high-frequency blocking component is used to block the high-frequency component included in the pulse voltage signal from being transmitted to the driving signal. The ultrasonic sensor chip is connected to the resonant circuit, and is used to receive the driving signal and output an ultrasonic signal generated according to the driving signal.

2. The device according to claim 1, characterized in that: The pulse generating circuit includes a first pulse output terminal and a second pulse output terminal; The first pulse output terminal is used to output a first pulse voltage signal, and the second pulse output terminal is used to output a second pulse voltage signal, and the first pulse voltage signal and the second pulse voltage signal are in opposite phases; The resonant circuit is connected to the first pulse output end and the second pulse output end, and is used to generate the driving signal according to the first pulse voltage signal and the second pulse voltage signal, wherein the waveform of the driving signal is a sine wave.

3. The device according to claim 2, characterized in that: The resonant circuit includes a first inductor and a first capacitor; one end of the first inductor is connected to the first pulse output end, one end of the first capacitor is connected to the second pulse output end, the other end of the first inductor and the other end of the first capacitor are both connected to one end of the high-frequency blocking component, and the other end of the high-frequency blocking component is connected to the ultrasonic sensor chip.

4. The device according to claim 2, characterized in that The resonant circuit includes a second inductor and a second capacitor; one end of the second inductor is connected to the first pulse output end, the high-frequency blocking component is connected between the second pulse output end and one end of the second capacitor, and the other end of the second inductor and the other end of the second capacitor are both connected to the ultrasonic sensor chip.

5. The device according to claim 2, characterized in that: The resonant circuit includes a third inductor and a third capacitor; one end of the third inductor is connected to the first pulse output end, the third capacitor is connected between the second pulse output end and one end of the high-frequency blocking component, and the other end of the third inductor and the other end of the high-frequency blocking component are both connected to the ultrasonic sensor chip.

6. The device according to any one of claims 1 to 5, characterized in that: The high-frequency blocking component includes a magnetic bead.

7. The device according to any one of claims 1 to 5, characterized in that: The high-frequency blocking component includes an inductor.

8. The device according to any one of claims 1 to 5, characterized in that: The impedance of the high-frequency blocking component is 10 ohms to 91 ohms in a frequency band of 100 MHz.

9. The device according to claim 2, characterized in that The resonant circuit includes a damping resistor; one end of the damping resistor is connected to the first pulse output end, and the other end of the damping resistor is grounded.

10. The device according to claim 9, characterized in that The resistance value of the damping resistor is between 0.8*Z and 2*Z. Between, where Z is the characteristic impedance of the resonant circuit.

11. The device according to claim 10, characterized in that The resistance value of the damping resistor is equal to 1.4*Z.

12. The device according to claim 10 or 11, characterized in that The resonant circuit includes a first inductor and a first capacitor; one end of the first inductor is connected to the first pulse output end, one end of the first capacitor is connected to the second pulse output end, the other end of the first inductor and the other end of the first capacitor are both connected to one end of the high-frequency blocking component, and the other end of the high-frequency blocking component is connected to the ultrasonic sensor chip; the characteristic impedance Z satisfies the following formula: z=Vn7cT; Wherein, 11 is the inductance value of the first inductor in the resonant circuit, and cl is the capacitance value of the first capacitor in the resonant circuit.

13. The device according to claim 10 or 11, characterized in that The resonant circuit includes a second inductor and a second capacitor; one end of the second inductor is connected to the first pulse output end, the high-frequency blocking component is connected between the second pulse output end and one end of the second capacitor, and the other ends of the second inductor and the second capacitor are both connected to the ultrasonic sensor chip; the characteristic impedance Z satisfies the following formula: Z=VH / cl; wherein, 11 is the inductance of the second inductor in the resonant circuit, and cl is the capacitance of the second capacitor in the resonant circuit.

14. The device according to claim 10 or 11, characterized in that The resonant circuit includes a third inductor and a third capacitor; one end of the third inductor is connected to the first pulse output end, the third capacitor is connected between the second pulse output end and one end of the high-frequency blocking component, and the other end of the third inductor and the other end of the high-frequency blocking component are both connected to the ultrasonic sensor chip; the characteristic impedance Z satisfies the following formula: Z=VH / cl; wherein, 11 is the inductance of the third inductor in the resonant circuit, and cl is the capacitance of the third capacitor in the resonant circuit.

15. The device according to claim 1, characterized in that The ultrasonic signal generating device further includes a main control module; the main control module includes a power supply, and the power supply is used to power the pulse generating circuit and the ultrasonic sensor chip.

16. The device according to claim 15, characterized in that The main control module includes a serial peripheral interface; the serial peripheral interface is used for communication between the main control module and the ultrasonic sensor chip.

17. The device according to claim 2, characterized in that The waveform of the driving signal is a sine waveform.

18. The device according to claim 2, characterized in that The waveform of the driving signal is a cosine waveform.

19. The device according to claim 1, characterized in that The pulse generating circuit is used to receive the control signal output by the ultrasonic sensor chip and output the pulse voltage signal generated according to the control signal.

20. The device according to claim 1, characterized in that The ultrasonic signal is used for fingerprint detection.

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