Ultrasonic transducer matching circuit based on adjustable frequency and ultrasonic device

Abstract

The utility model provides an ultrasonic transducer matching circuit based on adjustable frequency and an ultrasonic device, and a register is connected with an upper controller and a switching circuit and is used for controlling the on-off of the switching circuit according to a control instruction of the upper controller; the switching circuit is connected with the register, the resistor array and the capacitor array, and is used for respectively controlling the connection or disconnection of the resistor array and / or the capacitor array; the resistor array is connected with the switching circuit and the ultrasonic transducer and is used for providing a required resistor combination according to control information of the switching circuit; and the capacitor array is connected with the switching circuit and the ultrasonic transducer and is used for providing a required capacitor combination according to the control information of the switching circuit. According to the utility model, the number of resistors and / or capacitors connected in the resistor array and / or the capacitor array is controlled through the register and the switching circuit, so that the working frequency of the ultrasonic transducer is adjusted, and the stability and reliability of the ultrasonic transducer under different working conditions are improved.

Description

Technical Field

[0001] The utility model relates to the field of ultrasonic, in particular to an ultrasonic transducer matching circuit and an ultrasonic device based on adjustable frequency. Background Art

[0002] In modern automotive electronic systems, ultrasonic transducers, as key sensor components, play an indispensable role in various applications such as parking assistance and collision avoidance warnings. The efficiency and accuracy of ultrasonic transducers directly affect the performance and reliability of these systems. Ultrasonic transducers measure distance by transmitting and receiving ultrasonic signals at specific frequencies, and the accuracy of their operating frequencies is crucial for the performance of the entire system. Currently, the center frequency of ultrasonic systems is basically fixed, usually within the range of 38Khz - 72KHz, and the common frequencies are 40KHz, 48KHz, and 58KHz. In practical applications, if the frequency cannot be adjusted, errors will occur.

[0003] The problems of the current prior art are as follows:

[0004] 1. Frequency drift phenomenon: When the ultrasonic transducer is used for a long time or works in extreme environments, such as high temperature, low temperature, and large humidity changes, the physical properties of its internal materials may change, resulting in frequency drift. If the frequency cannot be adjusted, this frequency drift will seriously affect the ranging accuracy and reliability of ultrasonic signals.

[0005] 2. Manufacturing tolerance: During the manufacturing process of ultrasonic transducers, due to differences in materials and processes, the actual operating frequency of each transducer may be different from the designed frequency, that is, there is manufacturing tolerance. If the frequency cannot be adjusted later, actual errors may occur.

[0006] 3. Frequency fixity: Once the traditional ultrasonic transducer is manufactured, the parameters of its matching circuit are fixed, and users cannot adjust them according to environmental changes or frequency drift problems encountered in actual applications. This fixity limits the adaptability and flexibility of ultrasonic transducers.

[0007] In summary, there are many deficiencies in the frequency adjustment of ultrasonic transducers in the prior art, and these problems limit the application range and performance of ultrasonic transducers. Summary of the Utility Model

[0008] In order to solve the problems in the background art, the utility model proposes an ultrasonic transducer matching circuit and an ultrasonic device based on adjustable frequency.

[0009] An ultrasonic transducer matching circuit based on adjustable frequency includes:

[0010] A register, configured to connect to an upper controller and a switching circuit, and used to control the on / off of the switching circuit according to the control instructions of the upper controller;

[0011] A switching circuit, configured to connect to the register, a resistor array, and a capacitor array, and used to control the connection or disconnection of the resistor array and / or the capacitor array respectively;

[0012] A resistor array, configured to connect to the switching circuit and an ultrasonic transducer, and used to provide the required resistor combination according to the control information of the switching circuit;

[0013] A capacitor array, configured to connect to the switching circuit and an ultrasonic transducer, and used to provide the required capacitor combination according to the control information of the switching circuit.

[0014] Based on the above, the switching circuit includes a plurality of MOS transistors. The gates of the MOS transistors are connected to the register, the drains of the MOS transistors are connected to the positive power supply, and the sources of the MOS transistors are controllably connected to the resistor array or the capacitor array.

[0015] Based on the above, the resistor array includes a plurality of resistors connected in parallel. Each resistor is correspondingly connected to a MOS transistor, and the source of the MOS transistor is grounded through a resistor.

[0016] Based on the above, the resistor array includes a plurality of resistors connected in series. Each resistor is correspondingly connected to a MOS transistor, and the drain and source of the MOS transistor are respectively connected to both ends of a resistor.

[0017] Based on the above, the capacitor array includes a plurality of capacitors connected in parallel. Each capacitor is correspondingly connected to a MOS transistor, and the source of the MOS transistor is grounded through a capacitor.

[0018] Based on the above, the capacitor array includes a plurality of capacitors connected in series. Each capacitor is correspondingly connected to a MOS transistor, and the drain and source of the MOS transistor are respectively connected to both ends of a capacitor.

[0019] Based on the above, a temperature sensor is included. The temperature sensor is electrically connected to the upper controller, and the upper controller controls the connection to the register according to the detection information of the temperature sensor.

[0020] Based on the above, the register includes a first register and a second register. The first register is controllably connected to the resistor array through a switching circuit, and the second register is controllably connected to the capacitor array through another switching circuit.

[0021] An ultrasonic device includes a driving circuit and an ultrasonic transducer. The driving circuit is used to drive the ultrasonic transducer to generate ultrasonic waves, and the driving circuit adjusts the operating frequency of the ultrasonic transducer by using the ultrasonic transducer matching circuit based on adjustable frequency.

[0022] The present utility model has substantial features and progress compared with the prior art. Specifically, the present utility model controls the number of resistors and / or capacitors connected in the resistor array and / or capacitor array through a register and a switch circuit, thereby adjusting the operating frequency of the ultrasonic transducer and improving the stability and reliability of the ultrasonic transducer under different operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic block diagram of the circuit structure of the present utility model.

[0024] Figure 2 It is a schematic diagram of the circuit structure when the resistor array and the capacitor array of the present utility model are respectively in series.

[0025] Figure 3 It is a schematic diagram of the circuit structure when the resistor array and the capacitor array of the present utility model are respectively in parallel.

[0026] Figure 4 It is a schematic diagram of the circuit structure when the resistors in the resistor array of the present utility model are in series and the capacitors in the capacitor array are in parallel.

[0027] Figure 5 It is a schematic diagram of the circuit structure when the resistors in the resistor array of the present utility model are in parallel and the capacitors in the capacitor array are in series. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0028] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0029] As Figure 1 shown, a matching circuit for an ultrasonic transducer based on adjustable frequency includes: a register configured to connect to an upper controller and a switch circuit, and used to control the on / off of the switch circuit according to the control instruction of the upper controller; a switch circuit configured to connect to the register, the resistor array, and the capacitor array, and used to respectively control the connection or disconnection of the resistor array and / or the capacitor array; a resistor array configured to connect to the switch circuit and the ultrasonic transducer, and used to provide the required resistor combination according to the control information of the switch circuit, that is, the combined change of different numbers / resistances of resistors; a capacitor array configured to connect to the switch circuit and the ultrasonic transducer, and used to provide the required capacitor combination according to the control information of the switch circuit, that is, the combined change of different numbers / capacitances of capacitors.

[0030] The upper controller is an original unit of devices such as ultrasonic devices, such as a microprocessor chip. The upper controller controls the on / off quantity of switches in the switch circuit through registers, so as to control the quantity of resistors and / or capacitors connected in the resistor array and / or capacitor array, thereby changing and adjusting the working frequency of the ultrasonic transducer.

[0031] Specifically, the switch circuit includes a plurality of MOS transistors. The gates of the MOS transistors are connected to the registers, the drains of the MOS transistors are connected to the positive power supply, and the sources of the MOS transistors are controllably connected to the resistor array and / or capacitor array, such as Figure 2 and Figure 3As shown (the connection line between the MOS transistor and the register is actually a flexible cable). Generally, a small-power to medium-power N-channel enhancement-mode MOSFET (NMOS transistor) is selected as the MOS transistor, which can provide the required switching speed and efficiency. The specific model needs to be determined according to the working voltage, current of the ultrasonic transducer, and the expected power consumption. The register can be a single-register structure. The upper four bits of the single register are used to control the resistor array, and the lower four bits are used to control the capacitor array. In this system, each bit controls whether the corresponding MOS transistor is turned on, thereby determining whether the corresponding resistor or capacitor is connected to the circuit. For example, the resistor array consists of five resistor units with resistance values of R, 2R, 4R, 8R, and 16R respectively. For each resistor unit, there is a corresponding MOS transistor switch. When the upper four bits of the register have a value of 'F' (i.e., binary 1111), all MOS transistor switches are in the off state, and all resistor units will be connected to the circuit, achieving the maximum resistance value combination. For example, if R is 1 kΩ, then the total resistance is R + 2R + 4R + 8R + 16R = 31 kΩ, which will reduce the operating frequency of the transducer to the lower limit of 38 KHz. Similarly, the capacitor array also consists of five capacitor units with capacitance values of C, 2C, 4C, 8C, and 16C respectively. When the lower four bits of the register have a value of 'F' (i.e., binary 1111), all capacitor units are connected to the circuit, and the total capacitance value reaches the maximum value C + 2C + 4C + 8C + 16C = 31C, thereby reducing the operating frequency of the transducer. Or it can be a dual-register structure. The first register is used to control the resistor array, and the second register is used to control the capacitor array. Each register is 8 bits and is all used to control the MOS transistor switches of the corresponding array. In the control register of the resistor array, assume that each bit controls a resistor unit with a resistance value of R and its corresponding MOS transistor switch. When the register value is 'FF' (binary 11111111), all resistor units are connected in parallel to the circuit. Since the total resistance value decreases after parallel connection, this will increase the operating frequency of the transducer. In the control register of the capacitor array, the same logic applies. Each bit controls a capacitor unit with a capacitance value of C and its corresponding MOS transistor switch. When the register value is 'FF' (binary 11111111), all capacitor units are connected in parallel to the circuit, and the total capacitance value increases, and the operating frequency of the transducer decreases accordingly. In this way, the system can independently adjust the resistor and capacitor arrays to achieve more precise frequency adjustment. In these two embodiments, by programming to control the change of the register value, the MCU can dynamically adjust the operating frequency of the ultrasonic transducer to adapt to environmental changes or ensure measurement accuracy.

[0032] In practice, the resistor array can have various arrangements, including but not limited to parallel or series arrangements of multiple resistors with the same or different resistance values; the capacitor array can have various arrangements, including but not limited to parallel or series arrangements of capacitors with the same or different capacitances.Figure 2 The medium resistors and capacitors are respectively connected in parallel. Only 3 resistors, capacitors and their corresponding MOS transistors are shown in the figure, and the quantity can be set according to needs in practice. Figure 3 The medium resistors and capacitors are respectively connected in series. Only 3 resistors, capacitors and their corresponding MOS transistors are shown in the figure, and the quantity can be set according to needs in practice. Figure 4 The resistors are connected in series and the capacitors are connected in parallel. Only 3 resistors, capacitors and their corresponding MOS transistors are shown in the figure, and the quantity can be set according to needs in practice. Figure 5 The resistors are connected in parallel and the capacitors are connected in series. Only 3 resistors, capacitors and their corresponding MOS transistors are shown in the figure, and the quantity can be set according to needs in practice. In practice, the series and parallel connections of the resistors and capacitors can be set according to needs, such as resistors in series and capacitors in parallel, or resistors in parallel and capacitors in series, etc.

[0033] The resistor array can be arranged by the R-2R resistance value method. This arrangement is based on a basic unit with an R value, and then combined with resistors with resistance values of 2R, 4R, and 8R respectively. Through the control of MOS transistor switches, these resistors can be connected in series or parallel to the circuit. Series arrangement: If all resistor units are connected in series, the total resistance value will be the sum of R, 3R, 7R, and 15R. For example, if R is 1 kΩ, the total resistance values of the series arrangement are 1 kΩ, 3 kΩ, 7 kΩ, 15 kΩ, etc. This arrangement will significantly increase the impedance of the circuit, thereby reducing the operating frequency, because the relationship between the operating frequency f and the impedance Z is f ~ 1 / Z. Parallel arrangement: If all resistor units are connected in parallel, the total resistance value will be the reciprocal of the sum of the reciprocals of the resistance values of multiple resistors. Taking the same R = 1 kΩ as an example, four resistors connected in parallel will generate an impedance with a total resistance value lower than the resistance value of the basic unit R, and reducing the impedance will increase the operating frequency. In other embodiments, the resistance values can also be in other ways, such as all resistance values being the same, etc.

[0034] Similarly, the arrangement of the capacitor array is similar to that of the resistor array. For example, the capacitor array is arranged with capacitance values of C, 2C, 4C, and 8C. The capacitance values respectively represent the basic unit capacitance C and its integer multiples of capacitance. Series arrangement: When capacitors are connected in series, the total capacitance value is calculated as the reciprocal of the sum of the reciprocals of multiple capacitance values. For example, if C is 1 nF, the total capacitance value after series connection will be less than any single capacitor unit, which will increase the resonance frequency of the circuit, because the relationship between the resonance frequency f and the capacitance C is f ~ 1 / √C. Parallel arrangement: When capacitors are connected in parallel, the total capacitance value is equal to the sum of all capacitance values. Taking C = 1 nF as an example, four capacitors connected in parallel will generate a total capacitance value of 15 nF (C + 2C + 4C + 8C). Connecting capacitors in parallel increases the total capacitance of the circuit, resulting in a decrease in the resonance frequency.

[0035] Preferably, the matching circuit includes a temperature sensor electrically connected to an upper controller, and the upper controller controls the connection register according to the detection information of the temperature sensor. The temperature sensor is used to monitor the temperature associated with the ultrasonic transducer; the upper controller is configured with an input terminal for receiving a temperature feedback signal so as to automatically adjust the number of elements connected in the resistor array and / or capacitor array according to the temperature change, compensating for the influence of temperature on the operating frequency of the ultrasonic transducer.

[0036] Specific embodiments of temperature regulation:

[0037] In the ultrasonic transducer frequency adjustment device, a temperature sensor is designed and is closely attached to or built into the vicinity of the ultrasonic transducer. This sensor is used to monitor the temperature of the ultrasonic transducer and its surrounding environment in real time. When the temperature sensor detects a change in the ambient temperature, it sends the temperature reading to the upper controller (such as an MCU). The MCU updates the control register according to the detection information of the temperature sensor, and then controls the number of elements connected in the resistor array and / or capacitor array through a switching circuit. For example, if the increase in temperature causes the operating frequency of the ultrasonic transducer to become higher, the impedance in the array is increased through the switching circuit to lower the frequency; conversely, if the decrease in temperature causes the frequency to drop, the impedance is reduced through the switching circuit to increase the frequency. In this way, the device can automatically perform fine adjustment of the frequency, ensuring that the ultrasonic transducer can maintain the optimal operating state even under temperature fluctuations, greatly improving the stability and accuracy of the device in different working environments.

[0038] An ultrasonic device includes a driving circuit and an ultrasonic transducer. The driving circuit is used to drive the ultrasonic transducer to generate ultrasonic waves, and the driving circuit uses the above-mentioned ultrasonic transducer matching circuit with adjustable frequency to adjust the operating frequency of the ultrasonic transducer.

[0039] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above-mentioned exemplary embodiments, and without departing from the spirit or basic characteristics of the present invention, the present invention can be implemented in other specific forms. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes falling within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention. Any reference signs in the claims should not be regarded as limiting the claims involved.

Claims

1. An ultrasonic transducer matching circuit based on adjustable frequency, characterized in that: include: A register configured to connect the upper controller and the switch circuit, and to control the on and off of the switch circuit according to a control instruction of the upper controller; A switch circuit is configured to connect the register and the resistor array and the capacitor array, and is used to control the connection or disconnection of the resistor array and / or the capacitor array respectively; a resistor array configured to connect the switch circuit and the ultrasonic transducer and to provide a desired resistance combination according to control information of the switch circuit; The capacitor array is configured to connect the switch circuit and the ultrasonic transducer and is used to provide a required capacitor combination according to control information of the switch circuit.

2. The frequency-adjustable ultrasonic transducer matching circuit according to claim 1, characterized in that: The switch circuit comprises a plurality of MOS tubes, the gate of the MOS tube is connected to the register, the drain of the MOS tube is connected to the positive power supply, and the source of the MOS tube is controlled to be connected to a resistor array or a capacitor array.

3. The frequency-adjustable ultrasonic transducer matching circuit according to claim 2, characterized in that: The resistor array includes a plurality of resistors connected in parallel, each resistor is connected to a corresponding MOS tube, and the source of the MOS tube is grounded through a resistor.

4. The frequency-adjustable ultrasonic transducer matching circuit according to claim 2, characterized in that: The resistor array includes a plurality of resistors connected in series, each resistor is connected to a corresponding MOS tube, and the drain and source of the MOS tube are connected to two ends of a resistor respectively.

5. The frequency-adjustable ultrasonic transducer matching circuit according to claim 2, characterized in that: The capacitor array includes a plurality of capacitors connected in parallel, each capacitor is connected to a corresponding MOS tube, and the source of the MOS tube is grounded through a capacitor.

6. The frequency-adjustable ultrasonic transducer matching circuit according to claim 2, characterized in that: The capacitor array includes a plurality of capacitors connected in series, each capacitor is correspondingly connected to a MOS tube, and the drain and source of the MOS tube are respectively connected to two ends of a capacitor.

7. The frequency-adjustable ultrasonic transducer matching circuit according to claim 1, characterized in that: It includes a temperature sensor, which is electrically connected to a host controller. The host controller controls a connection register according to detection information of the temperature sensor.

8. The frequency-adjustable ultrasonic transducer matching circuit according to claim 1, characterized in that: The register includes a first register and a second register. The first register is controlled to be connected to a resistor array through a switch circuit, and the second register is controlled to be connected to a capacitor array through another switch circuit.

9. An ultrasonic device, comprising a driving circuit and an ultrasonic transducer, wherein the driving circuit is used to drive the ultrasonic transducer to generate ultrasonic waves, characterized in that: The driving circuit uses the ultrasonic transducer matching circuit based on adjustable frequency as described in any one of claims 1 to 8 to adjust the operating frequency of the ultrasonic transducer.

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