Ultrasonic transducer driving circuit and electronic artificial throat

Abstract

The invention discloses an ultrasonic transducer driving circuit and an electronic artificial throat, and relates to the field of medical instruments. In the ultrasonic transducer driving circuit, a power supply module is used for supplying power to the whole driving circuit; the glottal wave pulse modulator is used for carrying out amplitude modulation on a glottal wave signal of normal voice of a patient and a carrier signal of the excitation ultrasonic transducer to generate a modulation signal; the differential output power amplifier is used for carrying out signal conditioning and power amplification on the modulation signal and outputting the amplified driving signal in a differential mode; the transformer is used for boosting the amplified driving signal to generate a boosted driving signal; and the matching circuit is used for realizing impedance matching between the boosted driving signal and the ultrasonic transducer, so that the power of the boosted driving signal is loaded to the ultrasonic transducer to the maximum extent, and the ultrasonic transducer is driven to emit ultrasonic waves. According to the ultrasonic transducer driving circuit, the overall size of the driving circuit can be reduced, and the portable requirement of handheld electronic artificial throat equipment is met.

Description

Technical Field

[0001] The present application relates to the technical field of medical devices, and in particular to an ultrasonic transducer driving circuit and an electronic artificial larynx. Background Art

[0002] Electronic artificial larynx is often used to provide an external sound source for laryngeal cancer patients after laryngectomy. The external sound source is transmitted into the patient's vocal tract through the neck tissue and modulated into speech. The traditional electronic artificial larynx uses an armature motor as a sound source, but this sound source will generate strong radiation noise. In this regard, the art proposes a new electronic artificial larynx based on acoustic parametric array technology, such as a pathological speech assistant system based on acoustic parametric array technology, which can overcome the radiation noise problem of the electronic artificial larynx with the armature motor as the sound source. This electronic artificial larynx based on acoustic parametric array technology uses an ultrasonic transducer as an excitation sound source. Because the efficiency of ultrasonic waves in self-demodulating and generating glottal wave signals in human tissue is low, the ultrasonic transducer requires a relatively high-power drive signal. This driver requires a large supply voltage and a large output power, and the overall volume is large. The electronic artificial larynx device is a handheld battery-powered device, which requires a small device size. Therefore, it is urgent to carry out miniaturization and portable design of its drive circuit so that this new electronic artificial larynx can meet the design requirements of handheld devices. Summary of the invention

[0003] In view of the above problems existing in the prior art, the purpose of the present application is to provide an ultrasonic transducer driving circuit and an electronic artificial larynx to reduce the volume of the driving circuit and meet the portability requirements of a handheld electronic artificial larynx device.

[0004] To achieve the above objectives, this application provides the following solutions.

[0005] On the one hand, the present application provides an ultrasonic transducer driving circuit, comprising: a power supply module and a glottal wave pulse modulator, a differential output power amplifier, a transformer and a matching circuit connected in sequence;

[0006] The power supply module is used to provide power to the entire drive circuit;

[0007] The glottal wave pulse modulator is used to perform amplitude modulation on the glottal wave signal of the patient's normal speech and the carrier signal that excites the ultrasonic transducer to generate a modulation signal;

[0008] The differential output power amplifier is used to perform signal conditioning and power amplification on the modulated signal, and output the amplified driving signal in a differential manner;

[0009] The transformer is used to boost the amplified driving signal to generate a boosted driving signal;

[0010] The matching circuit is used to achieve impedance matching between the boosted driving signal and the ultrasonic transducer, so that the power of the boosted driving signal is maximized and loaded onto the ultrasonic transducer, thereby driving the ultrasonic transducer to emit ultrasonic waves.

[0011] Optionally, the power module is powered by a battery, and the battery voltage range is 3.2V to 5V.

[0012] Optionally, the glottal wave pulse modulator uses digital modulation technology to perform orthogonal amplitude modulation on the carrier signal and the glottal wave signal, and the frequency range of the generated modulation signal is 20kHz to 200kHz.

[0013] Optionally, the glottal wave pulse modulator uses digital modulation technology to perform orthogonal amplitude modulation on the carrier signal and the glottal wave signal, specifically including: performing single sideband modulation in MCU, DSP or FPGA.

[0014] Optionally, the glottal wave pulse modulator uses a digital modulation technique to perform quadrature amplitude modulation on the carrier signal and the glottal wave signal, specifically including: performing double-sideband modulation in an MCU, a DSP or an FPGA.

[0015] Optionally, the frequency of the carrier signal is the same as the center frequency of the ultrasonic transducer.

[0016] Optionally, the carrier signal is a sinusoidal wave signal.

[0017] Optionally, the signal conditioning performed by the differential output power amplifier on the modulated signal includes filtering conditioning and amplitude conditioning, and a differential output is used after power amplification.

[0018] Optionally, the turns ratio of the primary coil to the secondary coil of the transformer is 1:5 to 1:10.

[0019] On the other hand, the present application provides an electronic artificial larynx, which is based on acoustic parametric array technology and uses an ultrasonic transducer as an excitation sound source. The ultrasonic transducer is driven by the ultrasonic transducer driving circuit; the ultrasonic wave emitted by the ultrasonic transducer is self-demodulated into a glottal wave signal in the patient's body, allowing the patient to make normal speech.

[0020] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0021] In an ultrasonic transducer driving circuit provided by the present application, a glottal wave pulse modulator is used to amplitude modulate the glottal wave signal of the patient's normal speech and the carrier signal that excites the ultrasonic transducer, and the generated modulated signal is subjected to signal conditioning and power amplification via a differential output power amplifier, and the amplified driving signal is output in a differential manner, and the excitation transformer is used for voltage boosting, and after voltage boosting, the ultrasonic transducer can be driven to emit ultrasonic waves. The ultrasonic transducer driving circuit designed by the present application is small in size and light in weight, and is particularly suitable for high-power driving of ultrasonic transducers in portable electronic artificial laryngeal devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the overall structure of an ultrasonic transducer driving circuit;

[0024] Figure 2 It is a schematic diagram of amplitude modulation of glottal wave signal and carrier signal;

[0025] Figure 3 An example diagram of a glottal wave signal waveform;

[0026] Figure 4 Carrier signal waveform embodiment diagram;

[0027] Figure 5 It is the basic block diagram of the double-sideband amplitude signal processing method;

[0028] Figure 6 This is a diagram showing an embodiment of a modulation signal waveform;

[0029] Figure 7 This is a diagram of an embodiment of a differential output power amplifier, a transformer, and an ultrasonic transducer circuit. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0031] The purpose of the present application is to propose an ultrasonic transducer driving circuit and an electronic artificial larynx, which can reduce the volume of the driving circuit and meet the portability requirements of a handheld electronic artificial larynx device.

[0032] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] In an exemplary embodiment, the present application provides an ultrasonic transducer driving circuit. Figure 1 As shown, the ultrasonic transducer driving circuit includes: a power supply module and a glottal wave pulse modulator, a differential output power amplifier, a transformer and a matching circuit which are connected in sequence.

[0034] The power module is used to provide power for the entire drive circuit. Specifically, the power module is powered by a battery with a battery voltage range of 3.2V to 5V. In a specific embodiment, the power module uses a 3000mAh 18650 model 3.7V lithium battery with a discharge current of 1C.

[0035] like Figure 2 As shown, the glottal wave pulse modulator is used to amplitude modulate the stored glottal wave signal of the patient's normal speech (original pronunciation) with the carrier signal that excites the ultrasonic transducer to generate a modulation signal. Specifically, the glottal wave pulse modulator uses digital modulation technology to perform orthogonal amplitude modulation on the carrier signal and the glottal wave signal. For example, single-sideband modulation or double-sideband modulation can be performed in an MCU, DSP or FPGA. The frequency range of the modulation signal generated after modulation is 20kHz to 200kHz. The glottal wave signal is stored in the corresponding MCU, DSP or FPGA, and the carrier signal is generated by the MCU, DSP or FPGA.

[0036] The glottal wave signal of the patient's normal speech can be derived from the patient's normal speech before the onset of the disease, or from other normal human speech that is close to the patient's pronunciation. Figure 3 As shown, the horizontal axis is time and the vertical axis is the normalized amplitude of voltage.

[0037] The frequency of the carrier signal is the same as the center frequency of the ultrasonic transducer, so as to drive the ultrasonic transducer to emit ultrasonic waves of the corresponding frequency. In a specific embodiment, the center frequency of the target ultrasonic transducer is 40kHz. The carrier signal adopts a sine wave signal with a center frequency of 40kHz, and its waveform is as follows: Figure 4 As shown, the horizontal axis is time and the vertical axis is the normalized amplitude of voltage.

[0038] In a specific embodiment, the MCU uses an ARMCortex-M4 MCU of STMicroelectronics STM32G431CBT6 model with DSP and FPU. The glottal wave signal is stored in the Flash of the MCU, and the MCU generates a 40kHz sine wave signal as a carrier signal, and its waveform is as follows: Figure 4 As shown. Figure 5 The double-sideband amplitude signal processing method shown modulates the glottal wave signal and the 40kHz sine wave signal, and the obtained modulated signal is converted from a digital signal to an analog signal output through the analog-to-digital converter DAC of the MCU. Figure 5 The modulation process shown can be described by the following formula:

[0039] y DSB (t) = (mf(t) + 1)·cos(ω c t)

[0040] Where f(t) is the glottal wave signal; m represents the modulation depth, ranging from 0 to 1; cos(ω c t) is the center frequency ω c The carrier signal, in this embodiment, c 40kHz; DSB (t) is the generated modulation signal, and its waveform is as follows Figure 6 As shown, the horizontal axis is time and the vertical axis is the normalized amplitude of voltage.

[0041] The differential output power amplifier is used to perform signal conditioning and power amplification on the modulation signal output by the glottal wave pulse modulator, and output the amplified drive signal in a differential manner. Specifically, the signal conditioning performed by the differential output power amplifier on the modulation signal includes filter conditioning and amplitude conditioning, and the differential output is used after power amplification.

[0042] In a specific embodiment, the circuit connection relationship between the differential output power amplifier, the transformer and the ultrasonic transducer is as follows: Figure 7 As shown, the matching circuit is not shown for the sake of convenience. Figure 7 As shown, the differential output power amplifier includes resistors R1 to R3, capacitor C, operational amplifiers U1 and U2, and transistors Q1 to Q4. One end of the resistor R1 is connected to the modulation signal y DSB(t); The other end of the resistor R1 is respectively connected to the positive input end of the operational amplifier U1, one end of the resistor R2 and one end of the capacitor C. The reverse input end of the operational amplifier U1 is respectively connected to the output end of the operational amplifier U1, the base of the transistor Q1 and the base of the transistor Q2. The collector of the transistor Q1 is connected to the power supply voltage V; the emitter of the transistor Q1 and the emitter of the transistor Q2 are both connected to one end of the low-voltage side of the transformer T; the collector of the transistor Q2 is grounded. The positive input end of the operational amplifier U2 is respectively connected to the power supply voltage V and the other end of the capacitor C. The reverse input end of the operational amplifier U2 is respectively connected to the other end of the resistor R2 and one end of the resistor R3. The output end of the operational amplifier U2 is respectively connected to the other end of the resistor R3, the base of the transistor Q3 and the base of the transistor Q4. The collector of the transistor Q3 is connected to the power supply voltage V. The emitter of the transistor Q3 and the emitter of the transistor Q4 are both connected to the other end of the low voltage side of the transformer T; the collector of the transistor Q4 is grounded. The high voltage side of the transformer T is connected in parallel to both ends of the ultrasonic transducer B.

[0043] like Figure 7 As shown, in this embodiment, a resistor R1 and a capacitor C are used to form a high-pass filter to modulate the output modulation signal y after the pre-stage modulation. DSB Two AD8397 operational amplifiers U1 and U2 are used to form a 1x gain amplifier circuit ( Figure 1 In the figure, G is used to represent the inverting amplifier circuit with a gain of -1 ( Figure 1 -G is used to represent it), and the previous stage signal is converted into a differential output. A class AB power amplifier is added to each differential output signal. Each class AB power amplifier is composed of NPN transistor 2N5550 and PNP transistor 2N5401 to meet the power output requirements. Specifically, Q1 and Q3 use NPN transistor 2N5550, and Q2 and Q4 use PNP transistor 2N5401. Then transistors Q1 and Q2 constitute the class AB power amplifier corresponding to operational amplifier U1, and transistors Q3 and Q4 constitute the class AB power amplifier corresponding to operational amplifier U2. The resistance values ​​of resistors R2 and R3 are equal. Resistors R1 and capacitor C form a high-pass filter. The specific resistance values ​​of resistors R1 to R3 need to be determined according to the center frequency of the modulation signal, which are generally a few ohms. The power supply voltage V is the voltage output by the power module.

[0044] like Figure 7 As shown, the modulation signal y DSB(t) After being filtered by a high-pass filter composed of resistor R1 and capacitor C, the signal enters the 1x gain in-phase amplifier circuit composed of operational amplifier U1 and the -1x gain inverse amplifier circuit composed of operational amplifier U2 to enhance the driving capability. The two transistors Q1 and Q2 and the two transistors Q3 and Q4 respectively form a class AB power amplifier to increase the output power. The amplified drive signal is boosted by transformer T to drive the ultrasonic transducer B.

[0045] That is, the transformer T is used to boost the amplified driving signal to generate a boosted driving signal. Specifically, the turns ratio of the primary coil to the secondary coil of the transformer is 1:5 to 1:10.

[0046] In a specific embodiment, the turns ratio of the primary and secondary coils of the transformer T is 1:10, which can amplify the differential output excitation signal (driving signal) by 10 times. The peak-to-peak voltage of the driving signal can reach 70V.

[0047] The matching circuit is used to achieve impedance matching between the boosted driving signal and the ultrasonic transducer, so that the power of the boosted driving signal is maximized and loaded onto the ultrasonic transducer, driving the ultrasonic transducer to emit ultrasonic waves. The ultrasonic waves emitted by the ultrasonic transducer are self-demodulated into glottal wave signals in the patient's body, so that the patient can emit normal speech.

[0048] The matching circuit is generally composed of a network of resistors, capacitors, and inductors, and is used to match the output impedance of the entire drive circuit with the impedance of the ultrasonic transducer (usually 50 ohms) to optimize the power output. The specific design of the matching circuit needs to be based on the impedance of the ultrasonic transducer.

[0049] The above-mentioned ultrasonic transducer driving circuit uses a modulation signal after amplitude modulation of a normal speech glottal wave signal and a sinusoidal carrier signal, and after filtering and amplitude conditioning, performs power amplification, uses a differential output, and excites a transformer for voltage boosting. After voltage boosting, it can drive the ultrasonic transducer to emit ultrasonic waves. The ultrasonic wave of the ultrasonic transducer is self-demodulated into a glottal wave signal in the patient's body, allowing the patient to emit normal speech. Compared with the prior art, the present application can output a high-power ultrasonic transducer driving signal while reducing the amplitude requirement of the power supply voltage to drive the ultrasonic transducer to output an ultrasonic signal. Therefore, the volume of the system can be greatly reduced to meet the system requirements of a handheld acoustic parametric array. The ultrasonic transducer driving circuit designed in the present application can be powered by a battery, is compact in size, and lightweight, and is particularly suitable for high-power driving of ultrasonic transducers in miniaturized portable electronic artificial laryngeal devices.

[0050] Therefore, in an exemplary embodiment, the present application also provides an electronic artificial larynx, for example, a pathological speech aid system based on acoustic parametric array technology, which is based on acoustic parametric array technology and uses an ultrasonic transducer as an excitation sound source. Figure 1 The ultrasonic transducer driving circuit shown is used for driving. The ultrasonic wave emitted by the ultrasonic transducer is self-demodulated into a glottal wave signal in the patient's body, so that the patient can speak normally.

[0051] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An ultrasonic transducer driving circuit, characterized in that: include: A power module and a glottal wave pulse modulator, a differential output power amplifier, a transformer and a matching circuit connected in sequence; The power supply module is used to provide power to the entire drive circuit; The glottal wave pulse modulator is used to perform amplitude modulation on the glottal wave signal of the patient's normal speech and the carrier signal that excites the ultrasonic transducer to generate a modulation signal; The differential output power amplifier is used to perform signal conditioning and power amplification on the modulated signal, and output the amplified driving signal in a differential manner; The transformer is used to boost the amplified driving signal to generate a boosted driving signal; The matching circuit is used to achieve impedance matching between the boosted driving signal and the ultrasonic transducer, so that the power of the boosted driving signal is maximized and loaded onto the ultrasonic transducer, thereby driving the ultrasonic transducer to emit ultrasonic waves.

2. The ultrasonic transducer driving circuit according to claim 1, characterized in that: The power module is powered by a battery, and the battery voltage range is 3.2V to 5V.

3. The ultrasonic transducer driving circuit according to claim 1, characterized in that: The glottal wave pulse modulator uses digital modulation technology to perform orthogonal amplitude modulation on the carrier signal and the glottal wave signal, and the frequency range of the generated modulation signal is 20kHz to 200kHz.

4. The ultrasonic transducer driving circuit according to claim 3, characterized in that: The glottal wave pulse modulator uses digital modulation technology to perform orthogonal amplitude modulation on the carrier signal and the glottal wave signal, specifically including: performing single sideband modulation in MCU, DSP or FPGA.

5. The ultrasonic transducer driving circuit according to claim 3, characterized in that: The glottal wave pulse modulator uses digital modulation technology to perform orthogonal amplitude modulation on the carrier signal and the glottal wave signal, specifically including: performing double-sideband modulation in MCU, DSP or FPGA.

6. The ultrasonic transducer driving circuit according to claim 3, characterized in that: The frequency of the carrier signal is the same as the center frequency of the ultrasonic transducer.

7. The ultrasonic transducer driving circuit according to claim 6, characterized in that: The carrier signal is a sine wave signal.

8. The ultrasonic transducer driving circuit according to claim 1, characterized in that: The signal conditioning performed by the differential output power amplifier on the modulated signal includes filtering conditioning and amplitude conditioning, and the differential output is used after power amplification.

9. The ultrasonic transducer driving circuit according to claim 1, characterized in that: The turns ratio of the primary coil to the secondary coil of the transformer is 1:5 to 1:

10.

10. An electronic artificial larynx, based on acoustic parametric array technology, using an ultrasonic transducer as an excitation sound source, characterized in that: The ultrasonic transducer is driven by the ultrasonic transducer driving circuit described in any one of claims 1 to 9; the ultrasonic waves emitted by the ultrasonic transducer are self-demodulated into glottal wave signals in the patient's body, so that the patient can speak normally.

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