Current negative feedback phase-locked oscillation circuit, power supply and equipment for ultrasonic power supply

Abstract

The present application discloses a current negative feedback phase-locked oscillation circuit for ultrasonic power supply, ultrasonic power supply and electronic equipment, including: a multivibrator circuit and a current sensing circuit, wherein the multivibrator circuit is connected to a DC power supply and the current sensing circuit, the current sensing circuit is connected to an ultrasonic transducer, the multivibrator circuit is sequentially connected to a driving circuit, a filtering circuit and the ultrasonic transducer, the current sensing circuit is used to detect the motion state of the ultrasonic transducer, and feed back the induced current to the multivibrator circuit, by sensing the current of the ultrasonic transducer and inputting the current into the feedback network of the multivibrator circuit, thereby introducing current negative feedback control in the self-excited oscillation positive feedback circuit. The ultrasonic transducer is incorporated into the feedback loop to achieve phase locking, thereby stabilizing the output frequency of the self-excited oscillation circuit and reducing the circuit's sensitivity to system parameter deviations and temperature changes.

Description

Technical Field

[0001] The present application relates to the technical field of electric energy conversion, and in particular to a current negative feedback phase-locked oscillation circuit for an ultrasonic power supply, an ultrasonic power supply and an electronic device. Background Art

[0002] Ultrasonic power supply, also known as ultrasonic generator, is a key component of various ultrasonic equipment and is widely used in ultrasonic motors, ultrasonic cleaning, ultrasonic welding, ultrasonic machining and other fields. Its main function is to provide electrical energy to the ultrasonic transducer, so that it can convert most of the input electrical power into regular mechanical vibrations, namely ultrasonic waves. However, due to the complex piezoelectric characteristics of ultrasonic transducers, such as frequency characteristics, impedance characteristics, mechanical quality factor, temperature characteristics, etc., especially when the load and temperature change drastically, the transducer parameters will change, resulting in impedance changes and resonant frequency drift, thus affecting the working efficiency and stability of the system.

[0003] At present, in order to ensure the stable operation of the ultrasonic transducer in the prior art, a phase-locked loop circuit is usually required to lock the output voltage and current. However, the existing phase-locked loop circuit is relatively complex, resulting in a large circuit volume, which affects the miniaturization and portability of the ultrasonic power supply. Summary of the invention

[0004] The purpose of the present application is to provide a current negative feedback phase-locked oscillation circuit, power supply and electronic equipment for an ultrasonic power supply, aiming to solve at least one of the above problems.

[0005] In a first aspect, an embodiment of the present application provides a current negative feedback phase-locked oscillation circuit for an ultrasonic power supply, comprising: a multivibrator circuit and a current sensing circuit, wherein the multivibrator circuit is connected to a DC power supply and the current sensing circuit, the current sensing circuit is connected to an ultrasonic transducer, and the multivibrator circuit is sequentially connected to a drive circuit, a filter circuit, and the ultrasonic transducer, wherein:

[0006] The multivibrator circuit includes a feedback network, a window comparator, an RS trigger and a digital drive. The multivibrator circuit is connected to the drive circuit. The multivibrator circuit is used to convert the DC signal provided by the DC power supply into a high-frequency oscillation signal. The multivibrator circuit is also used to drive the filter circuit.

[0007] The feedback network includes a resistor and a capacitor, one end of the resistor is connected to one end of the capacitor, one end of the resistor is also connected to the output end of the current sensing circuit and the second node, the other end of the resistor and the output of the digital driver are connected to the first node, the other end of the capacitor is grounded, and the feedback network is used to generate a positive feedback signal;

[0008] The window comparator includes a resistor group, a first comparator and a second comparator, the resistor group is used to divide the power supply voltage to obtain a first threshold voltage and a second threshold voltage, the first threshold voltage is connected to the positive phase terminal of the first comparator, the second threshold voltage is connected to the negative phase terminal of the second comparator, the negative phase terminal of the first comparator is connected to the positive phase terminal of the second comparator and connected to one end of the capacitor, and is used to monitor the voltage change of the second node and generate a trigger signal when the voltage of the second node exceeds the threshold, the outputs of the first comparator and the second comparator are respectively connected to the set 0 terminal and the set 1 terminal of the RS trigger, and the output of the RS trigger is connected to the digital driver;

[0009] The digital driver is connected to one end of the resistor in the feedback network through a first node, and the digital driver is used to drive the feedback network;

[0010] The window comparator is also used to monitor the voltage change in the feedback network and generate a control signal to trigger the RS trigger to generate a positive feedback square wave signal;

[0011] The digital drive is used to convert the square wave signal into a control signal of the drive circuit;

[0012] The driving circuit and the filtering circuit are used to generate a driving signal to match the operating frequency of the ultrasonic transducer;

[0013] The current sensing circuit is used to detect the motion state of the ultrasonic transducer and feed back the induced current to the multivibrator circuit.

[0014] In an embodiment of the present application, the first threshold voltage is two-thirds of the power supply voltage, and the second threshold voltage is one-third of the power supply voltage.

[0015] In one embodiment of the present application, the filtering circuit includes an LC matching network, and the LC matching network is used to filter the output signal of the driving circuit to form a driving signal for the ultrasonic transducer by removing harmonic components in the output signal.

[0016] In one embodiment of the present application, the fundamental frequency of the multivibrator circuit is the same as the excitation frequency of the ultrasonic transducer.

[0017] In one embodiment of the present application, the current sensing circuit further includes a differential variable bridge circuit, which is used to detect current fluctuations in the ultrasonic transducer and input the current fluctuations into the multivibrator circuit as a feedback signal.

[0018] In one embodiment of the present application, the RS trigger includes two input terminals and one output terminal, which are respectively used to receive the output signal of the window comparator and the signal driving the digital drive. The RS trigger achieves phase synchronization by locking the feedback signal.

[0019] In one embodiment of the present application, the resistor in the feedback network is an adjustable resistor, the capacitor is an adjustable capacitor, and the feedback network achieves frequency matching and feedback adjustment according to the operating frequency of the ultrasonic transducer.

[0020] In an embodiment of the present application, the current sensing circuit is used to input a feedback current to the second node to achieve phase locking.

[0021] In a second aspect, an embodiment of the present application provides an ultrasonic power supply, such as the current negative feedback phase-locked oscillation circuit and the DC power supply, drive circuit, and filter circuit for an ultrasonic power supply as described in the first aspect.

[0022] In a third aspect, an embodiment of the present application provides an electronic device, comprising the ultrasonic power supply and the ultrasonic transducer as described in the second aspect.

[0023] The beneficial effect of the embodiment of the present application is that by sensing the current of the ultrasonic transducer and inputting the current into the feedback network of the multivibrator circuit, current negative feedback control is introduced into the self-excited oscillation positive feedback circuit. The ultrasonic transducer is included in the feedback loop to achieve phase locking, thereby stabilizing the output frequency of the self-excited oscillation circuit and reducing the circuit's sensitivity to system parameter deviations and temperature changes. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a current negative feedback phase-locked oscillation circuit module provided in an embodiment of the present application.

[0025] Figure 2 It is a schematic diagram of the ultrasonic power supply module provided in an embodiment of the present application.

[0026] Figure 3 It is a schematic diagram of an electronic device module provided in an embodiment of the present application.

[0027] Figure 4 It is a connection diagram of a current negative feedback phase-locked oscillation circuit provided in an embodiment of the present application.

[0028] Figure 5a and Figure 5b Schematic diagram of the waveform of the feedback network provided in the embodiment of the present application under different feedback current conditions.

[0029] Main component symbols

[0030] Ultrasonic power supply 10

[0031] Electronic devices 20

[0032] Current negative feedback phase-locked oscillation circuit 100

[0033] Multivibrator Circuit 110

[0034] Feedback Network 111

[0035] Window comparator 112

[0036] RS flip-flop 113

[0037] Digital Drive 114

[0038] Current sensing circuit 120

[0039] DC Power Supply 200

[0040] Driving circuit 300

[0041] Filter circuit 400

[0042] Ultrasonic transducer 500 DETAILED DESCRIPTION

[0043] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0044] Ultrasonic power supply, also known as ultrasonic generator, is a key component of various ultrasonic equipment and is widely used in ultrasonic motors, ultrasonic cleaning, ultrasonic welding, ultrasonic machining and other fields. Its main function is to provide electrical energy to the ultrasonic transducer, so that it can convert most of the input electrical power into regular mechanical vibrations, namely ultrasonic waves. However, due to the complex piezoelectric characteristics of ultrasonic transducers, such as frequency characteristics, impedance characteristics, mechanical quality factor, temperature characteristics, etc., especially when the load and temperature change drastically, the transducer parameters will change, resulting in impedance changes and resonant frequency drift, thus affecting the working efficiency and stability of the system.

[0045] At present, in order to ensure the stable operation of the ultrasonic transducer in the prior art, a phase-locked loop circuit is usually required to lock the output voltage and current. However, the existing phase-locked loop circuit is relatively complex, resulting in a large circuit volume, which affects the miniaturization and portability of the ultrasonic power supply.

[0046] Therefore, a current negative feedback phase-locked oscillation circuit, an ultrasonic power supply and an electronic device for an ultrasonic power supply are provided, which introduces current negative feedback control into a self-excited oscillation positive feedback circuit by sensing the current of an ultrasonic transducer and inputting the current into a feedback network of a multivibrator circuit. The ultrasonic transducer is incorporated into the feedback loop to achieve phase locking, thereby stabilizing the output frequency of the self-excited oscillation circuit and reducing the circuit's sensitivity to system parameter deviations and temperature changes.

[0047] Figure 1 Schematic diagram of the current negative feedback phase-locked oscillation circuit module provided in the embodiment of the present application. Figure 1 As shown, the current negative feedback phase-locked oscillation circuit 100 includes a multivibrator circuit 110 and a current sensing circuit 120. The multivibrator circuit 110 is connected to a DC power supply 200 and the current sensing circuit 120, the current sensing circuit 120 is connected to an ultrasonic transducer 500, and the multivibrator circuit 110 is sequentially connected to a driving circuit 300, a filtering circuit 400 and an ultrasonic transducer 500.

[0048] In the embodiment of the present application, the current negative feedback phase-locked oscillation circuit 100 includes a multivibrator circuit 110 and a current sensing circuit 120. The multivibrator circuit 110 receives a DC signal and converts it into a high-frequency oscillation signal by connecting to a DC power supply 200. This oscillation signal is processed by a driving circuit 300 and a filtering circuit 400, and finally drives an ultrasonic transducer 500 to generate an efficient ultrasonic output.

[0049] In the embodiment of the present application, the function of the current sensing circuit 120 is to monitor the working state of the ultrasonic transducer 500 in real time, especially to monitor the current fluctuations generated by the ultrasonic transducer 500. The current sensing circuit 120 can feed back the detected current signal to the multivibrator circuit 110, so that the multivibrator circuit 110 adjusts its output frequency, thereby achieving frequency locking. Specifically, when the load of the ultrasonic transducer 500 changes, the current sensing circuit 120 will capture these changes and feed back the sensed current to the multivibrator circuit 110 to ensure that the ultrasonic transducer 500 remains at a preferred operating frequency.

[0050] Through this current negative feedback mechanism, the system can automatically adapt to the frequency change of the ultrasonic transducer 500, avoiding large frequency deviations caused by load fluctuations, thereby achieving stable phase-locked control. The reliability of the system and the efficiency of the ultrasonic transducer 500 are improved, so that the ultrasonic transducer 500 can maintain the best working state under different load conditions.

[0051] Please also read Figure 4 , a schematic diagram of the connection of the current negative feedback phase-locked oscillation circuit provided in the embodiment of the present application. Figure 4As shown, the multivibrator circuit 110 includes a feedback network 111 , a window comparator 112 , an RS trigger 113 and a digital driver 114 .

[0052] In the embodiment of the present application, the multivibrator circuit 110 is connected to the driving circuit 300, and the multivibrator circuit 110 is used to convert the DC signal provided by the DC power supply 200 into a high-frequency oscillation signal. The multivibrator circuit 110 is also used to drive the filter circuit 400. Specifically, the oscillator in the multivibrator circuit 110 drives the ultrasonic transducer 500 by modulating the DC signal into a high-frequency AC signal, and the filter circuit 400 is used to eliminate excess high-frequency noise to ensure that the system maintains stable and efficient ultrasonic output during operation.

[0053] In the embodiment of the present application, the feedback network 111 includes a resistor R and a capacitor C, one end of the resistor R is connected to one end of the capacitor C, one end of the resistor R is also connected to the output end of the current sensing circuit 120 and the second node VCT, the other end of the resistor R and the output of the digital driver 114 are connected to the first node VRT, the other end of the capacitor C is grounded, and the feedback network 111 is used to generate a positive feedback signal. Specifically, when the current sensing circuit 120 detects a state change of the ultrasonic transducer 500, the feedback network 111 adjusts the change signal to a positive feedback signal, thereby affecting the oscillation frequency to ensure that the entire system remains in a phase-locked state. The selection of the resistor R and the capacitor C is to adjust the response speed and frequency characteristics of the feedback signal.

[0054] In an embodiment of the present application, the window comparator 112 includes a resistor group, a first comparator and a second comparator. The resistor group is used to divide the power supply voltage to obtain a first threshold voltage and a second threshold voltage. The first threshold voltage is connected to the positive phase terminal of the first comparator, and the second threshold voltage is connected to the negative phase terminal of the second comparator. The negative phase terminal of the first comparator is connected to the positive phase terminal of the second comparator and is connected to one end of the capacitor C, which is used to monitor the change of the voltage of the second node VCT and generate a trigger signal when the voltage of the second node VCT exceeds the threshold. The outputs of the first comparator and the second comparator are respectively connected to the set 0 terminal and the set 1 terminal of the RS trigger 113, and the output of the RS trigger 113 is connected to the digital drive 114. Specifically, when the voltage of the second node VCT exceeds the set threshold, the window comparator 112 will generate a corresponding trigger signal to control the state of the RS trigger 113 by comparing the first and second threshold voltages, thereby driving the digital drive 114 to change the working state of the system.

[0055] In the embodiment of the present application, the first threshold voltage is two-thirds of the power supply voltage VCC, and the second threshold voltage is one-third of the power supply voltage VCC. Specifically, since the three resistors in the resistor group in the window comparator 112 have equal resistance values, the first voltage threshold is two-thirds of the power supply voltage VCC, and the second voltage threshold is one-third of the power supply voltage VCC. It can be understood that the voltage division mechanism is implemented by the resistor group, which ensures that the window comparator 112 can divide the power supply voltage at a fixed ratio, so that the circuit can accurately detect different voltage critical points to determine the charge and discharge state of the capacitor C and ensure the phase-locking accuracy.

[0056] Specifically, the digital driver 114 receives the square wave signal from the RS trigger 113 , and feeds back the control signal to the feedback network 111 through the first node VRT to adjust the strength and frequency of the positive feedback signal, thereby achieving control over the multivibrator circuit 110 .

[0057] In the embodiment of the present application, the digital driver 114 is connected to one end of the resistor R in the feedback network 111 through the first node VRT. The digital driver 114 is used to drive the feedback network. Specifically, the digital driver 114 receives the square wave signal from the RS trigger 113, and feeds back the control signal to the feedback network 111 through the VRT node to adjust the strength and frequency of the positive feedback signal, thereby realizing the control of the multivibrator circuit 110.

[0058] In the embodiment of the present application, the window comparator 112 is also used to monitor the voltage change in the feedback network 111, and generate a control signal to trigger the RS trigger to generate a positive feedback square wave signal. Specifically, the window comparator 112 will continuously monitor the voltage fluctuation in the feedback network. When it is detected that the voltage of the feedback network reaches the set threshold, it will generate a trigger signal to switch the RS trigger 113 and generate a positive feedback square wave signal to ensure that the oscillation circuit is phase-locked within the required frequency range.

[0059] In the embodiment of the present application, the digital driver 114 is used to convert the square wave signal into a control signal of the driving circuit 300. Specifically, the digital driver 114 further modulates the positive feedback square wave signal output by the RS trigger 113 into a driving signal, and inputs it into the feedback network 111. At the same time, the positive feedback square wave signal is sent to the driving circuit 300, and the driving circuit 300 generates a corresponding power signal based on this signal to match the operating frequency of the ultrasonic transducer 500, so that the system maintains an efficient working state.

[0060] In the embodiment of the present application, the driving circuit 300 and the filtering circuit 400 are used to generate a driving signal to match the operating frequency of the ultrasonic transducer 500. Specifically, the driving circuit 300 outputs a signal consistent with the resonant frequency of the ultrasonic transducer 500 through power amplification and modulation based on the high-frequency oscillation signal generated by the multivibrator circuit 110. The filtering circuit 400 filters the driving signal through an LC matching network to remove unnecessary high-order harmonics and noise, ensuring that the output driving signal is pure and the frequency accurately matches the operating frequency of the ultrasonic transducer, thereby improving the transmission efficiency and working stability of the system.

[0061] In the embodiment of the present application, the current sensing circuit 120 is used to detect the motion state of the ultrasonic transducer and feed back the induced current to the multivibrator circuit 110. Specifically, the current sensing circuit 120 obtains the motion state information of the transducer, such as displacement, speed or load change, by real-time detecting the current change generated by the ultrasonic transducer 500 during operation. The induced current is input to the multivibrator circuit 110 as a feedback signal to adjust the oscillation frequency and phase, thereby realizing closed-loop control of the system, ensuring that the system maintains a phase-locked state under various working conditions, and avoiding frequency drift or efficiency reduction.

[0062] In the embodiment of the present application, the filter circuit 400 includes an LC matching network, which is used to filter the output signal of the driving circuit 300, and to form a driving signal for the ultrasonic transducer by removing the harmonic components in the output signal. Specifically, the LC matching network selectively filters out unnecessary high-frequency components through the resonance characteristics of the inductor and the capacitor, retains the baseband signal required by the ultrasonic transducer, and ensures that the output driving signal is pure and stable, thereby improving the efficiency and reliability of the system.

[0063] In the embodiment of the present application, the fundamental frequency of the multivibrator circuit 110 is the same as the excitation frequency of the ultrasonic transducer 500. Specifically, the design of the multivibrator circuit 110 takes into account the natural frequency of the ultrasonic transducer, and by adjusting the oscillation frequency to match the excitation frequency of the transducer, efficient energy transfer is achieved, ensuring that the transducer can generate ultrasonic waves at the optimal operating frequency.

[0064] In the embodiment of the present application, the current sensing circuit 120 also includes a differential variable bridge circuit, which is used to detect the current fluctuation in the ultrasonic transducer and input the current fluctuation as a feedback signal into the multivibrator circuit. Specifically, the differential variable bridge circuit can accurately detect the current change when the ultrasonic transducer is working, especially when the load fluctuates or the environmental conditions change, the current sensing circuit transmits the current fluctuation to the multivibrator circuit through the feedback signal, and adjusts the circuit working state in real time, thereby maintaining the stability of the system.

[0065] In the embodiment of the present application, the RS trigger 113 includes two input terminals and one output terminal, which are respectively used to receive the output signal of the window comparator and the signal driving the digital drive. The RS trigger 113 achieves phase synchronization by locking the feedback signal. Specifically, the RS trigger 113 ensures that the digital drive can switch states at the appropriate time by synchronously controlling the phase change of the feedback signal according to the input signal from the window comparator, thereby achieving stable phase locking of the multivibrator circuit and ensuring that the system always operates at the appropriate phase.

[0066] In the embodiment of the present application, the resistor R in the feedback network 111 is an adjustable resistor, the capacitor C is an adjustable capacitor, and the feedback network realizes frequency matching and feedback adjustment according to the operating frequency of the ultrasonic transducer. Specifically, by adjusting the values ​​of the resistor R and the capacitor C, the feedback network can dynamically adjust the amplitude and phase of the feedback signal to match the operating frequency of the ultrasonic transducer, thereby realizing automatic frequency tracking and ensuring that the system can still maintain phase-locked stability under different working conditions.

[0067] In the embodiment of the present application, the current sensing circuit is used to input feedback current to the second node to achieve phase lock. Specifically, the current sensing circuit detects the working state of the ultrasonic transducer and transmits the current information to the second node of the multi-vibrator circuit through a feedback signal. The feedback signal is used to adjust the oscillation frequency of the system to ensure that the oscillation circuit can adjust the frequency in time according to the actual working condition of the transducer, thereby maintaining the phase lock state and ensuring efficient and stable operation of the system.

[0068] Please also read Figure 4 , Figure 4 The ultrasonic transducer 500 shown in FIG. 5 is an equivalent circuit of a piezoelectric ultrasonic transducer. Specifically, Figure 4 The equivalent circuit of the piezoelectric ultrasonic transducer 500 shown in FIG. 5 is composed of four components, including an inductor L m , capacitor C m , resistor R m And the capacitor C P Among them, the inductor L m , capacitor C m , resistor R m And the capacitor C P connected in series to form a dynamic branch, capacitor C P A static branch is formed and connected in parallel with the dynamic branch. It is understandable that the piezoelectric ultrasonic transducer is only an example provided in the embodiment of the present application, and those skilled in the art may use, for example, a piezoelectric ceramic transducer, an electromagnetic ultrasonic transducer or a capacitive micromachined ultrasonic transducer (CMUT), which may be selected for use according to different application scenarios, and the present application does not limit this.

[0069] It is understandable that the inductor L mRepresents the inertial characteristics of the transducer's mechanical vibration. Because the piezoelectric transducer will produce mechanical vibration after being driven by an electrical signal, the inductor is used to simulate the inertial behavior of this vibration system. m Represents the elasticity in the mechanical system and simulates the energy storage capacity of the piezoelectric transducer. During the vibration process, the system stores mechanical energy, and the capacitor C m This is the equivalent capacitance of this energy storage characteristic. m Represents the energy loss of the system. It simulates the energy loss of the transducer during operation due to friction, heat loss, etc., which is mainly reflected in the attenuation of mechanical vibration. P Represents the static capacitance in the transducer and is used to simulate the electrical characteristics of the transducer when there is no mechanical movement. This is the capacitance value between the transducer electrodes and has nothing to do with the dynamic vibration characteristics.

[0070] It is understandable that the inductor L m , capacitor C m , resistor R m And the capacitor C P The series connection reflects the dynamic vibration characteristics of the piezoelectric ultrasonic transducer. The capacitor C in the static branch P The dynamic branch is connected in parallel with the dynamic branch to simulate the electrical behavior of the transducer when there is no mechanical vibration. The dynamic branch mainly affects the operating frequency and power transfer efficiency of the transducer, while the static branch affects the static capacitance of the system.

[0071] Through the combination of these equivalent elements, the present application can accurately simulate the response behavior of the piezoelectric ultrasonic transducer at different frequencies, and then optimize the power drive circuit according to the equivalent model of the circuit to ensure that the ultrasonic transducer 500 works in the best state.

[0072] Figure 5a and Figure 5b is a waveform diagram of the feedback network provided in the embodiment of the present application under different feedback current conditions. F The possible operating state of the feedback network 111 is shown below. Where A represents the feedback current i F Initial phase change.

[0073] The steady state of the circuit is analyzed below.

[0074] Understandably, Figure 5a and Figure 5b There are 5 different phase currents i F The working state of the circuit under the conditions, including i F,0 、i F,1 、i F,2 、i F,3 、i F,4 、i F,5. At current i F,0 In the case of R =i C , so i F =0, corresponding to the situation of a typical multivibrator circuit.

[0075]

[0076] Wherein, T is the oscillation period, and its expression is T=2RClog(2).

[0077] Performing Fourier analysis on (1), we can get the current i C The fundamental and harmonic distributions are as follows:

[0078]

[0079] It is understandable that I C The fundamental amplitude is dominant, the odd harmonics are significant, and the even harmonics are close to zero. CC =12V, R = 7.8kΩ, C = 2.2nF, we can get i C The fundamental amplitude is approximately 2.94, 4.89, 6.84, and 8.79 times that of the 3rd, 5th, 7th, and 9th harmonics. Therefore, the fundamental amplitude is mainly considered in the analysis. C situation, and i C The fundamental wave is denoted as i C,1 .

[0080] When the feedback current i is added to the second node VCT F When, due to i R ≠i C ,i C The charge and discharge current will become i C =i R+ i F , at this time, the frequency change of the circuit depends on the phase of the feedback current. The discussion is based on the different initial phases of the feedback current:

[0081] 1.i F,1 , at this time i F,1 The initial phase of the multivibrator is related to the fundamental frequency current i C，1 When θ=0, the charge and discharge current of capacitor C increases, shortening the time for the voltage to reach the threshold, thereby increasing the oscillation frequency. The waveform of the feedback current is in phase with the charge and discharge current of capacitor C, and the positive feedback effect is the strongest. F The charging and discharging current of the capacitor is increased, which means that the capacitor C reaches the first threshold voltage and the second threshold voltage more quickly in each cycle, so the frequency of the oscillator increases.

[0082] 2.iF,2 , at this time i F,2 The initial phase relative to i F,1 The initial phase of is delayed by 90°, that is, when θ = π / 2, the injected and extracted currents cancel each other out, so the oscillation frequency remains unchanged and reaches a steady state. F The injection and extraction currents are basically equal in each cycle, and their effects on the charging and discharging process of capacitor C cancel each other out. This situation is similar to having no obvious positive or negative feedback. The oscillator frequency remains basically unchanged, and the circuit is in a steady-state operation state.

[0083] 3.i F,3 , at this time i F,2 The initial phase relative to i F,1 The initial phase of the capacitor C is delayed by 180°, that is, when θ=π, the charge and discharge current of the capacitor C decreases, prolonging the time to reach the threshold, thereby reducing the oscillation frequency. At this time, the feedback current is in opposite phase to the capacitor charge and discharge current. F The charging and discharging current i of the capacitor C The negative feedback effect is obvious in the opposite direction. The feedback current offsets part of the charge and discharge current of the capacitor, causing the capacitor voltage to reach the first threshold and the second threshold voltage more slowly. The frequency of the oscillator is lower than the frequency without feedback current, the oscillation period of the circuit is extended, and the oscillation frequency is reduced.

[0084] 4.i F,4 , at this time i F,2 The initial phase relative to i F,1 The initial phase of is delayed by 270°, that is, when θ=3π / 2, similar to i F,2 , the circuit can also reach steady state. The phase of the feedback current is again orthogonal to the capacitor charging and discharging current, but is F,2 The situation is the opposite, the feedback current i F The injected and extracted currents in each cycle cancel each other out, so the circuit's oscillation frequency is not significantly affected. The circuit maintains steady-state operation, and the oscillation frequency is consistent with the typical multivibrator circuit frequency.

[0085] It can be seen that the feedback current i of different initial phases F It will affect the frequency change of the multivibrator circuit. When the initial phase is 0<θ<π / 2, the oscillation frequency increases; and when π / 2<θ<π, the oscillation frequency decreases. Similarly, when π<θ<3π / 2, the frequency continues to decrease, and when 3π / 2<θ<2π, the frequency increases.

[0086] In the embodiment of the present application, the steady-state solution of the circuit appears and At these two phase points, under the action of negative feedback, the system can achieve phase locking, thereby stabilizing the oscillation frequency. By injecting a suitable feedback current i F , which can make the circuit automatically adjust to a steady state and realize phase-locked control.

[0087] It can be understood that the oscillation frequency f of the current negative feedback phase-locked oscillation circuit 100 for ultrasonic power supply provided in the embodiment of the present application has only two steady-state solutions, namely and Therefore, when the phase or oscillation frequency of the ultrasonic transducer shifts, the current sensing circuit will detect it in time and inject the feedback signal into the multivibrator circuit, so that the circuit can quickly adjust back to the steady-state frequency. This design can effectively improve the anti-interference ability and stability of the circuit, ensure that the ultrasonic transducer can maintain a better operating frequency under different working conditions, and achieve efficient energy transfer.

[0088] Figure 2 Schematic diagram of the ultrasonic power module provided in the embodiment of the present application. Figure 2 As shown, the ultrasonic power supply 10 includes a current negative feedback phase-locked oscillation circuit 100, a DC power supply 200, a drive circuit 300, and a filter circuit 400. The ultrasonic power supply 10 is connected to an ultrasonic transducer 500.

[0089] In the embodiment of the present application, the current negative feedback phase-locked oscillation circuit 100 in the ultrasonic power supply 10 and the ultrasonic transducer 500 achieve frequency locking through the feedback circuit, so that the ultrasonic power supply 10 can adjust the output frequency in real time to ensure matching with the resonant frequency of the ultrasonic transducer, thereby improving the energy transfer efficiency. The DC power supply 200 provides a basic DC voltage for the circuit, and the drive circuit 300 modulates and filters the DC signal through the filter circuit 400 to generate a suitable high-frequency signal to drive the ultrasonic transducer 500 to generate the required ultrasonic wave.

[0090] Figure 3 Schematic diagram of an electronic device module provided in an embodiment of the present application. Figure 3 As shown, the electronic device 20 includes Figure 2 An ultrasonic power supply 10 and an ultrasonic transducer 500 are shown.

[0091] In the embodiment of the present application, the electronic device 20 realizes efficient driving and control of the ultrasonic transducer by optimizing the design of the power module, ensuring stable operation in a complex working environment. In addition, through the design of current negative feedback, the device can monitor the working state of the ultrasonic transducer in real time and make automatic adjustments, thereby improving the working efficiency and service life of the system.

[0092] The current negative feedback phase-locked oscillation circuit 100, ultrasonic power supply 10 and ultrasonic transducer 500 provided in the present application for ultrasonic power supply do not require external manual adjustment by introducing negative feedback. When the load or working conditions of the ultrasonic transducer change, the current sensing circuit will detect the corresponding current fluctuation and adjust the oscillation frequency through the feedback network so that the system automatically returns to the steady-state solution. This design simplifies the control structure of the circuit, while enhancing the adaptability and response speed of the circuit, effectively improving the working efficiency and reliability of the ultrasonic power supply, and is suitable for a variety of ultrasonic application scenarios.

[0093] Those skilled in the art can clearly understand that, for the convenience and simplicity of description, only the division of the above-mentioned functional modules and modules is used as an example for illustration. In practical applications, the above-mentioned function allocation can be completed by different functional modules and modules as needed, that is, the internal structure of the device can be divided into different functional modules or modules to complete all or part of the functions described above. The functional modules and modules in the embodiment can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into one module, and the above-mentioned integrated modules can be implemented in the form of hardware or in the form of software functional modules. In addition, the specific names of the functional modules and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0094] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0095] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A current negative feedback phase-locked oscillation circuit for ultrasonic power supply, characterized in that: include: A multivibrator circuit and a current sensing circuit, wherein the multivibrator circuit is connected to a DC power supply and the current sensing circuit, the current sensing circuit is connected to an ultrasonic transducer, and the multivibrator circuit is sequentially connected to a drive circuit, a filter circuit and the ultrasonic transducer, wherein: The multivibrator circuit includes a feedback network, a window comparator, an RS trigger and a digital drive. The multivibrator circuit is connected to the drive circuit. The multivibrator circuit is used to convert the DC power signal provided by the DC power supply into a high-frequency oscillation signal. The output end of the drive circuit is connected to the input end of the filter circuit, and is used to transmit the high-frequency oscillation signal after power amplification and modulation to the filter circuit. The feedback network includes a resistor and a capacitor, one end of the resistor is connected to one end of the capacitor, one end of the resistor is also connected to the output end of the current sensing circuit and the second node, the other end of the resistor and the output of the digital driver are connected to the first node, the other end of the capacitor is grounded, and the feedback network is used to generate a positive feedback signal; The window comparator includes a resistor group, a first comparator and a second comparator, the resistor group is used to divide the power supply voltage to obtain a first threshold voltage and a second threshold voltage, the first threshold voltage is connected to the positive phase terminal of the first comparator, the second threshold voltage is connected to the negative phase terminal of the second comparator, the negative phase terminal of the first comparator is connected to the positive phase terminal of the second comparator and connected to one end of the capacitor, and is used to monitor the voltage change of the second node and generate a trigger signal when the voltage of the second node exceeds the threshold, the outputs of the first comparator and the second comparator are respectively connected to the set 0 terminal and the set 1 terminal of the RS trigger, and the output of the RS trigger is connected to the digital driver; The digital driver is connected to the other end of the resistor in the feedback network through a first node, and the digital driver is used to drive the feedback network; The window comparator is also used to monitor the voltage change in the feedback network and generate a control signal to trigger the RS trigger to generate a positive feedback square wave signal; The digital drive is used to convert the square wave signal into a control signal of the drive circuit; The driving circuit and the filtering circuit are used to generate a driving signal to match the operating frequency of the ultrasonic transducer; The current sensing circuit is used to detect the motion state of the ultrasonic transducer and feed back the induced current to the second node in the multivibrator circuit.

2. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The first threshold voltage is two-thirds of the power supply voltage, and the second threshold voltage is one-third of the power supply voltage.

3. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The filtering circuit includes an LC matching network, and the LC matching network is used to filter the output signal of the driving circuit, and to form a driving signal for the ultrasonic transducer by removing harmonic components in the output signal.

4. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The fundamental frequency of the multivibrator circuit is the same as the excitation frequency of the ultrasonic transducer.

5. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The current sensing circuit also includes a differential variable bridge circuit, which is used to detect current fluctuations in the ultrasonic transducer and input the current fluctuations into the multivibrator circuit as a feedback signal.

6. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The RS trigger comprises two input terminals and one output terminal, which are respectively used to receive the output signal of the window comparator and the signal driving the digital drive. The RS trigger achieves phase synchronization by locking the feedback signal.

7. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The resistor in the feedback network is an adjustable resistor, the capacitor is an adjustable capacitor, and the feedback network realizes frequency matching and feedback adjustment according to the operating frequency of the ultrasonic transducer.

8. The current negative feedback phase-locked oscillation circuit for ultrasonic power supply according to claim 1, characterized in that: The current sensing circuit is used to input a feedback current to the second node to achieve phase locking.

9. An ultrasonic power supply, characterized in that: It comprises a current negative feedback phase-locked oscillation circuit for an ultrasonic power supply as described in any one of claims 1 to 8, a DC power supply, a drive circuit, and a filter circuit, wherein the ultrasonic power supply is connected to an ultrasonic transducer.

10. An electronic device, characterized in that: It comprises the ultrasonic power supply and ultrasonic transducer as claimed in claim 9.

Images