Sampling conditioning circuit and ultrasonic generator

Abstract

The invention relates to a sampling conditioning circuit and an ultrasonic generator, and the sampling conditioning circuit comprises a sampling circuit and a conditioning circuit. The sampling circuit comprises a divider resistor module, a mutual inductor module and a sampling resistor, the first end of the divider resistor module is used for being connected with the positive electrode of the output end of the ultrasonic generator, and the second end of the divider resistor module is connected with the first end of an input winding of the mutual inductor module; the second end of the input winding of the mutual inductor module is connected with the output end cathode of the ultrasonic generator; the sampling resistor is connected in series between two ends of an output winding of the mutual inductor module, a first end of the sampling resistor is connected with an input end of the conditioning circuit, a second end of the sampling resistor is connected with analog ground, and an output end of the conditioning circuit is used for being connected with a controller. Impact of a high-voltage signal on a controller in the ultrasonic generator can be avoided, and the reliability of the ultrasonic generator is enhanced.

Description

Technical Field

[0001] The present invention relates to the technical field of ultrasonic generators, and particularly relates to a sampling conditioning circuit applicable to an ultrasonic generator, and also relates to an ultrasonic generator. Background Art

[0002] An ultrasonic welding device includes an ultrasonic generator and a welding assembly. The welding assembly consists of a transducer, a horn, and a tool head connected in sequence, commonly known as a triple group. The ultrasonic generator is used to generate a high-frequency alternating current signal and input it to the transducer. The transducer converts the high-frequency alternating current signal into a mechanical vibration signal. The horn amplifies the amplitude of the mechanical vibration signal, and the tool head transfers the vibration energy to the workpiece to be welded to achieve the welding of the workpiece to be welded.

[0003] With the development of digital ultrasonic welding technology, the output power of today's high-power ultrasonic generators can reach 15 kW, and the corresponding working voltage is as high as 1500V - 4000V. The high-voltage output signal is one of the most important signals in the ultrasonic generator, which has a crucial impact on the stability, safety, and reliability of the welding process. And the ultrasonic generator is extremely prone to generating high-voltage impulses during the start-up stage, the end stage, frequency detuning, and abnormal load of welding.

[0004] The current solution is mainly to connect a sampling conditioning circuit at the output end of the ultrasonic generator. This sampling conditioning circuit is used to collect the output voltage of the ultrasonic generator, and after conditioning, it is output to the controller MCU. The controller controls the main power circuit of the ultrasonic generator to adjust the output of the ultrasonic generator. Among them, most of the schemes for collecting the output voltage directly adopt the pure resistance sampling method. However, after resistance sampling, it is also extremely easy to generate a relatively high impact voltage, exceeding the working voltage of some components (such as operational amplifiers) in the sampling conditioning circuit and the controller, resulting in damage to these components and the controller. At the same time, it will also generate signal interference to other peripheral circuits, seriously affecting the long-term stable operation of the welding equipment. Summary of the Invention

[0005] The present invention aims to provide a sampling conditioning circuit that can avoid the impact of high-voltage signals on the controller and enhance the reliability of the ultrasonic generator. At the same time, a corresponding ultrasonic generator with this sampling conditioning circuit is provided.

[0006] To achieve the above objectives, the present invention adopts the following technical solutions:

[0007] A sampling conditioning circuit includes a sampling circuit and a conditioning circuit. The sampling circuit is used to collect the output signal of the ultrasonic generator, and the conditioning circuit is used to condition the signal collected by the sampling circuit and then input it into the controller for the controller to adjust the output of the ultrasonic generator.

[0008] The sampling circuit includes a voltage-dividing resistor module, a mutual inductor module, and a sampling resistor. The first end of the voltage-dividing resistor module is used to connect to the positive output terminal of the ultrasonic generator. The second end of the voltage-dividing resistor module is connected to the first end of the input winding of the mutual inductor module. The second end of the input winding of the mutual inductor module is used to connect to the negative output terminal of the ultrasonic generator; The sampling resistor is connected in series between the two ends of the output winding of the mutual inductor module, and the first end of the sampling resistor is connected to the input end of the conditioning circuit, and the second end of the sampling resistor is connected to the analog ground. The output end of the conditioning circuit is used to connect to the controller.

[0009] In the present invention, the voltage-dividing resistor module can effectively decompose the high-voltage signal into an appropriate low-voltage signal, and the cooperation of the voltage-dividing resistor module and the mutual inductor module can realize the isolated transmission of the voltage signal, thereby effectively blocking the impact of the high-voltage signal on the MCU and enhancing the reliability of the ultrasonic generator.

[0010] In addition, using the voltage-dividing resistor module to share the power can also facilitate heat dissipation and reduce the pressure on the breakdown voltage strength of a single resistor.

[0011] Further, the mutual inductor module includes a first mutual inductor, a second mutual inductor, and a coupling coil. The input winding of the mutual inductor module is located on the first mutual inductor, and the output winding of the mutual inductor module is located on the second mutual inductor. The coupling coil simultaneously passes through the magnetic core window of the first mutual inductor and the magnetic core window of the second mutual inductor to be connected between the first mutual inductor and the second mutual inductor as a bridging winding.

[0012] Further, the coupling coil is specifically a wire, and the wire is connected end to end after passing through the magnetic core window of the first mutual inductor and the magnetic core window of the second mutual inductor in sequence.

[0013] Further, both the first mutual inductor and the second mutual inductor are high-frequency current transformers.

[0014] Further, the conditioning circuit includes a voltage follower, a voltage conversion circuit, a summing operational amplifier circuit, and a low-pass filter circuit connected in sequence; The first end of the sampling resistor is connected to the input end of the voltage follower circuit, and the low-pass filter circuit is used to connect to the controller.

[0015] Further, the voltage follower includes a first operational amplifier. The first end of the sampling resistor is connected to the non-inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier.

[0016] Further, the voltage conversion circuit includes a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first diode, and a second diode;

[0017] The first end of the first resistor is connected to the output end of the voltage follower, and the second end of the first resistor is connected to the inverting input end of the second operational amplifier;

[0018] The cathode of the first diode is connected to the second end of the first resistor, and the anode of the first diode is connected to the output end of the second operational amplifier;

[0019] The cathode of the second diode is connected to the output end of the second operational amplifier, the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the anode of the second diode;

[0020] The first end of the third resistor is connected to the anode of the second diode, and the second end of the third resistor is connected to the input end of the summing operational amplifier circuit;

[0021] The first end of the fourth resistor is connected to the output end of the voltage follower, and the second end of the fourth resistor is connected to the second end of the third resistor;

[0022] The first end of the fifth resistor is connected to the non-inverting input end of the second operational amplifier, and the second end of the fifth resistor is connected to the analog ground.

[0023] Further, the summing operational amplifier circuit includes: a third operational amplifier, a sixth resistor, a seventh resistor, and a first capacitor; the inverting input end of the third operational amplifier is connected to the output end of the voltage conversion circuit, both ends of the sixth resistor are respectively connected to the inverting input end of the third operational amplifier and the output end of the third operational amplifier, and the first capacitor is connected in parallel across both ends of the sixth resistor; the first end of the seventh resistor is connected to the non-inverting input end of the third operational amplifier, and the second end of the seventh resistor is connected to the analog ground.

[0024] Further, the conditioning circuit further includes a voltage clamping circuit; the low-pass filter circuit includes an eighth resistor and a second capacitor, the first end of the eighth resistor is connected to the output end of the summing operational amplifier circuit, the second end of the eighth resistor is connected to the first end of the second capacitor, and the second end of the second capacitor is connected to the analog ground;

[0025] The input end of the voltage clamping circuit is connected to the second end of the eighth resistor, and the output end of the voltage clamping circuit is used to be connected to the controller.

[0026] A corresponding ultrasonic generator provided by the present invention includes the sampling conditioning circuit described in any of the above solutions. Description of the Drawings

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can also be obtained based on these drawings.

[0028] Figure 1 A circuit structure block diagram of an ultrasonic generator provided for the embodiment (wherein its connection relationship with the triple group is also shown).

[0029] Figure 2 A structure block diagram of a sampling conditioning circuit provided for the embodiment.

[0030] Figure 3 A schematic structural diagram of a sampling circuit in the sampling conditioning circuit.

[0031] Figure 4 A schematic circuit diagram of an inductor module in the sampling circuit.

[0032] Figure 5 A physical reference diagram of an inductor module in the sampling circuit.

[0033] Figure 6 A schematic structural diagram of a conditioning circuit in the sampling conditioning circuit. Detailed implementation manners

[0034] To make the invention objectives, features, and advantages of the present invention more obvious and understandable, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the embodiments described below are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0035] Unless otherwise clearly specified and limited, the terms "connection", "fixation", and "setting" shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific situations.

[0036] In addition, the terms "first", "second", and "third" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", and "third" may explicitly or implicitly include one or more such features, unless otherwise specifically defined.

[0037] Please refer to Figure 1 , the overall circuit of the ultrasonic generator generally includes a main power circuit 100 and a control circuit 200. Among them, the main power circuit 100 is used to output a high-frequency alternating current signal to the triple group 300 (i.e., the transducer, the horn, and the tool head), and the control circuit 200 is used to regulate the main power circuit 100.

[0038] Among them, the control circuit 200 includes a sampling and conditioning circuit 210. The present invention mainly provides a new technical solution for this sampling and conditioning circuit 210. The following introduces its embodiments. It can be understood that the circuit structures in the main power circuit 100 or the control circuit 200 should not be construed as limiting the protection scope of the present invention.

[0039] Please refer to Figure 2 , a sampling and conditioning circuit provided in this embodiment includes a sampling circuit 211 and a conditioning circuit 212. The sampling circuit 211 is used to collect the output signal of the ultrasonic generator, and the conditioning circuit 212 is used to condition the signal collected by the sampling circuit 211 and then input it into the controller MCU for the controller MCU to adjust the output of the ultrasonic generator.

[0040] Please refer to Figure 2 and Figure 3 , the sampling circuit 211 includes a voltage-dividing resistor module, a mutual inductor module, and a sampling resistor R17. Among them, the voltage-dividing resistor module in this embodiment includes 16 mutually connected in series voltage-dividing resistors R1 to R16, and the resistance value of each is 47 KΩ; the resistance value of the resistor R17 is 4.7 KΩ. In other embodiments, the number of voltage-dividing resistors in the voltage-dividing resistor module and the resistance value of each resistor can be set as required.

[0041] The first end of the voltage-dividing resistor module is used to connect to the positive pole HF+ of the output end of the ultrasonic generator, the second end of the voltage-dividing resistor module is connected to the first end of the input winding of the mutual inductor module, and the second end of the input winding of the mutual inductor module is connected to the negative pole HF- (i.e., grounded) of the output end of the ultrasonic generator; the sampling resistor R17 is connected in series between the two ends of the output winding of the mutual inductor module, and the first end of the sampling resistor R17 is connected to the input end LOAD_VS of the conditioning circuit, the second end of the sampling resistor R17 is connected to the analog ground, and the output end of the conditioning circuit is used to connect to the controller MCU.

[0042] In this embodiment, the voltage-dividing resistor module can effectively decompose the high-voltage signal into appropriate low-voltage signals. The cooperation between the voltage-dividing resistor module and the transformer module can achieve the isolated transmission of voltage signals, thereby effectively blocking the impact of high-voltage signals on the controller MCU and enhancing the reliability of the ultrasonic generator.

[0043] In addition, using the voltage-dividing resistor module to share the power can also facilitate heat dissipation and reduce the pressure on the breakdown voltage strength of a single resistor.

[0044] Please continue to refer to Figure 3 , as a preferred solution, the transformer module includes a first transformer T1, a second transformer T2, and a coupling coil S1. The input winding of the transformer module is located on the first transformer T1, and the output winding of the transformer module is located on the second transformer T2. The coupling coil S1 passes through the core window of the first transformer T1 and the core window of the second transformer T2 at the same time to be used as a bridging winding to connect the first transformer T1 and the second transformer T2.

[0045] As Figure 3 shown, the second end of the voltage-dividing resistor module is connected to the first end of the input winding of the transformer module, that is, the pin 1 of the first transformer T1. The second end of the input winding of the transformer module is connected to the analog ground, that is, the pin 2 of the first transformer T1 is connected to the negative pole HF- of the output end of the ultrasonic generator (which is also grounded); the sampling resistor R17 is connected in series at both ends of the output winding of the transformer module, that is, between the pin 1 and the pin 2 of the second transformer T2. The pin 2 of the second transformer T2 is connected to the analog ground GNDA, that is, the second end of the sampling resistor R17 is connected to the analog ground.

[0046] Please refer to Figure 4 , the coupling coil S1 provides a bridging function for the input winding of the first transformer T2 and the output winding of the second transformer T2. Based on the principle of electromagnetic induction, the voltage signal of the input winding is converted into the voltage signal of the output winding through the coupling coil S1.

[0047] Please refer to Figure 5 together. In this embodiment, the coupling coil S1 can specifically be a wire, and the wire passes through the core window of the first transformer T1 and the core window of the second transformer T2 in sequence and then is connected end to end. In practice, in order to achieve better effects, the first transformer T1 and the first transformer T2 should be as close as possible.

[0048] In practice, the first transformer T1 and the second transformer T2 can also be directly implemented using high-frequency current transformers, that is, two high-frequency current transformers are placed close to each other and then connected with a wire. The selected high-frequency current transformers should preferably use materials with low magnetic loss, high saturation magnetic flux, small coercive force, good stability and anti-interference ability, and have good electrical insulation ability.

[0049] Please continue to refer to Figure 2 , further, the conditioning circuit 212 includes a voltage follower, a voltage conversion circuit, a summing operational amplifier circuit, and a low-pass filter circuit connected in sequence; the first end of the sampling resistor R17 is connected to the input end LOAD_VS of the voltage follower circuit, and the low-pass filter circuit is used to connect to the controller MCU (the input end LOAD_VAD of the controller MCU). The voltage conversion circuit and the summing operational amplifier circuit convert the AC voltage signal into a DC voltage signal, and the low-pass filter circuit can make the DC voltage signal smoother, thereby realizing the protection of the controller MCU.

[0050] The circuit structure of the conditioning circuit 212 can achieve the function of full-wave precision rectification.

[0051] Please refer to Figure 6 , the voltage follower includes a first operational amplifier U1A, the first end of the sampling resistor R17 is connected to the non-inverting input end of the first operational amplifier U1A, and the output end of the first operational amplifier U1A is connected to the inverting input end of the first operational amplifier U1A, thereby realizing the stability of the voltage signal input to the voltage conversion circuit.

[0052] As a preferred solution, the voltage conversion circuit includes a second operational amplifier U1B, a first resistor R18, a second resistor R19, a third resistor 20, a fourth resistor R21, a fifth resistor R22, a first diode D1A, and a second diode D1B.

[0053] The first end of the first resistor R18 is connected to the output end of the voltage follower, and the second end of the first resistor R18 is connected to the inverting input end of the second operational amplifier U1B.

[0054] The cathode of the first diode D1A is connected to the second end of the first resistor R18, and the anode of the first diode D1A is connected to the output end of the second operational amplifier U1B.

[0055] The cathode of the second diode D1B is connected to the output end of the second operational amplifier U1B, the first end of the second resistor R19 is connected to the second end of the first resistor R18, and the second end of the second resistor R19 is connected to the anode of the second diode D1B.

[0056] The first end of the third resistor R20 is connected to the anode of the second diode D1B, and the second end of the third resistor R20 is connected to the input end of the summing operational amplifier circuit.

[0057] The first end of the fourth resistor R21 is connected to the output end of the voltage follower, and the second end of the fourth resistor R21 is connected to the second end of the third resistor R20.

[0058] The first end of the fifth resistor R21 is connected to the non-inverting input terminal of the second operational amplifier U1B, and the second end of the fifth resistor R21 is connected to the analog ground GNDA.

[0059] As a preferred solution, the summing operational amplifier circuit includes: a third operational amplifier U1C, a sixth resistor R23, a seventh resistor R24, and a first capacitor C1; the inverting input terminal of the third operational amplifier U1C is connected to the output terminal of the voltage conversion circuit, both ends of the sixth resistor R23 are respectively connected to the inverting input terminal and the output terminal of the third operational amplifier U1C, and the first capacitor C1 is connected in parallel across both ends of the sixth resistor R23; the first end of the seventh resistor R24 is connected to the non-inverting input terminal of the third operational amplifier U1C, and the second end of the seventh resistor R24 is connected to the analog ground GNDA.

[0060] The above voltage conversion circuit and summing operational amplifier circuit can achieve full-wave precision rectification, thereby meeting the precision control requirements of ultrasonic generators and ultrasonic welding.

[0061] To further protect the MCU, the conditioning circuit further includes a voltage clamping circuit D2; the low-pass filter circuit includes an eighth resistor R25 and a second capacitor C2, the first end of the eighth resistor R25 is connected to the output terminal of the summing operational amplifier circuit, the second end of the eighth resistor R25 is connected to the first end of the second capacitor C2, and the second end of the second capacitor C2 is connected to the analog ground GNDA.

[0062] The input terminal of the voltage clamping circuit D2 is connected to the second end of the eighth resistor R25, and the output terminal of the voltage clamping circuit D2 is used to connect to the controller MCU.

[0063] For example, the resistance value of the eighth resistor R25 is 1 kΩ, the capacitance of the second capacitor C2 is 0.1 uF, and the cut-off frequency is 1600 Hz. By using this voltage clamping circuit D2, the voltage input into the ADC module of the controller MCU can be clamped between 0 - 3V, so as to prevent the input voltage from being too large and burning out the controller MCU.

[0064] In addition, a corresponding ultrasonic generator provided in this embodiment has the sampling conditioning circuit described in any of the above solutions, and its circuit structure will not be elaborated here.

[0065] As mentioned above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A sampling and conditioning circuit, comprising a sampling circuit and a conditioning circuit. The sampling circuit is used to collect the output signal of an ultrasonic generator, and the conditioning circuit is used to condition the signal collected by the sampling circuit and then input it into a controller for the controller to adjust the output signal of the ultrasonic generator; characterized in that: The sampling circuit includes a voltage-dividing resistor module, a mutual inductor module, and a sampling resistor. The first end of the voltage-dividing resistor module is used to connect to the positive pole of the output end of the ultrasonic generator, the second end of the voltage-dividing resistor module is connected to the first end of the input winding of the mutual inductor module, and the second end of the input winding of the mutual inductor module is used to connect to the negative pole of the output end of the ultrasonic generator; the sampling resistor is connected in series between the two ends of the output winding of the mutual inductor module, and the first end of the sampling resistor is connected to the input end of the conditioning circuit, the second end of the sampling resistor is connected to the analog ground, and the output end of the conditioning circuit is used to connect to the controller.

2. The sampling conditioning circuit according to claim 1, wherein The mutual inductor module includes a first mutual inductor, a second mutual inductor, and a coupling coil. The input winding of the mutual inductor module is located on the first mutual inductor, the output winding of the mutual inductor module is located on the second mutual inductor, and the coupling coil passes through the magnetic core window of the first mutual inductor and the magnetic core window of the second mutual inductor at the same time to be used as a bridging winding to connect the first mutual inductor and the second mutual inductor.

3. The sampling conditioning circuit according to claim 2, wherein, The coupling coil is specifically a wire, and the wire passes through the magnetic core window of the first mutual inductor and the magnetic core window of the second mutual inductor in sequence and then is connected end to end.

4. The sampling conditioning circuit according to claim 3, wherein Both the first mutual inductor and the second mutual inductor are high-frequency current mutual inductors.

5. The sampling conditioning circuit according to any one of claims 1-4, characterized in that The conditioning circuit includes a voltage follower, a voltage conversion circuit, a summing operational amplifier circuit, and a low-pass filter circuit connected in sequence; the first end of the sampling resistor is connected to the input end of the voltage follower circuit, and the low-pass filter circuit is used to connect to the controller.

6. The sampling conditioning circuit according to claim 5, wherein The voltage follower includes a first operational amplifier. The first end of the sampling resistor is connected to the non-inverting input terminal of the first operational amplifier, and the output terminal of the first operational amplifier is connected to the inverting input terminal of the first operational amplifier.

7. The sampling conditioning circuit according to claim 5, wherein The voltage conversion circuit includes a second operational amplifier, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first diode, and a second diode; The first end of the first resistor is connected to the output end of the voltage follower, and the second end of the first resistor is connected to the inverting input terminal of the second operational amplifier; The cathode of the first diode is connected to the second end of the first resistor, and the anode of the first diode is connected to the output terminal of the second operational amplifier; The cathode of the second diode is connected to the output terminal of the second operational amplifier, the first end of the second resistor is connected to the second end of the first resistor, and the second end of the second resistor is connected to the anode of the second diode; The first end of the third resistor is connected to the anode of the second diode, and the second end of the third resistor is connected to the input end of the summing operational amplifier circuit; The first end of the fourth resistor is connected to the output end of the voltage follower, and the second end of the fourth resistor is connected to the second end of the third resistor; The first end of the fifth resistor is connected to the non-inverting input end of the second operational amplifier, and the second end of the fifth resistor is connected to analog ground.

8. The sampling conditioning circuit according to claim 5, characterized in that, The summing operational amplifier circuit includes: a third operational amplifier, a sixth resistor, a seventh resistor, and a first capacitor; the inverting input end of the third operational amplifier is connected to the output end of the voltage conversion circuit, both ends of the sixth resistor are respectively connected to the inverting input end of the third operational amplifier and the output end of the third operational amplifier, and the first capacitor is connected in parallel across both ends of the sixth resistor; the first end of the seventh resistor is connected to the non-inverting input end of the third operational amplifier, and the second end of the seventh resistor is connected to analog ground.

9. The sampling conditioning circuit according to claim 4, wherein The conditioning circuit further includes a voltage clamping circuit; the low-pass filter circuit includes an eighth resistor and a second capacitor, the first end of the eighth resistor is connected to the output end of the summing operational amplifier circuit, the second end of the eighth resistor is connected to the first end of the second capacitor, and the second end of the second capacitor is connected to analog ground; The input end of the voltage clamping circuit is connected to the second end of the eighth resistor, and the output end of the voltage clamping circuit is used to be connected to the controller.

10. An ultrasonic generator, characterized in that, Comprising the sampling conditioning circuit according to any one of claims 1-9.

Images