Constant-voltage digital adjustable load circuit for ultrasonic power supply

Abstract

The utility model provides a constant voltage digital adjustable load circuit used for an ultrasonic power supply, comprising a control signal processing circuit, a subtraction circuit and a voltage control circuit which are connected in sequence, the voltage control circuit is also connected with a rectification circuit and an over-current protection circuit, and the input end of the rectification circuit is connected with a transformer; and the voltage control circuit is used for receiving an output signal of the subtraction circuit and the direct-current voltage output by the rectifying circuit, controlling the primary voltage of the ultrasonic circuit to be 0-100V linear adjustable constant voltage, and outputting the direct-current voltage to the ultrasonic circuit. According to the utility model, a multi-path output transformer is simplified into a single-path output transformer, and a multi-path relay required by voltage switching is removed, so that the volume of the ultrasonic power supply is reduced, the working stability is improved, the production cost is reduced, the linearly adjustable function of the output voltage is realized, the power supply function becomes stronger and more stable, and the power supply is more convenient to use. And the practicability of the power supply is greatly improved.

Description

Technical Field

[0001] This utility model relates to the field of ultrasonic power supply technology, and in particular to a constant voltage digitally adjustable load circuit for ultrasonic power supplies. Background Technology

[0002] Ultrasonic technology is widely used in many fields such as cleaning, welding, medical treatment, industrial processing, and industrial automation. As a key device that drives ultrasonic transducers, the performance of ultrasonic power supplies directly affects the working efficiency and stability of ultrasonic systems.

[0003] Existing ultrasonic power supplies require multiple transformers and relays to achieve various voltage switching outputs. However, this method results in a large and costly load circuit with low output stability. Utility Model Content

[0004] To address the problems existing in the prior art, this utility model proposes a constant voltage digitally adjustable load circuit for ultrasonic power supplies and its working method, aiming to solve the problems of low output voltage stability, large size, high assembly difficulty and high cost of traditional ultrasonic power supply load circuits.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0006] A constant voltage digitally adjustable load circuit for an ultrasonic power supply includes a control signal processing circuit, a subtraction circuit, a voltage control circuit, and an ultrasonic circuit connected in sequence. The voltage control circuit is also connected to a rectifier circuit, and the input terminal of the rectifier circuit is connected to a transformer, which is connected to the ultrasonic power supply.

[0007] A rectifier circuit is used to convert AC voltage into DC voltage and output DC voltage to the voltage control circuit;

[0008] A control signal processing circuit is used to convert the input control signal into a DC 0~5V analog signal. The control signal processing circuit selects the analog control signal input or the PWM digital signal input via a jumper. The PWM digital signal can be selected to be active high or active low.

[0009] The subtraction circuit is used to invert the DC 0~5V analog signal converted by the control signal processing circuit into a DC 5~0V analog signal;

[0010] The voltage control circuit compares and amplifies the DC 5~0V analog signal converted by the subtraction circuit and the DC voltage output by the rectifier circuit. Based on the comparison result, it controls the switching on and off of MOSFETs V1, V2, V3 and V4 in the voltage control circuit, thereby controlling the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0~100V and outputting a DC voltage to the ultrasonic circuit.

[0011] An ultrasonic circuit is used to convert the electrical energy received from the voltage control circuit into ultrasonic energy for output.

[0012] Furthermore, the control signal processing circuit includes diodes D11 and D13, transistors Q1, Q2, Q3, and Q5, capacitors C1, C2, C3, C4, C5, C7, and C42, resistors R2, R3, R4, R5, R6, R19, R20, R21, R23, and R24, connectors J4, J5, J6, and J7, and potentiometer RV2. One end of connectors J6 and J7 is connected to the signal input terminal, and the other end of each connector is connected to the base of transistor Q5. The other end of connector J7 is connected to the collector of transistor Q5 through diode D13. Transistor Q3... The base of transistor Q1 is connected to the collector of transistor Q5. The emitters of transistor Q3 and Q5 are grounded together. The collector of transistor Q3 is connected to one end of connector J5. A potentiometer RV2 is also provided between the collector and emitter of transistor Q3. The second pin of potentiometer RV2 is connected to one end of connector J4. The other ends of connector J4 and connector J5 are connected to the base of transistor Q1 through resistors R4, R21 and R23 in sequence. The emitter of transistor Q1 is connected to the base of transistor Q2. The base and collector of transistor Q2 are also connected to a 12V positive voltage through resistors R5 and R6 respectively. The emitter of transistor Q2 serves as the output terminal, outputting a 0~5V analog signal to the subtraction circuit.

[0013] Based on the above, the PWM input signal is selected as either high-level or low-level active via connectors J6 and J7. When connector J6 is shorted to select high-level active, transistor Q5 is used to invert the PWM digital signal, and transistor Q3 is used to convert the 12V PWM digital signal to a 5V PWM digital signal. Diode D11 ensures that when connector J7 is shorted to select low-level active, the low level of the PWM digital signal pulls down the voltage at point NER2, while the high level of the PWM digital signal does not bypass the current-limiting resistor R9 to directly drive transistor Q5. Potentiometer RV2 is used to adjust the amplitude range of the input analog signal. The power supply can be selected as either PWM digital signal control or 0~5V analog signal control via connectors J4 and J5. When connector J5 is shorted, it is controlled by the PWM digital signal; when connector J4 is shorted, it is controlled by the 0~5V analog signal.

[0014] Furthermore, the voltage control circuit includes an operational amplifier U1A, resistors R7, R8, R10, R36, R71, R79, and R83, Zener diodes Z1 and Z2, diode D14, capacitors C6, C45, and C49, and parallel first, second, third, and fourth MOSFET voltage regulation circuits. One end of resistor R7 is connected to the signal input terminal, and the other end is connected to one end of resistor R8. The other end of resistor R8 is connected to the inverting input terminal of operational amplifier U1A. The output terminal of operational amplifier U1A is connected to the first MOSFET voltage regulation circuit. A capacitor C45 and a resistor R10 are connected in series between the output terminal and the inverting input terminal of operational amplifier U1A. The negative terminal of Zener diode Z2 and resistor R7 are also connected in series. One end of resistor R9 and one end of capacitor C49 are both connected to the non-inverting input of operational amplifier U1A. The positive terminal of Zener diode Z2, the other end of resistor R79, and the other end of capacitor C49 are all connected to the positive terminal of Zener diode Z1. The negative terminal of Zener diode Z1 is connected to the common connection point of resistors R7 and R8. One end of resistor R71 is connected to the drain of MOSFET V1 and connected to the ultrasonic circuit, and the other end is connected to the non-inverting input of operational amplifier U1A. One end of resistor R83 is connected to a 5V positive voltage, and the other end is connected to the anode of diode D14. The cathode of diode D14 is connected to the non-inverting input of operational amplifier U1A. One end of resistor R36 and one end of capacitor C6 are both connected to one end of resistor R71, and the other ends of resistor R36 and capacitor C6 are grounded together.

[0015] Based on the above, the signal output from the subtraction circuit is input to the operational amplifier U1A via resistors R7 and R8. The operational amplifier U1A converts the input analog signal into a drive signal, adjusting the conduction of subsequent MOSFETs V1, V2, V3, and V4 to achieve linearly adjustable output voltage. Resistor R10 is used to feed back the information from the output of operational amplifier U1A to its inverting input, forming a feedback loop. Capacitor C45 filters out high-frequency noise, improving control accuracy. Zener diode Z1 clamps the reference voltage, limiting its amplitude to prevent overvoltage due to reference voltage runaway. Zener diode Z2 and resistor R79 form a clamping circuit to limit the input signal amplitude and prevent operational amplifier overload.

[0016] Furthermore, the first MOSFET voltage regulation circuit includes a MOSFET V1, a transistor Q10, resistors R11, R15, R35, and RS4. The output terminal of the operational amplifier U1A is connected to the gate of the MOSFET V1 through the resistor R11. The gate of the MOSFET V1 is also connected to the collector of the transistor Q10 and one end of the resistor R15. The emitter of the transistor Q10 and the other end of the resistor R15 are grounded together. The two ends of the resistor R35 are respectively connected to the source of the MOSFET V1 and the base of the transistor Q10. The source of the MOSFET V1 is also grounded through the resistor RS4.

[0017] Based on the above, the transistor Q10, resistors R15, R35, and RS4 constitute an overcurrent protection circuit. When the current of the MOSFET V1 is too high, the voltage across resistor R35 increases, causing transistor Q10 to conduct, pulling down the gate voltage of MOSFET V1, reducing its conduction level, and ultimately making the currents of the parallel MOSFETs more consistent, thus achieving adaptive current sharing. Furthermore, when the total current is too high, the voltage drop across resistor R35 exceeds the turn-on voltage of MOSFET V1, causing transistor Q10 to conduct on a large scale, forcibly pulling down the op-amp output, limiting the conduction of MOSFET V1, and achieving overcurrent protection.

[0018] Furthermore, the subtraction circuit includes an operational amplifier U1A, transistors Q7, Q9, and Q11, resistors R72, R73, R74, R75, R76, R77, and R30, and a capacitor C8. One end of each of resistors R72 and R73 is connected to the inverting input of the operational amplifier U1A, the other end of resistor R72 is connected to the analog signal input, and the other end of resistor R73 is connected to the analog signal output. One end of each of resistors R74 and R75 is connected to the non-inverting input of the operational amplifier U1A, the other end of resistor R74 is connected to a 5V positive voltage, and the other end of resistor R75 is connected to... The output terminal of the operational amplifier U1A is connected to the base of the transistor Q7. The collector of the transistor Q7 is connected to a 12V positive voltage through the resistor R31, and the emitter is connected to the output terminal of the analog signal and grounded through the capacitor C8. The output terminal of the operational amplifier U1A is also grounded through the resistor R77. The bases of the transistors Q9 and Q11 are connected to each other. The collector of the transistor Q9 is connected to the emitter of the transistor Q7, and the collector of the transistor Q11 is connected to a 5V positive voltage through the resistor R76. The emitters of the transistors Q9 and Q11 are grounded, and the base and collector of the transistor Q11 are shorted.

[0019] Based on the above, the subtraction circuit converts the input 0~5V analog signal into a 5~0V analog control signal through the operational amplifier U1A and the transistor Q7. The transistors Q9 and Q11 work together to act as a mirror constant current source, giving the output control signal efficient and stable driving capability.

[0020] Furthermore, the rectifier circuit includes a fuse F1, a capacitor C14, an inductor LF1, and a rectifier bridge D3. Pin 1 and pin 3 of the inductor LF1 are connected to pin 1 and pin 2 of the transformer, respectively. A fuse F1 is provided between pin 1 of the inductor LF1 and pin 2 of the transformer. The two ends of the capacitor C14 are connected to pin 1 and pin 2 of the transformer, respectively. Pin 2 of the transformer is connected to the live wire ACL, and pin 1 is connected to the neutral wire ACN. Pin 1 of the rectifier bridge D3 is connected to pin 2 of the inductor LF1. Pin 2 of the rectifier bridge D3 outputs a 141V positive voltage. Pins 3 and 4 are both grounded with pin 4 of the inductor LF1.

[0021] Based on the above, when the current is too high, the fuse F1 blows, providing overcurrent protection; the inductor LF1, as a common-mode inductor, filters common-mode electromagnetic interference signals and performs EMI filtering. The capacitor C14 is used to filter out high-frequency interference and improve power quality; the rectifier bridge is used to convert AC voltage to DC voltage and output a +141V DC voltage to the voltage control circuit.

[0022] Furthermore, the ultrasonic circuit includes current transformer T1, current transformer T3, inductor L1, operational amplifier U8, MOSFET V8, MOSFET V9, diode D8, diode D9, capacitors C23, C24, C27, C28, C29, C30, and C31, resistors R33, R34, R47, R48, R50, R51, R60, and R61, and an ultrasonic transducer P2; the drain of MOSFET V9 is connected to a positive voltage of 141V. The source of the resistor R33 is connected to the drain of the MOSFET V8. The two ends of the resistor R33 are connected to the gate and source of the MOSFET V9, respectively. The two ends of the resistor R34 are connected to the gate and source of the MOSFET V8, respectively. Pin 1 of the current transformer T1 is connected to the drain of the MOSFET V9 and the source of the MOSFET V8; pin 2 is connected to the source of the MOSFET V9 and the drain of the MOSFET V8; pin 3 is connected to one end of the inductor L1; pin 4 is connected to pin 1 of the current transformer T3; and the other end of the inductor L1... One end of the ultrasonic transducer P2 is connected to the other end of the current transformer T3, and the capacitors C23 and C24 are connected in parallel with the ultrasonic transducer P2. The fourth pin of the current transformer T3 is connected to the non-inverting input of the operational amplifier U8 through the resistor R60, and the third pin of the current transformer T3 is connected to the inverting input of the operational amplifier U8 through the resistor R47. One end of capacitor C28, one end of capacitor C27, one end of resistor R48, and one end of resistor R61... The cathode of diode D9 and the anode of diode D8 are all connected to the non-inverting input terminal of the operational amplifier U8. The other end of capacitor C28, one end of capacitor C29, one end of capacitor C31, one end of resistor R48, one end of resistor R49, one end of resistor R50, the anode of diode D9 and the cathode of diode D8 are all connected to the inverting input terminal of the operational amplifier U8. The other ends of resistor R50, resistor R61, capacitor C27 and capacitor C31 are all grounded. The other ends of capacitor C29 and resistor R49 are connected to a 12V positive voltage.

[0023] Based on the above, the inductor L1, capacitors C23 and C24, ultrasonic transducer P2, and current transformer T3 constitute a secondary resonant circuit. The current transformer T3 is a 1:200 current transformer that detects the phase sequence of the resonant circuit in real time. The resistors R47, R48, R60, and R61, capacitor C28, diodes D8 and D9, and capacitor C27 constitute a phase sequence detection clamping circuit. The operational amplifier U8 compares the phase sequence signal output from the secondary resonant circuit with the voltage divider circuit composed of capacitor C29, resistor R49, capacitor C31, and resistor R50, and outputs the signal to the next-stage chip circuit for frequency adjustment. The ultrasonic transducer P2 converts electrical energy into ultrasonic energy for output.

[0024] Furthermore, the ultrasonic circuit also includes capacitors C18 and C19, resistors R28 and R29. One end of capacitors C18, C19, R28, and R29 is connected to pin 1 of the current transformer T1, the other end of capacitor C18 and resistor R28 is connected to the source of MOSFET V8, and the other end of capacitor C19 and resistor R29 is connected to the drain of MOSFET V9.

[0025] Based on the above, capacitor C18, capacitor C19, resistor R28, resistor R29, current transformer T1, MOSFET V8, and MOSFET V9 form a half-bridge drive circuit, which transmits electrical energy from the current transformer T1 to the secondary resonant circuit.

[0026] Furthermore, the control signal processing circuit selects between analog control signal input and PWM digital signal input via jumpers, and the PWM digital signal can be selected as active high or active low.

[0027] The operation method of the constant voltage digitally adjustable load circuit for ultrasonic power supply includes the following steps:

[0028] Step 1: The ultrasonic power supply outputs 100V AC power through the transformer, and then the rectifier circuit rectifies the 100V AC power to a maximum value of 141V DC power, and outputs the 141V DC voltage to the voltage control circuit;

[0029] Step 2: The control signal is input to the control signal processing circuit. The control signal processing circuit selects analog control signal input or PWM digital signal input through jumpers. The PWM digital signal can be selected as active high or active low. The control signal processing circuit converts the input control signal into a DC 0~5V linearly adjustable analog signal.

[0030] Step 3: Use the subtraction circuit to invert the DC 0~5V linearly adjustable analog signal obtained in Step 2 into a DC 5~0V analog signal;

[0031] Step 4: The voltage control circuit receives the DC 5~0V analog signal converted by the subtraction circuit in Step 3, and compares and amplifies it with the ultrasonic primary voltage sampling signal through operational amplifier U1A. When the voltage value of the ultrasonic primary voltage sampling signal is lower than the voltage value of the input analog signal, the output of operational amplifier U1A decreases, and the gate voltages of MOSFETs V1, V2, V3, and V4 decrease. Since MOSFETs V1, V2, V3, and V4 operate in parallel in the amplification region of operational amplifier U1A, the drain voltages of MOSFETs V1, V2, V3, and V4 increase. The voltage of the ultrasonic primary voltage sampling signal input to the non-inverting input terminal of operational amplifier U1A also increases proportionally. When it rises to the same voltage value as the analog signal, the output of operational amplifier U1A stabilizes at a constant voltage value, thereby controlling the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0~100V.

[0032] In summary, the beneficial effects of this utility model are as follows: Compared with the traditional load circuit used for ultrasonic power supplies, this utility model simplifies the multi-output transformer into a single-output transformer, eliminates the multi-relay required for voltage switching, reduces the size of the ultrasonic power supply, improves working stability, and reduces production costs, while realizing the function of linearly adjustable output voltage, making the power supply more powerful and stable, and greatly improving the practicality of the power supply. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the circuit working principle of this utility model;

[0034] Figure 2 This is a schematic diagram of the voltage control circuit and ultrasonic circuit of this utility model;

[0035] Figure 3 This is a schematic diagram of the control signal processing circuit of this utility model;

[0036] Figure 4 This is the schematic diagram of the subtraction circuit of this utility model;

[0037] Figure 5 This is the schematic diagram of the rectifier circuit of this utility model. Detailed Implementation

[0038] like Figures 1 to 5As shown, a constant voltage digitally adjustable load circuit for an ultrasonic power supply includes a control signal processing circuit, a subtraction circuit, a voltage control circuit, and an ultrasonic circuit connected in sequence. The voltage control circuit is also connected to a rectifier circuit, and the input terminal of the rectifier circuit is connected to a transformer, which is connected to the ultrasonic power supply.

[0039] A rectifier circuit is used to convert AC voltage into DC voltage and output DC voltage to the voltage control circuit;

[0040] The control signal processing circuit is used to convert the input control signal into a DC 0~5V analog signal;

[0041] The subtraction circuit is used to invert the DC 0~5V analog signal converted by the control signal processing circuit into a DC 5~0V analog signal;

[0042] A voltage control circuit is used to receive the DC 5~0V analog signal converted by the subtraction circuit and the DC voltage output by the rectifier circuit, and to control the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0~100V, and to output DC voltage to the ultrasonic circuit.

[0043] An ultrasonic circuit is used to convert the electrical energy received from the voltage control circuit into ultrasonic energy for output.

[0044] The voltage control circuit includes an operational amplifier U1A, resistors R7, R8, R10, R36, R71, R79, and R83, Zener diodes Z1 and Z2, diode D14, capacitors C6, C45, and C49, as well as parallel first MOSFET voltage regulation circuit, second MOSFET voltage regulation circuit, third MOSFET voltage regulation circuit, and fourth MOSFET voltage regulation circuit.

[0045] The first MOSFET voltage regulation circuit includes a MOSFET V1, a transistor Q10, resistors R11, R15, R35, and RS4. One end of resistor R7 is connected to the signal input terminal, and the other end is connected to one end of resistor R8. The other end of resistor R8 is connected to the inverting input terminal of operational amplifier U1A. The output terminal of operational amplifier U1A is connected to the first MOSFET voltage regulation circuit. Specifically, the output terminal of operational amplifier U1A is connected to the gate of MOSFET V1 through resistor R11. The gate of MOSFET V1 is also connected to the collector of transistor Q10 and one end of resistor R15. The emitter of transistor Q10 and the other end of resistor R15 are grounded together. The two ends of resistor R35 are connected to the source of MOSFET V1 and the base of transistor Q10, respectively. The source of MOSFET V1 is also grounded through resistor RS4.

[0046] The second MOSFET voltage regulation circuit includes a MOSFET V2, a transistor Q8, resistors R12, R16, R80, and RS3. The output terminal of the operational amplifier U1A is connected to the gate of the MOSFET V2 via resistor R12. The gate of the MOSFET V2 is also connected to the collector of the transistor Q8 and one end of resistor R16. The emitter of the transistor Q8 and the other end of resistor R16 are grounded together. The two ends of resistor R80 are connected to the source of the MOSFET V2 and the base of the transistor Q8, respectively. The source of the MOSFET V2 is also grounded via resistor RS3. The third MOSFET voltage regulation circuit includes a MOSFET V3, a transistor Q6, resistors R13, R17, R81, and RS2. The output terminal of the operational amplifier U1A is connected to the gate of the MOSFET V3 via resistor R13. The gate of the MOSFET V3 is also connected to the collector of the transistor Q6 and one end of resistor R17. The emitter of the transistor Q6 and the other end of resistor R17 are grounded together. The two ends of resistor 81 are connected to the source of the MOSFET V3 and the base of the transistor Q6, respectively. The source of the MOSFET V3 is also grounded via resistor RS2. The fourth MOSFET voltage regulation circuit includes MOSFET V4, transistor Q4, resistors R14, R18, R82, and RS1. The output terminal of the operational amplifier U1A is connected to the gate of the MOS transistor V4 through the resistor R14. The gate of the MOS transistor V4 is also connected to the collector of the transistor Q4 and one end of the resistor R18. The emitter of the transistor Q4 and the other end of the resistor R18 are grounded together. The two ends of the resistor 82 are respectively connected to the source of the MOS transistor V4 and the base of the transistor Q4. The source of the MOS transistor V4 is also grounded through the resistor RS1.

[0047] In addition, a capacitor C45 and a resistor R10 are connected in series between the output terminal and the inverting input terminal of the operational amplifier U1A. The negative terminal of the Zener diode Z2, one end of the resistor R79, and one end of the capacitor C49 are all connected to the non-inverting input terminal of the operational amplifier U1A. The positive terminal of the Zener diode Z2, the other end of the resistor R79, and the other end of the capacitor C49 are all connected to the positive terminal of the Zener diode Z1. The negative terminal of the Zener diode Z1 is connected to the common connection point of the resistors R7 and R8. One end of the resistor R71 is connected to the drain of the MOSFET V1 and connected to the ultrasonic circuit, and the other end is connected to the non-inverting input terminal of the operational amplifier U1A. One end of the resistor R83 is connected to a 5V positive voltage, and the other end is connected to the anode of the diode D14. The cathode of the diode D14 is connected to the non-inverting input terminal of the operational amplifier U1A. One end of the resistor R36 and one end of the capacitor C6 are both connected to one end of the resistor R71, and the other ends of the resistor R36 and the capacitor C6 are grounded together.

[0048] The control signal processing circuit includes diodes D11, D12, and D13; transistors Q1, Q2, Q3, and Q5; capacitors C1, C2, C3, C4, C5, C7, and C42; resistors R2, R3, R4, R5, R6, R19, R20, R21, R23, and R24; connectors J2, J4, J5, J6, and J7; and potentiometer RV2. One end of each connector J6 and connector J7 is connected to a signal input terminal. The other end of each connector is connected to the base of transistor Q5. The other end of connector J7 is connected to the collector of transistor Q5 through diode D13. The base of transistor Q3 is connected to the collector of transistor Q5. The emitters of transistors Q3 and Q5 are grounded together. The collector of transistor Q3 is connected to one end of connector J5. A potential is also provided between the collector and emitter of transistor Q3. Potentiometer RV2 has its pin 2 connected to one end of connector J4. The other ends of connector J4 and connector J5 are connected to the base of transistor Q1 through resistors R4, R21 and R23 in sequence. The emitter of transistor Q1 is connected to the base of transistor Q2. The base and collector of transistor Q2 are also connected to a 12V positive voltage through resistors R5 and R6, respectively. The emitter of transistor Q2 serves as the output terminal, outputting a 0~5V analog signal to the subtraction circuit.

[0049] In addition, diode D11 is provided between connector J6 and the signal input terminal, and resistor R9 is provided between connector J7 and the signal input terminal. The other end of connector J7 is connected to a 12V positive voltage through resistor R19. Capacitor C1 is connected in parallel with resistor R9. Resistor R20 and diode D12 are connected in series and connected to both ends of connector J6. Capacitor C2 is connected in parallel with diode D12. The collector of transistor Q3 is connected to a 5V positive voltage and capacitor C42 through resistor R2. The collector of transistor Q3 is also connected to a 5V positive voltage through connector J2. One end of resistor R3 is connected to the common connection terminal of connectors J4 and J5, and the other end is grounded. One end of capacitors C3 and C4 is connected to both ends of resistor R21, and the other ends of capacitors C3 and C4 are grounded together. The capacitor C5 is disposed between the base and collector of the transistor Q1, and the emitter of the transistor Q2 is also connected to a capacitor C7 and a resistor R24, which are connected in parallel.

[0050] The rectifier circuit includes a fuse F1, a capacitor C14, an inductor LF1, and a rectifier bridge D3. Pin 1 and pin 3 of the inductor LF1 are connected to pin 1 and pin 2 of the transformer, respectively. A fuse F1 is installed between pin 1 of the inductor LF1 and pin 2 of the transformer. The two ends of the capacitor C14 are connected to pin 1 and pin 2 of the transformer, respectively. Pin 2 of the transformer is connected to the live wire ACL, and pin 1 is connected to the neutral wire ACN. Pin 1 of the rectifier bridge D3 is connected to pin 2 of the inductor LF1. Pin 2 of the rectifier bridge D3 outputs a 141V positive voltage. Pins 3 and 4 are both grounded with pin 4 of the inductor LF1.

[0051] The subtraction circuit includes an operational amplifier U1A, transistors Q7, Q9, and Q11, resistors R72, R73, R74, R75, R76, R77, and R30, and a capacitor C8. One end of resistors R72 and R73 is connected to the inverting input of operational amplifier U1A, and the other end of resistor R72 is connected to the analog signal input. The other end of resistor R73 is connected to the analog signal output. One end of resistors R74 and R75 is connected to the non-inverting input of operational amplifier U1A, and the other end of resistor R74 is connected to a 5V positive voltage. The other end of resistor R75 is grounded. The output of operational amplifier U1A is connected to the base of transistor Q7. The collector of transistor Q7 is connected to a 12V positive voltage through resistor R31, and the emitter is connected to the analog signal output and grounded through capacitor C8. Furthermore, the output of operational amplifier U1A is also grounded through resistor R77. The bases of transistors Q9 and Q11 are connected to each other. The collector of transistor Q9 is connected to the emitter of transistor Q7. The collector of transistor Q11 is connected to a 5V positive voltage through resistor R76. The emitters of transistors Q9 and Q11 are grounded. The base and collector of transistor Q11 are shorted.

[0052] The ultrasonic circuit includes current transformers T1 and T3, inductor L1, operational amplifier U8, MOSFETs V8 and V9, diodes D8 and D9, capacitors C18, C19, C23, C24, C27, C28, C29, C30, and C31, resistors R28, R33, R34, R47, R48, R50, R51, R60, and R61, and an ultrasonic transducer P2. The drain of MOSFET V9 is connected to a positive voltage of 141V, and its source is connected to the drain of MOSFET V8. The two ends of resistor R33 are connected to the gate and source of MOSFET V9, respectively, and the two ends of resistor R34 are connected to the gate and source of MOSFET V8, respectively. Pin 1 of the current transformer T1 is connected to the drain of MOSFET V9 and the source of MOSFET V8; pin 2 is connected to the source of MOSFET V9 and the drain of MOSFET V8; pin 3 is connected to one end of inductor L1; and pin 4 is connected to pin 1 of the current transformer T3. Additionally, pin 1 of the current transformer T1 is connected to one end of capacitors C18 and C19, resistors R28 and R29. The other ends of capacitors C18 and R28 are connected to the source of MOSFET V8, and the other ends of capacitors C19 and R29 are connected to the drain of MOSFET V9. The other end of inductor L1 is connected to one end of ultrasonic transducer P2, and the other end of ultrasonic transducer P2 is connected to pin 2 of the current transformer T3. Capacitors C23 and C24 are connected in parallel with ultrasonic transducer P2. Pin four of the current transformer T3 is connected to the non-inverting input of the operational amplifier U8 through resistor R60, and pin three of the current transformer T3 is connected to the inverting input of the operational amplifier U8 through resistor R47. One end of capacitor C28, one end of capacitor C27, one end of resistor R48, one end of resistor R61, the cathode of diode D9, and the anode of diode D8 are all connected to the non-inverting input of the operational amplifier U8. The other end of capacitor C28, one end of capacitor C29, one end of capacitor C31, one end of resistor R48, one end of resistor R49, one end of resistor R50, the anode of diode D9, and the cathode of diode D8 are all connected to the inverting input of the operational amplifier U8. The other ends of resistor R50, resistor R61, capacitor C27, and capacitor C31 are all grounded, and the other ends of capacitor C29 and resistor R49 are connected to a 12V positive voltage.

[0053] The working method of this embodiment includes the following steps:

[0054] Step 1: The rectifier circuit rectifies the 100V AC output from the transformer into a maximum DC voltage of 141V.

[0055] Step 2: The control signal is input to the control signal processing circuit. The control signal processing circuit selects analog control signal input or PWM digital signal input through jumpers. The PWM digital signal can be selected as active high or active low. The control signal processing circuit converts the input control signal into a DC 0~5V linearly adjustable analog signal.

[0056] Step 3: Use the subtraction circuit to invert the DC 0~5V linearly adjustable analog signal obtained in Step 2 into a DC 5~0V analog signal;

[0057] Step 4: The voltage control circuit receives the DC 5~0V analog signal converted by the subtraction circuit in Step 3, and compares it with the ultrasonic primary voltage sampling signal collected by resistors R71 and R79. Operational amplifier U1A amplifies and outputs this signal. When the voltage value of the ultrasonic primary voltage sampling signal is lower than the input analog signal voltage value, the output of operational amplifier U1A decreases, and the gate voltages of MOSFETs V1, V2, V3, and V4 decrease. Since MOSFETs V1, V2, V3, and V4 operate in parallel in the amplification region, their drain voltages rise. The ultrasonic primary voltage sampling signal voltage input at the non-inverting input terminal also rises proportionally to match the analog signal voltage value. At this point, the output of operational amplifier U1A stabilizes at a constant voltage value, thereby controlling the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0~100V. The formula for calculating the drain voltage U of MOSFETs V1, V2, V3, and V4 is:

[0058] ;

[0059] Where Ua represents the voltage value of the ultrasonic primary voltage sampling signal, resistor R71 has a resistance of 100K, and resistor R79 has a resistance of 5.1K.

[0060] The specific principle of the voltage regulation process is as follows:

[0061] When the analog signal input to the inverting input of operational amplifier U1A is 4.5V and the ultrasonic primary voltage sampling signal input to the non-inverting input is 4.4V, the drain voltage U of MOSFETs V1, V2, V3, and V4 is calculated to be 90.67V according to the formula. At this time, the output of operational amplifier U1A decreases. The integrator circuit formed by capacitor C45 and resistor R10 feeds back to the inverting input as negative feedback, which acts as a stabilizing circuit. As the output of operational amplifier U1A decreases, the gate voltages of MOSFETs V1, V2, V3, and V4 also decrease accordingly. Since the MOSFETs V1, V2, V3, and V4 operate in parallel in the amplification region of the operational amplifier U1A, when the drain voltages of the MOSFETs V1, V2, V3, and V4 rise, the ultrasonic primary voltage sampling signal voltage input to the non-inverting input terminal of the operational amplifier U1A also rises proportionally to 4.5V. At this point, the output of the operational amplifier U1A stabilizes at a constant voltage value, maintaining the drain voltage of the parallel MOSFETs V1, V2, V3, and V4 at 92.74V.

[0062] Similarly, when the analog signal input to the inverting input of operational amplifier U1A is 1.0V and the ultrasonic primary voltage sampling signal input to the non-inverting input is 0.9V, the drain voltage U of MOSFETs V1, V2, V3, and V4 is calculated to be 18.54V according to the formula. At this time, the output of operational amplifier U1A decreases. The integrator circuit formed by capacitor C45 and resistor R10 feeds back to the inverting input as negative feedback, which acts as a stabilizing circuit. As the output of operational amplifier U1A decreases, the gate voltages of MOSFETs V1, V2, V3, and V4 also decrease accordingly. As the voltage decreases, since MOSFETs V1, V2, V3, and V4 operate in parallel within the amplification region of the operational amplifier U1A, the drain voltages of MOSFETs V1, V2, V3, and V4 rise. Consequently, the ultrasonic primary voltage sampling signal input to the non-inverting input of the operational amplifier U1A also rises proportionally to 1.0V. At this point, the output of the operational amplifier U1A stabilizes at a constant voltage value, maintaining the drain voltage of the parallel MOSFETs V1, V2, V3, and V4 at 20.61V.

[0063] This controls the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0~100V, and outputs DC voltage to the ultrasonic circuit.

[0064] The above description is only the optimal solution embodiment of this utility model and is not intended to limit this utility model. Various modifications or substitutions made by those skilled in the art to this utility model without departing from the essence and protection scope of this utility model should also be within the protection scope of this utility model.

Claims

1. A constant voltage digitally adjustable load circuit for ultrasonic power supplies, characterized in that: The system includes a control signal processing circuit, a subtraction circuit, a voltage control circuit, and an ultrasonic circuit connected in sequence. The voltage control circuit is also connected to a rectifier circuit, and the input terminal of the rectifier circuit is connected to a transformer. The transformer is connected to the ultrasonic power supply. A rectifier circuit is used to convert AC voltage into DC voltage and output DC voltage to the voltage control circuit; A control signal processing circuit is used to convert the input control signal into a DC 0~5V analog signal. The control signal processing circuit selects the analog control signal input or the PWM digital signal input via a jumper. The PWM digital signal can be selected to be active high or active low. The subtraction circuit is used to invert the DC 0~5V analog signal converted by the control signal processing circuit into a DC 5~0V analog signal; The voltage control circuit compares and amplifies the DC 5~0V analog signal converted by the subtraction circuit and the DC voltage output by the rectifier circuit. Based on the comparison result, it controls the switching on and off of MOSFETs V1, V2, V3 and V4 in the voltage control circuit, thereby controlling the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0~100V and outputting a DC voltage to the ultrasonic circuit. An ultrasonic circuit is used to convert the electrical energy received from the voltage control circuit into ultrasonic energy for output.

2. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 1, characterized in that: The control signal processing circuit includes diodes D11 and D13, transistors Q1, Q2, Q3, and Q5, capacitors C1, C2, C3, C4, C5, C7, and C42, resistors R2, R3, R4, R5, R6, R19, R20, R21, R23, and R24, connectors J4, J5, J6, and J7, and potentiometer RV2. One end of connectors J6 and J7 is connected to a signal input terminal, and the other end of each connector is connected to the base of transistor Q5. The other end of connector J7 is connected to the collector of transistor Q5 through diode D13. The collector of transistor Q1 is connected to the collector of transistor Q5. The emitters of transistor Q3 and transistor Q5 are grounded together. The collector of transistor Q3 is connected to one end of connector J5. A potentiometer RV2 is also provided between the collector and emitter of transistor Q3. The second pin of potentiometer RV2 is connected to one end of connector J4. The other ends of connector J4 and connector J5 are connected to the base of transistor Q1 through resistors R4, R21 and R23 in sequence. The emitter of transistor Q1 is connected to the base of transistor Q2. The base and collector of transistor Q2 are also connected to a 12V positive voltage through resistors R5 and R6 respectively. The emitter of transistor Q2 serves as the output terminal, outputting a 0~5V analog signal to the subtraction circuit.

3. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 1, characterized in that: The voltage control circuit includes an operational amplifier U1A, resistors R7, R8, R10, R36, R71, R79, and R83, Zener diodes Z1 and Z2, diode D14, capacitors C6, C45, and C49, and parallel-connected first, second, third, and fourth MOSFET voltage regulation circuits. One end of resistor R7 is connected to the signal input terminal, and the other end is connected to one end of resistor R8. The other end of resistor R8 is connected to the inverting input terminal of operational amplifier U1A. The output terminal of operational amplifier U1A is connected to the first MOSFET voltage regulation circuit. A capacitor C45 and a resistor R10 are connected in series between the output terminal and the inverting input terminal of operational amplifier U1A. The negative terminal of Zener diode Z2 and the resistor R79 are connected in parallel. One end of the resistor R1 and one end of the capacitor C49 are both connected to the non-inverting input of the operational amplifier U1A. The positive terminal of the Zener diode Z2, the other end of the resistor R79, and the other end of the capacitor C49 are all connected to the positive terminal of the Zener diode Z1. The negative terminal of the Zener diode Z1 is connected to the common connection point of the resistors R7 and R8. One end of the resistor R71 is connected to the drain of the MOSFET V1 and connected to the ultrasonic circuit. The other end is connected to the non-inverting input of the operational amplifier U1A. One end of the resistor R83 is connected to a 5V positive voltage. The other end is connected to the anode of the diode D14. The cathode of the diode D14 is connected to the non-inverting input of the operational amplifier U1A. One end of the resistor R36 and one end of the capacitor C6 are both connected to one end of the resistor R71. The other ends of the resistor R36 and the capacitor C6 are grounded together.

4. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 3, characterized in that: The first MOSFET voltage regulation circuit includes a MOSFET V1, a transistor Q10, resistors R11, R15, R35, and RS4. The output terminal of the operational amplifier U1A is connected to the gate of the MOSFET V1 through resistor R11. The gate of the MOSFET V1 is also connected to the collector of the transistor Q10 and one end of resistor R15. The emitter of the transistor Q10 and the other end of resistor R15 are grounded together. The two ends of resistor R35 are respectively connected to the source of the MOSFET V1 and the base of the transistor Q10. The source of the MOSFET V1 is also grounded through resistor RS4.

5. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 1, characterized in that: The subtraction circuit includes an operational amplifier U1A, transistors Q7, Q9, and Q11, resistors R72, R73, R74, R75, R76, R77, and R30, and a capacitor C8. One end of resistors R72 and R73 is connected to the inverting input of operational amplifier U1A, the other end of resistor R72 is connected to the analog signal input, and the other end of resistor R73 is connected to the analog signal output. One end of resistors R74 and R75 is connected to the non-inverting input of operational amplifier U1A, the other end of resistor R74 is connected to a 5V positive voltage, and the other end of resistor R75 is grounded. The output terminal of the operational amplifier U1A is connected to the base of the transistor Q7. The collector of the transistor Q7 is connected to a 12V positive voltage through the resistor R31, and the emitter is connected to the output terminal of the analog signal and grounded through the capacitor C8. The output terminal of the operational amplifier U1A is also grounded through the resistor R77. The bases of the transistors Q9 and Q11 are connected to each other. The collector of the transistor Q9 is connected to the emitter of the transistor Q7. The collector of the transistor Q11 is connected to a 5V positive voltage through the resistor R76. The emitters of the transistors Q9 and Q11 share a common ground, and the base and collector of the transistor Q11 are shorted.

6. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 1, characterized in that: The rectifier circuit includes a fuse F1, a capacitor C14, an inductor LF1, and a rectifier bridge D3. Pin 1 and pin 3 of the inductor LF1 are connected to pin 1 and pin 2 of the transformer, respectively. A fuse F1 is installed between pin 1 of the inductor LF1 and pin 2 of the transformer. The two ends of the capacitor C14 are connected to pin 1 and pin 2 of the transformer, respectively. Pin 2 of the transformer is connected to the live wire ACL, and pin 1 is connected to the neutral wire ACN. Pin 1 of the rectifier bridge D3 is connected to pin 2 of the inductor LF1. Pin 2 of the rectifier bridge D3 outputs a 141V positive voltage. Pins 3 and 4 are both grounded with pin 4 of the inductor LF1.

7. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 1, characterized in that: The ultrasonic circuit includes current transformers T1 and T3, inductor L1, operational amplifier U8, MOSFET V8 and V9, diodes D8 and D9, capacitors C23, C24, C27, C28, C29, C30, and C31, resistors R33, R34, R47, R48, R50, R51, R60, and R61, and an ultrasonic transducer P2; the drain of MOSFET V9 is connected to a positive voltage of 141V, and the source is connected to... The drain of MOSFET V8 is connected to the gate of MOSFET V9, and the two ends of resistor R33 are connected to the gate and source of MOSFET V9, respectively. The two ends of resistor R34 are connected to the gate and source of MOSFET V8, respectively. Pin 1 of current transformer T1 is connected to the drain of MOSFET V9 and the source of MOSFET V8, pin 2 is connected to the source of MOSFET V9 and the drain of MOSFET V8, pin 3 is connected to one end of inductor L1, pin 4 is connected to pin 1 of current transformer T3, and the other end of inductor L1 is connected to the gate of MOSFET V9. One end of the ultrasonic transducer P2 is connected to the [connection point], and the other end of the ultrasonic transducer P2 is connected to pin 2 of the current transformer T3. Capacitors C23 and C24 are connected in parallel with the ultrasonic transducer P2. Pin 4 of the current transformer T3 is connected to the non-inverting input of the operational amplifier U8 through resistor R60, and pin 3 of the current transformer T3 is connected to the inverting input of the operational amplifier U8 through resistor R47. One end of capacitor C28, one end of capacitor C27, one end of resistor R48, and one end of resistor R61 are [connected to the [connection point]... The cathode of diode D9 and the anode of diode D8 are both connected to the non-inverting input terminal of operational amplifier U8. The other end of capacitor C28, one end of capacitor C29, one end of capacitor C31, one end of resistor R48, one end of resistor R49, one end of resistor R50, the anode of diode D9 and the cathode of diode D8 are all connected to the inverting input terminal of operational amplifier U8. The other ends of resistor R50, resistor R61, capacitor C27 and capacitor C31 are all grounded. The other ends of capacitor C29 and resistor R49 are connected to a 12V positive voltage.

8. The constant voltage digitally adjustable load circuit for ultrasonic power supply according to claim 7, characterized in that: The ultrasonic circuit also includes capacitors C18 and C19, resistors R28 and R29. One end of capacitors C18, C19, R28, and R29 is connected to pin 1 of the current transformer T1. The other end of capacitor C18 and resistor R28 is connected to the source of MOSFET V8, and the other end of capacitor C19 and resistor R29 is connected to the drain of MOSFET V9.

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