Constant voltage digital adjustable load circuit for ultrasonic power supply and working method thereof

Abstract

The application provides a constant voltage digital adjustable load circuit for an ultrasonic power supply and a working method thereof, the constant voltage digital adjustable load circuit comprises a control signal processing circuit, a subtraction circuit and a voltage control circuit connected in sequence, the voltage control circuit is further connected with a rectifier circuit and an overcurrent protection circuit, an input end of the rectifier circuit is connected with a transformer; the voltage control circuit is used for receiving an output signal of the subtraction circuit and a direct current voltage output by the rectifier circuit, controlling a primary voltage of an ultrasonic circuit to be a linear adjustable constant voltage of 0-100V, and outputting the direct current voltage to the ultrasonic circuit. The application simplifies a multi-output transformer into a single-output transformer, removes a plurality of relays required for switching voltage, realizes the function of linear adjustable output voltage while reducing the volume of the ultrasonic power supply, improving working stability and reducing production cost, makes the power supply function more powerful and stable, and greatly improves the practicability of the power supply.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ultrasonic power supply, in particular to a constant voltage digital adjustable load circuit for ultrasonic power supply and a working method thereof. BACKGROUND

[0002] Ultrasonic technology is widely used in many fields such as cleaning, welding, medical treatment, industrial processing and industrial automation, and the performance of ultrasonic power supply as a key device for driving ultrasonic transducer directly affects the working efficiency and stability of the ultrasonic system.

[0003] The existing ultrasonic power supply needs to use a multi-way transformer to work with multiple relays, so as to realize the function of multiple voltage switching output. However, the load circuit of the existing ultrasonic power supply is not only large in size and high in cost, but also low in output stability. SUMMARY

[0004] In view of the problems in the prior art, the present application provides a constant voltage digital adjustable load circuit for ultrasonic power supply and a working method thereof, aiming to solve the problems of low output stability, large size, high assembly difficulty and high cost of the load circuit of the traditional ultrasonic power supply.

[0005] To achieve the above-mentioned purpose, the technical solution adopted by the present application is as follows:

[0006] The constant voltage digital adjustable load circuit for ultrasonic power supply comprises a control signal processing circuit, a subtraction circuit, a voltage control circuit connected in sequence, and an ultrasonic circuit connected with the voltage control circuit, wherein the voltage control circuit is further connected with a rectifier circuit, the input end of the rectifier circuit is connected with a transformer, and the transformer is connected with the ultrasonic power supply;

[0007] The rectifier circuit is used for converting alternating voltage into direct current voltage and outputting the direct current voltage to the voltage control circuit;

[0008] The control signal processing circuit is used for converting the input control signal into a direct current 0-5V analog signal;

[0009] The subtraction circuit is used for inverting the direct current 0-5V analog signal converted by the control signal processing circuit into a direct current 5-0V analog signal;

[0010] The voltage control circuit is used for receiving the direct current 5-0V analog signal converted by the subtraction circuit and the direct current voltage output by the rectifier circuit, controlling the primary voltage of the ultrasonic circuit to be a linear adjustable constant voltage of 0-100V, and outputting the direct current voltage to the ultrasonic circuit;

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

[0012] Further, the control signal processing circuit comprises diode D11, diode D13, triode Q1, triode Q2, triode Q3, triode Q5, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C7, capacitor C42, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R19, resistor R20, resistor R21, resistor R23, resistor R24, connector J4, connector J5, connector J6, connector J7 and potentiometer RV2; one end of the connector J6 and the connector J7 is connected to the signal input end, the other end of the connector is connected to the base of the triode Q5, the other end of the connector J7 is connected to the collector of the triode Q5 through the diode D13, the base of the triode Q3 is connected to the collector of the triode Q5, the triode Q3 and the emitter of the triode Q5 are commonly grounded, the collector of the triode Q3 is connected to one end of the connector J5, the collector and the emitter of the triode Q3 are further provided with the potentiometer RV2, pin two of the potentiometer RV2 is connected to one end of the connector J4, the connector J4 and the other end of the connector J5 are sequentially connected to the base of the triode Q1 through the resistor R4, the resistor R21 and the resistor R23, the emitter of the triode Q1 is connected to the base of the triode Q2, the base and the collector of the triode Q2 are further connected to 12V positive voltage through the resistor R5 and the resistor R6 respectively, the emitter of the triode Q2 is used as an output end to output 0-5V analog signal to the subtraction circuit.

[0013] Based on the above, the PWM input signal selects high level effective or low level effective through the connector J6 and the connector J7, when the connector J6 is shorted to select high level effective, the triode Q5 is used for the inversion of the PWM digital signal, and the triode Q3 is used for converting the 12V level PWM digital signal into 5V level PWM digital signal. The diode D11 is used for, when the connector J7 is shorted to select low level effective, the low level of the PWM digital signal can pull down the voltage of NER2 point, while the high level of the PWM digital signal will not directly drive the triode Q5 through the current limiting resistor R9. The potentiometer RV2 is used for adjusting the amplitude range of the input analog signal. The power supply can be selected to be controlled by the PWM digital signal or 0-5V analog signal through the connector J4 and the connector J5, when the connector J5 is shorted, it is PWM digital signal control, and when the connector J4 is shorted, it is 0-5V analog signal control.

[0014] Further, the voltage control circuit comprises an operational amplifier U1A, a resistor R7, a resistor R8, a resistor R10, a resistor R36, a resistor R71, a resistor R79, a resistor R83, a voltage stabilizing tube Z1, a voltage stabilizing tube Z2, a diode D14, a capacitor C6, a capacitor C45, a capacitor C49, and a first MOS transistor voltage regulating circuit, a second MOS transistor voltage regulating circuit, a third MOS transistor voltage regulating circuit, and a fourth MOS transistor voltage regulating circuit in parallel. One end of the resistor R7 is connected to a signal input end, and the other end is connected to one end of the resistor R8. The other end of the resistor R8 is connected to an inverting input end of the operational amplifier U1A. An output end of the operational amplifier U1A is connected to the first MOS transistor voltage regulating circuit. The output end and the inverting input end of the operational amplifier U1A are further connected in series with the capacitor C45 and the resistor R10. The negative electrode of the voltage stabilizing tube Z2, one end of the resistor R79, and one end of the capacitor C49 are all connected to a non-inverting input end of the operational amplifier U1A. The positive electrode of the voltage stabilizing tube Z2, the other end of the resistor R79, and the other end of the capacitor C49 are all connected to a positive electrode of the voltage stabilizing tube Z1. The negative electrode of the voltage stabilizing tube Z1 is connected to a common connection point of the resistor R7 and the resistor R8. One end of the resistor R71 is connected to a drain electrode of the MOS transistor V1 and connected to the ultrasonic circuit, and the other end is connected to the non-inverting input end 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 an anode of the diode D14. A cathode of the diode D14 is connected to the non-inverting input end 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 end of the resistor R36 and the other end of the capacitor C6 are both grounded.

[0015] Based on the above, the signal output by the subtraction circuit is input to the operational amplifier U1A through the resistor R7 and the resistor R8. The operational amplifier U1A converts the input analog signal into a driving signal, adjusts the conduction of the subsequent MOS transistor V1, MOS transistor V2, MOS transistor V3, and MOS transistor V4, and realizes linear adjustment of the output voltage. The resistor R10 is used to feed back the information at the output end of the operational amplifier U1A to the inverting input end of the operational amplifier U1A, forming a feedback closed loop. The capacitor C45 plays a role in filtering high-frequency noise and improving control accuracy. The voltage stabilizing tube Z1 is used to clamp the reference voltage, limit the reference voltage amplitude, and avoid overvoltage output caused by out-of-control reference voltage. The voltage stabilizing tube Z2 and the resistor R79 form a clamping circuit to limit the input signal amplitude and avoid operational amplifier overload.

[0016] Further, the first MOS transistor voltage regulating circuit comprises MOS transistor V1, transistor Q10, resistor R11, resistor R15, resistor R35 and resistor RS4; the output terminal of the operational amplifier U1A is connected with the gate of the MOS transistor V1 through the resistor R11, the gate of the MOS transistor V1 is also connected with 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, the two ends of the resistor R35 are connected with the source of the MOS transistor V1 and the base of the transistor Q10 respectively, and the source of the MOS transistor V1 is grounded through the resistor RS4.

[0017] Based on the above, the transistor Q10, resistor R15, resistor R35 and resistor RS4 constitute an overcurrent protection circuit. When the current of the MOS transistor V1 is too large, the voltage of the resistor R35 rises, the transistor Q10 is turned on, the gate voltage of the MOS transistor V1 is pulled down, the conduction degree is reduced, and finally the current of the parallel MOS transistors tends to be consistent, thereby playing a self-adaptive current sharing role. In addition, when the total current is too large, the voltage drop of the resistor R35 exceeds the conduction voltage of the MOS transistor V1, the transistor Q10 is turned on on a large scale, the operational amplifier output is forcibly pulled down, the MOS transistor V1 is limited to be turned on, and the overcurrent protection function is realized.

[0018] Further, the subtraction circuit comprises operational amplifier U1A, transistor Q7, transistor Q9, transistor Q11, resistor R72, resistor R73, resistor R74, resistor R75, resistor R76, resistor R77, resistor R30 and capacitor C8; one end of the resistor R72 and one end of the resistor R73 are connected with the inverting input terminal of the operational amplifier U1A, the other end of the resistor R72 is connected with the analog signal input terminal, the other end of the R73 is connected with the analog signal output terminal, one end of the resistor R74 and one end of the resistor R75 are connected with the non-inverting input terminal of the operational amplifier U1A, the other end of the resistor R74 is connected with 5V positive voltage, the other end of the resistor R75 is grounded, the output terminal of the operational amplifier U1A is connected with the base of the transistor Q7, the collector of the transistor Q7 is connected with 12V positive voltage through the resistor R31, the emitter of the transistor Q7 is connected with the analog signal output terminal 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 transistor Q9 and the transistor Q11 are connected with each other, the collector of the transistor Q9 is connected with the emitter of the transistor Q7, the collector of the transistor Q11 is connected with 5V positive voltage through the resistor R76, the emitters of the transistor Q9 and the transistor Q11 are grounded, and the base and the collector of the transistor Q11 are short-circuited.

[0019] Based on the above, the subtraction circuit converts the input 0-5V analog signal into 5-0V analog control signal through the operational amplifier U1A and the transistor Q7. The transistor Q9 and the transistor Q11 cooperate to act as a mirror constant current source, so that the output control signal has high efficient and stable driving ability.

[0020] Further, the rectifier circuit includes a fuse F1, a capacitor C14, an inductor LF1 and a rectifier bridge D3. The pin one and the pin three of the inductor LF1 are connected with the pin one and the pin two of the transformer respectively. The pin one of the inductor LF1 is connected with the pin two of the transformer through the fuse F1. The two ends of the capacitor C14 are connected with the pin one and the pin two of the transformer respectively. The pin two of the transformer is connected with the live wire ACL, and the pin one is connected with the neutral wire ACN. The pin one of the rectifier bridge D3 is connected with the pin two of the inductor LF1. The pin two of the rectifier bridge D3 outputs 141V positive voltage, and the pin three and the pin four are grounded with the pin four of the inductor LF1.

[0021] Based on the above, when the current is too large, the fuse F1 is fused to play the role of overcurrent protection. The inductor LF1 acts as a common mode inductor to filter common mode electromagnetic interference signals and EMI filtering. The capacitor C14 is used to filter high frequency interference and improve power quality. The rectifier bridge is used to convert alternating voltage into direct voltage and output +141V direct voltage to the voltage control circuit.

[0022] Further, the ultrasonic circuit comprises a current transformer T1, a current transformer T3, an inductor L1, an operational amplifier U8, a MOS tube V8, a MOS tube V9, a diode D8, a diode D9, a capacitor C23, a capacitor C24, a capacitor C27, a capacitor C28, a capacitor C29, a capacitor C30, a capacitor C31, a resistor R33, a resistor R34, a resistor R47, a resistor R48, a resistor R50, a resistor R51, a resistor R60, a resistor R61 and an ultrasonic transducer P2; a drain of the MOS tube V9 is connected to a 141V positive voltage, a source of the MOS tube V9 is connected to a drain of the MOS tube V8, two ends of the resistor R33 are connected to a gate and a source of the MOS tube V9 respectively, two ends of the resistor R34 are connected to a gate and a source of the MOS tube V8 respectively; a pin one of the current transformer T1 is connected to the drain of the MOS tube V9 and the source of the MOS tube V8, a pin two of the current transformer T1 is connected to the source of the MOS tube V9 and the drain of the MOS tube V8, a pin three of the current transformer T1 is connected to one end of the inductor L1, a pin four of the current transformer T1 is connected to a pin one of the current transformer T3, the other end of the inductor L1 is connected to one end of the ultrasonic transducer P2, the other end of the ultrasonic transducer P2 is connected to a pin two of the current transformer T3, the capacitor C23 and the capacitor C24 are connected to the ultrasonic transducer P2 in parallel; the pin four of the current transformer T3 is connected to a non-inverting input terminal of the operational amplifier U8 through the resistor R60, the pin three of the current transformer T3 is connected to an inverting input terminal of the operational amplifier U8 through the resistor R47; one end of the capacitor C28, one end of the capacitor C27, one end of the resistor R48, one end of the resistor R61, a cathode of the diode D9 and an anode of the diode D8 are connected to the non-inverting input terminal of the operational amplifier U8, the other end of the capacitor C28, one end of the capacitor C29, one end of the capacitor C31, one end of the resistor R48, one end of the resistor R49, one end of the resistor R50, an anode of the diode D9 and a cathode of the diode D8 are connected to the inverting input terminal of the operational amplifier U8, the other ends of the resistor R50, the resistor R61, the capacitor C27 and the capacitor C31 are grounded, the other ends of the capacitor C29 and the resistor R49 are connected to a 12V positive voltage.

[0023] Based on the above, the inductance L1, the capacitance C23, the capacitance C24, the ultrasonic transducer P2 and the current transformer T3 constitute a secondary resonance circuit, the current transformer T3 is a 1:200 current transformer, real-time detection of the phase sequence of the resonance circuit, the resistance R47, the resistance R48, the resistance R60, the resistance R61, the capacitance C28, the diode D8, the diode D9 and the capacitance C27 constitute a phase sequence detection embedding circuit, the operational amplifier U8 compares the voltage of the phase sequence signal output by the secondary resonance circuit with the voltage of the voltage dividing circuit composed of the capacitance C29, the resistance R49, the capacitance C31 and the resistance R50, and outputs a signal to the previous stage chip circuit for frequency adjustment, and the ultrasonic transducer P2 converts electrical energy into ultrasonic energy for output.

[0024] Further, the ultrasonic circuit further comprises a capacitance C18, a capacitance C19, a resistance R28 and a resistance R29, one end of the capacitance C18, the capacitance C19, the resistance R28 and the resistance R29 is connected to the pin one of the current transformer T1, the other end of the capacitance C18 and the resistance R28 is connected to the source of the MOS tube V8, and the other end of the capacitance C19 and the resistance R29 is connected to the drain of the MOS tube V9.

[0025] Based on the above, the capacitance C18, the capacitance C19, the resistance R28, the resistance R29, the current transformer T1, the MOS tube V8 and the MOS tube V9 constitute a half-bridge drive circuit, and electrical energy is transmitted from the current transformer T1 to the secondary resonance circuit.

[0026] Further, the control signal processing circuit selects analog control signal input or PWM digital signal input through a jumper, and the PWM digital signal can be selected as high level effective or low level effective.

[0027] The working method of the constant voltage digital adjustable load circuit for the ultrasonic power supply comprises the following steps:

[0028] Step 1: The ultrasonic power supply outputs 100V alternating current through the transformer, then the rectifier circuit rectifies the 100V alternating current to a maximum value of 141V direct current, and outputs the 141V direct current 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 a jumper, and the PWM digital signal can be selected as high level effective or low level effective, and the control signal processing circuit converts the input control signal into a direct current 0-5V linear adjustable analog signal;

[0030] Step 3: using the subtraction circuit to convert the direct current 0-5V linear adjustable analog signal in step 2 into a direct current 5-0V analog signal;

[0031] Step 4: the voltage control circuit receives the direct current 5-0V analog signal converted by the subtraction circuit in step 3, and compares and amplifies the output with the ultrasonic primary voltage sampling signal through the 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 the operational amplifier U1A drops, the gate voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 drops, since the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 work in parallel in the amplification zone of the operational amplifier U1A, the drain voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 rises, and the voltage of the ultrasonic primary voltage sampling signal input at the same-phase input end of the operational amplifier U1A also rises in proportion; when it rises to the voltage value of the analog signal, the output of the operational amplifier U1A is stabilized at a constant voltage value, so as to control the primary voltage of the ultrasonic circuit to be a linearly adjustable constant voltage of 0-100V.

[0032] In summary, compared with the traditional load circuit for the ultrasonic power supply, the present application simplifies the multi-output transformer into a single-output transformer, removes the multi-relay required for switching voltage, reduces the volume of the ultrasonic power supply, improves the working stability, reduces the production cost, realizes the function of linearly adjustable output voltage, makes the power supply function more powerful and stable, and greatly improves the practicability of the power supply. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 It is a circuit working principle framework diagram of the present application;

[0034] Figure 2 It is a voltage control circuit and ultrasonic circuit principle diagram of the present application;

[0035] Figure 3 It is a control signal processing circuit principle diagram of the present application;

[0036] Figure 4 It is a subtraction circuit principle diagram of the present application;

[0037] Figure 5 It is a rectifier circuit principle diagram of the present application. DETAILED DESCRIPTION

[0038] As Figures 1 to 5The constant voltage digital adjustable load circuit for ultrasonic power supply shown in the application comprises a control signal processing circuit, a subtraction circuit, a voltage control circuit and an ultrasonic circuit connected in sequence, the voltage control circuit is further connected with a rectifier circuit, the input end of the rectifier circuit is connected with a transformer, and the transformer is connected with the ultrasonic power supply.

[0039] The rectifier circuit is used for converting alternating voltage into direct current voltage and outputting the direct current voltage to the voltage control circuit.

[0040] The control signal processing circuit is used for converting the input control signal into a direct current 0-5V analog signal.

[0041] The subtraction circuit is used for inverting the direct current 0-5V analog signal converted by the control signal processing circuit into a direct current 5-0V analog signal.

[0042] The voltage control circuit is used for receiving the direct current 5-0V analog signal converted by the subtraction circuit and the direct current voltage output by the rectifier circuit, controlling the primary voltage of the ultrasonic circuit to be a linear adjustable constant voltage of 0-100V, and outputting the direct current voltage to the ultrasonic circuit.

[0043] The ultrasonic circuit is used for converting the electric energy received by the voltage control circuit into ultrasonic energy for output.

[0044] The voltage control circuit comprises an operational amplifier U1A, resistors R7, R8, R10, R36, R71, R79, R83, voltage stabilizing tubes Z1 and Z2, a diode D14, capacitors C6, C45 and C49, and parallelly connected first, second, third and fourth MOS transistor voltage regulating circuits.

[0045] The first MOS voltage regulating circuit comprises MOS V1, triode Q10, resistor R11, resistor R15, resistor R35 and resistor RS4. One end of resistor R7 is connected to signal input end, and the other end is connected to one end of resistor R8. The other end of resistor R8 is connected to the inverting input end of operational amplifier U1A. The output end of operational amplifier U1A is connected to the first MOS voltage regulating circuit. Specifically, the output end of operational amplifier U1A is connected to the gate of MOS V1 through resistor R11. The gate of MOS V1 is also connected to the collector of triode Q10 and one end of resistor R15. The emitter of triode Q10 and the other end of resistor R15 are both grounded. The two ends of resistor R35 are connected to the source of MOS V1 and the base of triode Q10 respectively. The source of MOS V1 is also grounded through resistor RS4.

[0046] The second MOS voltage regulating circuit comprises MOS V2, triode Q8, resistor R12, resistor R16, resistor R80 and resistor RS3. The output end of operational amplifier U1A is connected to the gate of MOS V2 through resistor R12. The gate of MOS V2 is also connected to the collector of triode Q8 and one end of resistor R16. The emitter of triode Q8 and the other end of resistor R16 are both grounded. The two ends of resistor R80 are connected to the source of MOS V2 and the base of triode Q8 respectively. The source of MOS V2 is also grounded through resistor RS3. The third MOS voltage regulating circuit comprises MOS V3, triode Q6, resistor R13, resistor R17, resistor R81 and resistor RS2. The output end of operational amplifier U1A is connected to the gate of MOS V3 through resistor R13. The gate of MOS V3 is also connected to the collector of triode Q6 and one end of resistor R17. The emitter of triode Q6 and the other end of resistor R17 are both grounded. The two ends of resistor R81 are connected to the source of MOS V3 and the base of triode Q6 respectively. The source of MOS V3 is also grounded through resistor RS2. The fourth MOS voltage regulating circuit comprises MOS V4, triode Q4, resistor R14, resistor R18, resistor R82 and resistor RS1. The output end of operational amplifier U1A is connected to the gate of MOS V4 through resistor R14. The gate of MOS V4 is also connected to the collector of triode Q4 and one end of resistor R18. The emitter of triode Q4 and the other end of resistor R18 are both grounded. The two ends of resistor R82 are connected to the source of MOS V4 and the base of triode Q4 respectively. The source of MOS V4 is also grounded through resistor RS1.

[0047] Further, the output terminal and the inverting input terminal of the operational amplifier U1A are connected in series with the capacitor C45 and the resistor R10, the negative electrode of the stabilizing tube Z2, one end of the resistor R79 and one end of the capacitor C49 are connected to the non-inverting input terminal of the operational amplifier U1A, the positive electrode of the stabilizing tube Z2, the other end of the resistor R79 and the other end of the capacitor C49 are connected to the positive electrode of the stabilizing tube Z1, and the negative electrode of the stabilizing tube Z1 is connected to the common connection point of the resistor R7 and the resistor R8. One end of the resistor R71 is connected to the drain of the MOS tube 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 the 5V positive voltage, and the other end is connected to the anode of the diode D14, and 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 connected to one end of the resistor R71, and the other end of the resistor R36 and the other end of the capacitor C6 are commonly grounded.

[0048] The control signal processing circuit includes diode D11, diode D12, diode D13, triode Q1, triode Q2, triode Q3, triode Q5, capacitor C1, capacitor C2, capacitor C3, capacitor C4, capacitor C5, capacitor C7, capacitor C42, resistor R2, resistor R3, resistor R4, resistor R5, resistor R6, resistor R19, resistor R20, resistor R21, resistor R23, resistor R24, connector J2, connector J4, connector J5, connector J6, connector J7 and potentiometer RV2. One end of the connector J6 and the connector J7 is connected to the signal input terminal, the other end of the connector is connected to the base of the triode Q5, the other end of the connector J7 is connected to the collector of the triode Q5 through the diode D13, the base of the triode Q3 is connected to the collector of the triode Q5, the triode Q3 and the emitter of the triode Q5 are commonly grounded, the collector of the triode Q3 is connected to one end of the connector J5, the collector and the emitter of the triode Q3 are further provided with the potentiometer RV2, pin two of the potentiometer RV2 is connected to one end of the connector J4, the connector J4 and the other end of the connector J5 are sequentially connected to the base of the triode Q1 through the resistor R4, the resistor R21 and the resistor R23, the emitter of the triode Q1 is connected to the base of the triode Q2, the base and the collector of the triode Q2 are further connected to the 12V positive voltage through the resistor R5 and the resistor R6, and the emitter of the triode Q2 is used as the output terminal to output 0-5V analog signal to the subtraction circuit.

[0049] In addition, the plug J6 and signal input between the two diodes D11, J7 and signal input between the resistor R9, the plug J7 the other end is also through the resistance R19 access 12V positive voltage, the capacitor C1 and the resistor R9 parallel, the resistor R20 and diode D12 in series, and access the plug J6 both ends, the capacitor C2 and the diode parallel, the collector of the transistor Q3 through the resistance R2 access 5V positive voltage and capacitor C42, the collector of the transistor Q3 is also through the plug J2 access 5V positive voltage. The resistor R3 one end access the plug J4 and plug J5 common connection, the other end is grounded; the capacitor C3 and capacitor C4 one end respectively access the resistor R21 both ends, the other end of the capacitor C3 and capacitor C4 common ground. The capacitor C5 is provided between the base and collector of the transistor Q1, the emitter of the transistor Q2 is also connected with capacitor C7 and resistor R24, the capacitor C7 and resistor R24 parallel.

[0050] The rectifier circuit includes a fuse F1, capacitor C14, inductor LF1 and rectifier bridge D3, the pin one and pin three of the inductor LF1 are connected with the pin one and pin two of the transformer respectively, the pin one of the inductor LF1 and the pin two of the transformer are provided with a fuse F1, the two ends of the capacitor C14 are connected with the pin one and pin two of the transformer respectively, the pin two of the transformer is connected with the live wire ACL, the pin one is connected with the neutral wire ACN, the pin one of the rectifier bridge D3 is connected with the pin two of the inductor LF1, the pin two of the rectifier bridge D3 outputs 141V positive voltage, the pin three and pin four are grounded with the pin four of the inductor LF1.

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

[0052] The ultrasonic wave circuit comprises a current transformer T1, a current transformer T3, an inductor L1, an operational amplifier U8, a MOS tube V8, a MOS tube V9, a diode D8, a diode D9, a capacitor C18, a capacitor C19, a capacitor C23, a capacitor C24, a capacitor C27, a capacitor C28, a capacitor C29, a capacitor C30, a capacitor C31, a resistor R28, a resistor R33, a resistor R34, a resistor R47, a resistor R48, a resistor R50, a resistor R51, a resistor R60, a resistor R61 and an ultrasonic wave transducer P2. The drain of the MOS tube V9 is connected to a 141V positive voltage, the source of the MOS tube V9 is connected to the drain of the MOS tube V8, the resistor R33 is connected to the gate and the source of the MOS tube V9, and the resistor R34 is connected to the gate and the source of the MOS tube V8. The pin 1 of the current transformer T1 is connected to the drain of the MOS tube V9 and the source of the MOS tube V8, the pin 2 of the current transformer T1 is connected to the source of the MOS tube V9 and the drain of the MOS tube V8, the pin 3 of the current transformer T1 is connected to one end of the inductor L1, and the pin 4 of the current transformer T1 is connected to the pin 1 of the current transformer T3. In addition, the pin 1 of the current transformer T1 is also connected to one end of the capacitor C18, the capacitor C19, the resistor R28 and the resistor R29, the other end of the capacitor C18 and the resistor R28 is connected to the source of the MOS tube V8, and the other end of the capacitor C19 and the resistor R29 is connected to the drain of the MOS tube V9. The other end of the inductor L1 is connected to one end of the ultrasonic wave transducer P2, the other end of the ultrasonic wave transducer P2 is connected to the pin 2 of the current transformer T3, and the capacitor C23 and the capacitor C24 are connected in parallel to the ultrasonic wave transducer P2. The pin 4 of the current transformer T3 is connected to the non-inverting input terminal of the operational amplifier U8 through the resistor R60, and the pin 3 of the current transformer T3 is connected to the inverting input terminal of the operational amplifier U8 through the resistor R47. The capacitor C28, the capacitor C27, the resistor R48, the resistor R61, the cathode of the diode D9 and the anode of the diode D8 are all connected to the non-inverting input terminal of the operational amplifier U8, the other end of the capacitor C28, the capacitor C29, the capacitor C31, the resistor R48, the resistor R49, the resistor R50, the anode of the diode D9 and the cathode of the diode D8 are all connected to the inverting input terminal of the operational amplifier U8, and the other end of the resistor R50, the resistor R61, the capacitor C27 and the capacitor C31 is grounded, and the other end of the capacitor C29 and the resistor R49 is connected to a 12V positive voltage.

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

[0054] Step 1: rectify the 100V alternating current output by the transformer into a direct current with a maximum value of 141V through the rectifier circuit.

[0055] Step 2: control signal input to the control signal processing circuit, the control signal processing circuit by jumper selection analog control signal input or PWM digital signal input, PWM digital signal can be selected high level or low level effective, the control signal processing circuit converts the input control signal to DC 0-5V linear adjustable analog signal;

[0056] Step 3: using the subtraction circuit in step 2 converted into DC 0-5V linear adjustable analog signal to DC 5-0V analog signal;

[0057] Step 4: the voltage control circuit receives the subtraction circuit in step 3 converted into DC 5-0V analog signal, and the resistance R71 and resistance R79 collected by the operational amplifier U1A comparison amplification output, 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 the operational amplifier U1A drops, the gate voltage of the MOS tube V1, MOS tube V2, MOS tube V3 and MOS tube V4 drops, because the MOS tube V1, MOS tube V2, MOS tube V3 and MOS tube V4 work in parallel in the amplification zone, the drain voltage rises, the voltage of the ultrasonic primary voltage sampling signal input by the same phase input end also rises in proportion to the voltage value of the analog signal, when the output of the operational amplifier U1A is stable at a constant voltage value, thereby controlling the primary voltage of the ultrasonic circuit to be 0-100V linear adjustable constant voltage. The drain voltage U of the MOS tube V1, MOS tube V2, MOS tube V3 and MOS tube V4 is calculated as follows:

[0058]

[0059] Wherein Ua represents the voltage value of the ultrasonic primary voltage sampling signal, the resistance R71 is 100K, and the resistance R79 is 5.1K.

[0060] The specific voltage regulating process principle is as follows:

[0061] When the analog signal inputted to the inverting terminal of the operational amplifier U1A is 4.5V and the ultrasonic primary voltage sampling signal inputted to the non-inverting terminal is 4.4V, the drain voltage U of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 is calculated as 90.67V according to the formula, at this time the output of the operational amplifier U1A drops, the negative feedback is formed by the integral circuit composed of the capacitor C45 and the resistor R10 and fed back to the inverting terminal, which plays a role of stabilizing the circuit, the output of the operational amplifier U1A drops, the gate voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 also drops, since the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 work in parallel in the amplification zone of the operational amplifier U1A, the drain voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 rises, when the ultrasonic primary voltage sampling signal voltage inputted to the non-inverting terminal of the operational amplifier U1A rises to 4.5V in proportion, the output of the operational amplifier U1A stabilizes at a constant voltage value, and the drain voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 working in parallel is always kept as 92.74V.

[0062] Similarly, when the analog signal inputted to the inverting terminal of the operational amplifier U1A is 1.0V and the ultrasonic primary voltage sampling signal inputted to the non-inverting terminal is 0.9V, the drain voltage U of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 is calculated as 18.54V according to the formula, at this time the output of the operational amplifier U1A drops, the negative feedback is formed by the integral circuit composed of the capacitor C45 and the resistor R10 and fed back to the inverting terminal, which plays a role of stabilizing the circuit, the output of the operational amplifier U1A drops, the gate voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 also drops, since the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 work in parallel in the amplification zone of the operational amplifier U1A, the drain voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 rises, when the ultrasonic primary voltage sampling signal voltage inputted to the non-inverting terminal of the operational amplifier U1A rises to 1.0V in proportion, the output of the operational amplifier U1A stabilizes at a constant voltage value, and the drain voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 working in parallel is always kept as 20.61V.

[0063] Thus the primary voltage of the ultrasonic circuit is linearly adjustable constant voltage from 0 to 100V, and the DC voltage is outputted to the ultrasonic circuit.

[0064] The above merely describes the best mode of the present application, and is not used to limit the present application, and various modifications or replacements made by those skilled in the art without departing from the spirit and protection scope of the present application shall be within the protection scope of the present application.

Claims

1. A constant voltage digitally adjustable load circuit for an ultrasonic power supply, characterized by: The ultrasonic power supply comprises a control signal processing circuit, a subtraction circuit, a voltage control circuit, and an ultrasonic circuit connected with the voltage control circuit in sequence, and the voltage control circuit is further connected with a rectifier circuit, an input end of the rectifier circuit is connected with a transformer, and the transformer is connected with an ultrasonic power supply; The rectifier circuit is used for converting an alternating voltage into a direct current voltage and outputting the direct current voltage to the voltage control circuit; The control signal processing circuit is used for converting an input control signal into a direct current 0-5V analog signal; The subtraction circuit is used for converting the direct current 0-5V analog signal converted by the control signal processing circuit into a direct current 5-0V analog signal; The voltage control circuit is used for receiving the direct current 5-0V analog signal converted by the subtraction circuit and the direct current voltage output by the rectifier circuit, and controlling a primary voltage of the ultrasonic circuit to be a 0-100V linear adjustable constant voltage, and outputting the direct current voltage to the ultrasonic circuit; The voltage control circuit comprises an operational amplifier U1A, resistors R7, R8, R10, R36, R71, R79, R83, voltage stabilizing tubes Z1, Z2, a diode D14, capacitors C6, C45, C49, and first, second, third and fourth MOS transistor voltage regulating circuits connected in parallel, one end of the resistor R7 is connected with a signal input end, the other end is connected with one end of the resistor R8, the other end of the resistor R8 is connected with an inverting input end of the operational amplifier U1A, an output end of the operational amplifier U1A is connected with the first MOS transistor voltage regulating circuit, the output end and the inverting input end of the operational amplifier U1A are further connected with the capacitor C45 and the resistor R10 in series, a negative electrode of the voltage stabilizing tube Z2, one end of the resistor R79 and one end of the capacitor C49 are all connected with a non-inverting input end of the operational amplifier U1A, a positive electrode of the voltage stabilizing tube Z2, the other end of the resistor R79 and the other end of the capacitor C49 are all connected with a positive electrode of the voltage stabilizing tube Z1, a negative electrode of the voltage stabilizing tube Z1 is connected with a common connection point of the resistor R7 and the resistor R8, one end of the resistor R71 is connected with a drain electrode of the MOS transistor V1 and connected with the ultrasonic circuit, the other end is connected with the non-inverting input end of the operational amplifier U1A, one end of the resistor R83 is connected with a 5V positive electrode voltage, the other end is connected with an anode of the diode D14, a cathode of the diode D14 is connected with the non-inverting input end of the operational amplifier U1A, one end of the resistor R36 and one end of the capacitor C6 are both connected with one end of the resistor R71, the other end of the resistor R36 and the other end of the capacitor C6 are both grounded; The ultrasonic circuit is used for converting electric energy received by the voltage control circuit into ultrasonic energy for output.

2. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 1, wherein: The control signal processing circuit comprises a diode D11, a diode D13, a triode Q1, a triode Q2, a triode Q3, a triode Q5, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a capacitor C7, a capacitor C42, a resistor R2, a resistor R3, a resistor R4, a resistor R5, a resistor R6, a resistor R19, a resistor R20, a resistor R21, a resistor R23, a resistor R24, a connector J4, a connector J5, a connector J6, a connector J7 and a potentiometer RV2; one end of the connector J6 and the connector J7 is connected to a signal input end, the other end of the connector is connected to the base of the triode Q5, the other end of the connector J7 is connected to the collector of the triode Q5 through the diode D13, the base of the triode Q3 is connected to the collector of the triode Q5, the triode Q3 and the emitter of the triode Q5 are commonly grounded, the collector of the triode Q3 is connected to one end of the connector J5, the collector and the emitter of the triode Q3 are further provided with the potentiometer RV2, pin two of the potentiometer RV2 is connected to one end of the connector J4, the connector J4 and the other end of the connector J5 are sequentially connected to the base of the triode Q1 through the resistor R4, the resistor R21 and the resistor R23, the emitter of the triode Q1 is connected to the base of the triode Q2, the base and the collector of the triode Q2 are further connected to 12V positive voltage through the resistor R5 and the resistor R6 respectively, the emitter of the triode Q2 is used as an output end and outputs 0-5V analog signals to the subtraction circuit.

3. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 1, wherein: The first MOS tube voltage regulating circuit comprises a MOS tube V1, a triode Q10, a resistor R11, a resistor R15, a resistor R35 and a resistor RS4; the output end of the operational amplifier U1A is connected to the gate of the MOS tube V1 through the resistor R11, the gate of the MOS tube V1 is further connected to the collector of the triode Q10 and one end of the resistor R15, the emitter of the triode Q10 and the other end of the resistor R15 are commonly grounded, the two ends of the resistor R35 are connected to the source of the MOS tube V1 and the base of the triode Q10 respectively, and the source of the MOS tube V1 is further grounded through the resistor RS4.

4. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 1, wherein: The subtraction circuit includes operational amplifier U1A, transistor Q7, transistor Q9, transistor Q11, resistor R72, resistor R73, resistor R74, resistor R75, resistor R76, resistor R77, resistor R30 and capacitor C8; one end of the resistor R72 and the resistor R73 is connected to the inverting input terminal of the operational amplifier U1A, the other end of the resistor R72 is connected to the analog signal input terminal, the other end of the R73 is connected to the analog signal output terminal, one end of the resistor R74 and resistor R75 is connected to the non-inverting input terminal of the operational amplifier U1A, the other end of the resistor R74 is connected to 5V positive voltage, the other end of the resistor R75 is grounded, the output terminal of the operational amplifier U1A is connected with the base of the transistor Q7, the collector of the transistor Q7 is connected to 12V positive voltage through the resistor R31, the emitter is connected to the analog signal output terminal, and is grounded through the capacitor C8 at the same time; the output terminal of the operational amplifier U1A is also grounded through the resistor R77; the bases of the transistor Q9 and the transistor Q11 are connected with 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 5V positive voltage through the resistor R76, the emitters of the transistor Q9 and the transistor Q11 are grounded, and the base and the collector of the transistor Q11 are short-circuited.

5. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 1, wherein: The rectifier circuit includes a fuse F1, a capacitor C14, an inductor LF1 and a rectifier bridge D3, the pin one and the pin three of the inductor LF1 are connected with the pin one and the pin two of the transformer respectively, the fuse F1 is arranged between the pin one of the inductor LF1 and the pin two of the transformer, the two ends of the capacitor C14 are connected with the pin one and the pin two of the transformer respectively, the pin two of the transformer is connected to the live wire ACL, and the pin one is connected to the neutral wire ACN, the pin one of the rectifier bridge D3 is connected to the pin two of the inductor LF1, the pin two of the rectifier bridge D3 outputs 141V positive voltage, and the pin three and the pin four are grounded with the pin four of the inductor LF1.

6. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 1, wherein: The ultrasonic circuit comprises a current transformer T1, a current transformer T3, an inductor L1, an operational amplifier U8, a MOS tube V8, a MOS tube V9, a diode D8, a diode D9, a capacitor C23, a capacitor C24, a capacitor C27, a capacitor C28, a capacitor C29, a capacitor C30, a capacitor C31, a resistor R33, a resistor R34, a resistor R47, a resistor R48, a resistor R50, a resistor R51, a resistor R60, a resistor R61 and an ultrasonic transducer P2; a drain of the MOS tube V9 is connected to a 141V positive voltage, a source of the MOS tube V9 is connected to a drain of the MOS tube V8, two ends of the resistor R33 are connected to a gate and a source of the MOS tube V9 respectively, two ends of the resistor R34 are connected to a gate and a source of the MOS tube V8 respectively; a pin one of the current transformer T1 is connected to the drain of the MOS tube V9 and the source of the MOS tube V8, a pin two of the current transformer T1 is connected to the source of the MOS tube V9 and the drain of the MOS tube V8, a pin three of the current transformer T1 is connected to one end of the inductor L1, a pin four of the current transformer T1 is connected to a pin one of the current transformer T3, the other end of the inductor L1 is connected to one end of the ultrasonic transducer P2, the other end of the ultrasonic transducer P2 is connected to a pin two of the current transformer T3, the capacitor C23 and the capacitor C24 are connected to the ultrasonic transducer P2 in parallel; the pin four of the current transformer T3 is connected to a non-inverting input terminal of the operational amplifier U8 through the resistor R60, the pin three of the current transformer T3 is connected to an inverting input terminal of the operational amplifier U8 through the resistor R47; one end of the capacitor C28, one end of the capacitor C27, one end of the resistor R48, one end of the resistor R61, a cathode of the diode D9 and an anode of the diode D8 are connected to the non-inverting input terminal of the operational amplifier U8, the other end of the capacitor C28, one end of the capacitor C29, one end of the capacitor C31, one end of the resistor R48, one end of the resistor R49, one end of the resistor R50, an anode of the diode D9 and a cathode of the diode D8 are connected to the inverting input terminal of the operational amplifier U8, the other ends of the resistor R50, the resistor R61, the capacitor C27 and the capacitor C31 are grounded, the other ends of the capacitor C29 and the resistor R49 are connected to a 12V positive voltage.

7. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 6, wherein: The ultrasonic circuit further comprises a capacitor C18, a capacitor C19, a resistor R28 and a resistor R29, one end of the capacitor C18, the capacitor C19, the resistor R28 and the resistor R29 is connected to the pin one of the current transformer T1, the other end of the capacitor C18 and the resistor R28 is connected to the source of the MOS tube V8, the other end of the capacitor C19 and the resistor R29 is connected to the drain of the MOS tube V9.

8. The constant voltage digitally adjustable load circuit for an ultrasonic power supply of claim 6, wherein: The control signal processing circuit selects analog control signal input or PWM digital signal input through a jumper, and the PWM digital signal can be selected as high level effective or low level effective.

9. Method for operating a constant voltage digitally adjustable load circuit for an ultrasonic power supply, characterized in that The constant voltage digital adjustable load circuit for the ultrasonic power supply according to any one of claims 1 to 8 comprises the following steps: Step 1: The ultrasonic power supply outputs 100V AC voltage through the transformer, and then the rectifier circuit rectifies the 100V AC voltage into a DC voltage with a maximum value of 141V and outputs the DC voltage to the voltage control circuit; Step 2: The control signal is input to the control signal processing circuit, the control signal processing circuit selects the input of the analog control signal or the input of the PWM digital signal through the jumper, the PWM digital signal can be selected to be high-level active or low-level active, and the control signal processing circuit converts the input control signal into a DC 0-5V linear adjustable analog signal; Step 3: The converted DC 0-5V linear adjustable analog signal in step 2 is inverted into a DC 5-0V analog signal by using the subtraction circuit; 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 the output with the ultrasonic primary voltage sampling signal through the 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 the operational amplifier U1A decreases, the gate voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 decreases, since the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 work in parallel in the amplification zone of the operational amplifier U1A, the drain voltage of the MOS tube V1, the MOS tube V2, the MOS tube V3 and the MOS tube V4 rises, and the ultrasonic primary voltage sampling signal voltage input at the same-phase input end of the operational amplifier U1A also rises proportionally, when it rises to the same voltage value as the analog signal, the output of the operational amplifier U1A is stable at a constant voltage value, thereby controlling the primary voltage of the ultrasonic circuit to be a linear adjustable constant voltage of 0-100V.

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