Current-voltage conversion circuit structure for electroporation delivery

Abstract

The invention discloses a current-to-voltage conversion circuit structure for electroporation delivery. The current-to-voltage conversion circuit structure comprises a current-to-voltage conversion circuit and a voltage-to-pulse conversion circuit. The current-to-voltage circuit converts current signals into voltage through an input signal processing module, high-precision amplification is achieved through an operational amplifier and a feedback network of a signal amplification module, the driving capacity is enhanced through a transistor cascade circuit, and temperature drift is dynamically compensated in combination with a thermistor. The voltage-to-pulse circuit corrects non-linear errors through a resistance network of the linearization processing module, achieves gain adjustment through an operational amplifier and an adjustable resistor, and finally adapts to load changes through a field effect transistor and a negative feedback network. The circuit realizes high conversion precision, wide temperature range stability and load adaptive capability, and is suitable for high-precision scenes such as medical treatment or beauty electroporation, industrial sensing and the like.

Description

Technical Field

[0001] The present invention relates to the field of medical electronic circuits, and in particular to a current-voltage conversion circuit structure for electroporation delivery. Background Art

[0002] In modern electronic systems, current signals and current signal conversion are common signal processing requirements. For example, in sensor signal processing, analog signal transmission, and data acquisition systems, it is often necessary to convert current signals into current signals for further processing or measurement. Traditional current-to-voltage conversion circuits typically use a simple resistance conversion method, but this method has problems such as low accuracy, large temperature drift, and poor linearity, making it difficult to meet the needs of high-precision measurement and complex signal processing. In addition, traditional circuits often require redesigning circuit parameters when facing different input current ranges, which lacks flexibility and versatility.

[0003] Therefore, how to overcome the above-mentioned defects has become an important issue to be solved urgently by those skilled in the art. Summary of the Invention

[0004] The present invention overcomes the shortcomings of the above-mentioned technologies and provides a current-voltage conversion circuit structure for electroporation delivery, solving the problems of low precision, large temperature drift and poor linearity caused by simple resistance conversion in traditional circuits.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A current-to-voltage conversion circuit structure for electroporation delivery, comprising: a current-to-voltage conversion circuit 1 connected to an external signal source; the current-to-voltage conversion circuit 1 comprises:

[0007] An input signal processing module 11, whose input terminal is connected to an external signal source and is used to convert the input current signal into a voltage signal;

[0008] The signal amplification processing module 12 is connected to the output end of the input signal processing module 11 and is used to amplify the converted voltage signal;

[0009] The output driving module 13 is connected to the output end of the signal amplification processing module 12 and is used to enhance the current driving capability of the circuit and output a stable voltage signal;

[0010] The temperature compensation module 14 is connected to the power supply circuit of the signal amplification processing module 12 and is used to dynamically adjust the equivalent impedance of the power supply circuit to compensate for the impact of temperature changes on circuit accuracy; wherein, the signal amplification processing module 12 includes a first operational amplifier 121.

[0011] Preferably, the input signal processing module 11 includes: a current signal input terminal 111 connected to an external signal source and a sampling unit 112 for converting the input current into a voltage; the sampling unit 112 includes: a first resistor R20, and the current signal input terminal 111 is connected to the non-inverting input terminal of the first operational amplifier 121 through the first resistor R20.

[0012] Preferably, the signal amplification processing module 12 includes the first operational amplifier 121 and a feedback network for optimizing frequency characteristics; the feedback network includes a second resistor R14, a fourth resistor R5 and a first capacitor C4; one end of the second resistor R14 is grounded through the fourth resistor R5, and the other end is connected to the inverting input terminal of the first operational amplifier 121, and a first capacitor C4 is connected between the inverting input terminal and the output terminal of the first operational amplifier 121.

[0013] Preferably, the first operational amplifier 121 is an operational amplifier of model LMV321 IDBVR; the second resistor R14 is a metal film resistor with a precision of 0.1%.

[0014] Preferably, the output drive module 13 includes a cascaded transistor circuit 131 for enhancing current driving capability, a voltage clamping circuit (132) for stabilizing output voltage, and a first interface P1; the transistor circuit 131 includes: a fifth resistor R13, a first transistor Q5, a second transistor Q3, the output end of the first operational amplifier 121 is connected to the base of the first transistor Q5 through the fifth resistor R13, and the collector of the first transistor Q5 is connected to the emitter of the second transistor Q3; the voltage clamping circuit (132) includes: a first diode D1, a second diode D2, and a third resistor (R10), the base of the second transistor Q3 is respectively connected to the DC voltage input end VC3 and the positive electrode of the second diode D2 through the third resistor R10, the cathode of the second diode D2 is respectively connected to the collector of the second transistor Q3 and the negative electrode of the first diode D1, and the positive electrode of the first diode D1 is connected to the first interface P1.

[0015] Preferably, the temperature compensation module 14 includes a temperature sensitive element for adjusting the power supply circuit parameters according to temperature changes; the temperature sensitive element is a thermistor R19 connected between the power supply terminal of the first operational amplifier 121 and the ground.

[0016] Preferably, it also includes: a voltage-to-pulse conversion circuit 2 connected to an external signal source; the voltage-to-pulse conversion circuit 2 includes: a linearization processing module 21, a gain adjustment module 22 for adjusting the output voltage amplitude and a load adaptation module 23 for automatically adjusting the output impedance according to load changes; the input end of the linearization processing module 21 is used to receive the input voltage, and the output end is connected to the input end of the gain adjustment module 22; the output end of the gain adjustment module 22 is connected to the input end of the load adaptation module 23, and the output end of the load adaptation module 23 is used to output a pulse signal; wherein, the linearization processing module 21 adopts a nonlinear correction circuit for correcting the nonlinear relationship between the input current and the output voltage.

[0017] Preferably, the nonlinear correction circuit of the linearization processing module 21 includes: a sixth resistor R21, a seventh resistor R24, an eighth resistor R23, and a ninth resistor R18; the external signal source is respectively connected to one end of the sixth resistor R21, one end of the ninth resistor R18, and one end of the seventh resistor R24 through the eighth resistor R23, the other end of the sixth resistor R21 is connected to the DC voltage input terminal VC3, the other end of the ninth resistor R18 is grounded, and one end of the seventh resistor R24 is connected to the input terminal of the gain adjustment module 22, and the other end is connected to the DC voltage input terminal VC3.

[0018] Preferably, the gain adjustment module 22 includes: a second operational amplifier U1 and its peripheral circuits, the operational amplifier U1 adopts an amplifier chip model LTC6090 IS8E; wherein an adjustable resistor or digital potentiometer is connected between the inverting input terminal and the output terminal of the operational amplifier U1.

[0019] Preferably, the load adaptation module 23 includes: a third transistor Q1, a field-effect transistor Q4, a fourteenth resistor R2, a fifteenth resistor R1, a sixteenth resistor R8, a seventeenth resistor R9, a nineteenth resistor R4, and a second interface P2; the output end of the gain adjustment module 22 is respectively connected to the source of the field-effect transistor Q4 and one end of the sixteenth resistor R8, the gate of the field-effect transistor Q4 is respectively connected to the other end of the sixteenth resistor R8 and one end of the nineteenth resistor R4, the drain of the field-effect transistor Q4 is connected to the second interface P2 and is grounded through the seventeenth resistor R9, and the other end of the nineteenth resistor R4 is connected to the collector of the third transistor Q1; the external signal source is connected to one end of the fifteenth resistor R1 and the base of the third transistor Q1 through the fourteenth resistor R2, the other end of the fifteenth resistor R1 is grounded, and the emitter of the third transistor Q1 is grounded; the collector of the third transistor Q1 is also connected to the gate of the field-effect transistor Q4.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. This case achieves highly linear conversion of current signals to voltage signals through a cascaded design of an input signal processing module and a signal amplification processing module, meeting the signal accuracy requirements of electroporation delivery. The output drive module enhances current drive capability, enabling the circuit to stably drive loads of varying impedances and avoid voltage drops due to load changes. The temperature compensation module, in collaboration with the signal amplification processing module, directly acts on the power supply terminal of the first operational amplifier to specifically compensate for temperature-induced precision drift, enabling dynamic compensation of the conversion circuit in response to temperature changes, effectively reducing the impact of temperature drift on conversion accuracy.

[0022] 2. The linearization processing module of the voltage-to-pulse conversion circuit in this case adopts the setting of a nonlinear correction circuit, which facilitates the correction of the nonlinear relationship between the input current and the output voltage, so as to improve the linearity of the circuit through precise linearization processing, ensure high-precision conversion within a wide input current range, and make the output pulse signal more accurately reflect the actual changes of the input voltage signal, thereby greatly reducing nonlinear errors, significantly improving the conversion accuracy of the circuit, and meeting the needs of high-precision measurement. Through the setting of the gain adjustment module, a gain adjustment function is provided, allowing the user to adjust the amplitude range of the output voltage according to actual needs, thereby enhancing the versatility and flexibility of the circuit. Through the setting of the load adaptation module, the circuit in this case can automatically adjust the output impedance according to load changes, ensure the stability of the output voltage, further improve the adaptability and reliability of the circuit, enable it to be widely used in different load environments, and also enhance the versatility and flexibility of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the circuit diagram of the overall current-voltage conversion circuit structure of this case.

[0024] Figure 2 This is the circuit diagram of the current-to-voltage conversion circuit.

[0025] Figure 3 This is the circuit diagram of the voltage-to-pulse conversion circuit in this case. DETAILED DESCRIPTION

[0026] The following examples further illustrate the features of the present invention and other related features to facilitate understanding by those skilled in the art:

[0027] like Figures 1 to 3 As shown, this embodiment provides a current-voltage conversion circuit structure for electroporation delivery, which includes a current-to-voltage conversion circuit 1 and a voltage-to-pulse conversion circuit 2 respectively connected to the voltage output terminal.

[0028] The current-to-voltage conversion circuit 1 is mainly composed of the following modules:

[0029] Input signal processing module 11: Its input terminal is connected to an external signal source and is used to convert the input current signal into a voltage signal. The input signal processing module 11 includes: a current signal input terminal 111 connected to an external signal source (such as a signal output pin of a single-chip microcomputer) and a sampling unit 112 for converting the input current into a voltage. The voltage sampling unit 112 is a first resistor R20, which can serve as an input resistor. Specifically, one end of the first resistor R20 is connected to the current signal input terminal 111 and the other end is connected to the non-inverting input terminal of a first operational amplifier 121. The input current is sampled through the first resistor R20 and initially converted into a voltage signal.

[0030] In this way, the input current signal is converted into a voltage signal through R20 (according to Ohm's law (V = I times R_{20})). R20 acts as a sampling resistor, linearly converting the input current signal into a voltage signal. The non-inverting input of the first operational amplifier receives this voltage signal, utilizing the high input impedance of the op amp to isolate the input signal from subsequent circuits and reduce loading effects. Furthermore, the resistance of the first resistor (R20) is ≤ 200Ω, with 100Ω selected in the figure. This low-impedance design reduces signal source loading effects and prevents input signal distortion.

[0031] Signal amplification processing module 12: It is connected to the output end of the input signal processing module 11 and is used to amplify the converted voltage signal; the signal amplification processing module 12 includes a first operational amplifier 121 and a feedback network, and the feedback network is used to optimize the frequency characteristics. The first operational amplifier 121 is provided with a non-inverting input end, an inverting input end, a power supply end, a ground end, and an output end. The feedback network includes a second resistor R14, a fourth resistor R5, and a first capacitor C4; one end of the second resistor R14 is grounded through the fourth resistor R5, and the other end is connected to the inverting input end of the first operational amplifier 121. The first capacitor C4 is connected between the inverting input end and the output end of the first operational amplifier 121; the output end of the first operational amplifier 121 is connected to the output driver module 13 through the fifth resistor R13.

[0032] In this case, the inverting input of the first operational amplifier U2 of the signal amplification processing module 12 is grounded via the second resistor R14 and the fourth resistor R5. A first capacitor C4 is connected between the output terminal and the second resistor R14, forming a negative feedback amplifier circuit. This amplifies the initially converted voltage signal and optimizes the frequency characteristics through the first capacitor C4. Thus, the feedback network, consisting of the second resistor R14, the fourth resistor R5, and the first capacitor C4, forms a negative feedback amplifier circuit with the first operational amplifier 121. On the one hand, the feedback network feeds back a portion of the output signal to the inverting input terminal, automatically adjusting the operational amplifier gain and ensuring a linear relationship between the output voltage and the input voltage. On the other hand, negative feedback suppresses the nonlinear error of the operational amplifier open-loop gain, improving signal amplification accuracy. An RC network is also formed between the first capacitor C4 and the fourth resistor R5 to filter out high-frequency noise and avoid signal distortion. Furthermore, the fifth resistor R13 can limit the output current, protect subsequent circuits, and cooperate with the input impedance of the output driver module 13 to form an impedance match and reduce signal reflections.

[0033] Output driver module 13: connected to the output end of the signal amplification processing module 12, used to enhance the current driving capability of the circuit and output a stable voltage signal; the output driver module 13 includes a cascaded transistor circuit 131 and a voltage clamping circuit 132, the transistor circuit 131 is used to enhance the current driving capability, and the voltage clamping circuit 132 is used to stabilize the output voltage; wherein, the transistor circuit 131 includes: the fifth resistor R13, the first transistor Q5, and the second transistor Q3, the output end of the first operational amplifier 121 is connected to the base of the first transistor Q5 through the fifth resistor R13, and the collector of the first transistor Q5 is connected to the emitter of the second transistor Q3, thereby enhancing the current driving capability to stabilize the output. The voltage clamping circuit (132) includes: a first diode D1, a second diode D2, and a third resistor (R10). The base of the second transistor Q3 is connected to the DC voltage input terminal VC3 and the positive electrode of the second diode D2 respectively through the third resistor R10. The negative electrode of the second diode D2 is connected to the collector of the second transistor Q3 and the negative electrode of the first diode D1 respectively. The positive electrode of the first diode D1 is connected to the first interface P1. The first interface P1 outputs a stable voltage signal through the diode clamping action. In a specific implementation, when the output voltage is higher than the DC voltage (VC3) plus the forward voltage drop of the diode, the first diode (D1) is turned on, limiting the output voltage to VC3+0.7V, thereby achieving forward clamping. When the output voltage is lower than the ground potential, the first diode (D1) is turned on, limiting the output voltage to -0.7V, thereby achieving reverse clamping. Through the current amplification action of the cascade transistors (Q5, Q3), it is ensured that the clamping circuit can quickly respond and maintain a stable output voltage under different load conditions, thereby achieving dynamic stability. The transistor is a triode.

[0034] In this way, the cascade design of the first transistor Q5 and the second transistor Q3 forms a complementary push-pull output stage, which significantly improves the output current capability, enhances the output drive capability, and reduces the output impedance; and the push-pull structure can quickly respond to load changes and maintain a stable output voltage. In addition, the push-pull structure maintains high linearity (distortion <0.1%) within the signal amplification range, which is suitable for precision signal processing. The fifth resistor R13 limits the base current of the first transistor Q5 to prevent op amp overload; the third resistor (R10) serves as the base bias resistor of the second transistor Q3 to provide a static operating point. The second diode D2 is used to clamp the collector voltage of Q3 to prevent reverse breakdown. The first diode (D1) is used for reverse voltage protection or level shifting at the output end. By forming a bidirectional clamping circuit composed of the first diode D1, the second diode D2, and the third resistor R10, the output voltage is prevented from exceeding the safe range, avoiding overvoltage damage to the subsequent circuit. The output signal is transmitted to the external load through the interface P1.

[0035] Temperature compensation module 14: Connected to the power supply circuit of the signal amplification and processing module 12, it is used to dynamically adjust the equivalent impedance of the power supply circuit to compensate for the impact of temperature changes on circuit accuracy. The temperature compensation module 14 includes a temperature-sensitive element for adjusting the power supply circuit parameters based on temperature changes. The temperature-sensitive element is a thermistor R19 connected between the power supply terminal and ground of the first operational amplifier 121. The impedance of the operational amplifier power supply circuit is dynamically adjusted by changing its resistance value with temperature, compensating for the impact of temperature drift on conversion accuracy.

[0036] Specifically, the entire current-to-voltage conversion circuit 1 includes: a current signal input terminal 111, a DC voltage input terminal VC3, a first resistor R20, a second resistor R14, a first operational amplifier 121, a first transistor Q5, a second transistor Q3, a third resistor R10, a first diode D1, a second diode D2, a fourth resistor R5, a fifth resistor R13, a thermistor R19, and a first interface P1; the current signal input terminal T2 is connected to the non-inverting input terminal of the first operational amplifier 121 through the first resistor R20, one end of the second resistor R14 is grounded through the fourth resistor R5, and the other end is connected to the inverting input terminal of the first operational amplifier 121; the power supply terminal of the first operational amplifier 121 is connected to the DC voltage input terminal VC3 and A thermistor R19 is connected between its power supply terminal and ground; the ground terminal of the first operational amplifier 121 is grounded, and the output terminal is connected to the base of the first transistor Q5 via a fifth resistor R13. The emitter of the first transistor Q5 is grounded via a third resistor R5, and the collector is connected to the emitter of the second transistor Q3. The base of the second transistor Q3 is connected to the DC voltage input terminal VC3 and the anode of the second diode D2 via a third resistor R10, respectively. The cathode of the second diode D2 is connected to the collector of the second transistor Q3 and the cathode of the first diode D1, respectively. The anode of the first diode D1 is connected to the first port P1. A first capacitor C4 is connected between the other end of the second resistor R14 and the output terminal of the first operational amplifier 121.

[0037] As described above, this case achieves high-linearity conversion of current signals to voltage signals through the cascade design of the input signal processing module 11 and the signal amplification processing module 12, meeting the signal accuracy requirements of electroporation delivery. The output drive module 13 enhances the current driving capability, enabling the circuit to stably drive loads of different impedances and avoid voltage drops due to load changes. The temperature compensation module 14 can cooperate with the signal amplification processing module 12 to directly act on the power supply terminal of the first operational amplifier 121, specifically compensating for the accuracy drift caused by temperature, so that the conversion circuit of this case can be dynamically compensated according to temperature changes, effectively reducing the impact of temperature drift on conversion accuracy.

[0038] like Figure 2 As shown in the figure, as a preferred embodiment, the first operational amplifier 121 is an LMV321 IDBVR first operational amplifier; the second resistor R14 is a 0.1% precision metal film resistor. Specifically, the LMV321 IDBVR is a low-power, low-offset voltage operational amplifier, which reduces system errors. The 0.1% precision metal film resistor has a low temperature coefficient, avoiding the gain drift caused by traditional carbon film resistors. Furthermore, the 0.1% precision metal film resistor is a high-precision resistor, achieving high-precision current-voltage conversion.

[0039] like Figure 3 As shown, as a preferred embodiment, the circuit of this case also includes: a voltage-to-pulse conversion circuit 2 connected to an external signal source (such as an output pin of a single-chip microcomputer); the voltage-to-pulse conversion circuit 2 includes: the voltage-to-pulse conversion circuit 2 includes: a linearization processing module 21, a gain adjustment module 22 and a load adaptation module 23; the input end of the linearization processing module 21 is used to receive the input voltage, and the output end is connected to the input end of the gain adjustment module 22; the output end of the gain adjustment module 22 is connected to the input end of the load adaptation module 23, and the output end of the load adaptation module 23 is used to output a pulse signal. Specifically, the linearization processing module 21 uses a nonlinear correction circuit to correct the nonlinear relationship between the input current and the output voltage. The linearization process ensures that the change in input voltage can be accurately converted into a signal that can be processed by subsequent modules, laying the foundation for generating an accurate pulse signal. The gain adjustment module 22 is used to provide a gain adjustment function, allowing the user to adjust the amplitude range of the output voltage according to actual needs. Specifically, the external voltage signal (such as the output of the single-chip microcomputer) first enters the linearization module, and the nonlinear error is corrected by the resistor network to output a voltage signal with high linearity. The linearized signal enters the gain adjustment module, where the operational amplifier amplifies or reduces the signal based on the ratio of the feedback resistors, setting the target amplitude of the pulse signal. The gain-adjusted voltage signal is converted into a pulse signal by the load adaptation module.

[0040] As described above, the linearization processing module 21 of the voltage-to-pulse conversion circuit 2 of this case adopts the setting of a nonlinear correction circuit, which is convenient for correcting the nonlinear relationship between the input current and the output voltage, so as to improve the linearity of the circuit through precise linearization processing, ensure that high-precision conversion is maintained within a wide input current range, and make the output pulse signal more accurately reflect the actual changes of the input voltage signal, thereby significantly reducing nonlinear errors, significantly improving the conversion accuracy of the circuit, and meeting the needs of high-precision measurement. Through the setting of the gain adjustment module 22, a gain adjustment function is provided, allowing the user to adjust the amplitude range of the output voltage according to actual needs, thereby enhancing the versatility and flexibility of the circuit. Through the setting of the load adaptation module 23, the circuit of this case can automatically adjust the output impedance according to load changes, ensure the stability of the output voltage, further improve the adaptability and reliability of the circuit, enable it to be widely used in different load environments, and also enhance the versatility and flexibility of the circuit.

[0041] As a preferred embodiment, the linearization processing module 21 includes: a sixth resistor R21, a seventh resistor R24, an eighth resistor R23, and a ninth resistor R18. The external signal source is connected to one end of the sixth resistor R21, one end of the ninth resistor R18, and one end of the seventh resistor R24, respectively, via the eighth resistor R23. The other end of the sixth resistor R21 is connected to the DC voltage input terminal VC3. The other end of the ninth resistor R18 is grounded. One end of the seventh resistor R24 is connected to the input of the gain adjustment module 22, and the other end is connected to the DC voltage input terminal VC3. The sixth resistor R21, the seventh resistor R24, the eighth resistor R23, and the ninth resistor R18 constitute the nonlinear correction circuit. In a specific implementation, if the microcontroller outputs an analog current signal via a DAC (digital-to-analog converter), the current-to-voltage conversion circuit 1 converts the current signal into a voltage and performs amplification, temperature compensation, and drive enhancement. The microcontroller outputs a modulated signal via a PWM pin. After linearization, gain adjustment, and load adaptation, the voltage-to-pulse conversion circuit 2 outputs a pulse signal that meets the electroporation requirements. The final pulse signal drives the load (such as the electroporation electrode) through the second interface P2, thereby driving the electroporation electrode to perform a perforation operation on the cells.

[0042] As described above, the linearization processing module 21 of this case can accurately correct the nonlinear relationship between the input current and the output voltage through the nonlinear correction circuit composed of the sixth resistor R21, the seventh resistor R24, the eighth resistor R23, and the ninth resistor R18. The resistor network design composed of the resistor combination facilitates the dynamic adjustment of the feedback amount according to the changes in the input signal, ensuring the effectiveness of the linearization processing, so that the circuit can maintain good linear performance when facing input signals of different amplitudes. In addition, only four resistors are used to form the nonlinear correction circuit, the structure is relatively simple, and it is easy to implement and debug. This simple design reduces the complexity of the circuit, reduces the number of components and cost, and at the same time improves the reliability of the circuit and reduces the probability of failure. In this way, the signal processed by the linearization processing module 21 has higher linearity and stability, providing better input signal conditions for the subsequent gain adjustment module 22 and the load adaptation module 23, thereby improving the performance and accuracy of the entire voltage-to-pulse conversion circuit.

[0043] As a preferred embodiment, the gain adjustment module 22 includes a second operational amplifier U1 connected to the output of the linearization processing module 21 and its peripheral circuitry, and achieves gain adjustment by changing the feedback resistor ratio of the feedback network. Specifically, the second operational amplifier U1 uses an amplifier chip model LTC6090 IS8E. The chip pinout is as follows:

[0044] COM pin (pin 1): Common terminal (ground). This pin is the reference potential point of the chip, and other voltages in the circuit are usually measured with this pin as the reference.

[0045] -IN Pin (Pin 2): Inverting input. When an input signal is applied to this pin, the output signal has a phase opposite to that of the input signal. In the feedback circuit of the second operational amplifier, this pin is often used to construct a negative feedback network to stabilize the amplifier's gain and performance.

[0046] +IN Pin (Pin 3): Non-inverting input. When an input signal is applied to this pin, the output signal has the same phase as the input signal. This pin can be used to construct positive feedback circuits or in applications requiring non-inverting amplification.

[0047] V- pin (Pin 4): Negative power input. Provides negative voltage power to the second operational amplifier, ensuring normal operation of the chip's internal circuits and achieving signal amplification and processing functions.

[0048] *TFLAG pin (pin 5): Temperature flag pin. This pin can be used to monitor the temperature status of the chip. When the chip temperature reaches a certain threshold, it may output a corresponding flag signal for temperature protection or monitoring functions.

[0049] OUT pin (Pin 6): Output. The second operational amplifier amplifies the input signal and outputs the result at this pin. The amplitude and phase of the output signal depend on the input signal and the amplifier configuration (e.g., inverting, non-inverting, etc.).

[0050] V+ pin (Pin 7): Positive power input. Provides positive voltage power to the second operational amplifier and, together with the negative power input (V-), provides the required power to the internal circuits of the chip.

[0051] OD pin (Pin 8): An open-drain pin that may indicate an open-drain output. In an open-drain configuration, this pin can be wired-ANDed with other similar pins or used to drive an external pull-up resistor to implement specific level shifting or logic functions. During specific implementation, the common terminal (pin 1) of the second operational amplifier U1 is grounded; the inverting input terminal (pin 2) is connected to the DC voltage input terminal VC3 through the tenth resistor R22 and to ground through the eleventh resistor R17; the non-inverting input terminal (pin 3) is connected to one end of the seventh resistor R24, and the other end of the seventh resistor R24 is connected to the non-inverting input terminal of the second operational amplifier U1; the negative power supply input terminal (pin 4) is grounded; the temperature mark pin (pin 5) is vacant and not connected to any device; the output terminal (pin 6) is connected to the load adaptation module 23; the positive power supply input terminal (pin 7) is connected to an external DC voltage source to provide a positive voltage power supply for the second operational amplifier, and is grounded at the same time through the second capacitor C3; the open drain pin (pin 8) is connected to the DC voltage input terminal (VC3); wherein, the twelfth resistor R11 and the thirteenth resistor R12 are also connected in series between the inverting input terminal and the output terminal of the second operational amplifier U1. In specific implementation, the gain adjustment module achieves gain adjustment through the composite feedback structure of the second operational amplifier U1. Specifically, the inverting input terminal (pin 2) of the second operational amplifier U1 is connected to the DC voltage terminal VC3 through R22 and grounded through R17, forming a voltage divider bias network. The inverting input terminal (pin 2) is also connected in series to the output terminal (pin 6) through R11 and R12, forming a feedback path. The voltage divider bias network cooperates with the feedback path to form a composite feedback structure. At this time, the twelfth resistor R11 and the thirteenth resistor R12 can be used as feedback resistors. Specifically, when an adjustable resistor (i.e., a potentiometer) is used to adjust its resistance, the total feedback resistance changes accordingly, thereby adjusting the gain. Alternatively, a digital potentiometer can be used to replace the twelfth resistor R11 or the thirteenth resistor R12. The microcontroller sends instructions to control the digital potentiometer to adjust the resistance value, thereby feedback resistance changes, achieving automatic gain adjustment.

[0052] As mentioned above, this solution uses an adjustable resistor or digital potentiometer to adjust the gain of the second operational amplifier, enabling flexible adjustment of the output voltage amplitude. The second operational amplifier, combined with a voltage divider and bias network, effectively suppresses power supply ripple and environmental electromagnetic interference, making it particularly suitable for high-precision applications such as sensor signal conditioning.

[0053] As a preferred embodiment, the load adaptation module 23 includes: a third transistor Q1, a field-effect transistor Q4, a fourteenth resistor R2, a fifteenth resistor R1, a sixteenth resistor R8, a seventeenth resistor R9, a nineteenth resistor R4, and a second interface P2; the output end of the gain adjustment module 22 is respectively connected to the source of the field-effect transistor Q4 and one end of the sixteenth resistor R8, the gate of the field-effect transistor Q4 is respectively connected to the other end of the sixteenth resistor R8 and one end of the nineteenth resistor R4, the drain of the field-effect transistor Q4 is connected to the second interface P2 and grounded through the seventeenth resistor R9, and the other end of the nineteenth resistor R4 is connected to the collector of the third transistor Q1; the external signal source is connected to one end of the fifteenth resistor R1 and the base of the third transistor Q1 through the fourteenth resistor R2, the other end of the fifteenth resistor R1 is grounded, and the emitter of the third transistor Q1 is grounded; the collector of the third transistor Q1 is also connected to the gate of the field-effect transistor Q4. During specific implementation, the external signal source (from an output pin of the single-chip microcomputer) is input through the fourteenth resistor R2, and after being divided by the fifteenth resistor R1, a bias voltage is provided for the base of the third transistor Q1. The voltage divider ratio is determined by R2 and R1, which affects the conduction degree of Q1. When the input signal changes, the base voltage of Q1 changes accordingly, resulting in a change in the collector current. The collector of Q1 is connected to the gate of the field effect tube Q4, and the current change of Q1 will directly adjust the gate voltage of Q4. Q4 acts as a variable resistor, and its on-resistance is controlled by the gate voltage. When the collector voltage of Q1 increases, the conduction of Q4 is enhanced and the equivalent resistance decreases; otherwise, it increases; the drain of Q4 is connected to the load through the second interface P2, so the change in its equivalent resistance directly affects the impedance characteristics of the load. The seventeenth resistor R9 acts as a sampling resistor, converting the load current into a voltage and feeding it back to the gate loop of the field effect tube. When the load changes and the current changes, the voltage change on R9 will form negative feedback through Q4 and Q1, automatically adjusting the conduction state of Q4, thereby maintaining the stability of the load end, so as to ensure the stability of the output pulse voltage.

[0054] As described above, the load adaptation module 22 of this embodiment utilizes a combination of transistors and field-effect transistors, leveraging the principles of current negative feedback and impedance transformation to achieve dynamic response and automatic adjustment to load changes. This allows it to adapt to a wide range of loads without requiring complex control circuitry, while ensuring stable signal transmission and low distortion, as well as output voltage stability, making it suitable for electronic system designs requiring high compatibility and reliability. Furthermore, the current amplification of Q1 combined with the impedance transformation of Q4 enhances the module's load-driving capability, allowing for the connection of higher-power loads.

[0055] In summary, the current-to-voltage conversion circuit 1 described in this case realizes high-precision and high-stability current-to-voltage conversion through modular design (input processing, signal amplification, output drive, temperature compensation), and is particularly suitable for electroporation delivery systems that have stringent requirements on signal accuracy and temperature stability; its innovative temperature compensation mechanism and strong driving capability design also give it broad application prospects in industrial control, medical equipment and other fields. The voltage-to-pulse circuit in this case improves the linearity of the conversion through the linearization processing module, the gain adjustment module enhances the versatility and flexibility of the circuit, and the load adaptation module ensures output stability under different loads. Overall, the circuit can achieve high-precision and stable voltage-to-pulse signal conversion within a wide input current range, and is suitable for application scenarios with high requirements on signal conversion accuracy and stability, such as industrial control, instrumentation and other fields.

[0056] As mentioned above, this case protects a current-voltage conversion circuit structure for electroporation delivery, and all technical solutions that are identical or similar to this case should be deemed to fall within the scope of protection of this case.

Claims

1. A current-voltage conversion circuit structure for electroporation delivery, characterized in that: include: A current-to-voltage conversion circuit (1) connected to an external signal source; The current-to-voltage conversion circuit (1) comprises: An input signal processing module (11), whose input end is connected to an external signal source and is used to convert an input current signal into a voltage signal; A signal amplification processing module (12), connected to the output end of the input signal processing module (11), for amplifying the converted voltage signal; An output driving module (13) is connected to the output end of the signal amplification processing module (12) and is used to enhance the current driving capability of the circuit and output a stable voltage signal; A temperature compensation module (14) is connected to the power supply circuit of the signal amplification processing module (12) and is used to dynamically adjust the equivalent impedance of the power supply circuit to compensate for the influence of temperature changes on circuit accuracy; wherein the signal amplification processing module (12) includes a first operational amplifier (121).

2. The current-voltage conversion circuit structure according to claim 1, characterized in that: The input signal processing module (11) comprises: a current signal input terminal (111) connected to an external signal source and a sampling unit (112) for converting the input current into a voltage; the sampling unit (112) comprises: a first resistor (R20), and the current signal input terminal (111) is connected to the non-inverting input terminal of a first operational amplifier (121) via the first resistor (R20).

3. The current-voltage conversion circuit structure according to claim 1, wherein: The signal amplification processing module (12) comprises the first operational amplifier (121) and a feedback network for optimizing frequency characteristics; the feedback network comprises a second resistor (R14), a fourth resistor (R5) and a first capacitor (C4); one end of the second resistor (R14) is grounded via the fourth resistor (R5), and the other end is connected to the inverting input terminal of the first operational amplifier (121); and the first capacitor (C4) is connected between the inverting input terminal and the output terminal of the first operational amplifier (121).

4. The current-voltage conversion circuit structure according to claim 3, characterized in that: The first operational amplifier (121) is an operational amplifier of model LMV321 IDBVR; the second resistor (R14) is a metal film resistor with a precision of 0.1%.

5. The current-voltage conversion circuit structure according to claim 1, wherein: The output drive module (13) comprises a cascaded transistor circuit (131) for enhancing current driving capability, a voltage clamping circuit (132) for stabilizing output voltage, and a first interface (P1); the transistor circuit (131) comprises: a fifth resistor (R13), a first transistor (Q5), and a second transistor (Q3); the output end of the first operational amplifier (121) is connected to the base of the first transistor (Q5) through the fifth resistor (R13), and the collector of the first transistor (Q5) is connected to the emitter of the second transistor (Q3); the voltage clamping circuit (132) comprises: a first diode (D1), a second diode (D2), and a third resistor (R10); the base of the second transistor (Q3) is respectively connected to the DC voltage input end (VC3) and the positive electrode of the second diode (D2) through the third resistor (R10); the negative electrode of the second diode (D2) is respectively connected to the collector of the second transistor (Q3) and the negative electrode of the first diode (D1); and the positive electrode of the first diode (D1) is connected to the first interface (P1).

6. The current-voltage conversion circuit structure according to claim 1, wherein: The temperature compensation module (14) includes a temperature sensitive element for adjusting power supply circuit parameters according to temperature changes; the temperature sensitive element is a thermistor (R19) connected between the power supply terminal of the first operational amplifier (121) and the ground.

7. The current-voltage conversion circuit structure according to claim 1, characterized in that: Also includes: A voltage-to-pulse conversion circuit (2) connected to an external signal source; The voltage-to-pulse conversion circuit (2) comprises: a linearization processing module (21), a gain adjustment module (22) for adjusting the output voltage amplitude, and a load adaptation module (23) for automatically adjusting the output impedance according to load changes; the input end of the linearization processing module (21) is used to receive the input voltage, and the output end is connected to the input end of the gain adjustment module (22); the output end of the gain adjustment module (22) is connected to the input end of the load adaptation module (23), and the output end of the load adaptation module (23) is used to output a pulse signal; wherein the linearization processing module (21) adopts a nonlinear correction circuit for correcting the nonlinear relationship between the input current and the output voltage.

8. The current-voltage conversion circuit structure according to claim 7, characterized in that: The nonlinear correction circuit of the linearization processing module (21) comprises: a sixth resistor (R21), a seventh resistor (R24), an eighth resistor (R23), and a ninth resistor (R18); the external signal source is connected to one end of the sixth resistor (R21), one end of the ninth resistor (R18), and one end of the seventh resistor (R24) respectively through the eighth resistor (R23); the other end of the sixth resistor (R21) is connected to a DC voltage input end (VC3); the other end of the ninth resistor (R18) is grounded; one end of the seventh resistor (R24) is connected to an input end of the gain adjustment module (22), and the other end is connected to the DC voltage input end (VC3).

9. The current-voltage conversion circuit structure according to claim 8, characterized in that: The gain adjustment module (22) comprises: a second operational amplifier (U1) and its peripheral circuits, wherein the operational amplifier (U1) adopts an amplifier chip of model LTC6090 IS8E; wherein an adjustable resistor or a digital potentiometer is connected between the inverting input terminal and the output terminal of the operational amplifier (U1).

10. The current-voltage conversion circuit structure according to claim 7, characterized in that: The load adaptation module (23) comprises: a third transistor (Q1), a field effect tube (Q4), a fourteenth resistor (R2), a fifteenth resistor (R1), a sixteenth resistor (R8), a seventeenth resistor (R9), a nineteenth resistor (R4), and a second interface (P2); the output end of the gain adjustment module (22) is respectively connected to the source of the field effect tube (Q4) and one end of the sixteenth resistor (R8), and the gate of the field effect tube (Q4) is respectively connected to the other end of the sixteenth resistor (R8) and one end of the nineteenth resistor (R9). 4), the drain of the field effect tube (Q4) is connected to the second interface (P2) and is grounded through a seventeenth resistor (R9), and the other end of the nineteenth resistor (R4) is connected to the collector of the third transistor (Q1); the external signal source is connected to one end of the fifteenth resistor (R1) and the base of the third transistor (Q1) through a fourteenth resistor (R2), the other end of the fifteenth resistor (R1) is grounded, and the emitter of the third transistor (Q1) is grounded; the collector of the third transistor (Q1) is also connected to the gate of the field effect tube (Q4).

Images