CN112666397A - Detection circuit and detection method for contact impedance of negative plate of high-frequency electrotome - Google Patents
Detection circuit and detection method for contact impedance of negative plate of high-frequency electrotome Download PDFInfo
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Abstract
The invention relates to a multi-detection-mode parallel high-frequency electrotome negative plate contact impedance detection circuit, which belongs to the technical field of high-frequency electrotomes and comprises a negative plate input end, an impedance conversion transformer, an impedance voltage division circuit, a signal preprocessing circuit, a contact impedance detection circuit, an AD sampling output end and a signal generator which are sequentially connected; the contact impedance detection circuit is divided into a linear detection circuit with sampling impedance changing linearly and a nonlinear detection circuit with high AD sampling precision when the sampling impedance is large. The invention automatically adjusts the contact impedance basic value through peripheral matching circuits such as system software design, an impedance detection circuit and the like, adapts to different patient groups, improves the detection flexibility, judges the state of the contact impedance through judging the change rate of the contact impedance, and realizes timely and accurate detection of the contact impedance through the combined action of software and hardware in the whole situation.
Description
Technical Field
The application relates to the technical field of high-frequency electrotomes, in particular to a multi-detection-mode parallel high-frequency electrotome negative plate contact impedance detection circuit and a detection method.
Background
At present, domestic high-frequency electric knives are widely applied due to high cutting speed, good hemostatic effect and simple operation, but have a larger gap in the safety detection link compared with foreign countries, and the safety performance needs to be improved. Especially, whether the negative plate is in full contact with a patient in the operation process is directly related to whether the safety of the electrotome is ensured in the operation process. In the operation process, because the patient is in an anesthesia state, the patient cannot sense the heating and burning of the skin, and if the contact state of the negative plate cannot be detected in time, irreversible burning can be caused in a short time. The domestic negative plate detection circuit has the problems of single detection mode, insufficient detection precision, poor detection flexibility and false alarm operation, and can not timely and accurately reflect the real state of contact impedance, thereby bringing great potential safety hazard to the operation.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention provides a multi-detection-mode parallel high-frequency electrotome negative plate contact impedance detection circuit and a detection method. The characteristics of respective sampling of the two detection modes are utilized, so that the flexibility of contact impedance detection is improved, and the contact impedance detection precision is improved.
The invention provides the following technical scheme:
a high-frequency electrotome negative plate contact impedance detection circuit comprises:
the negative plate input end (1) is connected with the negative plate of the high-frequency electrotome;
the impedance transformer (2) is used for collecting and converting the contact impedance of the negative plate of the high-frequency electrotome through the negative plate input end (1);
an impedance voltage divider circuit (3) using the impedance transformation transformer (2) as a variable impedance load;
the signal preprocessing circuit (4) is used for acquiring voltages at two ends of an equivalent load impedance in the impedance voltage dividing circuit (3) and filtering the acquired signals;
a contact impedance linear detection circuit (5) for performing contact impedance linear detection and a contact impedance nonlinear detection circuit (6) for performing contact impedance nonlinear detection based on an output signal of the signal preprocessing circuit (4);
an AD sampling output terminal (7) for performing AD sampling output on the detection results of the contact impedance linear detection circuit (5) and the contact impedance nonlinear detection circuit (6);
and the signal generator (8) is used for providing a stable alternating current signal for the impedance voltage division circuit (3).
Further, the negative plate input terminal (1) comprises a first input terminal, a second input terminal and a third input terminal;
the impedance transformation transformer (2) comprises a transformer, a first capacitor, a second capacitor, a first resistor and a second resistor; the first capacitor, the first resistor, the second capacitor and the second resistor are connected in parallel, and a first end of the first capacitor is connected with the first input end; the first end of the second capacitor is connected with the second input end; a second end of the first capacitor is connected with the third input end; two ends of the primary side of the transformer are respectively connected with the first end of the first capacitor and the first end of the second capacitor; the secondary side of the transformer is connected with the contact impedance and impedance voltage division circuit (3).
Further, the impedance voltage-dividing circuit (3) includes a third resistor and the transformer; and the first end of the secondary side of the transformer is connected with the output end of the signal generator (8), and the second end of the transformer is grounded through the third resistor.
Furthermore, the signal preprocessing circuit (4) comprises a first signal preprocessing sub-circuit and a second signal preprocessing sub-circuit which are used for respectively acquiring voltages at two ends of the secondary side of the transformer;
the first signal pre-processing sub-circuit comprises: the circuit comprises a first operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor and a fourth capacitor; the positive input end of the first operational amplifier is connected to the second end of the transformer through the third capacitor and the fourth capacitor; the positive input end of the first operational amplifier is grounded through the seventh resistor; the inverting input end of the first operational amplifier is grounded through the fourth resistor; the inverting input end of the first operational amplifier is connected to the output end of the first operational amplifier through the fifth resistor; the output end of the first operational amplifier is connected between the third capacitor and the fourth capacitor through the sixth resistor; the output end of the first operational amplifier is used as the output end of the first signal preprocessing sub-circuit and is respectively connected to the contact impedance linear detection circuit (5) and the contact impedance nonlinear detection circuit (6);
the second signal preprocessing sub-circuit has the same structure as the first signal preprocessing sub-circuit.
Further, the contact impedance linear detection circuit (5) comprises a first sub-detection circuit connected with the output terminal of the first signal preprocessing sub-circuit and a second sub-detection circuit connected with the output terminal of the second signal preprocessing sub-circuit;
the first sub-detection circuit includes: the circuit comprises an RC filter circuit, a third operational amplifier, a fourth operational amplifier, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a first diode and a second diode; a positive input end of the third operational amplifier is grounded through the fourteenth resistor; the reverse input end of the third operational amplifier is connected with the output end of the first signal preprocessing sub-circuit through the twelfth resistor; the reverse input end of the third operational amplifier is connected with the output end of the third operational amplifier through the first diode; an inverting input terminal of the third operational amplifier is connected between the second diode and the sixteenth resistor through the thirteenth resistor; the output end of the first signal preprocessing sub-circuit is connected between the second diode and the sixteenth resistor through the fifteenth resistor; the output end of the third operational amplifier is connected to the inverting input end of the fourth operational amplifier through the second diode and the sixteenth resistor, the forward input end of the fourth operational amplifier is grounded through the eighteenth resistor, and the inverting input end of the fourth operational amplifier is connected to the output end of the fourth operational amplifier through the seventeenth resistor; the output end of the fourth operational amplifier is connected to the first AD sampling output end through the RC filter circuit;
the second sub-detection circuit has the same structure as the first sub-detection circuit.
Further, the contact impedance nonlinearity detection circuit (6) includes a first voltage comparator, a second voltage comparator, a ninth operational amplifier, a twenty-eighth resistor, a twenty-ninth resistor, a thirtieth resistor, a thirty-eleventh resistor, a thirty-second resistor, a thirty-third resistor, a thirty-fourth resistor, and a ninth capacitor; the reverse input end of the first voltage comparator is connected with the output end of the first signal preprocessing sub-circuit; the positive input end of the first voltage comparator is connected with a reference voltage through the twenty-eighth resistor; the positive input end of the first voltage comparator is connected with the negative input end of the second voltage comparator through the twenty-ninth resistor; the output end of the first voltage comparator is connected with a voltage end Vcc through the thirty-first resistor; the inverting input end of the second voltage comparator is grounded through the thirtieth resistor; the positive input end of the second voltage comparator is connected with the output end of the second signal preprocessing sub-circuit; the output end of the second voltage comparator is connected with the output end of the first voltage comparator; the output end of the second voltage comparator is connected with the positive input end of the ninth operational amplifier through the thirty-second resistor; the positive input end of the ninth operational amplifier is grounded through the ninth capacitor; the inverting input terminal of the ninth operational amplifier is grounded through the thirty-third resistor; and the inverting input end of the ninth operational amplifier is connected with the output end of the ninth operational amplifier through the thirty-fourth resistor, and the output end of the ninth operational amplifier is connected with the second AD sampling end.
Further, the signal generator (8) comprises an IC, a series resonant network and a peripheral circuit; wherein the IC is connected with a first end of the secondary side of the transformer through the series resonant network; the IC is connected with a matched peripheral circuit.
The invention also provides a method for detecting the contact impedance of the negative plate of the high-frequency electrotome by using the negative plate contact impedance detection circuit, which comprises the following steps:
taking the contact impedance of the initial moment registered by a base value register in the central control unit as a base value resistor;
sampling by using the high-frequency electrotome negative plate contact impedance detection circuit, and registering the contact resistance obtained by each sampling in an instantaneous register;
comparing the sampled contact resistance with the base value resistance to determine whether the contact impedance changes;
when the contact impedance changes, judging whether the contact impedance is in a safety resistance range set by a system, and simultaneously judging whether the change rate of the contact impedance exceeds 40% of a base value resistance;
if any one of the two conditions is not met, the system stops outputting and gives an alarm.
Further, when the contact resistance decreases, the contact resistance is fed into the base value register.
The invention has the advantages and positive effects that:
1. the invention adopts a high-frequency alternating current detection mode, and utilizes the characteristic that the impedance of a human body is reduced along with the rise of frequency, so that the contact impedance is reduced, the output impedance of a detected circuit is greatly reduced, and the precision of the detection circuit is improved.
2. The invention adopts various detection modes, impedance linear detection and nonlinear detection, increases the detection diversity, improves the precision of contact impedance detection and prevents the circuit from misoperation.
3. The invention automatically adjusts the contact impedance basic value through peripheral matching circuits such as system software design, an impedance detection circuit and the like, adapts to different patient groups, improves the detection flexibility, judges the state of the contact impedance through judging the change rate of the contact impedance, and realizes timely and accurate detection of the contact impedance through the combined action of software and hardware in the whole situation.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.
FIG. 1 is a schematic block diagram of a detection circuit according to an embodiment of the present invention;
FIG. 2 is a circuit diagram of a detection circuit according to an embodiment of the present invention;
FIG. 3 is a graph of the magnitude of the contact impedance versus the output signal of the impedance detection module according to an embodiment of the present invention;
in fig. 3, curve 1 represents a schematic curve of the relationship between the contact impedance of the impedance nonlinear detection circuit in the impedance detection circuit and the collected voltage signal;
curve 2 represents a schematic curve of the relationship between the contact impedance of the impedance linear detection circuit in the impedance detection circuit and the collected voltage signal;
FIG. 4 is a flow chart of a detection method provided by the embodiment of the invention;
the device comprises a negative plate input end 1, a negative plate input end 2, an impedance conversion transformer 3, an impedance voltage division circuit 4, a signal preprocessing circuit 5, a contact impedance linear detection circuit 6, a contact impedance nonlinear detection circuit 7, an AD sampling output end 8 and a signal generator.
Detailed Description
The invention provides a negative plate contact state detection circuit with multiple parallel detection modes, which is developed aiming at the problems of single detection mode, insufficient detection precision, poor detection flexibility and false alarm operation of a negative plate detection circuit in the prior art, and can not reflect the real state of contact impedance timely and accurately, thereby bringing great potential safety hazard to the operation.
In order to make the technical solutions of the present invention better understood, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
As shown in fig. 1, it shows a structural schematic block diagram of a negative plate contact state detection circuit with multiple parallel detection modes in an embodiment of the present invention, where the detection circuit includes a negative plate input terminal 1, an impedance transformer 2, an impedance voltage division circuit 3, a signal preprocessing circuit 4, a contact impedance detection circuit with multiple parallel detection modes, an AD sampling output terminal 7, and a signal generator 8; the contact impedance detection circuit is divided into a contact impedance linear detection circuit 5 and a contact impedance nonlinear detection circuit 6; the output ends of the contact impedance linear detection circuit 5 and the contact impedance nonlinear detection circuit 6 are connected with an AD sampling output end 7;
the negative plate input end 1 comprises three input ends which are respectively connected with the split negative plates;
the impedance transformation transformer 2 is mainly used for acquiring and converting contact impedance between the split negative plate and a patient and is connected to the impedance voltage division circuit 3 as a variable impedance load;
the impedance voltage division circuit 3 utilizes an impedance voltage division principle, and the output end of the impedance voltage division circuit is connected with the input end of the signal preprocessing circuit 4;
the signal preprocessing circuit 4 mainly collects voltages at two ends of an equivalent load impedance in the impedance voltage division circuit 3 and carries out filtering processing on the collected signals, and two output ends of the module are connected with the input end of the contact impedance detection circuit;
the signal generator 8 mainly provides a stable alternating current signal for the impedance voltage dividing circuit 3, and an output end of the signal generator is connected with one input end of the impedance voltage dividing circuit 3.
As shown in fig. 2, a circuit diagram of a detection circuit in an embodiment of the present invention is shown.
The negative plate input end 1 comprises three input ends including a first input end, a second input end and a third input end, and is connected with the split type negative plates respectively.
The impedance transforming transformer 2 includes a transformer T, a first capacitor C1, a second capacitor C2, a first resistor R1, and a second resistor R2. The first capacitor C1, the first resistor R1, the second capacitor C2 and the second resistor R2 are connected in parallel, and the first end of the first capacitor C1 is connected with the first input end; a first end of the second capacitor C2 is connected to the second input terminal; the second end of the first capacitor C1 is connected to the third input end; two ends of the primary side of the transformer T are respectively connected with a first end of a first capacitor C1 and a first end of a second capacitor C2; the secondary side of the transformer T is connected with a contact impedance and impedance voltage division circuit 3.
The impedance transformation transformer is provided with a first resistor R1 and a second resistor R2; the first ends of the first capacitor C1 and the second capacitor C2 are connected with the input end 1 of the negative plate, so that the acquisition and conversion of contact impedance are realized; the arrangement of the transformer T can realize the isolation of the detection circuit and the negative plate circuit, and can realize the effect of changing the equivalent contact impedance in the detection circuit by adjusting the transformation ratio of the transformer, and the contact impedance which can be changed finally is connected with the impedance voltage division circuit 3.
The impedance voltage-dividing circuit 3 includes a third resistor R3 and a transformer T; the output end of the signal generator 8 is connected to one end of the secondary side of the transformer T, the other end of the transformer T is connected with a third resistor R3, and finally, the divider resistor R3 is connected with the ground; the judgment of the contact impedance state is realized by collecting the partial pressure at the two ends of the equivalent contact impedance of the impedance conversion transformer T.
The signal preprocessing circuit 4 comprises a first signal preprocessing sub-circuit and a second signal preprocessing sub-circuit which respectively collect voltages at two ends of the secondary side of the transformer, collects voltages at two points, carries out high-pass filtering on the signals, avoids the influence of the voltage of a power grid on the detection signals, and improves the stability and the precision of the detection. The circuit specifically comprises a first operational amplifier U1, a second operational amplifier U2, resistors R4-R11 and capacitors C3-C6; the first signal preprocessing sub-circuit includes: the circuit comprises a first operational amplifier U1, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a third capacitor C3 and a fourth capacitor C4; the positive input end of the first operational amplifier U1 is connected to the second end of the transformer T through a third capacitor C3 and a fourth capacitor C4; the positive input end of the first operational amplifier U1 is grounded through a seventh resistor R7; the inverting input terminal of the first operational amplifier U1 is connected to ground through a fourth resistor R4; the inverting input terminal of the first operational amplifier U1 is connected to the output terminal of the first operational amplifier U1 through a fifth resistor R5; the output end of the first operational amplifier U1 is connected between the third capacitor C3 and the fourth capacitor C4 through a sixth resistor R6; the output end of the first operational amplifier U2 is used as the output end of the first signal preprocessing sub-circuit and is respectively connected to the contact impedance linear detection circuit (5) and the contact impedance nonlinear detection circuit (6).
The second signal preprocessing sub-circuit has the same structure as the first signal preprocessing sub-circuit.
The contact resistance linearity detecting circuit 5 includes operational amplifiers U3-U6, resistors R12-R18, resistors R20-R26, and diodes D1-D4. The devices form a first sub-detection circuit connected with the output end of the first signal preprocessing sub-circuit and a second sub-detection circuit connected with the output end of the second signal preprocessing sub-circuit, and the filtered signals are processed; the method specifically comprises the following steps: the first sub-detection circuit includes: an RC filter circuit, a third operational amplifier U3, a fourth operational amplifier U4, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixteenth resistor R16, a seventeenth resistor R17, an eighteenth resistor R18, a first diode D1 and a second diode D2; the positive input end of the third operational amplifier U3 is grounded through a fourteenth resistor R14; the reverse input end of the third operational amplifier U3 is connected with the output end of the first signal preprocessing sub-circuit through a twelfth resistor R12; the inverting input terminal of the third operational amplifier U3 is connected to the output terminal of the third operational amplifier U3 through the first diode D1; the inverting input terminal of the third operational amplifier is connected between the second diode D2 and the sixteenth resistor R16 through a thirteenth resistor R13; the output end of the first signal preprocessing sub-circuit is connected between the second diode D2 and the sixteenth resistor R16 through a fifteenth resistor R15; the output end of the third operational amplifier U3 is connected to the inverting input end of the fourth operational amplifier U4 through a second diode D2 and a sixteenth resistor R16, the forward input end of the fourth operational amplifier U4 is grounded through an eighteenth resistor R18, and the inverting input end of the fourth operational amplifier U4 is connected to the output end of the fourth operational amplifier U4 through a seventeenth resistor R17; the output of the fourth operational amplifier U4 is connected to the first AD sample output via an RC filter circuit.
The RC filter circuit comprises a nineteenth resistor R19, a twenty-seventh resistor R27, a seventh filter capacitor C7 and an eighth filter capacitor C8, passive low-pass filtering is achieved, the finally output signal is connected with an AD sampling output end 7, and one end of each of the resistor R19 and the resistor R27 is connected with the output ends of the fourth operational amplifier U4 and the sixth operational amplifier U6 respectively.
The second sub-detection circuit has the same structure as the first sub-detection circuit.
The contact impedance nonlinear detection circuit 6 comprises resistors R28-R31 and voltage comparators U7-U8; the required threshold voltage can be obtained by reasonably setting the resistance values of the resistors R28-R30 and the voltage of the reference voltage Vref; the input signals of U7 and U8 are connected with the output terminals of U1 and U2 in the signal preprocessing circuit 4; the U9, the R32-R34 and the C9 form active filtering, the processing of signals is realized through the active filtering, and meanwhile, the attenuation of the signals due to passive filtering is reduced; the output signal of U9 is connected with the AD sampling output terminal 7; r32 is connected with the output sides of U7 and U8; and finally, sending the output signal to an AD (analog-to-digital) sampling unit, sending the acquired and processed digital signal to an MCU (microprogrammed control unit), and judging the state of the contact impedance by the MCU through the acquired signal.
The specific circuit structure is as follows: the reverse input end of the first voltage comparator U7 is connected with the output end of the first signal preprocessing sub-circuit; the positive input end of the first voltage comparator U7 is connected with the reference voltage Vref through a twenty-eighth resistor R28; the positive input end of the first voltage comparator U7 is connected with the negative input end of the second voltage comparator U8 through a twenty-ninth resistor R29; the output end of the first voltage comparator U7 is connected with a voltage end Vcc through a thirty-one resistor R31; the inverting input terminal of the second voltage comparator U8 is grounded through a thirtieth resistor R30; the positive input end of the second voltage comparator U8 is connected with the output end of the second signal preprocessing sub-circuit; the output end of the second voltage comparator U8 is connected with the output end of the first voltage comparator U7; the output end of the second voltage comparator U8 is connected with the positive input end of the ninth operational amplifier U9 through a thirty-second resistor R32; the positive input end of the ninth operational amplifier U9 is grounded through a ninth capacitor C9; the inverting input terminal of the ninth operational amplifier U9 is connected to ground through a thirty-third resistor R33; an inverting input terminal of the ninth operational amplifier U9 is connected to an output terminal of the ninth operational amplifier U9 through a thirty-fourth resistor R34, and an output terminal of the ninth operational amplifier U9 is connected to the second AD sampling terminal.
The signal generator 8 mainly comprises an IC, a series resonance network C and a peripheral circuit; the IC adopts SG 11, SG 11 is a monolithic integrated PWM chip with excellent performance, complete functions and strong universality, pulse signals with adjustable duty ratio and frequency can be output through SG 11, and required alternating current signals are output through a series resonance network C and a resonance network L, wherein a VCC pin of SG 11 is connected with one end of a resistor R36, a VC pin is connected with one end of a R37, a + VIN is connected with Vref, VIN is connected with one end of a capacitor C10 and one end of a capacitor C11, CT and DIS are connected with a discharge capacitor C12, RT is connected with R35, OUTPUTA is used as an output pin to be connected with the resonance network L and the resonance network C to finally provide a signal source for the impedance voltage division circuit 3; because the contact impedance is reduced along with the rise of the frequency, the high-frequency alternating current is used as a power supply, the size of the contact impedance is greatly reduced, the output resistance of the detected circuit is reduced, and the precision of the detection circuit is improved.
In the whole system circuit, the filter circuit in the signal preprocessing circuit 4 adopts an amplifier of LM7121 model; u3 and U5 in the contact impedance linear detection circuit 5 adopt TL082AC type amplifiers, U4 and U6 adopt LM321 type operational amplifiers; u7 and U8 in the contact impedance nonlinear detection circuit 6 adopt a voltage comparator of LM319M model, and U9 adopts an operational amplifier of LM321 model.
As shown in FIG. 3, the magnitude and detection of the contact resistance are shownThe measurement circuit collects a relationship schematic curve of the voltage signal. Wherein the dotted line represents a schematic curve of the magnitude of the contact impedance in the contact impedance nonlinear detection circuit versus the collected voltage signal. Selecting AD sampling voltage range of 0-3.3V, contact impedance of 125-2000 omega, and delta U1＝ΔU2,ΔR1<ΔR2The circuit has the advantages that the AD sampling resolution ratio is the same, the curve slope is larger when the contact impedance is larger, and the circuit has larger sampling precision, so that the contact impedance is more accurately detected when the contact impedance is high impedance, and the burning phenomenon caused by insufficient detection precision is greatly avoided. The solid line shows a schematic curve of the relationship between the magnitude of the contact impedance and the collected voltage signal in the contact impedance linear detection circuit. The contact resistance is linear with the output voltage, which increases linearly when the contact resistance increases. Through the detection circuit, the linear relation between the contact impedance and the output voltage is utilized, the collected voltage signals can be linearly compared, and the judgment on the contact impedance is realized. By adopting a parallel detection mode, the sampling precision is improved, and the precision of contact impedance detection is further improved.
As shown in fig. 4, the MCU-based reference register REG _ Rb registers the contact resistance Rb at the initial time, the instantaneous register REG _ R registers the contact resistance obtained at each sampling, when the contact resistance changes, it is determined whether the contact resistance is within the safety resistance range set by the system, and at the same time, it is determined whether the contact resistance change rate exceeds 40% of the reference resistance, if any condition is not met, the system stops outputting and generates an alarm, and when the contact resistance decreases, the contact resistance R is sent to the reference register REG _ Rb to decrease the reference resistance, so as to be suitable for different patients and improve the flexibility of the system.
The embodiment of the invention has the advantages and positive effects that:
1. the invention adopts a high-frequency alternating current detection mode, and utilizes the characteristic that the impedance of a human body is reduced along with the rise of frequency, so that the contact impedance is reduced, the output impedance of a detected circuit is greatly reduced, and the precision of the detection circuit is improved.
2. The invention adopts various detection modes, impedance linear detection and nonlinear detection, increases the detection diversity, improves the precision of contact impedance detection and prevents the circuit from misoperation.
3. The invention automatically adjusts the contact impedance basic value through peripheral matching circuits such as system software design, an impedance detection circuit and the like, adapts to different patient groups, improves the detection flexibility, judges the state of the contact impedance through judging the change rate of the contact impedance, and realizes timely and accurate detection of the contact impedance through the combined action of software and hardware in the whole situation.
Finally, it should be noted that: the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
In the embodiments provided in the present application, it should be understood that the disclosed technology can be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, the division of the units may be a logical division, and in actual implementation, there may be another division, for example, multiple units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, units or modules, and may be in an electrical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a removable hard disk, a magnetic or optical disk, and other various media capable of storing program codes.
The above embodiments are only used to illustrate the technical solution of the present invention, and not to limit the same; while the invention has been described in detail and with reference to the foregoing embodiments, it will be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some or all of the technical features may be equivalently replaced; and the modifications or the substitutions do not make the essence of the corresponding technical solutions depart from the scope of the technical solutions of the embodiments of the present invention.
Claims (9)
1. A high frequency electrotome negative plate contact impedance detection circuit, characterized by comprising:
the negative plate input end (1) is connected with the negative plate of the high-frequency electrotome;
the impedance transformer (2) is used for collecting and converting the contact impedance of the negative plate of the high-frequency electrotome through the negative plate input end (1);
an impedance voltage divider circuit (3) using the impedance transformation transformer (2) as a variable impedance load;
the signal preprocessing circuit (4) is used for acquiring voltages at two ends of an equivalent load impedance in the impedance voltage dividing circuit (3) and filtering the acquired signals;
a contact impedance linear detection circuit (5) for performing contact impedance linear detection and a contact impedance nonlinear detection circuit (6) for performing contact impedance nonlinear detection based on an output signal of the signal preprocessing circuit (4);
an AD sampling output terminal (7) for performing AD sampling output on the detection results of the contact impedance linear detection circuit (5) and the contact impedance nonlinear detection circuit (6);
and the signal generator (8) is used for providing a stable alternating current signal for the impedance voltage division circuit (3).
2. The detection circuit according to claim 1, wherein the negative plate input terminal (1) comprises a first input terminal, a second input terminal, and a third input terminal;
the impedance transformation transformer (2) comprises a transformer, a first capacitor, a second capacitor, a first resistor and a second resistor; the first capacitor, the first resistor, the second capacitor and the second resistor are connected in parallel, and a first end of the first capacitor is connected with the first input end; the first end of the second capacitor is connected with the second input end; a second end of the first capacitor is connected with the third input end; two ends of the primary side of the transformer are respectively connected with the first end of the first capacitor and the first end of the second capacitor; the secondary side of the transformer is connected with the contact impedance and impedance voltage division circuit (3).
3. The detection circuit according to claim 2, wherein the impedance voltage divider circuit (3) comprises a third resistor and the transformer; and the first end of the secondary side of the transformer is connected with the output end of the signal generator (8), and the second end of the transformer is grounded through the third resistor.
4. The detection circuit according to claim 3, wherein the signal preprocessing circuit (4) comprises a first signal preprocessing sub-circuit and a second signal preprocessing sub-circuit for respectively acquiring the voltages across the secondary side of the transformer;
the first signal pre-processing sub-circuit comprises: the circuit comprises a first operational amplifier, a fourth resistor, a fifth resistor, a sixth resistor, a third capacitor and a fourth capacitor; the positive input end of the first operational amplifier is connected to the second end of the transformer through the third capacitor and the fourth capacitor; the positive input end of the first operational amplifier is grounded through the seventh resistor; the inverting input end of the first operational amplifier is grounded through the fourth resistor; the inverting input end of the first operational amplifier is connected to the output end of the first operational amplifier through the fifth resistor; the output end of the first operational amplifier is connected between the third capacitor and the fourth capacitor through the sixth resistor; the output end of the first operational amplifier is used as the output end of the first signal preprocessing sub-circuit and is respectively connected to the contact impedance linear detection circuit (5) and the contact impedance nonlinear detection circuit (6);
the second signal preprocessing sub-circuit has the same structure as the first signal preprocessing sub-circuit.
5. The detection circuit according to claim 4, wherein the contact impedance linearity detection circuit (5) comprises a first sub-detection circuit connected to the output of the first signal pre-processing sub-circuit and a second sub-detection circuit connected to the output of the second signal pre-processing sub-circuit;
the first sub-detection circuit includes: the circuit comprises an RC filter circuit, a third operational amplifier, a fourth operational amplifier, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a first diode and a second diode; a positive input end of the third operational amplifier is grounded through the fourteenth resistor; the reverse input end of the third operational amplifier is connected with the output end of the first signal preprocessing sub-circuit through the twelfth resistor; the reverse input end of the third operational amplifier is connected with the output end of the third operational amplifier through the first diode; an inverting input terminal of the third operational amplifier is connected between the second diode and the sixteenth resistor through the thirteenth resistor; the output end of the first signal preprocessing sub-circuit is connected between the second diode and the sixteenth resistor through the fifteenth resistor; the output end of the third operational amplifier is connected to the inverting input end of the fourth operational amplifier through the second diode and the sixteenth resistor, the forward input end of the fourth operational amplifier is grounded through the eighteenth resistor, and the inverting input end of the fourth operational amplifier is connected to the output end of the fourth operational amplifier through the seventeenth resistor; the output end of the fourth operational amplifier is connected to the first AD sampling output end through the RC filter circuit;
the second sub-detection circuit has the same structure as the first sub-detection circuit.
6. The detection circuit according to claim 5, wherein the contact impedance non-linear detection circuit (6) comprises a first voltage comparator, a second voltage comparator, a ninth operational amplifier, a twenty-eighth resistor, a twenty-ninth resistor, a thirty-eleventh resistor, a thirty-second resistor, a thirty-third resistor, a thirty-fourth resistor, and a ninth capacitor; the reverse input end of the first voltage comparator is connected with the output end of the first signal preprocessing sub-circuit; the positive input end of the first voltage comparator is connected with a reference voltage through the twenty-eighth resistor; the positive input end of the first voltage comparator is connected with the negative input end of the second voltage comparator through the twenty-ninth resistor; the output end of the first voltage comparator is connected with a voltage end Vcc through the thirty-first resistor; the inverting input end of the second voltage comparator is grounded through the thirtieth resistor; the positive input end of the second voltage comparator is connected with the output end of the second signal preprocessing sub-circuit; the output end of the second voltage comparator is connected with the output end of the first voltage comparator; the output end of the second voltage comparator is connected with the positive input end of the ninth operational amplifier through the thirty-second resistor; the positive input end of the ninth operational amplifier is grounded through the ninth capacitor; the inverting input terminal of the ninth operational amplifier is grounded through the thirty-third resistor; and the inverting input end of the ninth operational amplifier is connected with the output end of the ninth operational amplifier through the thirty-fourth resistor, and the output end of the ninth operational amplifier is connected with the second AD sampling end.
7. The detection circuit according to claim 6, wherein the signal generator (8) comprises an IC, a series resonant network and a peripheral circuit;
wherein the IC is connected with a first end of the secondary side of the transformer through the series resonant network; the IC is connected with the matched peripheral circuit.
8. A method for detecting contact impedance of a negative plate of a high-frequency electric knife by using the contact impedance detection circuit of the negative plate of the high-frequency electric knife as claimed in any one of claims 1 to 7, the method comprising:
taking the contact impedance of the initial moment registered by a base value register in the central control unit as a base value resistor;
sampling by using the high-frequency electrotome negative plate contact impedance detection circuit, and registering the contact resistance obtained by each sampling in an instantaneous register;
comparing the sampled contact resistance with the base value resistance to determine whether the contact impedance changes;
when the contact impedance changes, judging whether the contact impedance is in a safety resistance range set by a system, and simultaneously judging whether the change rate of the contact impedance exceeds 40% of a base value resistance;
if any one of the two conditions is not met, the system stops outputting and gives an alarm.
9. The method of claim 8, wherein the contact impedance is entered into the base register when the contact impedance decreases.
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