A circuit for identifying electrosurgery pen coagulation signals using a transformer

Abstract

The present invention relates to a circuit for identifying electrosurgical pen coagulation signals using a transformer, comprising: a first switch, a second switch, a transformer, and an oscillating circuit; one end of the first switch and the second switch are connected together; the other end of the first switch is connected to the other end of the second switch via a first identification resistor; one end of the first switch is connected to the other end of the first switch via a second identification resistor; the two ends of the primary coil of the transformer are respectively connected to one end of the first switch and the other end of the second switch; one end of the secondary coil of the transformer is grounded; and the output end of the oscillating circuit is connected to the input end of a first inverter. The circuit for identifying electrosurgical pen coagulation signals using a transformer provided by the present invention can effectively solve the problem of signal sampling under high withstand voltage and high isolation conditions. A set of circuits can be used to detect multiple signals, which can reduce circuit costs.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic circuits, and in particular relates to a circuit for identifying electrosurgery pen coagulation signals using a transformer. Background Art

[0002] High-frequency surgical systems are widely used in the clinical medical field due to their advantages over traditional surgical instruments. Under high output voltage conditions, how to control the energy excitation effectively and safely is an important difficulty in the interface circuit.

[0003] The traditional control method mainly consists of optocouplers, comparators and isolated power supplies. This method can basically meet the needs when the voltage is small and the types of buttons are relatively few, but it has the following defects:

[0004] 1. The voltage at the application end (interface) of high-frequency surgical systems is often relatively high. For example, jet coagulation requires a peak-to-peak voltage of more than 8kV, which results in a voltage withstand requirement of 11kV for the mains power supply. This traditional approach struggles to meet this voltage requirement. Conventional optocouplers can generally withstand AC voltage stress of 4-5kV. This circuit form can only be used on equipment with specific functions and has significant limitations.

[0005] 2. There are many types of devices, especially when multiple buttons are required. Each time a signal is recognized, a set of circuit components (op amp, isolation optocoupler, isolation power supply) is required. This makes the devices highly redundant, resulting in a large size and a significant increase in cost. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the disadvantages of the above-mentioned technology and provide an identification circuit which uses a transformer with a higher withstand voltage as a key isolation.

[0007] To solve the above technical problems, the present invention proposes a technical solution: a circuit for identifying electrosurgical pen coagulation signals using a transformer, comprising: a first switch, a second switch, a transformer, and an oscillation circuit; one end of the first switch and the second switch are connected together; the other end of the first switch is connected to the other end of the second switch via a first identification resistor; one end of the first switch is connected to the other end of the first switch via a second identification resistor;

[0008] Two ends of the primary coil of the transformer are connected to one end of the first switch and the other end of the second switch respectively; one end of the secondary coil of the transformer is grounded;

[0009] The output end of the oscillation circuit is connected to the input end of the first inverter; the output of the oscillation circuit is further connected in series with a seventh resistor and a fourth capacitor, and then connected to the other end of the secondary coil of the transformer; the other end of the secondary coil of the transformer is also connected to the input end of the electronic switch via a second resistor; the output end of the first inverter is connected to the control end of the electronic switch; when the first switch or the second switch is triggered, the output end of the electronic switch can output different signals.

[0010] A further improvement of the above solution is that a fourth resistor is connected in series with the node between the second resistor and the input terminal of the electronic switch relative to the ground.

[0011] A further improvement of the above scheme is that: the oscillation circuit includes a second inverter and a third inverter; the input end of the second inverter is grounded via a seventh capacitor, and the output end is connected to the input end of the third inverter; the input end of the second inverter is also connected to the input end of the third inverter via an eighth resistor; and the output end of the third inverter is the output end of the oscillation circuit.

[0012] A further improvement of the above solution is that an amplifier chip is connected in series between the oscillation circuit and the first inverter.

[0013] A further improvement of the above solution is that: the amplifier chip is EG3112.

[0014] A further improvement of the above solution is that the output end of the electronic switch is connected to a signal conditioning circuit.

[0015] A further improvement of the above scheme is that: the signal conditioning circuit includes an operational amplifier; the output end of the electronic switch is connected to the inverting input end of the operational amplifier through a third resistor; the non-inverting input end of the operational amplifier is grounded through a fifth resistor; the output end of the operational amplifier is connected to the inverting input end of the operational amplifier through a first resistor; the first resistor is connected in parallel with a first capacitor; and the output end of the operational amplifier is output through an interface.

[0016] A further improvement of the above solution is that the non-inverting input terminal of the operational amplifier is further connected to the ground of the external circuit through a sixth resistor.

[0017] A further improvement of the above solution is that the first identification resistor and the second identification resistor have the same resistance value.

[0018] A further improvement of the above solution is that the turns ratio of the primary coil to the secondary coil of the transformer is 1:50.

[0019] The circuit for identifying electrosurgical pen coagulation signals using a transformer provided by the present invention can effectively solve the problem of signal sampling under high voltage and high isolation conditions. A set of circuits can be used to detect multiple signals, which can reduce circuit costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described below with reference to the accompanying drawings.

[0021] Figure 1 It is a circuit block diagram of a preferred embodiment of the present invention.

[0022] Figure 2 yes Figure 1 Schematic diagram of the oscillation circuit structure.

[0023] Figure 3 yes Figure 1 Schematic diagram of the circuit structure of the drive circuit, transformer and electronic switch.

[0024] Figure 4 yes Figure 1 Schematic diagram of the circuit structure of the signal conditioning circuit. DETAILED DESCRIPTION Example

[0025] The circuit of this embodiment uses a transformer to identify the electrosurgical pen cutting and coagulation signal, such as Figure 1 As shown, it includes: several switches, transformers, oscillation circuits, drive circuits, electronic switches and signal conditioning circuits for operation.

[0026] Two of the switches are defined as "cut switch" and "freeze switch" to control the working mode of the electrosurgical pen. That is, when the electrosurgical pen receives the "cut signal" or "freeze signal", it works at different power and temperature.

[0027] like Figure 2 As shown, the oscillation circuit includes a second inverter U4A and a third inverter U4B; the input of the second inverter U4A is grounded via a seventh capacitor C7, and the output is connected to the input of the third inverter U4B; the input of the second inverter U4A is also connected to the input of the third inverter U4B via an eighth resistor R8; the output of the third inverter U4B serves as the output of the oscillation circuit. An inverter is also known as a NOT gate in a logic circuit. In this embodiment, considering factors such as procurement costs and material management, a NAND gate is used to construct the inverter. That is, the two inputs of the NAND gate are connected together and used as one input, thus forming a NOT gate.

[0028] When an operating voltage is applied to the NAND gate, the initial input of the second inverter U4A is low, representing a digital circuit value of 0. Its output is high, representing a digital circuit value of 1. This value is then output through the third inverter U4B, which then outputs 0. Simultaneously, the eighth resistor R8 at the output of the second inverter U4A charges the seventh capacitor C7. After charging is complete, the input of the second inverter U4A becomes 1, resulting in a 0 output. This value is then output through the third inverter U4B, which then outputs 1. Simultaneously, the seventh capacitor C7 discharges through the eighth resistor R8 to the output of the second inverter U4A, which is 0, before returning to 0 again. This process is repeated, resulting in a square wave signal with a frequency of tens of kHz. By adjusting the resistance of the eighth resistor R8 and the capacitance of the seventh capacitor C7, the charge and discharge times can be varied, thereby changing the frequency of the output square wave.

[0029] like Figure 2 As shown, one end of the first switch S1 and the second switch S2 are connected together; the other end of the first switch S1 is connected to the other end of the second switch S2 via a first identification resistor R10; one end of the first switch S1 is connected to the other end of the first switch S1 via a second identification resistor R9; the two ends of the primary coil of the transformer T1 are respectively connected to one end of the first switch S1 and the other end of the second switch S2; and one end of the secondary coil of the transformer T1 is grounded.

[0030] like Figure 3 As shown, the output of the oscillation circuit is connected to the amplifier chip U3, which stabilizes the waveform and increases the load capacity. The output of the amplifier chip U3 is connected to the input of the first inverter U4C; the inverter here is also built with a NAND gate. The output of the amplifier chip U3 is also connected in series with the seventh resistor R7 and the fourth capacitor C4, and then connected to the other end of the secondary coil of the transformer; the other end of the secondary coil of the transformer T1 is also connected to the input of the electronic switch U1A through the second resistor R2; the node between the second resistor R2 and the input of the electronic switch U1A is connected in series with the fourth resistor R4 to ground; the output of the first inverter U4C is connected to the control end of the electronic switch U1A. The output of the electronic switch U1A is connected to the signal conditioning circuit.

[0031] like Figure 4 As shown, the signal conditioning circuit includes an operational amplifier U2B; the output of the electronic switch U1A is connected to the inverting input of the operational amplifier U2B via a third resistor R3; the non-inverting input of the operational amplifier U2B is grounded via a fifth resistor R5; the output of the operational amplifier U2B is connected to the inverting input of the operational amplifier U2B via a first resistor R1; the first resistor R1 is connected in parallel with a first capacitor C1; and the output of the operational amplifier U2B is output via an interface CN2. To ensure that external devices share a common ground with the circuit of this embodiment, a ground point is provided on the interface CN2. Furthermore, the non-inverting input of the operational amplifier U2B is also connected to the external circuit ground via a sixth resistor R6.

[0032] In this embodiment, the first switch S1 is defined as a cut signal switch, and the second switch S2 is defined as a freeze signal switch; these two switches are located at the operator, and there is high voltage in the working environment of the electrosurgical pen. Therefore, the electrosurgical pen needs to be isolated from the operator. The isolation in this embodiment is achieved by the transformer T1. The transformer's withstand voltage far exceeds that of components such as optocouplers. Moreover, it can be appropriately adjusted by changing the shape, structure, and material of the transformer to adapt to different withstand voltage requirements.

[0033] The specific working process of this embodiment is as follows: the oscillation circuit generates a square wave. After being stabilized and amplified by the amplifier chip U3, the high level of the square wave charges the secondary coil of the transformer T1 through the seventh resistor R7 and the fourth capacitor C4, and the primary coil of the transformer T1 obtains an induced current. This process is to charge the primary coil of the transformer T1; at the same time, the high level is also converted into a low level by the first inverter U4C, turning off the electronic switch U1A. Subsequently, the next low-level signal arrives; the current in the loop of the primary coil of transformer T1 in turn induces current in the secondary coil of transformer T1, which is a discharge process; since one end of the secondary coil of transformer T1 is grounded, the NP1 point at the other end is also the induced voltage point. This induced voltage reaches the electronic switch U1A through the voltage divider of resistors R2 and R4. Since the low level is also converted to a high level through the first inverter U4C at this time, the electronic switch U1A is triggered to turn on, thereby outputting this signal; it is then filtered, amplified, and shaped by C1, R3, and R1, and provided to the back-end equipment for identification to determine whether it is a "cut signal" or a "freeze signal".

[0034] During this process, the triggering of the first and second switches S1 and S2 changes the resistance of the primary coil of transformer T1. That is, if both switches S1 and S2 are open, resistors R9 and R10 are connected to the primary coil of transformer T1. At this point, the resistance is maximum, the induced current is minimum, and the energy generated during discharge is minimal. The resistance of the secondary coil of transformer T1 is fixed, so the voltage is also minimal. If the first switch S1 is on, the resistance of the primary coil of transformer T1 is R10. If the second switch S1 is on, the resistance of the primary coil of transformer T1 is zero. These currents are different, resulting in different reverse induced voltages. By detecting the output waveform, it is possible to identify whether a switch has been pressed and which switch has been pressed.

[0035] In this embodiment, to simplify the measurement range, the first identification resistor R10 and the second identification resistor R9 have the same resistance value. Theoretically, simply changing the resistance value can change the current. Any resistor value can change the resistance of the connected circuit, thereby changing the current. With sufficiently accurate detection methods, any resistor value can be used.

[0036] Furthermore, by adding switches and resistors in parallel, more switch detections can be achieved instead of using only two. Compared with the traditional method of requiring a set of circuits for each signal recognition, the cost is almost zero.

[0037] Since the primary coil of the transformer T1 changes the current value, and the secondary coil detects the voltage value, the turns ratio of the primary coil and the secondary coil of the transformer T1 in this embodiment is 1:50; specifically, the primary coil of T1 has 0.5 turns and the secondary coil has 25 turns.

[0038] Similarly, the number of turns and the turns ratio of the transformer set in this embodiment are both relatively common values; the number of turns and the turns ratio only affect the detection accuracy. Through detection means with sufficient accuracy, any reasonable number of turns can also be used.

[0039] The present invention is not limited to the above embodiments. Any technical solutions formed by equivalent replacement fall within the protection scope required by the present invention.

Claims

1. A circuit for identifying electrosurgical pen coagulation signals using a transformer, characterized in that: include: a first switch, a second switch, a transformer, and an oscillation circuit; one end of the first switch and the second switch are connected together; the other end of the first switch is connected to the other end of the second switch via a first identification resistor; one end of the first switch is connected to the other end of the first switch via a second identification resistor; Two ends of the primary coil of the transformer are connected to one end of the first switch and the other end of the second switch respectively; one end of the secondary coil of the transformer is grounded; The output end of the oscillation circuit is connected to the input end of the first inverter; the output of the oscillation circuit is further connected in series with a seventh resistor and a fourth capacitor, and then connected to the other end of the secondary coil of the transformer; the other end of the secondary coil of the transformer is also connected to the input end of the electronic switch via a second resistor; the output end of the first inverter is connected to the control end of the electronic switch; when the first switch or the second switch is triggered, the output end of the electronic switch can output different signals.

2. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 1, characterized in that: A fourth resistor is connected in series with a node between the second resistor and the input terminal of the electronic switch and the ground.

3. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 1, characterized in that: The oscillation circuit includes a second inverter and a third inverter; the input end of the second inverter is grounded via a seventh capacitor, and the output end is connected to the input end of the third inverter; the input end of the second inverter is also connected to the input end of the third inverter via an eighth resistor; the output end of the third inverter is the output end of the oscillation circuit.

4. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 1, characterized in that: An amplifier chip is connected in series between the oscillation circuit and the first inverter.

5. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 4, characterized in that: The amplifier chip is EG3112.

6. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 1, characterized in that: The output end of the electronic switch is connected to a signal conditioning circuit.

7. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 6, characterized in that: The signal conditioning circuit includes an operational amplifier; the output end of the electronic switch is connected to the inverting input end of the operational amplifier through a third resistor; the non-inverting input end of the operational amplifier is grounded through a fifth resistor; the output end of the operational amplifier is connected to the inverting input end of the operational amplifier through a first resistor; the first resistor is connected in parallel with a first capacitor; and the output end of the operational amplifier is output through an interface.

8. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 7, characterized in that: The non-inverting input terminal of the operational amplifier is also connected to the ground of the external circuit through a sixth resistor.

9. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 1, characterized in that: The first identification resistor and the second identification resistor have the same resistance value.

10. The circuit for identifying electrosurgical pen coagulation signals using a transformer according to claim 1, characterized in that: The turns ratio of the primary coil to the secondary coil of the transformer is 1:50.

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