Electrode slice falling-off pre-detection circuit applied to low and medium frequency electro-therapeutic apparatus

Abstract

The invention provides an electrode slice falling-off pre-detection circuit applied to a low and medium frequency electro-therapeutic apparatus. The electrode slice falling-off pre-detection circuit is used for improving the pre-detection capability of poor contact of an electrode slice. A human body capacitance detection principle is adopted, when a human body makes contact with the surface of equipment with a capacitance sensor, the human body can form a capacitance, and the contact quality of the human body and the equipment is judged by measuring the change of the capacitance; according to the invention, electrode shedding detection is carried out based on a human body capacitance effect, sensitivity is adjustable, a signal relay switching function is provided, a charge accumulation effect can be prevented, and circuit calibration and fusion application with an electrical stimulation signal generation circuit are facilitated; the circuit is simple in structure, small in size, low in cost, high in reliability and capable of accurately judging whether the electrode plate falls off or not in advance.

Description

Technical Field

[0001] The invention belongs to the technical field of circuits, and mainly relates to an electrode sheet shedding pre-detection circuit used in medium and low frequency electrotherapy apparatuses. Background Art

[0002] Widely used in rehabilitation medicine and physical therapy, low- and medium-frequency electrotherapy devices deliver electrical currents of specific frequencies to specific areas of the body, achieving therapeutic benefits such as pain relief, blood circulation stimulation, and tissue healing. A core component of these devices is the electrode pad, which directly contacts the patient's skin and conducts electrical current to achieve therapeutic effects. Secure contact between the electrodes is crucial for both effective and safe treatment.

[0003] In existing technology, electrodes often fall off or experience poor contact. This can occur for a variety of reasons, including sweating, friction from exercise, and adhesive failure. If an electrode falls off, the medium- and low-frequency electrotherapy device will continue to output high-voltage electrical stimulation signals, posing a risk to the human body. For example, accidental contact could cause current to flow through the heart, or children could experience an inappropriate voltage shock.

[0004] To avoid these issues, some existing low- and medium-frequency electrotherapy devices rely on operator visual inspection or patient subjective experience to determine whether the electrodes are functioning properly before use. However, this method is not only unreliable but also prone to delays, thus affecting the treatment process.

[0005] Some existing technologies attempt to pre-determine electrode contact using simple resistance detection circuits, but this approach has significant shortcomings in practical applications. For example, changes in skin resistance are affected by a variety of factors, and relying solely on resistance values ​​to determine electrode status can easily lead to misjudgments. Furthermore, most of these solutions lack the ability to pre-detect poor electrode contact, making it impossible to detect electrode detachment before low- and medium-frequency electrotherapy devices are activated and to initiate prompt alarm processing.

[0006] Therefore, in order to solve the above problems, it is of great practical significance to propose a circuit solution that can effectively detect the electrode sheet falling off in advance. Summary of the Invention

[0007] In order to overcome the deficiencies of the prior art and to improve the accuracy of electrode sheet detachment detection of medium and low frequency electrotherapy apparatuses, the present invention provides an electrode sheet detachment pre-detection circuit for use in medium and low frequency electrotherapy apparatuses.

[0008] The technical solution adopted by the present invention to solve its technical problem is: An electrode sheet shedding pre-detection circuit for medium and low frequency electrotherapy apparatus, comprising a relay detection module, a first touch detection module and a single chip microcomputer; The relay detection module is respectively connected to the first electrode sheet and the first touch detection module of the medium and low frequency electrotherapy instrument output channel; when the medium and low frequency electrotherapy instrument is working normally, based on the human body capacitance effect, the human body and the first touch detection module constitute a first circuit; the first touch detection module is used to detect the connectivity status of the first circuit; when the first touch detection module detects that the total capacitance value in the first circuit increases, it sends a normal working signal to the single-chip microcomputer; if the total capacitance value in the first circuit decreases, the first touch detection module will send an electrode sheet detachment signal to the single-chip microcomputer; after the single-chip microcomputer receives the electrode sheet detachment signal from the first touch detection module, it sends a switching signal to the relay detection module, and the relay detection module resets the coil of the relay detection module according to the switching signal, and disconnects the relay detection module from the first electrode sheet of the output channel of the medium and low frequency electrotherapy instrument.

[0009] Furthermore, the electrode sheet detachment pre-detection circuit used for medium and low frequency electrotherapy apparatus includes a second touch detection module; the relay detection module is respectively connected to the second electrode sheet and the second touch detection module of the output channel of the medium and low frequency electrotherapy apparatus; the human body and the second touch detection module constitute a second circuit; the second touch detection module is used to detect the connectivity status of the second circuit; the detection principle of the second touch detection module is the same as the detection principle of the first touch detection module.

[0010] Furthermore, the single chip microcomputer includes a first input / output port, a second input / output port and a third input / output port; The input of the relay detection module includes a first input terminal of the relay, a second input terminal of the relay, a third input terminal of the relay, a fourth input terminal of the relay, a fifth input terminal of the relay, a sixth input terminal of the relay, and a seventh input terminal of the relay; the input of the first touch detection module is a first detection input terminal; the output of the first touch detection module is a first detection output terminal; the input of the second touch detection module is a second detection input terminal; and the output of the second touch detection module is a second detection output terminal; The first electrode sheet of the output channel of the medium and low frequency electrotherapy instrument is connected to the third input terminal of the relay; the second electrode sheet of the output channel of the medium and low frequency electrotherapy instrument is connected to the fourth input terminal of the relay; the fifth input terminal of the relay and the sixth input terminal of the relay are both connected to the positive pole of the high-voltage circuit of the medium and low frequency electrotherapy instrument; the first input / output port is connected to the seventh input terminal of the relay; the first input terminal of the relay is connected to the first detection input terminal; the second input terminal of the relay is connected to the second detection input terminal; the first detection output terminal is connected to the second input / output port; and the second detection output terminal is connected to the third input / output port.

[0011] Furthermore, the relay detection module includes a signal relay KJ1, a first diode D1, a first transistor Q1, a third resistor R3, a fourth resistor R4 and an electrode sheet lead connector XS1; The third input terminal of the relay is connected to the first pin of the electrode sheet lead connector XS1; the fourth input terminal of the relay is connected to the second pin of the electrode sheet lead connector XS1; The first pin of the signal relay KJ1 is connected to the cathode of the first diode D1; the cathode of the first diode D1 is connected to the +3.3V power supply; the eighth pin of the signal relay KJ1 is connected to the anode of the first diode D1; the anode of the first diode D1 is connected to the collector of the first transistor Q1; the base of the first transistor Q1 is respectively connected to one end of the third resistor R3 and one end of the fourth resistor R4; the emitter of the first transistor Q1 is connected to GND; the other end of the third resistor R3 is connected to the seventh input terminal of the relay; the other end of the fourth resistor R4 is connected to GND; the second pin of the signal relay KJ1 is connected to the anode of the first diode D1; the anode of the first diode D1 is connected to the collector of the first transistor Q1; the base of the first transistor Q1 is respectively connected to one end of the third resistor R3 and one end of the fourth resistor R4; the emitter of the first transistor Q1 is connected to GND; the other end of the third resistor R3 is connected to the seventh input terminal of the relay; the other end of the fourth resistor R4 is connected to GND; Connected to the fifth input terminal of the relay; the third pin of the signal relay KJ1 is connected to the first pin of the electrode sheet lead-out connector XS1; the fourth pin of the signal relay KJ1 is connected to the first input terminal of the relay; the fifth pin of the signal relay KJ1 is connected to the second input terminal of the relay; the sixth pin of the signal relay KJ1 is connected to the second pin of the electrode sheet lead-out connector XS1; the seventh pin of the signal relay KJ1 is connected to the sixth input terminal of the relay; the first pin of the electrode sheet lead-out connector XS1 is connected to the third input terminal of the relay; the second pin of the electrode sheet lead-out connector XS1 is connected to the fourth input terminal of the relay.

[0012] Furthermore, the first touch detection module includes a touch detection chip U1, a first resistor R1, a first capacitor C1 and a second capacitor C2; The first pin of the touch detection chip U1 is connected to the first detection output end; the second pin of the touch detection chip U1 is connected to GND; the fourth pin of the touch detection chip U1 and the sixth pin of the touch detection chip U1 are both suspended; the fifth pin of the touch detection chip U1 is respectively connected to the +3.3V power supply and one end of the second capacitor C2; the other end of the second capacitor C2 is connected to GND; the third pin of the touch detection chip U1 is connected to one end of the first resistor R1; the other end of the first resistor R1 is respectively connected to one end of the first capacitor C1 and the first detection input end; the other end of the first capacitor C1 is connected to GND.

[0013] Furthermore, the second touch detection module includes a touch detection chip U2, a second resistor R2, a third capacitor C3 and a fourth capacitor C4; The first pin of the touch detection chip U2 is connected to the second detection output end; the second pin of the touch detection chip U2 is connected to GND; the fourth pin of the touch detection chip U2 and the sixth pin of the touch detection chip U2 are both suspended; the fifth pin of the touch detection chip U2 is respectively connected to the +3.3V power supply and one end of the fourth capacitor C4; the other end of the fourth capacitor C4 is connected to GND; the third pin of the touch detection chip U2 is connected to one end of the second resistor R2; the other end of the second resistor R2 is respectively connected to one end of the third capacitor C3 and the second detection input end; the other end of the third capacitor C3 is connected to GND.

[0014] Furthermore, the model of the signal relay KJ1 is G6K-2F-YDC3.

[0015] Furthermore, the touch detection chip U1 and the touch detection chip U2 are of model TTP-233H.

[0016] Furthermore, the cable between the first electrode of the output channel of the medium and low frequency electrotherapy device and the third input terminal of the relay is a lead-out line; when the length of the lead-out line is less than or equal to 1m, the range of the first capacitor C1 is 1pF to 50pF, and the detection sensitivity is optimal; when the length of the lead-out line is greater than 1m, the capacitance value of the first capacitor C1 is increased to improve the detection sensitivity.

[0017] The beneficial effects of the present invention are as follows: due to the use of the human body capacitance effect, the present invention can quickly and accurately detect the detachment of the electrode sheet in advance, thereby improving the safety of treatment; the contact circuit of the electrode sheet lead wire is switched by the signal relay, thereby avoiding the high voltage on the electrode sheet from being introduced into the low-voltage control system, ensuring the safety of the human body and the circuit; improving the safety of the system; when the abnormal situation of the electrode sheet detachment is detected, a signal is automatically sent to the single-chip microcomputer control system to remind the patient or operator to deal with it in time; improving the real-time nature of the early warning; the circuit design of the present invention is simple, the cost is low, and it is easy to be integrated into the existing medium and low frequency electrotherapy device. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a circuit diagram of the present invention; In the figure, KJ1-signal relay; D1-first diode; Q1-first transistor; R3-third resistor; R4-fourth resistor; XS1-electrode lead connector; U1-touch detection chip, R1-first resistor; C1-first capacitor; C2-second capacitor; U2-touch detection chip; -second resistor R2; C3-third capacitor; C4-fourth capacitor; I / O-1 is the first input / output port; I / O-2 is the second input / output port; I / O-3 is the third input / output port. DETAILED DESCRIPTION

[0019] An electrode sheet shedding pre-detection circuit for medium and low frequency electrotherapy apparatus, comprising a relay detection module, a first touch detection module, a second touch detection module and a single chip microcomputer; The relay detection module is respectively connected to the first electrode sheet of the output channel of the medium and low frequency electrotherapy instrument and the second electrode sheet of the output channel of the medium and low frequency electrotherapy instrument; the relay detection module is respectively connected to the first touch detection module and the second touch detection module; based on the human body capacitance effect, during normal operation, the human body and the first touch detection module constitute a first loop; the human body and the second touch detection module constitute a second loop; the first touch detection module is used to detect the connectivity status of the first loop; the second touch detection module is used to detect the connectivity status of the second loop; when the first touch detection module detects that the total capacitance value in the first loop increases, it sends a normal working signal to the single-chip microcomputer; if the total capacitance value in the first loop decreases, the first touch detection module will send an electrode sheet detachment signal to the single-chip microcomputer; the detection principle of the second touch detection module is the same as that of the first touch detection module; After receiving the electrode sheet detachment signal from the first touch detection module or the second touch detection module, the single chip computer sends a switching signal to the relay detection module. The relay detection module resets the coil of the relay detection module according to the switching signal and disconnects the relay detection module from the first electrode sheet or the second electrode sheet of the output channel of the medium and low frequency electrotherapy instrument; The single chip microcomputer includes a first input / output port, a second input / output port and a third input / output port; The input of the relay detection module includes a first input terminal of the relay, a second input terminal of the relay, a third input terminal of the relay, a fourth input terminal of the relay, a fifth input terminal of the relay, a sixth input terminal of the relay, and a seventh input terminal of the relay; the input of the first touch detection module is a first detection input terminal; the output of the first touch detection module is a first detection output terminal; the input of the second touch detection module is a second detection input terminal; and the output of the second touch detection module is a second detection output terminal; The first electrode sheet of the output channel of the medium and low frequency electrotherapy instrument is connected to the third input terminal of the relay; the second electrode sheet of the output channel of the medium and low frequency electrotherapy instrument is connected to the fourth input terminal of the relay; the fifth input terminal of the relay and the sixth input terminal of the relay are both connected to the positive electrode of the high-voltage circuit of the medium and low frequency electrotherapy instrument; the first input / output port is connected to the seventh input terminal of the relay; the first input terminal of the relay is connected to the first detection input terminal; the second input terminal of the relay is connected to the second detection input terminal; the first detection output terminal is connected to the second input / output port; and the second detection output terminal is connected to the third input / output port; The relay detection module includes a signal relay KJ1, a first diode D1, a first transistor Q1, a third resistor R3, a fourth resistor R4 and an electrode lead connector XS1; The third input terminal of the relay is connected to the first pin of the electrode lead connector XS1; The fourth input terminal of the relay is connected to the second pin of the electrode lead connector XS1; The first pin of the signal relay KJ1 is connected to the cathode of the first diode D1; the cathode of the first diode D1 is connected to the +3.3V power supply; the eighth pin of the signal relay KJ1 is connected to the anode of the first diode D1; the anode of the first diode D1 is connected to the collector of the first transistor Q1; the base of the first transistor Q1 is respectively connected to one end of the third resistor R3 and one end of the fourth resistor R4; the emitter of the first transistor Q1 is connected to GND; the other end of the third resistor R3 is connected to the seventh input terminal of the relay; the other end of the fourth resistor R4 is connected to GND; the second pin of the signal relay KJ1 is connected to the anode of the first diode D1; the anode of the first diode D1 is connected to the collector of the first transistor Q1; the base of the first transistor Q1 is respectively connected to one end of the third resistor R3 and one end of the fourth resistor R4; the emitter of the first transistor Q1 is connected to GND; the other end of the third resistor R3 is connected to the seventh input terminal of the relay; the other end of the fourth resistor R4 is connected to GND; Connected to the fifth input terminal of the relay; the third pin of the signal relay KJ1 is connected to the first pin of the electrode sheet lead connector XS1; the fourth pin of the signal relay KJ1 is connected to the first input terminal of the relay; the fifth pin of the signal relay KJ1 is connected to the second input terminal of the relay; the sixth pin of the signal relay KJ1 is connected to the second pin of the electrode sheet lead connector XS1; the seventh pin of the signal relay KJ1 is connected to the sixth input terminal of the relay; the first pin of the electrode sheet lead connector XS1 is connected to the third input terminal of the relay; the second pin of the electrode sheet lead connector XS1 is connected to the fourth input terminal of the relay; The first touch detection module includes a touch detection chip U1, a first resistor R1, a first capacitor C1 and a second capacitor C2; The first pin of the touch detection chip U1 is connected to the first detection output terminal; the second pin of the touch detection chip U1 is connected to GND; the fourth pin of the touch detection chip U1 and the sixth pin of the touch detection chip U1 are both left floating; the fifth pin of the touch detection chip U1 is respectively connected to the +3.3V power supply and one end of the second capacitor C2; the other end of the second capacitor C2 is connected to GND; the third pin of the touch detection chip U1 is connected to one end of the first resistor R1; the other end of the first resistor R1 is respectively connected to one end of the first capacitor C1 and the first detection input terminal; the other end of the first capacitor C1 is connected to GND; The second touch detection module includes a touch detection chip U2, a second resistor R2, a third capacitor C3 and a fourth capacitor C4; The first pin of the touch detection chip U2 is connected to the second detection output terminal; the second pin of the touch detection chip U2 is connected to GND; the fourth pin of the touch detection chip U2 and the sixth pin of the touch detection chip U2 are both suspended; the fifth pin of the touch detection chip U2 is respectively connected to the +3.3V power supply and one end of the fourth capacitor C4; the other end of the fourth capacitor C4 is connected to GND; the third pin of the touch detection chip U2 is connected to one end of the second resistor R2; the other end of the second resistor R2 is respectively connected to one end of the third capacitor C3 and the second detection input terminal; the other end of the third capacitor C3 is connected to GND; The model of the signal relay KJ1 is G6K-2F-YDC3; The model of the touch detection chip U1 and the touch detection chip U2 is TTP-233H; The cable between the first electrode of the output channel of the low-frequency electrotherapy device and the first pin of the electrode lead-out connector XS1 is the lead-out line; when the length of the lead-out line is less than or equal to 1m, the range of the first capacitor C1 is 1pF to 50pF, and the detection sensitivity is optimal; when the length of the lead-out line is greater than 1m, the capacitance value of the first capacitor C1 is increased to improve the detection sensitivity.

[0020] The function of the signal relay KJ1 is as follows: when the circuit is powered on, the single-chip microcomputer first outputs a low-level signal to close the coil of the signal relay KJ1, and the first and second pins of the electrode lead connector XS1 are connected to the touch chips U1 and U2 respectively to determine whether the electrode has fallen off; when an electrode of a medium-low frequency electrotherapy device channel has fallen off, the first pin of the touch detection chip U1 or U2 will output a high-level signal to the single-chip microcomputer; when the electrode has not fallen off, the first pin of the touch detection chip U1 or U2 will output a low-level signal to the single-chip microcomputer to detect whether the electrode has fallen off; after the judgment is completed, the single-chip microcomputer outputs a low-level signal to reset the coil of the signal relay KJ1, and the first and second pins of the electrode lead connector XS1 are connected to the high-voltage pulse output terminal of the medium-low frequency electrotherapy device respectively, to carry out normal medium-low frequency treatment, thereby preventing the high voltage of the medium-low frequency electrotherapy device from being introduced into the low-voltage control system of the single-chip microcomputer during the electrode fall-off detection process.

[0021] The present invention will be further described below with reference to the accompanying drawings and examples.

[0022] Human body capacitance detection is a method that uses a capacitive sensor to detect human contact. When the human body touches the surface of a device with a capacitive sensor, the human body forms a capacitor. By measuring the change in this capacitance, the quality of the contact between the human body and the device can be determined.

[0023] In order to realize the pre-detection of electrode shedding of medium and low frequency electrotherapy apparatus, the present invention adopts the principle of human body capacitance detection. Considering the practicality, a mature and reliable touch detection chip is selected to replace the capacitance sensor.

[0024] The present invention will be further described below with reference to the accompanying drawings.

[0025] like Figure 1 As shown, a circuit for detecting electrode sheet detachment in advance for medium and low frequency electrotherapy apparatus includes touch detection chips U1 and U2, a signal relay KJ1, and an electrode sheet lead-out connector XS1.

[0026] Specifically, the first pin of the touch detection chip U1 is connected to the microcontroller, the third pin of the touch detection chip U1 is connected to one end of the first resistor R1, the other end of the first resistor R1 is connected to the fourth pin of the signal relay KJ1 and one end of the first capacitor C1, the other end of the first capacitor C1 is connected to GND, the fifth pin of the touch detection chip U1 is connected to the +3.3V power supply and one end of the second capacitor C2, the other end of the second capacitor C2 is connected to GND, and the fourth and sixth pins of the touch detection chip U1 are not connected.

[0027] Specifically, the first pin of the touch detection chip U2 is connected to the microcontroller, the third pin of the touch detection chip U2 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to the fifth pin of the signal relay KJ1 and one end of the third capacitor C3, the other end of the third capacitor C3 is connected to GND, the fifth pin of the touch detection chip U2 is connected to the +3.3V power supply and one end of the fourth capacitor C4, the other end of the fourth capacitor C4 is connected to GND, and the fourth and sixth pins of the touch detection chip U2 are not connected.

[0028] Specifically, the first pin of the signal relay KJ1 is connected to the +3.3V power supply and the negative electrode of the first diode D1, the eighth pin of the signal relay KJ1 is connected to the positive electrode of the first diode D1 and the collector of the first transistor Q1, the base of the first transistor Q1 is connected to one end of the third resistor R3 and one end of the fourth resistor R4, the emitter of the first transistor Q1 is connected to the other end of the fourth resistor R4 and GND, the other end of the third resistor R3 is connected to the single-chip microcomputer, the third and sixth pins of the signal relay KJ1 are respectively connected to the first and second pins of the electrode lead-out connector XS1, and the second and seventh pins of the signal relay KJ1 are connected to the high-voltage circuit of the medium and low frequency electrotherapy device.

[0029] Specifically, the capacitance values ​​of the first capacitor C1 and the third capacitor C3 need to be adapted according to factors such as the material and length of the electrode sheet lead wire, so as to adjust the sensitivity of the electrode sheet detachment detection.

[0030] Specifically, the working process of the electrode sheet detachment pre-detection circuit of the medium and low frequency electrotherapy device is as follows: The two electrodes of a channel of a medium- and low-frequency electrotherapy device are connected to the first and second pins of the electrode lead connector XS1, respectively. When the circuit is powered on, the microcontroller first outputs a low-level signal to close the coil of signal relay KJ1. The first and second pins of the electrode lead connector XS1 are then connected to touch chips U1 and U2, respectively, to determine if the electrode is detached. Once the determination is complete, the microcontroller outputs a low-level signal to reset the coil of signal relay KJ1. The first and second pins of the electrode lead connector XS1 are then connected to the high-voltage pulse output of the medium- and low-frequency electrotherapy device, respectively, to carry out normal medium- and low-frequency treatment. This prevents the high voltage of the medium- and low-frequency electrotherapy device from being introduced into the low-voltage control system of the microcontroller during the electrode detachment detection process. When an electrode of a medium- and low-frequency electrotherapy device channel is detached, the first pin of the touch detection chip U1 or U2 outputs a high-level signal to the microcontroller. When an electrode is intact, the first pin of the touch detection chip U1 or U2 outputs a low-level signal to the microcontroller. This is used to detect whether the electrode sheet has fallen off.

[0031] In the above embodiments, the specific circuits can be replaced accordingly according to actual needs, and the specific circuits of this application do not represent all embodiments of the technical solutions of this application.

[0032] The above description is only a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by technicians in this technical field within the technical scope disclosed in the present invention should be covered by the scope of protection of the present invention.

Claims

1. A circuit for detecting electrode shedding in advance for use in medium and low frequency electrotherapy apparatus, characterized by: It includes a relay detection module, a first touch detection module and a single chip microcomputer; When the medium and low frequency electrotherapy device is working normally, based on the human body capacitance effect, the human body and the first touch detection module form a first circuit; the first touch detection module is used to detect the connectivity status of the first circuit; when the first touch detection module detects that the total capacitance value in the first circuit has increased, it sends a normal working signal to the single-chip microcomputer; if the total capacitance value in the first circuit has decreased, the first touch detection module sends an electrode sheet detachment signal to the single-chip microcomputer; after the single-chip microcomputer receives the electrode sheet detachment signal from the first touch detection module, it sends a switching signal to the relay detection module, and the relay detection module resets the coil of the relay detection module according to the switching signal, and disconnects the relay detection module from the first electrode sheet of the output channel of the medium and low frequency electrotherapy device.

2. The electrode sheet fall-off pre-detection circuit for a medium- and low-frequency electrotherapy apparatus according to claim 1, characterized in that: It includes a second touch detection module; the relay detection module is respectively connected to the second electrode sheet of the medium and low frequency electrotherapy device output channel and the second touch detection module; the human body and the second touch detection module constitute a second circuit; the second touch detection module is used to detect the connectivity status of the second circuit; the detection principle of the second touch detection module is the same as the detection principle of the first touch detection module.

3. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 2, characterized in that: The single chip microcomputer includes a first input / output port, a second input / output port and a third input / output port; The input of the relay detection module includes a first input terminal of the relay, a second input terminal of the relay, a third input terminal of the relay, a fourth input terminal of the relay, a fifth input terminal of the relay, a sixth input terminal of the relay, and a seventh input terminal of the relay; the input of the first touch detection module is a first detection input terminal; the output of the first touch detection module is a first detection output terminal; the input of the second touch detection module is a second detection input terminal; and the output of the second touch detection module is a second detection output terminal; The first electrode sheet of the output channel of the medium and low frequency electrotherapy instrument is connected to the third input terminal of the relay; the second electrode sheet of the output channel of the medium and low frequency electrotherapy instrument is connected to the fourth input terminal of the relay; the fifth input terminal of the relay and the sixth input terminal of the relay are both connected to the positive pole of the high-voltage circuit of the medium and low frequency electrotherapy instrument; the first input / output port is connected to the seventh input terminal of the relay; the first input terminal of the relay is connected to the first detection input terminal; the second input terminal of the relay is connected to the second detection input terminal; the first detection output terminal is connected to the second input / output port; and the second detection output terminal is connected to the third input / output port.

4. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 3, characterized in that: The relay detection module includes a signal relay (KJ1), a first diode (D1), a first transistor (Q1), a third resistor (R3), a fourth resistor (R4) and an electrode lead connector (XS1); The third input terminal of the relay is connected to the first pin of the electrode sheet lead connector (XS1); the fourth input terminal of the relay is connected to the second pin of the electrode sheet lead connector (XS1); The first pin of the signal relay (KJ1) is connected to the cathode of the first diode (D1); the cathode of the first diode (D1) is connected to a +3.3V power supply; the eighth pin of the signal relay (KJ1) is connected to the anode of the first diode (D1); the anode of the first diode (D1) is connected to the collector of the first transistor (Q1); the base of the first transistor (Q1) is respectively connected to one end of the third resistor (R3) and one end of the fourth resistor (R4); the emitter of the first transistor (Q1) is connected to GND; the other end of the third resistor (R3) is connected to the seventh input terminal of the relay; The other end of the four resistors (R4) is connected to GND; the second pin of the signal relay (KJ1) is connected to the fifth input terminal of the relay; the third pin of the signal relay (KJ1) is connected to the first pin of the electrode sheet lead connector (XS1); the fourth pin of the signal relay (KJ1) is connected to the first input terminal of the relay; the fifth pin of the signal relay (KJ1) is connected to the second input terminal of the relay; the sixth pin of the signal relay (KJ1) is connected to the second pin of the electrode sheet lead connector (XS1); and the seventh pin of the signal relay (KJ1) is connected to the sixth input terminal of the relay; The first pin of the electrode sheet lead-out connector (XS1) is connected to the third input terminal of the relay; the second pin of the electrode sheet lead-out connector (XS1) is connected to the fourth input terminal of the relay.

5. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 3, characterized in that: The first touch detection module comprises a touch detection chip (U1), a first resistor (R1), a first capacitor (C1) and a second capacitor (C2); The first pin of the touch detection chip (U1) is connected to the first detection output terminal; the second pin of the touch detection chip (U1) is connected to GND; The fourth pin of the touch detection chip (U1) and the sixth pin of the touch detection chip (U1) are both suspended; the fifth pin of the touch detection chip (U1) is respectively connected to a +3.3V power supply and one end of a second capacitor (C2); the other end of the second capacitor (C2) is connected to GND; the third pin of the touch detection chip (U1) is connected to one end of a first resistor (R1); the other end of the first resistor (R1) is respectively connected to one end of the first capacitor (C1) and a first detection input end; and the other end of the first capacitor (C1) is connected to GND.

6. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 3, characterized in that: The second touch detection module includes a touch detection chip (U2), a second resistor (R2), a third capacitor (C3) and a fourth capacitor (C4); The first pin of the touch detection chip (U2) is connected to the second detection output terminal; the second pin of the touch detection chip (U2) is connected to GND; the fourth pin of the touch detection chip (U2) and the sixth pin of the touch detection chip (U2) are both suspended; the fifth pin of the touch detection chip (U2) is respectively connected to a +3.3V power supply and one end of a fourth capacitor (C4); the other end of the fourth capacitor (C4) is connected to GND; the third pin of the touch detection chip (U2) is connected to one end of a second resistor (R2); the other end of the second resistor (R2) is respectively connected to one end of a third capacitor (C3) and the second detection input terminal; and the other end of the third capacitor (C3) is connected to GND.

7. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 3, characterized in that: The cable between the first electrode of the output channel of the medium and low frequency electrotherapy device and the third input terminal of the relay is a lead wire; when the length of the lead wire is less than or equal to 1m, the range of the first capacitor (C1) is 1pF to 50pF, and the detection sensitivity is optimal; when the length of the lead wire is greater than 1m, the capacitance value of the first capacitor (C1) is increased to improve the detection sensitivity.

8. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 4, characterized in that: The model of the signal relay (KJ1) is G6K-2F-YDC3.

9. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 5, characterized in that: The touch detection chip (U1) is of model TTP-233H.

10. The electrode sheet fall-off pre-detection circuit for use in a medium- and low-frequency electrotherapy apparatus according to claim 6, characterized in that: The model of the touch detection chip (U2) is TTP-233H.

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