CZ2013175A3 - Electric shock-preventing control device in instruments employing electricity for medical treatment and method of eliminating such eclectic shock - Google Patents

Abstract

An electrical shock control device for devices employing electrotherapy for treatment consists of a starting circuit (5) that is connected to a slow current control circuit (6) that is further coupled to a control deviation amplifier (8) and is coupled to an output current stabilizer (7) with a delay member and a device standby and operating mode switch (9). In order to avoid electric shock at the device using electrotherapy for treatment, the following conditions must be met between the time delay of the output current from the controller block (4), over time. quick switching of the device from the operating mode to the sleep mode and by the time of the .tau..sub.run.n.the slow adjustment of the output current amplitude setting: .tau..sub.reg.n. .tau..sub.reg .n. << .tau..sub.run.n .. Apparatus using electrotherapy for treatment, consisting of a power block (1), an indication block (2) and a switched-mode power supply block (3), connected to the output current controller block (4) with delay, does not cause an electric shock to patients in the event of an accidental interruption of therapy during the device's operating mode.

Description

Technical field

The invention relates to the field of healthcare, in particular medical devices using electrotherapy as a physical method of treatment.

BACKGROUND OF THE INVENTION

Electrotherapy is a medical method used to treat various diseases and health problems. DC or beat current is used to treat the beneficial effects of electricity. Devices are powered by batteries or mains. The devices are characterized by a high degree of safety against the mains.

The actual treatment procedures are carried out in such a way that the patient is connected to a circuit in which one of the types of electrotherapy takes place. Current and length of procedures are individual. After a certain time of the procedure, the current is reversed and the therapy is repeated in the same way with the opposite polarity.

The devices used, such as those in WO 97/15348 and KR 20120111708, have a built-in soft-start or re-soft-start solution which regulates the gradual rise of the input voltage.

The procedures are terminated by shutting down the device from work to sleep and then disconnecting the patient from the circuit to which it was connected.

Even low current values, about 5mA, are high enough to cause an electric shock to the treated person at the time when they have to accidentally or coercively disconnect from the circuit to which they were connected before shutting down the device from working to idle mode. For some, this electric shock can cause some inconvenience.

Current devices using electrotherapy as a physical treatment method have no limitation against the electric shock that could occur if the patient suddenly disconnects from the circuit during the treatment procedure - before shutting down the device from work to sleep.

Existing electrotherapy devices work with a conventional output current regulator that responds to a change in the load being treated by a person being connected or disconnected from the circuit during therapy, by a sharp voltage change, and thus the patient does not avoid electric shock. By interrupting the patient-device current circuit, the patient is normally shocked.

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SUMMARY OF THE INVENTION

The aforementioned drawbacks are eliminated by control devices preventing electric shock in those devices that use electrotherapy as a physical method of treatment and a method of preventing such electric shock.

It is an object of the present invention to provide control devices for devices that use electrotherapy as a physical treatment method so as not to cause electrical shock to patients upon accidental discontinuation of treatment.

As mentioned above, electrotherapy devices are safe to the mains, are powered by the AC adapter, or are powered by batteries. DC or pulse current is used for electrotherapy.

However, already low current values, about 5mA, are high enough to cause electric shock to the treated person at the moment when they inadvertently or forcibly have to disconnect from the circuit before turning off the device - putting the device from work to sleep. For some, this electric shock can cause some inconvenience.

Thus, it is an object of the invention for patients to undergo medical procedures without suffering an electrical shock upon accidental interruption of the procedure, for example by removing the patient's hands from the electrodes from the water, i.e. during the operating mode of the device.

SUMMARY OF THE INVENTION The present invention is based on a new design of a control device to prevent electric shock in electrotherapy devices as a physical treatment method.

The reason for the positive function of the device that it does not cause an electric shock is its adaptation as a power source to change the load impedance of the patient's body, just as the patient unplanned pulls his hands away from the electrodes from the water. The power source is a controllable direct current source.

Regulatory versus regulated load impedance system of the patient receiving treatment is important to eliminate electrical shock.

To set the parameters of the regulator leading to the regulation of the controlled system with zero or negligible regulation deviation, its properties - speed, reaction, response time, inertia.

The load impedance of the body of a patient receiving treatment as a regulated system has the following characteristics:

of direct current only puts ohmic resistance »

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In the course of therapy, the magnitude of the ohmic resistance varies within approximately ± 5%, ie relatively little and slowly

- at the beginning and end of therapy, the value of ohmic resistance varies several times due to the connection or disconnection of the patient from / to the circuit.

The delayed output current regulator τ _reg consists of a delayed output current stabilizer, a deviation amplifier, a start circuit, an output current slow control circuit, and a standby and operating switch.

The output current regulator with delay τ reg - type PI - proportional integration regulator, where the derivative component is suppressed, regulates with zero regulation deviation only during treatment therapy when changes in the patient's ohmic resistance are small in the order of one percent and slowly changing in seconds. Large and relatively rapid changes in resistance of the patient's body at the start and end of treatment therapy work as follows:

After switching on the device - before starting therapy, the voltage value at the device output is about 10V. At this voltage level - in sleep mode, the patient connects to the circuit. When the patient is connected to the circuit, a current of approx. When this current value is reached, the voltage in the circuit is further reduced to about 3V and the current starts to rise slowly until it reaches its preset amplitude value. The rise time of the current is about 0 to 60s depending on the amplitude of the preset current, ie, a shorter time for a smaller size and a longer time for a larger size.

After adjusting the preset magnitude of the current, the therapy itself begins. When treatment is complete, the patient is disconnected from the circuit and the device automatically enters sleep mode.

But if the patient suddenly interrupted therapy unexpectedly take the hands from the electrodes of the water, the device is not switched off, there was a rapid change of current rise to its nominal value while the control device responds to a rapid change in current withholding its current state delay T _re g · During this time, however, the device simply switches to sleep mode. Sleep is the same as the power-on state. The device is ready to resume treatment therapy.

The function of the control device completely eliminates the occurrence of electric shock at the start and end of the treatment therapy under the following conditions between the time delay r _{reg of the} output current from the controller block (4), the time τ _νγρ for rapid switching of the device »9

from the working mode to the sleep mode and the r _run time of slow adjustment of the output current amplitude setting:

Treg> Fvyp

Treg «J-run

The device, using electrotherapy as a physical treatment method, by connection to the output current regulator block (4) with a delay of delay _reg function, completely eliminates the occurrence of electric shock upon accidental interruption of therapy.

This feature of the device allows the patient to interrupt and re-establish the therapy at any time without having to put the device from work to sleep and vice versa.

Clarification of drawings

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a medical device in which electrical shock is prevented during electrotherapy therapy; FIG. 2 is a block diagram of an output current regulator with delay; and FIG. electrical diagram of the output current regulator with delay.

DETAILED DESCRIPTION OF THE INVENTION

The control device for preventing electric shock in apparatuses using electrotherapy for treatment, shown in the accompanying drawings in Figures 2 and 3, consists of an output current stabilizer 7 with a delay member, a control deviation amplifier 8, a starter circuit 5, a circuit 6 slowly adjusting the output current and the idle switch 9 of the apparatus.

The output current stabilizer 7 with the delay member allows setting a certain output current value and maintaining it independently of the instantaneous load parameters, just as the patient unplanned pulls his hand away from the electrodes from the water. The delay member cancels this "immediately" and creates a delay of the stabilizer reaction in the order of tenths of seconds. The output current stabilizer 7 with the delay τ _reg is circumferentially solved by a transistor T2 in a common base connection. The voltage drop caused by the output current at resistors R11, R26 and the schottky diode D18 is compared at the base transition with the preset voltage of the potentiometer JP1. The control deviation is routed through the R16 resistor to the amplifier input. 1 »· *

regulatory deviations. The diode D15 linearizes the adjustment process with a potentiometer, the zener diode D8 together with the resistor R22 serves for its stabilization. The capacitors C1, C13 together with the error circuit R1, R26 and D18 determine the amount of time delay of the output current stabilizer (7). In the standby state and the output current is slowly regulated, the output current stabilizer 7 is delayed and the residual voltage appears on the resistor R26 depending on the current setting of the potentiometer JP1. Standby mode. A standby measurement error is corrected by the presence of the emitter tracer TI3 and the input V2, which bridges the diode D8 and generates zero bias of the base of transistor T2. After switching to the operating mode, the residual voltage is removed by the Schottky diode D18 connected for this voltage in the reverse direction.

The control deviation amplifier 8 consists of transistors T4 and T5. The deviation amplifier 8 is controlled by an N-FET T7 transistor that limits its operation to the source operating mode. In standby mode, the bias amplifier 8 is switched off by the high resistance of channel T7. By input from the electrode, the control deviation amplifier 8 limits the maximum output voltage at the electrodes of the instrument.

The starter circuit 5 is used to switch the source from standby to working mode and vice versa. It consists of transistor T6 with output current sensing circuit with diodes D9, D17 and resistors R12], R25. Resistor R25 is set to the size of the switching current and functional ⁱⁿ both modes. The forward-connected Zener diode limits the voltage drop across the resistor R25 to approx. 0.6V. The Schottky diode D17 separates the base circuit of transistor T6 from the delay element C12 → C13 → R11. Output VI controls the instrument indication.

The low-current output current slow-circuit 6 is a RC charging element consisting of high-capacity ceramic capacitors C10-C11 and a resistor R18. The time regulation of the output current is approximately determined by the RC constant of this circuit and here is approx. 60 seconds. This time also depends on the output current setting value. The high input resistor N-FET T7, which does not load the charging RC member, directly controls the gain of the amplifier 8 of the control deviation.

The discharge circuit of capacitors C10, jcil is transistor T8 together with resistor R19. The start of regulating the output current is given by the closure of transistor T8 due to the signal from the starter circuit.

The idle and operating switch (9) directly controls the control circuit of the switching power supply (3) of the device. This connection is an analog controller solution to eliminate shock in devices using electrotherapy to treat accidental discontinuation of therapy.

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A digital solution is also possible.

Apparatus utilizing electrotherapy for treatment, consisting of a power supply block (1), an indication block (2), and a closed-loop switching power supply block (3) connected to the output current regulator block (4) with delay τ _re g, does not cause electrical shock to patients accidental discontinuation of therapy.

Industrial applicability

The control device according to the invention is applicable to all devices or devices that use some kind of electrotherapy for treatment.

Claims (2)

PATENT CLAIMS Control device for preventing electric shock in apparatuses using electrotherapy for treatment, characterized in that it comprises a starter circuit (5) which is connected to a slow control circuit (6) of the output current, which is further connected to a control amplifier (8). This is coupled to the output current stabilizer (7) with the delay member and the sleep mode switch (9) of the apparatus. Method of using an electric shock control device in apparatus according to claim 1, characterized in that, in the event of a sudden interruption of therapy, the control device prevents the occurrence of electric shock in that the time delay T _{reg of the} output current from the controller block (4) is greater than time T _off for fast switching of the instrument to the idle mode and that the time delay r _{reg of the} output current from the controller block (4) is of the order of magnitude smaller than the time T _{run of} slow adjustment of the output current amlitude setting; Treg> Typ Treg <<Throne. . . Λ _t '* * * * t