JP2612347B2 - Low frequency treatment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a low-frequency therapeutic device for performing treatment by applying a therapeutic electric pulse to a human body and applying a stimulus.

(Prior Art) An example of a human body detection circuit in a conventional low frequency treatment device, for example, a home electronic massager will be described with reference to FIG.

In FIG. 3, CN1 and CN2 are output electrodes mounted on the human body, respectively, and a therapeutic electric pulse is applied between these output electrodes CN1 and CN2 at a predetermined period by a therapeutic electric pulse generating circuit (not shown). A resistor R1 and a collector and an emitter of the npn transistor Tr1 are connected in series between both ends of a battery (electromotive force V _D ) which is a DC power supply, and a connection point of the resistor R1 and the transistor Tr1 is It is connected to the input port of a microcomputer that controls the electric pulse generator for therapy. The base of the transistor Tr1 is connected to the negative output electrode CN2, and a parallel connection made up of a resistor R2, a diode D1, and a capacitor C1 is connected between the base and the emitter of the transistor Tr1.

Then, if both output electrodes CN1 and CN2 are not worn on the human body, even if the therapeutic electric pulse is output to the output electrodes CN1 and CN2, no current flows between these output electrodes CN1 and CN2,
Therefore, the base current does not flow through the transistor Tr1, so that the transistor Tr1 is in the OFF state.
At this time, although the input port of the microcomputer is HIGH, the microcomputer determines that the output electrodes CN1 and CN2 are not mounted on the human body, and performs a process in accordance therewith. For example, the output operation of the therapeutic electric pulse is stopped.

On the other hand, if both output electrodes CN1 and CN2 are mounted on the human body as a load, when a therapeutic electric pulse is output to the output electrodes CN1 and CN2, a current flows between these output electrodes CN1 and CN2, and the transistor Since the base current also flows through Tr1, this transistor Tr1 turns on. At this time, the input port is L
Although the state becomes OW, the microcomputer determines that the output electrodes CN1 and CN2 are mounted on the human body.

(Problems to be Solved by the Invention) However, in the above-described conventional structure, the base current flowing through the transistor Tr1 is not particularly limited, and therefore, for example, the output electrodes CN1 and CN2 are short-circuited for some reason or a strong treatment is performed. When an electric pulse is output, a large current flows through the base of the transistor Tr1, and the transistor Tr1 may be destroyed.

Also, only noise enters the negative output electrode CN2, the transistor Tr1 turns on, the input port of the microcomputer goes low, and it may be determined that the microcomputer is worn on the human body. Is easy to malfunction.

Furthermore, the human body has a capacitive component instead of a simple resistance component, and when a pulse is input, a time difference occurs between the current between the emitter and the collector of the transistor, and the human body may not be accurately detected. Also have.

The present invention has been made in view of the above problems, and has as its object to provide a low-frequency treatment device that can accurately detect the presence or absence of connection of a human body.

[Configuration of the invention]

(Means for Solving the Problems) A low-frequency therapeutic device according to claim 1, a microcomputer, a therapeutic electric pulse generating circuit controlled by the microcomputer to generate a therapeutic electric pulse,
A pair of output electrodes for outputting the therapeutic electric pulse generated by the therapeutic electric pulse generation circuit, and a human body detection circuit for detecting a resistance value between the output electrodes and outputting a detection result to the microcomputer. The human body detection circuit includes a series circuit of a resistor and a transistor connected to a DC power supply, and a capacitor connected between an emitter and a collector of the transistor, and connects a base of the transistor to the output electrode. In addition, an input port of the microcomputer is connected to a connection point between the resistor and the transistor.

According to a second aspect of the present invention, there is provided the low-frequency therapeutic device according to the first aspect, wherein a zener diode is connected between the base and the emitter of the transistor.

(Function) The low-frequency therapeutic device according to claim 1, wherein the therapeutic electric pulse generated by the therapeutic electric pulse generation circuit while being controlled by the microcomputer is applied to the human body via a pair of output electrodes mounted on the human body. Is output to the human body so that the stimulus is given to the human body and the treatment is performed. Then, when the therapeutic electric pulse is output to the output electrode, if this output electrode is not attached to the human body, no current flows between the output electrodes, and current also flows to the base of the transistor connected to this output electrode. Since no current flows, this transistor is in the OFF state. On the other hand, if the pair of output electrodes is mounted on the human body, a current flows between the output electrodes via the human body resistance and a base current also flows through the transistor, so that the transistor is turned on. Then, according to ON / OFF of the transistor, the input port of the microcomputer connected to the connection point of the resistor and the transistor connected in series to the DC power supply becomes LOW or HIGH. Thereby, the microcomputer determines whether or not the output electrode is worn on the human body. By connecting a capacitor between the emitter and collector of this transistor,
After generating a therapeutic electric pulse in the therapeutic electric pulse generation circuit, even if there is a time difference between the pulse generation and the current between the collector and the emitter of the transistor due to capacitive components in the human body, etc.
Since the current input to the microcomputer can be adjusted by charging the capacitor, the presence / absence of attachment to the human body is reliably detected.

In the low-frequency therapeutic device according to the second aspect, since the Zener diode is connected between the base and the emitter of the transistor in the low-frequency therapeutic device according to the first aspect, even if the output electrodes forming a pair are short-circuited. However, the voltage between the base and the emitter of the transistor does not exceed the Zener voltage of the Zener diode, and a large current is prevented from flowing through the base of the transistor. Further, noise entering the output electrode is absorbed to some extent by the zener diode.

(Embodiment) An embodiment of the low frequency treatment device of the present invention will be described below with reference to FIG.

In FIG. 1, E is a battery (electromotive force V _D ) such as a lithium battery which is a DC power supply. This battery E is connected in parallel with an electrolytic capacitor C11. MC is a CMOS microcomputer (for example, NEC µPD7554G etc.)
It is. Then, the battery E + electrode is connected to the contact S ₁ of the power switch SW11, contact T _1, M of the contact S 3 one contact T ₁ is selectively connected to _1, O _1, M _{1 1} is connected to the positive pole power terminal 10 of the microcomputer MC. on the other hand,
The negative pole power terminal 20 of the microcomputer MC is connected to the negative pole of the battery E and grounded.

In addition, the contact to work with the contact S ₁ of the power switch SW11 S
₂ is connected to the output port 15 of the microcomputer MC, and is grounded via a resistor R11.
The three contacts which are selectively connected to the contact S ₂ T _2, O _2,
Contact O ₂ of M ₂ is connected via a resistor R12 to contact point T _1, M _1. Also, the contacts M _2, together with being connected to an input port 16 of the microcomputer MC, and is grounded through a resistor R13. Furthermore, the microcomputer MC
Input port 18 is grounded via a resistor R14.

Further, the input ports 1 and 2 of the microcomputer MC are connected to the contacts T ₁ and M ₁ of the power switch SW11, respectively.
Connected through. Also a microcomputer
A resistor R15 and a variable resistor VR11 are connected in series between the clock terminals 8 and 9 of the MC. In addition, microcomputer
The reset terminal 11 of the MC is connected to the contacts T ₁ and M ₁ of the power switch SW11 via the capacitor C12. The ports 3, 17, and 19 of the microcomputer MC are grounded.

Then, the variable resistor to the contact T _1, M ₁ of the power switch SW11 VR1
One end of each of the coils L11 and L12 is connected to the other end of the coil L11 and L12, and the other end of each of the coils L11 and L12 is connected to the collector of each of the npn-type transistors Tr11 and Tr12. The emitters of these transistors Tr11 and Tr12 are each grounded. The bases of these transistors Tr11 and Tr12 are
They are connected to output ports 5 and 6 of a microcomputer MC serving as an oscillator via resistors R16 and R17, respectively. Further, a series circuit of capacitors C13 and C14 and resistors R18 and R19 is connected in parallel to the resistors R16 and R17, respectively.

Then, the coils L11 and L12 and the transistors Tr11 and Tr12
Are connected to one end of a capacitor C15 via diodes D11 and D12, respectively.
Is grounded.

In addition, these diodes D11 and D12 and capacitor C15
Is grounded via a resistor R20 and an npn-type transistor Tr13. And this transistor Tr13
The base of the microcomputer MC through the resistor R21
Output port 12.

In addition, the same diodes D11, D12 and capacitor C15
Is connected to the emitter of the pnp transistor Tr14, and the collector of the transistor Tr14 is connected to the positive electrode output terminal CN11. Also this transistor
The base of Tr14 is an npn-type transistor Tr via a resistor R22.
Connected to the collector of the transistor Tr15
Are grounded. The base of the transistor Tr15 is connected to the output port 7 of the microcomputer MC via the resistor R23. Further, a resistor R24 is connected between the emitter and the base of the transistor Tr15.

On the other hand, the negative output electrode CN12 is connected to the base of an npn-type transistor Tr16 via a series circuit of resistors R25 and R26, and the connection point of both resistors R25 and R26 is a Zener diode Z.
D is grounded. The collector of the transistor Tr16, together with being connected to the contact T _1, M ₁ of the power switch SW11 via the resistor R27, is connected to an input port 4 of the microcomputer MC. On the other hand, transistor Tr16
Are grounded. Also this transistor
A resistor R28 is connected between the emitter and the base of Tr16. Further, the collector of the transistor Tr16 is grounded via the capacitor C16.

The output electrodes CN11 and CN12 are detachably attached to a human body.

A circuit connected to the positive output terminal CN1 of the circuit shown in FIG. 1 (c) described above is a therapeutic electric pulse generating circuit controlled by the microcomputer MC to generate a therapeutic electric pulse. It is. Also, the first
The circuit connected to the negative output terminal CN12 of the circuit shown in FIG. 9C is a human body detection circuit that detects the resistance value between the two output electrodes CN11 and CN12 and outputs the detection result to the microcomputer MC. . FIG. 1 shows only the human body detection circuit.

Then, the voltage of the electric pulse for treatment and the resistance R25, R26, R28
The relationship between the resistance of the Zener diode ZD and the Zener voltage of the Zener diode ZD is determined when a therapeutic electric pulse is applied while a human body resistance (resistance value is, for example, about 10 KΩ) is connected between the output electrodes CN11 and CN12. The diode ZD is set to turn on. When the Zener diode ZD is ON, the voltage of the connection point of the resistors R25 and R28 to the ground point is slightly higher than the base-emitter voltage V _BEO when the collector of the transistor Tr16 is open. Further, the resistor R27 and the capacitor C16 connected in series between the two poles of the battery E form a time constant circuit, and the time constant is set to be smaller than the generation cycle of the therapeutic electric pulse. The frequency of the electric pulse for treatment is a constant value of, for example, about 3 to 33.3 Hz.

 Next, the operation of the above embodiment will be described.

First, an outline of a method of using the low frequency treatment device will be described.

The power switch SW11 is operated by the user, but is turned off when not in use. Then, at the time of use, the user operates the power switch SW11 to turn it on. At this time, the waveform of the therapeutic electric pulse output to the human body is also selected. Next, a pair of output electrodes CN11 and CN12 are mounted on the affected part of the human body. Along with this, the tact switch SW
By pressing the button 12, the output of the therapeutic electric pulse from the output electrodes CN11 and CN12 starts.

Then, by applying the electric pulse for treatment to the human body, an electric current flows through the human body to stimulate the human body, and treatment such as shoulder stiffness and muscle pain is performed. At this time, the tact switch
By pressing SW12, the intensity of the therapeutic electric pulse can be adjusted. That is, at the start of the output of the therapeutic electric pulse, the intensity of the therapeutic electric pulse, that is, the voltage is minimum, but the user operates the tact switch SW.
Each time 12 is turned on by operating 12, the voltage of the electric pulse for treatment gradually increases. After the voltage reaches the maximum, the voltage of the therapeutic electric pulse does not change even if the tact switch SW12 is turned on.

 Next, the operation of the electric circuit will be described in detail.

Power switch SW11 is OFF state when the contact S _1, O ₁ is in contact. When the contacts S ₁ and T ₁ are in contact, the tapping is selected as the waveform, and when the contacts S ₁ and M ₁ are in contact, the fir is selected as the waveform. State. In a state where “hit” is selected, the contacts S ₂ and T ₂ are in contact, and in a state where “fir” is selected, the contacts S ₂ and M ₂ are in contact. The microcomputer M
A signal is always output from the output port 15 of C, and the contacts S ₂ and T ₂
If contacts, the input port 16 is LOW, the microcomputer MC is determined to be selected is "tapping", if in contact the contact S _2, M _2, input port 1
Since MC is HIGH, the microcomputer MC determines that “fir” has been selected.

Then, when the input port 1 becomes HIGH by turning on the tact switch SW12 in a state where the output electrodes CN11 and CN12 are mounted on the human body, the microcomputer MC starts the output operation of the therapeutic electric pulse.

First, a high-frequency pulse is output to the bases of the transistors Tr11 and Tr12 several times from one or both of the output ports 5 and 6 of the microcomputer MC. Output port 5, 6
When the output of the transistor goes high, the transistors Tr11 and Tr12 turn off.
Then, current flows from the battery E to the coils L11 and L12 via the transistors Tr11 and Tr12. After that, the output of output ports 5 and 6 becomes LOW, and transistors Tr11 and Tr12
Turns off and the current flowing through coils L11 and L12 is cut off.
A high voltage is generated in the coils L11 and L12 by the back electromotive force.
By repeatedly charging the capacitor C15 with this high voltage, the charging voltage of the capacitor C15 is sufficiently increased.

The microcomputer MC is a tact switch SW
When input port 1 becomes HIGH by turning on 12,
Switches the number of high-frequency pulse outputs from output ports 5 and 6. Thereby, the charging voltage of the capacitor C15 is variably set, and the voltage, that is, the intensity of the electric pulse for treatment can be adjusted.

Then, after the charging of the capacitor C15 is completed, the output port 7 which has been LOW until then temporarily becomes HIGH. As a result, the transistor Tr15 is turned on, the transistor Tr14 is turned on, and the voltage charged in the capacitor C15 is output as therapeutic electric pulses to the output electrodes CN11 and CN12.
Is output to the human body. When “hit” is selected, the output port 7 goes high only once,
When "fir" is selected, the output port 7 goes high several times in succession.

Then, the output port 12 which has been LOW becomes temporarily HIGH. As a result, the transistor Tr13
This capacitor C15 is discharged until it turns ON and the charging voltage of the capacitor C15 becomes 0V.

Thereafter, as described above, charging of the capacitor C15 starts again.

In this way, the above-described series of operations are repeated at a constant cycle, whereby the therapeutic electric pulse is output to the human body at a low frequency.

By the way, when the therapeutic electric pulse is output to the output electrodes CN11 and CN12, if the output electrodes CN11 and CN12 are not attached to the human body, no current flows between these output electrodes CN11 and CN12, so the transistor Tr16 Also, no base current flows, and this transistor Tr16 is in the OFF state.
Therefore, the input port 4 of the microcomputer MC is
Although it is HIGH, the microcomputer MC determines that the output electrodes CN11 and CN12 are not mounted on the human body. In this case, the microcomputer MC stops the output from the output ports 5 and 6, and stops the output operation of the therapeutic electric pulse.

On the other hand, if both the output electrodes CN11 and CN12 are worn on the human body, a current flows between the output electrodes CN11 and CN12 via the human body resistance when the electric pulse for treatment is output. Then, the pulse current flowing into the negative electrode output electrode CN12 flows into the Zener diode ZD via the resistor R25. With this current, the Zener diode ZD generates a Zener voltage. The generated Zener voltage is divided by the resistors R26 and R28, and the voltage at the connection point of the resistors R26 and R27 with respect to the ground is applied between the base and the emitter of the transistor Tr16. A base current flows through Tr16, and this transistor Tr16 turns ON. Accordingly, the input port 4 goes LOW, whereby the microcomputer MC determines that the output electrodes CN11 and CN12 are mounted on the human body. In this case, the output electrodes CN11, CN12
The output of the pulse to continues. This human body detection is performed for each output of the therapeutic electric pulse.

In addition, tact switch SW12 is turned on and input port 1 is
For example, a pulse is always output to the output electrodes CN11 and CN12 unconditionally for 2 seconds after it becomes HIGH. This is, of course, for activating the output operation of the therapeutic electric pulse.

By the way, if both output electrodes CN11 and CN12 are stuck on the surface of the table, both output electrodes CN11 and CN12
The resistance value between them becomes, for example, 1 MΩ or more, which is larger than the human body resistance. In this case, the voltage drop between the two output electrodes CN11 and CN12 increases, and the voltage of the connection point of the resistors R25 and R26 to the ground point becomes smaller than the Zener voltage, so that the Zener diode ZD does not turn on. And the resistor R2 at this time
6, the voltage at the connection point of R28 becomes smaller than when the zener diode ZD is turned on, becomes smaller than V _{BEO of} the transistor Tr16, and the transistor Tr16 does not turn on. Therefore, the output operation of the therapeutic electric pulse is stopped. in this way,
By setting the voltage between the base and the emitter of the transistor Tr16 by the voltage division of the resistors R26 and R28, both output electrodes C1 when the output operation of the therapeutic electric pulse is stopped.
The range of the resistance between C1 and C12 can be appropriately limited.

When the Zener diode ZD is ON, no matter how much the voltage of the negative electrode
The voltage at the connection point of R26 and R28 has a constant value lower than the Zener voltage. Therefore, for example, even when the two output electrodes CN11 and CN12 are short-circuited for some reason or a strong therapeutic electric pulse is output, a large current does not flow through the base of the transistor Tr16. Therefore, destruction of the transistor Tr16 and other elements can be prevented, and these can be reliably protected.

Further, when the output electrodes CN11 and CN12 are not mounted on the human body, noise entering the negative electrode output electrode CN12 can be absorbed to some extent by the zener diode ZD, and malfunction of the human body detection circuit due to the noise can be prevented to some extent.
That is, when very short noise enters even at a high voltage, a sufficient base current does not flow through the transistor Tr16.

Here, the relationship between ON / OFF of the transistor Tr16 and LOW / HIGH of the input port 4 of the microcomputer MC will be described.

After the generation of one therapeutic electric pulse is completed and the transistor Tr16 is turned off, the capacitor C16 is connected via the resistor R27.
Is gradually charged. Then, when the generation of the therapeutic electric pulse in the next cycle starts and the transistor Tr16 is turned on,
Since the capacitor C16 is connected between the emitter and the collector of the transistor Tr16, the capacitor C16 is discharged, and after the transistor Tr16 is turned off, the capacitor C16 is charged again. At this time, the resistor R27
Since the time constant of the time constant circuit including the capacitor C16 and the time constant of the treatment electric pulse is shorter than that of the electric pulse for therapy, the capacitor C16 is almost fully charged immediately before the transistor Tr16 is turned on. Then, if a sufficient base current is supplied to the transistor Tr16, the capacitor C16 is discharged to 0V while the therapeutic electric pulse is generated and the transistor Tr16 is turned on. The pulse width of the therapeutic electric pulse is, for example, about 0.1 ms.

Since the input port 4 is connected to the connection point between the resistor R27 and the capacitor C16, the LO of the input port 4 is
W · HIGH is determined by the charging voltage of the capacitor C16. However, since the microcomputer MC determines digitally, the input port 4 is determined to be LOW when the charging voltage of the capacitor C16 is equal to or less than a certain value which is larger than 0V. Will be. Therefore, when the output electrodes CN11 and CN12 are worn on the human body, the input port 4 is substantially in the LOW state for a certain period of time after the generation of one therapeutic electric pulse.

By the way, the microcomputer MC takes a certain period of time after generating a therapeutic electric pulse in the therapeutic electric pulse generation circuit and reading LOW / HIGH of the input port 4 to detect the presence or absence of a human body resistance. This time
For example, it is 30 μs or more. Therefore, the input port 4 must be LOW for 30 μs or more after the generation of the therapeutic electric pulse. However, due to the operation of the time constant circuit as described above, the input port 4 is actually input for a period of 30 μs or more after the generation of the therapeutic electric pulse. 4 can be kept LOW. In this manner, a human body detection circuit that can reliably detect a human body is provided.

Also, when the output electrodes CN11 and CN12 are not mounted on the human body, even if noise enters the negative electrode output electrode CN12 and the transistor Tr16 is temporarily turned on, if the total energy amount of noise is small, the capacitor C16 is Since the discharge is not sufficiently performed, the input port 4 is not determined to be LOW. That is, the microcomputer MC mistakenly treats the treatment electrode CN1.
1, Does not judge that CN12 is worn on the human body.

Thus, by providing the time constant circuit in addition to the zener diode ZD, a human body detection circuit that is strong against noise and does not malfunction can be obtained.

〔The invention's effect〕

According to the low frequency treatment device of the present invention, a resistor and a transistor are connected in series to a DC power supply, a base of the transistor is connected to an output electrode, and an input port of the microcomputer is connected to a connection point of the resistor and the transistor. In the human body detection circuit configured by connecting,
A resistor and a capacitor are connected in series to the DC power supply, and an input port is connected to the connection point of the resistor and the capacitor, and a capacitor is connected between the emitter and the collector of the transistor. Even if there is a time difference between the pulse generation and the current between the collector and the emitter of the transistor, the human body can be reliably detected by keeping the input port LOW or HIGH for a certain period of time after the generation of the therapeutic electric pulse. When the output electrode is not attached to the human body, noise enters this output electrode and the transistor turns on temporarily.
However, in this case, since the capacitor is not sufficiently discharged, the malfunction of the human body detection circuit can be more reliably prevented, and the operation of the human body detection circuit can be more reliably performed.

According to the low frequency treatment device of the second aspect, in addition to the low frequency treatment device of the first aspect, a zener diode is connected between the base and the emitter of the transistor via a resistor, so that the low frequency treatment device is mounted on a human body. Even if multiple output electrodes should be short-circuited, a large current does not flow to the base of the transistor, so that the transistor can be prevented from being destroyed, and the output electrode can be attached to the human body. Even if noise enters the output electrode when it is not performed, the noise can be absorbed to some extent by the zener diode, and therefore, malfunction of the human body detection circuit can be prevented to some extent, and the operation of the human body detection circuit can be reliably performed. And reliability can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a human body detection circuit showing an embodiment of a low frequency treatment device of the present invention, FIGS. 2 (a), 2 (b) and 2 (c) are circuit diagrams of the whole of the same, and FIG. It is a circuit diagram showing an example of a human body detection circuit of a frequency treatment device. MC: microcomputer, 4 ... input port, CN1
1, CN12 …… Output electrode, E …… Battery which is DC power supply, R27
…… Resistance, Tr16 …… Transistor, R26 …… Resistance, ZD…
… Zener diode, C16 …… Capacitor.

Claims (2)

(57) [Claims] 1. A microcomputer, a treatment electric pulse generating circuit controlled by the microcomputer to generate a treatment electric pulse, and a pair for outputting the treatment electric pulse generated by the treatment electric pulse generation circuit. An output electrode, and a human body detection circuit that detects a resistance value between the output electrodes and outputs a detection result to the microcomputer. The human body detection circuit includes a series circuit of a resistor and a transistor connected to a DC power supply. And a capacitor connected between the emitter and the collector of the transistor,
A low-frequency therapeutic device wherein a base of the transistor is connected to the output electrode, and an input port of the microcomputer is connected to a connection point between the resistor and the transistor. 2. The low-frequency therapeutic device according to claim 1, wherein a zener diode is connected between the base and the emitter of the transistor.