JPS596839Y2 - low frequency treatment device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a low-frequency treatment device that energizes a human body with back electromotive force pulses generated in an inductor through a conductor.

An example of a conventional low frequency treatment device is shown in FIG.

That is, reference pulse generation circuits 1 and 2 each generate pulse groups with waveforms suitable for treatment, a selection circuit 3 that selects a pulse group according to the purpose of treatment, a volume circuit 5 that adjusts the output, and a pulse power control circuit. It consists of an output circuit 11 that amplifies and generates high-voltage pulses, and two or more conductors 8, 9, etc. that apply the output of this output circuit 11 to the human body to supply electricity.

Note that 4 is an amplification transistor, and vCC is a power supply.

In this case, if we adjust the setting position of the volume 5 and keep the amplitude level of the input signal low, the output transistor 6 will not be saturated, so the difference obtained by subtracting the voltage drop due to the inductor from the voltage of the power supply Vcc will be the output It will be consumed by transistor 6.

Originally, even in the case of a low-power, low-frequency treatment device that is desired to have low power consumption, the output transistor 6 will consume several times more wasted energy.

In addition, there are many examples of low-frequency treatment devices that have a volume interposed between the output circuit and the conductor, but in this case, reducing the output level only causes the volume to consume energy, and it is not possible to reduce energy consumption. it dose not connect.

As stated above, an object of the present invention is to provide a low frequency treatment device that can change the output level without wasting power even when the output level is small.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 2 is a circuit diagram showing the main part of the embodiment of the present invention, in which a variable pulse width circuit 10 for output level adjustment is provided before the output circuit 11, and this variable pulse width circuit 10 is connected to a capacitor 12 and 13, the variable time constant circuit is turned on or off depending on whether the output of the variable time constant circuit exceeds the threshold voltage of the inverter 14 or not.

Further, in FIG. 2, the same reference numerals as in FIG. 1 indicate the same parts.

The central point of the present invention is to effectively utilize the characteristics of the output circuit 11, and first, the characteristics of the output circuit 11 will be explained.

The output transistor 6 in the output circuit 11 is operated in saturation by the output pulse of the variable pulse width circuit 10, and when the output transistor 6 is on,
The voltage applied to inductor 7 is approximately equal to the voltage of power supply Vcc.

When the input pulse to the output transistor 6 is cut off, a back electromotive force is generated in the inductor 7 at that moment, and its amplitude depends on the product of the excitation current and the energization time, but it is generally 10 to 10 times higher than the voltage applied by the power supply Vcc. It can be made about 100 times larger.

If the inductor 7 becomes magnetically saturated during the energization time, the magnitude of the back electromotive force becomes irrelevant to the energization time width, but within this limit time width, the inductor's back electromotive force changes according to the time width. However, if the limit is exceeded, the back electromotive force does not change, so power is simply supplied to the inductor 7 in vain.

The time width at which magnetic saturation occurs is approximately determined by the product τ of the inductance of the inductor and the series equivalent resistance, and is approximately 3
Corresponds to τ.

FIGS. 3 to 6 schematically show this change.

However, FIG. 3 is an output waveform diagram of the time constant variable circuit of the variable circuit 10, FIG. 4 is a waveform diagram of the input pulse to the output circuit 11,
FIG. 5 is an excitation current waveform diagram, and FIG. 6 is a diagram showing voltage changes from the start of excitation in the inductor 7 to the point at which a back electromotive force is generated.

In addition, in Figures 3 to 6, (a) is a short pulse time width in which the current is cut off long before the excitation current is saturated, and (b) is an intermediate pulse time width when the excitation current is about to be saturated. In the case of (C) is the case where the pulse time width is such that the excitation current is almost saturated, and (d) is the case where the pulse time width is such that the excitation current is completely saturated.

When the volume 13 of the variable pulse width circuit 10 is changed,
Differential waveforms as shown in Fig. 3 a to d are obtained by the variable time constant circuit, and the differential waveforms shown in Fig. 4 a to d are obtained at the threshold level th.
This rectangular wave pulse is converted into a rectangular wave pulse having a different time width as shown in FIG.

At this time, the inductor 7 is excited by the time width of the input pulse as shown in FIGS. 5a-d, and when the output transistor 6 is turned off, the back electromotive force pulses as shown in FIGS. 6a-d are output pulses. obtained as.

If the excitation current is not saturated as shown in Figures 5a to 5C, as the input pulse width increases from Figure 4a to Figure 4C, the output voltage will decrease as shown in Figure 6C. However, if the excitation current is saturated as shown in Figure 5 d, the output voltage in this case will become saturated as shown in Figure 6 d, regardless of the input pulse width being large as shown in Figure 4 d. The output voltage is the same as in Figure 6C.

For this reason, a variable pulse width circuit 10 is provided which adjusts the time width of the input pulse to the output circuit 11 within an appropriate range less than or equal to the time width (approximately 3τ) determined by the time constant of the output circuit 11. It was established.

As is clear from the above explanation, the present invention has an output circuit 11
Since the pulse width variable circuit 10 for output level adjustment is provided, which allows the energization time width of the input pulse to be adjusted within a range 1 narrower than 3τ, it is possible to easily and reliably do so without wasting power. The output pulse can be changed,
This has a great practical effect, especially in battery-powered low-frequency treatment devices where power consumption must be kept as low as possible.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an example of a conventional low frequency treatment device, and FIG. 2 is a circuit diagram showing the main parts of the low frequency treatment device according to an embodiment of the present invention. In addition, Figures 3 to 6 are explanatory diagrams of the operation of the circuit in Figure 2, Figure 3 is an output waveform diagram of the time constant variable circuit in the variable circuit, and Figure 4 is an input waveform diagram to the output circuit. Pulse waveform diagram,
FIG. 5 is a diagram showing current changes in the inductor, and FIG. 6 is an output voltage waveform diagram. Description of symbols 1, 2...Reference pulse generator, 3.
... Selection circuit, 4 ... Amplification transistor, 5 ... Volume, 6 ... Output transistor, 7 ... Inductor, 8, 9. ...
... Conductor, 10... Pulse width variable circuit, 11.
...output circuit, 12...condenser,
13...Volume, 14...Inharta.

Claims (1)

[Scope of utility model registration request] An output circuit is configured to output a back electromotive force pulse by intermittent excitation current to the inductor by an output transistor, and has a constant τ during magnetic saturation of the inductor, and a manual pulse to the output circuit. The energization time width is 3τ
1. A low-frequency treatment device characterized by comprising a variable circuit for adjusting an output level, which can be adjusted in a narrower range.