TW201434507A - Transcutaneous nerve stimulator - Google Patents

Abstract

A transcutaneous nerve stimulator uses a control circuit to detect a transformer inductive current of a boost circuit and compares a sensing voltage generated by the transformer inductive current with a limiting voltage, such that the operation of a switch element in the boost circuit can be determined so as to turn on or off the boost conversion operation of the transformer. Thereby, the boost circuit can generate sufficient working voltage with the lowest power consumption of the transformer. In addition, a conversion circuit can be utilized to convert the working voltage to a simulation signal outputted at a positive-negative cycle for eliminating charge accumulation in a human body, such that the transcutaneous nerve stimulator can be directly modulated to a particular electrotherapy frequency via the conversion circuit.

Description

Transcutaneous nerve stimulator

The present invention relates to electrotherapeutic machines, and more particularly to a transcutaneous nerve stimulator that covers broadband operation.

In general physical therapy, electrotherapy is the most widely used, and the auxiliary instruments used to relieve pain are generally based on the Transcutaneous Electrical Nerve Stimulation (TENS), which uses the current on the skin. Pulses are created to alter the brain's perception of pain and can be used to relieve pain from arthritis or chronic conditions.

In practice, the conventional transcutaneous nerve stimulator outputs the stimulation current in a high-voltage pulse mode. For different body impedance factors, the stimulation intensity is difficult to control and consumes electricity; for example, it is generally connected to the output end of the stimulator. The variable resistance is used to adjust the magnitude of the control output current, so the current operating power generated by the variable resistor causes a large amount of heat consumption of the product circuit.

The main object of the present invention is to provide a transcutaneous nerve stimulator that effectively modulates the operating frequency and saves circuit power consumption.

In order to achieve the above object, a transcutaneous nerve stimulator according to the present invention includes a control circuit, a sequential circuit, a boosting circuit and a converting circuit, wherein: the control circuit is configured to receive a sensing voltage when the sensing voltage When a predetermined voltage is exceeded, the control circuit outputs a cutoff voltage; the timing circuit is electrically connected to the control circuit to transmit the cutoff voltage, and after the timing of the cutoff voltage is connected, a pilot signal is output; The boosting circuit has a switching component, a transformer and a voltage stabilizing circuit. The switching component is electrically connected to the sequential circuit, and the cutoff signal and the communication signal respectively control the switching component to operate in an off state and a conducting state, and the switching component is Transmitting a current of one of the primary side coils of the transformer and generating the sensing voltage is received by the control circuit, and one of the secondary side coils of the transformer is electrically connected to the voltage stabilizing circuit, and the voltage stabilizing circuit is configured to output one The operating voltage is used by the conversion circuit to convert the operating voltage into one of the positive and negative potentials of the timing change, and output to the human skin from an output group.

The control circuit of the transcutaneous nerve stimulator provided by the present invention further has a comparator for receiving the limited voltage and the sensing voltage respectively by a first input terminal and a second input terminal. Preferably, the limited voltage received by the comparator is adjusted in response to a change in the stimulus signal. Preferably, the first input end of the comparator is electrically connected to an error amplifier, and one input end of the error amplifier is electrically connected to the output terminal group of the conversion circuit.

The sequential circuit of the transcutaneous nerve stimulator provided by the invention further has a bistable circuit, and the conduction signal and the cut-off potential respectively trigger the bistable circuit to output a high and a low level voltage from a true terminal. Preferably, the switching element of the boosting circuit has a triggering end and a second conducting end. The triggering end is electrically connected to the true end of the bistable circuit, and the two conducting ends are electrically connected to the transformer. The primary side coil and a sensing resistor, the sensing voltage received by the control circuit is the voltage across the sensing resistor in the conducting state of the switching element.

In the booster circuit of the transcutaneous nerve stimulator according to the present invention, the current of the secondary side coil of the transformer in the conducting state is further flowing through an inductor and a capacitor in the voltage stabilizing circuit, and the voltage stabilizing circuit The output operating voltage is the voltage across the capacitor. Preferably, the discharge rate of the capacitor is less than the frequency of the pilot signal output by the sequential circuit.

The transcutaneous nerve stimulator conversion circuit provided by the invention further receives a set of timing phase complementary modulation signals to control the switching operation of the two logic transistors in a full bridge converter, so that the full bridge type Inverter output Wave exchange signal. Preferably, the logic electro-crystal system of the full-bridge converter is connected in series with one of the first, a second logic transistor and one of the third and fourth logic transistors connected to each other. The modulation signal controls the conduction operations of the first and fourth logic transistors and the second and third logic transistors, respectively, at a phase complementary phase.

Therefore, the transcutaneous nerve stimulator provided by the present invention only needs to compare the sensing voltage generated by the transformer inductor current sensed by the control circuit with the limiting voltage, and can turn on or off the transformer through the switching element of the boosting circuit. The conversion operation enables the booster circuit to generate sufficient operating voltage with the lowest transformer power consumption; and the conversion circuit is used to form the stimulation voltage of the positive and negative half-cycle output to eliminate the body charge accumulation, so that the transcutaneous nerve stimulator The specific electrotherapy frequency required is directly modulated by the conversion circuit.

1‧‧‧Transcutaneous nerve stimulator

10‧‧‧Control circuit

12‧‧‧ comparator

14‧‧‧Error amplifier

20‧‧‧Sequence Circuit

22‧‧‧Bistable circuit

30‧‧‧Boost circuit

32, 52‧‧‧ Transformers

322, 522‧‧‧ primary side coil

324‧‧‧second side coil

34‧‧‧Variable circuit

40‧‧‧Transition circuit

402‧‧‧DC end group

404‧‧‧Output group

526‧‧‧magnetic coil

528‧‧‧magnetic switch

Vs‧‧‧ sense voltage

Ve‧‧‧Limited voltage

VRb‧‧‧Stimulus signal

CK‧‧‧ communication number

Q‧‧‧true end

Qt‧‧‧Switching elements

R‧‧‧Sensor resistance

Vcc‧‧‧ power supply

Vout‧‧‧ working voltage

L‧‧‧Inductance

C‧‧‧ capacitor

Vc1, Vc2‧‧‧ modulated signal

Q1, Q2, Q3, Q4‧‧‧ first to fourth logic transistors

The first figure is a schematic diagram of the circuit structure provided by the preferred embodiment of the present invention.

The second figure is a timing change diagram of the sequential circuit and the control circuit provided by the above preferred embodiment.

The third figure is a schematic diagram of the conversion circuit provided by the above preferred embodiment.

The fourth figure is a schematic diagram of the input and output timing changes of the conversion circuit provided by the above preferred embodiment.

Figure 5 is a block diagram showing the circuit structure of another preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following, the preferred embodiments are illustrated with reference to a number of drawings to illustrate the structure, fabrication and efficacy of the present invention. However, the preferred embodiments of the present invention are only intended to illustrate the use of the present invention in a specific structure and manufacturing method, and are not intended to limit the scope of the present invention; in the drawings, the shapes and sizes of the components are merely for convenience of labeling. It is not intended to limit the structure of the invention.

Referring to the first figure, a transcutaneous nerve stimulator 1 according to a preferred embodiment of the present invention outputs a variable frequency and voltage stimulation signal to human skin having different resistance values Rb at the load end. Skin nerve stimulator There is a control circuit 10, a sequential circuit 20, a boost circuit 30 and a conversion circuit 40, wherein:

Referring to the first and second figures together, the control circuit 10 is configured to detect a sensing voltage Vs generated by the boosting circuit 30, and output a cutoff voltage when the sensing voltage Vs exceeds a limited voltage Ve. The booster circuit 30; therefore, in order to enable the control circuit 10 to detect and determine whether the sense voltage Vs fed back by the booster circuit 30 reaches a critical limit voltage Ve, the comparator 12 can perform the above determination and The first and second input terminals of the comparator 12 are respectively configured to receive the limiting voltage Ve and the sensing voltage Vs. When the peak value of the sensing voltage Vs reaches the limiting voltage Ve, the comparator 12 Send the cutoff signal. The control circuit 10 provided by the present invention has a function of adjusting the limited voltage Ve, including connecting to the first input end of the comparator 12 by an element that can be changed by the user; or as exemplified in the embodiment. An error amplifier 14 is electrically connected to the first input end of the comparator 12, and one input end of the error amplifier 14 is electrically connected to the conversion circuit 40, so as to receive the stimulation signal of the human skin provided on the load end. VRb. Since the transcutaneous nerve stimulator 1 has different output loads due to changes in the skin and physiological conditions of different human bodies, the error amplifier 14 provided in this embodiment can immediately detect the change of the stimulation signal VRb and change the limit voltage Ve. The size allows the transcutaneous nerve stimulator 1 to modulate the stimulation signal VRb that outputs an appropriate voltage.

The timing circuit 20 is electrically connected to the control circuit 10 to transmit the cutoff voltage, and outputs a conduction signal number CK to the boosting circuit 30. The sequential circuit 20 has a latch circuit such as an RS flip-flop. The steady state circuit 22 outputs a logic signal having a high and a low level voltage from a true terminal Q. The logic signal of the low level voltage is only triggered by the cutoff voltage, and the logic signal of the high level voltage is After the cutoff voltage is connected, the output is triggered by the communication number CK.

The boosting circuit 30 has a switching element Qt, a transformer 32 and a voltage stabilizing circuit 34. The switching element Qt is electrically connected to the sequential circuit 20 and the The primary side coil 322 of the transformer 32, the cutoff signal and the communication number outputted by the sequential circuit 20 respectively control the switching element Qt to operate in an off state and a conducting state; the bipolar junction transistor is provided in the embodiment. For example, the switching element Qt has a trigger terminal (base) and two current guiding ends (emitter and collector), and the trigger terminal is electrically connected to the true end of the bistable circuit 22 Q, the two current guiding ends are electrically connected to the primary side coil 322 of the transformer 32 and a sensing resistor R, and the switching element Qt can transmit the transformer 32 power supply Vcc through the primary side coil 322 in an on state. The current is applied to the control circuit 10 by boosting the emitter of the switching element Qt by the sense resistor R to generate the sense voltage Vs. The secondary side coil 324 of the transformer 32 is electrically connected to the voltage stabilizing circuit 34. When the switching element Qt is in an on state, the power supply Vcc having an alternating current characteristic is boosted by the transformer 32, and the voltage stabilizing circuit 34 is circuitized. The rectification function output is one of the DC characteristics of the operating voltage Vout; the circuit rectification function provided by the embodiment is such that the current of the secondary side coil 324 of the transformer 32 flows through an inductor L and a capacitor C in one direction, so that the capacitor C The discharge rate is less than the frequency of the conduction signal number CK outputted by the timing circuit 20, when the current of the primary side coil 322 is raised to the peak value of the sensing voltage Vs to reach the limit voltage Ve, and the control circuit 10 outputs the cutoff voltage to trigger the switch. When the component Qt is in the off state, the voltage across the capacitor C is still stably outputting the operating voltage Vout. Actually, the switching element Qt may also be a Field-Effect Transistor (FET), and therefore, it is not limited to the aforementioned bipolar junction transistor. In addition, the circuit structure of the booster circuit 30 can also adopt a circuit architecture of a flyback converter. Therefore, the booster circuit 30 is not limited to the first figure.

Since the control circuit 10 senses the low inductance current of the primary side coil 322 of the transformer 32, the sensing voltage Vs can reach the limited voltage Ve in a short time, so that the transformer 32 can be clamped in time through the switching element Qt as long as the limiting voltage Ve is modulated. The boosting operation enables the output operating voltage Vout of the voltage stabilizing circuit 34 to meet the load requirements, and effectively controlling the secondary side coil 324 of the transformer 32 does not generate unnecessary current power consumption.

The conversion circuit 40 receives the operating voltage Vout by the DC terminal group 402, converts the stimulation signal into a positive and negative potential with time series, and outputs the stimulation signal to the human skin from an output terminal group 404. Referring to the third figure, the conversion circuit 40, which is composed of a bridge converter, is controlled by a set of timing-phase complementary modulation signals Vc1 and Vc2 to make the first to fourth The logic transistors Q1, Q2, Q3, and Q4 are synchronized and switch the square wave AC signal whose positive and negative potentials change with the timing, and refer to the fourth figure. Taking the logic transistors Q1, Q2, Q3, and Q4 made of a bipolar junction transistor as an example, the high and low level timings of the modulation signals Vc1 and Vc2 are complementary. 1. The fourth logic transistors Q1 and Q4 are synchronously controlled by the modulation signal Vc1 at the timing of the high-level operation, and the second and third logic transistors Q2 and Q3 are synchronously controlled by the modulation signal Vc2. The timing of the level is cut off. When the logic transistors Q2 and Q3 are synchronously controlled by the modulation signal Vc2 to operate at the timing of the high level, the logic transistors Q1 and Q4 are synchronously controlled by the modulation signal Vc2 to the low level. The timing of the bit is cut off.

As shown in the fifth figure, the transformer 52 of the fifth figure further has a bleeder coil 526 and a bleeder switch 528 connected in series with the bleeder coil 526. In this embodiment, the bleeder is shown. The switch 528 is a diode, but the diode can also be replaced by a transistor. Therefore, the bleeder switch 528 is not limited to the diode. Wherein, when the switching element Qt is turned on, the bleeder switch 528 is turned off, indicating that the bleeder coil 526 is in an open state. When the switching element Qt is turned off, the bleeder switch 528 is turned on, and the energy of the primary measuring coil 522 of the transformer 52 is discharged via the bleeder coil 526, so that the magnetic saturation of the transformer 52 can be avoided.

In summary, the transcutaneous nerve stimulator provided by the present invention only needs to compare the sensing voltage generated by the inductor current of the primary side coil of the transformer sensed by the control circuit with the limiting voltage to determine the switch in the boosting circuit. The operation of the component to turn on or off the transformer's boost conversion operation, so that the booster circuit can generate sufficient operating voltage with the lowest transformer power consumption, and utilize the turn The modulation signal received by the circuit changes the working voltage to form a stimulation signal outputted in positive and negative half cycles to eliminate the accumulation of body charge, and the transcutaneous nerve stimulator can directly modulate the specific electrotherapy frequency required by the conversion circuit. The constituting elements disclosed in the embodiments are merely illustrative and are not intended to limit the scope of the present invention. The alternative or variations of other equivalent elements are also covered by the scope of the patent application.

1‧‧‧Transcutaneous nerve stimulator

10‧‧‧Control circuit

12‧‧‧ comparator

14‧‧‧Error amplifier

20‧‧‧Sequence Circuit

22‧‧‧Bistable circuit

30‧‧‧Boost circuit

32‧‧‧Transformers

322‧‧‧One-side coil

324‧‧‧second side coil

34‧‧‧Variable circuit

40‧‧‧Transition circuit

402‧‧‧DC end group

404‧‧‧Output group

C‧‧‧ capacitor

CK‧‧‧ communication number

Q‧‧‧true end

Qt‧‧‧Switching elements

L‧‧‧Inductance

R‧‧‧Sensor resistance

Vcc‧‧‧ power supply

Ve‧‧‧Limited voltage

Vout‧‧‧ working voltage

VRb‧‧‧Stimulus signal

Vs‧‧‧ sense voltage

Claims (11)

A transcutaneous nerve stimulator for providing a stimulation signal to human skin, comprising: a control circuit for receiving a sensing voltage, wherein the control circuit outputs a cutoff voltage when the sensing voltage exceeds a limited voltage; a sequence circuit electrically connected to the control circuit to transmit the cutoff voltage, and outputting a conduction number after the timing of the cutoff voltage; a boosting circuit having a switching element, a transformer and a voltage stabilizing circuit, the switching element Electrically connecting the timing circuit, the cutoff signal and the communication signal respectively control the switching element to operate in an off state and a conduction state, and the switching element transmits a current of one primary side coil of the transformer in an on state and generates the sensing The voltage is received by the control circuit, and a secondary side coil of the transformer is electrically connected to the voltage stabilizing circuit, wherein the voltage stabilizing circuit is configured to output an operating voltage; and a converting circuit is connected to the boosting circuit, and is configured to The operating voltage is converted into the stimulation signal that changes positive and negative with time, and the stimulation signal is output to the human skin. The percutaneous nerve stimulator of claim 1, wherein the control circuit has a comparator that receives the defined voltage and the sensed voltage respectively at a first and a second input. The percutaneous nerve stimulator according to claim 2, wherein the limited voltage received by the comparator is adjusted in response to a change in the stimulation signal. The transcutaneous nerve stimulator according to claim 3, wherein the first input end of the comparator is electrically connected to an error amplifier, and one input end of the error amplifier is electrically connected to the conversion circuit. The percutaneous nerve stimulator according to claim 1, wherein the sequential circuit has a bistable circuit, and the conduction signal and the cutoff potential are respectively touched The bistable circuit outputs a high level voltage and a low level voltage from a true terminal. The transcutaneous nerve stimulator according to claim 5, wherein the switching element of the boosting circuit has a triggering end and a second conducting end, and the triggering end is electrically connected to the true end of the bistable circuit. The two current guiding ends are electrically connected to the primary side coil of the transformer and a sensing resistor respectively, and the sensing voltage received by the control circuit is the voltage across the sensing resistor in the conducting state of the switching element. The transcutaneous nerve stimulator according to claim 1, wherein the current of the secondary side coil of the transformer in the conducting state flows through an inductor and a capacitor in the voltage stabilizing circuit, respectively The operating voltage of the output of the voltage circuit is the voltage across the capacitor. The percutaneous nerve stimulator according to claim 7, wherein the discharge rate of the capacitor is less than the frequency of the conduction signal output by the sequential circuit. The percutaneous nerve stimulator according to claim 1, wherein the conversion circuit receives a set of timing phase complementary modulation signals to control two logic transistors switching in a full bridge converter. The conduction operation enables the full bridge converter to output a square wave AC signal. The transcutaneous nerve stimulator according to claim 9, wherein the logic electro-crystal system of the full-bridge inverter is connected in series with one of the first and second logic transistors. One of the third and fourth logic transistors is connected to each other, and the modulation signal controls the conduction operations of the first and fourth logic transistors and the second and third logic transistors respectively at a timing complementary to the second timing. . The percutaneous nerve stimulator according to claim 1, wherein the transformer further has a bleeder coil and a bleeder switch connected in series with the bleeder coil, wherein the damper is blocked when the switch element is turned off. The switch is turned on, and one of the transformers The energy of the secondary coil is dissipated via the bleeder coil; and when the switching element is turned on, the bleeder switch is turned off.