WO2015071850A1

WO2015071850A1 - Apparatus for therapeutic transdermal electrostimulation

Info

Publication number: WO2015071850A1
Application number: PCT/IB2014/066011
Authority: WO
Inventors: Siddarth AGRAWAL; Anil Kumar AGRAWAL
Original assignee: Uniwersytet Medyczny Im. Piastów Śląskich We Wrocławiu
Priority date: 2013-11-13
Filing date: 2014-11-13
Publication date: 2015-05-21
Also published as: PL228476B1; PL406018A1

Abstract

Apparatus for therapeutic transdermal electrostimulation, equipped with an executive module comprising the module power supply system, communication and control system, and the executive system, characterized in that the module power supply system comprises a lithium-ion battery ( 1 ) coupled with the battery charging system (2) which is coupled with 3.0 V voltage stabilizer (3) and a converter raising the voltage up to +30V (4), the communication and control system comprises a microcontroller (5) communicating with the software on a PC via a USB interface (6), and the executive system comprises an analog-digital current converter working in the range of 0 mA to 10 mA (7), wherefrom the electric current is directed to electrode outputs (8) which the output voltage controller (9) coupled with the microcontroller (5) is connected to, wherein all electronic components constituting the executive system are mounted on both sides of a four layer PCB.

Description

Apparatus for therapeutic transdermal electrostimulation

The present invention relates to an apparatus for therapeutic transdermal electrostimulation, designed for stimulation of appropriate spots in human organism with electric current, applying the knowledge of acupuncture.

Acupuncture is an ancient healing method originating from Chinese folk medicine. The therapeutic effect in acupuncture is obtained by inserting special silver or gold needles in strictly indicated points on the body, which results in stimulating effect on the peripheral and central nervous system, activating nerve endings. Acupuncture has pain relief and healing effects, improves blood circulation in capillaries. The method is used to cure a wide range of diseases and pain conditions as well as in inflammations, palsies, or epilepsy. Electro-acupuncture is a variation of classical acupuncture, wherein the stimulation of characteristic points on the body is aided with specifically determined electric stimuli. Two kinds of electro-acupuncture can be distinguished. The first one, which uses needles inserted into the patient's body. The second one, wherein the stimulation is effected transdermally . The second method is more desired due to the lack of interference with the patient's body, i.e. no skin puncture. Research demonstrates that stimulating appropriate areas of the body with electric pulses is widely applied and is effectively used in healing arterial hypertension, obesity, infertility, or depression. An apparatus for electrostimulation of characteristic spots on human body, KWD-808 L from SINIC, is known. The apparatus performs many functions, also enabling administration of electro-acupuncture. The apparatus is a stationary device and therefore it can not be used by patients for regular therapy administered for a certain longer period of time, e.g. one month at specified intervals, e.g. every few hours. The device is not portable and therefore it does not allow for running a long-term acupuncture healing. A medical device for electro-therapy is also known, named AWQ- 104L which is also a stationary device not enabling for carrying out long-term healing in specified cycles.

An electro-acupuncture system is known from patent application US2009192406 , used to measure energetic balance of patient's meridians and to affect them. The system uses a pressure sensitive probe and a return path contact connected to the source of potential. The probe and the contact are used for diagnosing and treating disorders in patient's meridians energy balance. The selection of electro-stimulation parameters is effected based on the interpretation of the measured energetic balance values. The presented apparatus is a compact device for manual stimulation in specified individual points and is therefore unsuitable for administering long-term therapy at specified intervals without the necessity to visit the clinic.

The technical problem faced by the present invention is to provide construction of such an apparatus for therapeutic transdermal electrostimulation that will be characterized by structural simplicity, relatively cheap in construction, small, make it possible for the patient to carry it for a longer period of therapy, and will provide electric signal of controlled characteristics, intensity, frequency, will automatically administer the therapy for the period of at least 4 weeks without charging, and will inform about the loss of contact with patient's skin as well as register the battery voltage and the skin contact resistance during the time of therapy. Unexpectedly, the technical problems mentioned above have been solved by the present invention.

The present invention relates to an apparatus for therapeutic transdermal electrostimulation, equipped with an executive module comprising the module power supply system, communication and control system, and the executive system, characterized in that the module power supply system comprises a lithium-ion battery coupled with the battery charging system which is coupled with 3.0 V voltage stabilizer and a converter raising the voltage up to +30V, the communication and control system comprises a microcontroller communicating with the software on a PC via a USB interface, and the executive system comprises an analog-digital current converter working in the range of 0 mA to 10 mA, wherefrom the electric current is directed to electrode outputs which the output voltage controller coupled with the microcontroller is connected to, wherein all electronic components constituting the executive system are mounted on both sides of a four layer PCB.

The apparatus for therapeutic transdermal electrostimulation occupies a small space due to the application of small components on both sides of the four layer PCB, which results in its reduced weight and enables comfortable carrying it for a longer therapy period. The applied lithium-ion battery provides for long time operation of the device, which enables administering the therapy for 4 weeks without replacing and/or charging the battery. The applied microcontroller with the digital-analog current converter enables for random shaping of electric signal contours, which makes it possible to administer a broad range of electro-acupuncture therapies. The implemented USB interface, connected with the battery charging system, enables to charge the device with any USB charger and to communicate with the software installed on a PC. Exemplary embodiments of the invention have been presented in the drawings, where fig. 1 is a block diagram of the electronic executive module system of the apparatus for therapeutic transdermal electrostimulation, fig. 2 is the circuit diagram of the executive module USB interface, fig. 3 is the circuit diagram of battery charging system, fig. 4 is the circuit diagram of the 3.0 V stabilizer to power the microcontroller, fig. 5 is the circuit diagram of the voltage converter, fig. 6 is the circuit diagram of the digital-analog converter, fig. 7 is the circuit diagram of the microcontroller system, fig. 8 is a full circuit diagram of the electronic executive module system of the apparatus for therapeutic transdermal electrostimulation, fig. 9 shows the top layer of the executive module PCB, fig. 10 shows the internal layer of the executive module PCB, fig. 11 shows the bottom layer of the executive module PCB, fig. 12 illustrates the deployment of the elements on the top layer of the PCB, and fig. 13 illustrates the deployment of the elements on the bottom layer of the PCB.

Example The block diagram of the electronic executive module system of the apparatus for therapeutic transdermal electrostimulation is presented in fig. 1, where three main groups of elements can be differentiated, i.e. systems relating to powering the whole apparatus, comprising lithium-ion battery 1, the battery charging system 2, 3.0 V voltage stabilizer 3, and the voltage converter raising the voltage to +30V 4; communication and control systems comprising a microcontroller communicating with software installed on a PC via USB interface 6, the task of microcontroller 5 being to control all other systems and emitting stimulating impulses of predetermined characteristics; executive systems comprising digital-analog current converter (DAC) 0-10 mA 7, where electric current of precisely determined intensity originates and is directed to output electrodes 8, the signal from the electrodes traveling via the output voltage control system 9 to microcontroller 5. The application of microcontroller 5 with DAC 7 enables virtually random shaping of electric signal contours on stimulating electrodes. It is possible to determine the repetition frequency and width of the impulses, their intensity and stimulation time. Communication with a PC via USB interface 6 enables programing module functions and monitoring its operation. At the same time, USB interface 6 enables charging battery 1 present in the module. Figures 2 7 represent circuit diagrams illustrating individual component blocks of the electronic executive module system of the apparatus for therapeutic transdermal electrostimulation. Fig. 2 represents a part of the circuit diagram relating to the USB interface being a component of the executive module of the apparatus for therapeutic transdermal electrostimulation. USB interface 6 was implemented with the application of FT230XS integrated circuit from FTDI. The circuit possesses characteristics enabling effective construction of a link between microcontroller 5 and the software on the PC. Due to the limited space for USB socket 10, USB-miniB standard connector was used. The majority of the components connected to the integrated circuit follow the application diagram provided by the manufacturer. The FT230XS chip was programmed to inform microcontroller 5 on connection to the computer - CBUS2 terminal is used for that purpose. RXD and TXD terminals are provided for data transmission between the computer and microcontroller 5. Signals on CBUSO and CBUSl terminals switch transistor Tl on. This happens when the module is connected to the computer USB socket or a USB charger. Switching transistor Tl on powers the remaining electronic systems and enables charging battery 1. Lithium-ion battery 1 is implemented in the executive module, model LP- 402025 with dimensions of 26 mm x 20 mm x 4 mm and 155 mAh capacity. Due to their specific properties, lithium-ion batteries 1 require suitable, dedicated charging system 2. The project utilizes MCP73831T system by Microchip, characterized with a very low number of internal elements and small dimension - SOT-23 chassis. Fig. 3 represents the charging system 2 circuit diagram. The LED present in the system signals charging battery 1. If it emits continuous light, it means that accumulator 1 is being charged. If it blinks, accumulator 1 has been fully charged. Resistor Rl sets the maximum charging current for battery 1 at 130 mA. During discharging, the voltage of battery 1 changes (decreases) from 4.2 V to 3.5 V. This is not a desired situation for powered electronic circuits. Therefore, the voltage powering microcontroller 5 is stabilized by MCP1801 chip at 3.0V by voltage stabilizer 3 whose circuit diagram is illustrated in fig. 4. Stimulation of human body with impulses with current reaching up to 10 mA requires application of higher voltage pulses. It is assumed the electric resistance of human body is at about 1 kQ. In order to force the current of 10 mA it is necessary to apply voltage of 10 V. Taking into account that contact of electrodes 8 with the skin introduces additional resistance, the stimulating voltage has to be increased so as to assure proper current, it was assumed that the maximum stimulation voltage should be at 30 V. Since the battery 1 provides about 4 V, it is necessary to apply boost converter 4. Due to the limited space, the most important criterion on selection of converter 4 are small dimensions of the integrated circuit and as few external elements as possible. Additional requirements comprise the possibility to obtain output voltage of 30 V, high efficiency of the system, reducing power loss, output for switching the system off, and the possibility to use a small coil. The above requirements were met by LM2733Y chip by National Semiconductor. Fig. 5 represents the circuit diagram of converter 3. The executive systems comprise first of all the digital-analog current converter (DAC) 7. In order to set the stimulating current, digital-analog converter 7 AD5410 from Analog Devices was implemented. Thus, a very flexible control of the stimulating contour is possible. Fig. 6 represents the circuit diagram for the digital-analog converter 7 with electronic elements responsible for measuring stimulation voltage: D8, C25, R12, R13. By measuring the voltage present on stimulating electrodes 8 during operation, system 9 is able to determine the skin contact resistance. Thus, it is possible to determine whether electrodes 8 are in proper contact with patient's skin. The current generated on IOUT output of AD5410 converter is determined by digital communication. AD5410 chip is equipped with SPI format data transmission interface. Terminals SCLK, SDIN, SDO, LATCH create that interface. The diagram (fig. 6) also shows electrodes 8 in contact with skin: J4 - active electrode, J2 , J3 - reference electrodes. The most important element of the apparatus for therapeutic transdermal electrostimulation is microcontroller 5 which controls the operation of the whole module. PIC18LF26K22 chip from Microchip was used. The chip is characterized by low power consumption during operation which enables construction of a device which operates for a long time without the need to charge battery 1. PIC18LF26K22 microcontroller is an electronic circuit comprising a processor executing a program stored in the memory, and many additional circuits enabling implementation of various functions. In one small integrated circuit chip, there is a processor executing a program and controlling the operation of the module; program memory (Flash), where the program executed by the processor is stored; RAM memory used to store data during the operation of the program; EEPROM memory, where module operating parameters are stored and later read by the PC software; communication interfaces: SPI - for setting working parameters for AD5410 converter, UART - communication with PC; analog-digital converter measuring the battery voltage and the resistance of electrodes 8 contact with skin; and counters and timers which count the time down to stimulation start, and specify the frequency of sending stimulation pulses. Fig. 7 represents the circuit diagram of microcontroller 5 system. Terminal J6 in ICSP standard is provided for programming microcontroller 5 at the apparatus development stage. Elements T2 , R6 , R7 enable measurement of battery 1 voltage. The measured value is stored in non-volatile EEPROM memory. Therefore, it is possible to track the discharging process of battery 1. Oscillator XI together with capacitors C18 and C19 constitutes a clock working with the frequency of 32.768 kHz. The system and the timer comprised in the controller 5 measure the time between consecutive stimulation cycles. Diode D7 is used to signal the activity of the system. During stimulation, the diode blinks. Therefore it is evident if current pulses are sent to the electrodes at a given time. The complete circuit diagram of the executive module is illustrated in fig. 8. All elements illustrated in the circuit diagram in fig. 8 were deployed on a small PCB. Electronic elements of the following chassis sizes were used: the majority of the passive elements (resistors, capacitors) - size 0603 ( 1.6 mm x 0.8 mm), 50 V capacitors) - size 1206 (3.2 mm x 1.6 mm), transistors and small chips - SOT23, diodes - SOD110, "large" chips (PIC, AD, FT) - TSSOP chassis characterized with dense spacing of terminals. Using miniature elements allowed for their deployment on a PCB measuring 35 mm x 25 mm, provided that, however, they are mounted on both sides of the PCB. It turned out that due to the high density of the elements it was necessary to execute a PCB with four conducting layers. Figures 10 - 12 illustrate connection diagrams on PCB layers, respectively: top layer, internal layer, bottom layer. The fourth (internal) layer is the so called power plane, i.e. surface connected to one point in the system. In the presented project, it is circuit ground which provides shielding of electronic systems and reduces interference from power lines.

Figures 12 and 13 illustrate deployment of elements from the presented circuit diagrams on the PCB, including both sides of the PCP. Such deployment allowed for maximum reduction of the space used and size reduction of the whole executive system of the apparatus for therapeutic transdermal electrostimulation. The presented system is characterized by the following properties:

• measurements: 50 x 30 x 15mm,

^• integrated Li-Ion battery allowing for about 4 hours of continuous operation which means 4 weeks without required charging at 2 cycles of 5 minutes each per day,

• stimulation frequency 1 Hz - 200 Hz, set at every 0.1 Hz,

^• width of stimulating impulses regulated within 10 - 300 με range with 1 με step, · current of 0 - 10 mA, with 0.1 mA step, • various stimulation modes: continuous wave, burst, 2 alternating frequencies (dense-disperse mode),

• remembering stimulation parameters,

• automating switching on at specified time and performing stimulation,

• detection of lack of contact with skin during stimulation,

• registering battery voltage and resistance of contact with skin for the last 30 days,

• USB mini socket for connection to a PC, · executive module battery charged from USB port or any USB charger .

Reaching the above properties allowed embodiment of the apparatus for therapeutic transdermal electrostimulation, which enables performance of long lasting automatic acupuncture therapy in unattended manner without the need to charge and in a device that can be easily carried by the patient.

Claims

1. Apparatus for therapeutic transdermal electrostimulation, equipped with an executive module comprising the module power supply system, communication and control system, and the executive system, characterized in that the module power supply system comprises a lithium-ion battery (1) coupled with the battery charging system (2) which is coupled with 3.0 V voltage stabilizer (3) and a converter raising the voltage up to +30V (4), the communication and control system comprises a microcontroller (5) communicating with the software on a PC via a USB interface (6), and the executive system comprises an analog-digital current converter working in the range of 0 mA to 10 mA (7), wherefrom the electric current is directed to electrode outputs (8) which the output voltage controller (9) coupled with the microcontroller (5) is connected to, wherein all electronic components constituting the executive system are mounted on both sides of a four layer PCB.