FSM like device

Thread Starter

dheena0104

Joined Jul 10, 2019
36
The circuit design by Mr Wayneh worked perfectly in alleviating Myokymia of right side.
Frequency of the myokymia was reduced from 10 to 6 within 6 days. Application: 2 times daily for 2 min.
One electrode just below tragus and the other just above the maxillary sinus area towards nose. For other pains like knee, improvement from 10 to 8. No placebo effect. Mr Wayneh has to be thanked for his intuitive efforts.
In order to improve his efforts further, I am trying to use FSM instead TENS (Wayneh in his first efforts) along with the micro-current stimulating device (MCD). I have planned to carry out the design in two steps; 1) creating a variable frequency from 0.5 to 1 KHz (optimum and more than sufficient) and 2) Changing the output voltage (20v -25V) to higher level keeping the current constant at 500 micro-ampere (either automatic with respect to change in load resistance or manual w.r.t improvement). I hope that this can be achieved by using boost circuit in boost-buck circuit. At this juncture I am collecting all possible technical data and trying to get inputs from experts. FSM for suffering reversal in quick time and Waneh MSD for fine tuning the state to original, means no re-occurrence please. One again I thank Mr Wayneh for the created inspiration in me.
 

Thread Starter

dheena0104

Joined Jul 10, 2019
36
Thank you Mr DickCappels. I have forgotten to thank you the unsung hero as said by Mr Wayneh.
I am chekking at every point of the approach and use it as a feed back to fine tune the approach pathway.
The first step is not a problem one.
In the second step, I have to keep in mind the limits of the boost-buck converter.
The switching frequencies cannot be lower than 1KHz (literature says 100Hz to 10KHz) because of the current the inductor has to deal with and the frequency has to maintain the balance between dynamic and statistic losses in MOSFET, Because I am a novice, I am trying to find out a way to deal this! Is there a way to to use a separate frequency to do the job without interfering with the input variable one. Proves, really a novice!
Alternatively, making changes in step 1; mean using different oscillator IC like 8038. Input Vcc 10V-30V with an input current of 25mA and output sink current 25mA. The minimum sink current at 10V is 12mA (literature value).
Plan: Increase the input Voltage to 20V and reduce the corresponding current (not known, but may be below 25mA) to the required level by using a compatible Op-Amp as done by Mr Wayneh in MCD.
Inputs from Mr Wayneh and other learned members are warranted to complete this project successfully please.
 

wayneh

Joined Sep 9, 2010
17,498
Thank you Mr DickCappels. I have forgotten to thank you the unsung hero as said by Mr Wayneh.
I am chekking at every point of the approach and use it as a feed back to fine tune the approach pathway.
The first step is not a problem one.
In the second step, I have to keep in mind the limits of the boost-buck converter.
The switching frequencies cannot be lower than 1KHz (literature says 100Hz to 10KHz) because of the current the inductor has to deal with and the frequency has to maintain the balance between dynamic and statistic losses in MOSFET, Because I am a novice, I am trying to find out a way to deal this! Is there a way to to use a separate frequency to do the job without interfering with the input variable one. Proves, really a novice!
Alternatively, making changes in step 1; mean using different oscillator IC like 8038. Input Vcc 10V-30V with an input current of 25mA and output sink current 25mA. The minimum sink current at 10V is 12mA (literature value).
Plan: Increase the input Voltage to 20V and reduce the corresponding current (not known, but may be below 25mA) to the required level by using a compatible Op-Amp as done by Mr Wayneh in MCD.
Inputs from Mr Wayneh and other learned members are warranted to complete this project successfully please.
Why not just use a 20V source, such as the power brick from an old laptop? Or even two 9V batteries in series.
 

Thread Starter

dheena0104

Joined Jul 10, 2019
36
Thank you
If it is possible to use 8038 (Vcc 36V) instead 556 (Vcc 18V), I can use old laptop power supply or two 9V batteries in series as per your suggestion.Now the point is selecting a compatible Op-amp controlled-current circuit to ensure the supply of constant current to load. For example: OpAx171, 36V, band width 3 MHZ, will it be compatible? Here I need your suggestions and guidelines please.
Apart from this, if it is permissible kindly let me to have clarification regarding your preference for 30 second triangle wave form in your MCES device and its appropriate combined wave form posted in MCESD thread #2.
I changed the value of the C5 capacitor to 12uF instead 47uF and got a roundabout 10 second triangle wave form (using Proteus 8). I can not move further due to my limited knowledge in this field. I tried to check the wave form at different outputs after changing C5 but in vain due to displayed error messages.
If possible and time permits, can you please let me to know the combined waveform (triangle and square) as posted by you in your thread MCESD #2 after changing the C5 value from 47uF to 12 or 15 uF.
 

Thread Starter

dheena0104

Joined Jul 10, 2019
36
Dear Mr Wauneh Ji
Namaskar
Greetings
My learning process took that much long time, hence this delay in reaching you for further learning process please.
I made a simple biphasic microcurrent circuit using LM358 IC and NE555 IC. The idea behind this circuit is to have an out put voltage of the order of 27V, by replacing NE555 (test circuit) with commercially available 2 channel PWM board with a supply voltage of 27.
The circuit works fine in LTspice, exhibiting a biphasic wave but not in assembled one (tested with DSO 138 pocket size oscilloscope. The exhibited wave is polarized not biphasic as exhibited in LTspice.
Due to my limited knowledge I am unable to understand such a type of exhibition, hence trying to reach you for corrections please.

@wayneh
 

Attachments

Last edited by a moderator:

Thread Starter

dheena0104

Joined Jul 10, 2019
36
Dear Mr Wauneh Ji
Namaskar
Greetings for the day and days ahead.
The problem that I described in my previous post was solved.
It was due to some careless DPDT switch connection for switching from bi-phasic to polarized.
At present I have completed and successfully tested FSM like device using commercial 2 channel PWM, Buck boost DC converter, dual H-bridge (L298N), 5 V step down power supply (7805) and two assembled counter boards (4017BE as described by Mr Weynah). Power supply 7 lithium ion 18650 batteries. All seven (25.9V) for H-bridge input and 3 mid connection (11.1V to 5V ) for other boards.
Every thing worked fine until two leads from H-bridge came in contact with each other during application. This short circuit damaged the dual H-bridge. Replacing the damaged dual H-bridge is not a problem but some thing more is there to get your valuable advice to fine tune the device please.
1)Dr. Carolyn McMakin was using tied leads at the graphite glove electrode. (I have not tied the electrodes but accidentally they came in contact with each other)
I searched for literature and found one useful information regarding tying principle from Texas Instrument data sheet for DRV8873. in page number 16_______
"TI does not recommend tying the OUT1 and OUT2 pins together and drive a load. The half bridges may be out of synchronization in this configuration and any mismatch in the input commands can momentarily result in shoot through condition. This mismatch can be mitigated by adding an inductor in-line with the outputs".
Here I need your advice please.
1) Is it possible to add an inductor inline with the outputs
2) If it is, What value of the inductor I have to use
3) Inductor has to be added to all the four leads or only two each for one output
These are not for tying the output leads but may be useful during accidental contacts between the leads please
 

Attachments

Top