Matt's still working on it.

Matt
Did you noticed 100uF/35V capacitor connected in between the base of TIP 120 and +12V rail on the VIC card?
How it affect  the work of whole driver and switching on and off the TIP 120?
thank
andy

Quote from andy on January 11th, 2017, 10:04 AM

Did you noticed 100uF/35V capacitor connected in between the base of TIP 120 and +12V rail on the VIC card?

No, I did not notice a capacitor placed there.  Can you please post a snippet where you see that.

Quote from andy on January 11th, 2017, 10:04 AM

How it affect  the work of whole driver and switching on and off the TIP 120?

Snubbing the base of the main pulse transistor would vastly change the behavior.  I would kind of need to see that before I believe it.  In all the schematics, photos and thread postings, this is the first I've heard of such a thing.

Quote from haxar on January 11th, 2017, 03:28 AM

Matt's still working on it.

Found one bug so far.   The CLR and B inputs of the CD74HCT221 need to be pulled high for normal operation.  I have that on my bread-board but didn't do it in the schematic or the PCB.

I'll post an update before day's end.  In the meantime, here's what the board looks like so far.

And updated PDFs.

Check'm closely, especially those who are actually interested having one of these boards.


And just a little note to those that don't understand why there are dots on the resistors.  I have the resistors vertically mounted so the dot is the side where the resistor faces the board; the other side sticking up then becomes a test point.  Diodes are done similarly with the anode facing the board.

This Matt

It is beside 470 ohm resistor going to base of the TIP 120

And this

@Matt,

Great stuff!!!  :-)

The current transformer feedback solution is interesting, I hope the zero crossings are spot on!

I have some questions:

-This new design holds the PLL in lock when on/off gate signal is used?
-What is the min, max frequency of the PLL locking range?
-Is the duty cycle still 50% at the TIP120?
-Is the PLL VCO_OUT frequency still in phase with the signal from the TIP120 when it goes through all the transistors?
-Signal from the TIP120 P- (cap 10pF and res 22Mohm) are left out compared with Stan circuit, pin 3 CIN PLL / COMP_I is not needed?
-Is your feedback signal LM393 (digital) in phase with the coils (analog) on resonance frequency when testing on a LC tank circuit?

~webmug

Just FYI. i have NOT been able to look this over.... ~Russ

It'll take some time to know these introduced chips and what they're doing in the circuit.

Quote from Webmug on January 11th, 2017, 12:47 PM

Great stuff!!!  :-)

Thank you Webmug.  When I go several months without making a board like this, it only takes a about ten minutes to remind myself it's going to be another all nighter.  I wish there was an easier way.

Quote from Webmug on January 11th, 2017, 12:47 PM

The current transformer feedback solution is interesting, I hope the zero crossings are spot on!

From what I can tell so far, this reduces electrostatic false detection considerably.  It doesn't go completely away, but it's an order of magnitude less to deal with.

Quote from Webmug on January 11th, 2017, 12:47 PM

-This new design holds the PLL in lock when on/off gate signal is used?

It seems to.  At gate you can see the PLL start to hunt a little, but it comes right back in unless you aggressively gate, then the PLL looses its mind.

Quote from Webmug on January 11th, 2017, 12:47 PM

-What is the min, max frequency of the PLL locking range?

Starts at about 1kHz and goes up beyond 50kHz.  I don't know if that is enough range or not, but this particular chip handles a much wider bandwidth than the CD4046B.

Quote from Webmug on January 11th, 2017, 12:47 PM

-Is the duty cycle still 50% at the TIP120?

Correct.

Quote from Webmug on January 11th, 2017, 12:47 PM

-Is the PLL VCO_OUT frequency still in phase with the signal from the TIP120 when it goes through all the transistors?

Relatively--better at lower frequencies than higher.  I can't help but think Stan put all those transistors in there intentionally to create delay.  I wish I knew how much he was looking for and why.

Quote from Webmug on January 11th, 2017, 12:47 PM

-Signal from the TIP120 P- (cap 10pF and res 22Mohm) are left out compared with Stan circuit, pin 3 CIN PLL / COMP_I is not needed?

That's still a bit of an open-ended discussion as to what Stan was trying to accomplish.  I left them out on this board, but may try to shoehorn them back in with a jumper selection.  I personally didn't like the idea of slamming output signals together.  If this signal needs to be filtered and fed back in, it should IMHO go through some sort of dedicated mixer.

Quote from Webmug on January 11th, 2017, 12:47 PM

-Is your feedback signal LM393 (digital) in phase with the coils (analog) on resonance frequency when testing on a LC tank circuit?

Again, relatively.  Better at lower frequencies.

I have a hunch everything will tighten up when I go from a bread-board solution to the final PCB.  I'm still in decision mode whether to push the button on ordering fabs.  Kind of want to let this sit for a few more days and see if I discover any more whoops'.  It's not like I haven't screwed up before--I have a pile of no-workie boards in a box already.  Just hate to add to that collection.

give it some days. I do want to look at it. Just havnt had the time this week. !!! ~Russ

Matt
Do you see this capacitor?

Quote from andy on January 11th, 2017, 10:04 AM

Did you noticed 100uF/35V capacitor connected in between the base of TIP 120 and +12V rail on the VIC card?

It is beside 470 ohm resistor going to base of the TIP 120

Do you see this capacitor?

I'm pretty sure this big electrolytic capacitor doesn't connect to the base of the TIP120.  I think we would have caught that one by now.  If I'm looking at the wrong thing, can you point it out to me with a screenshot like this.

Yes it is connected to + 12V and ground.
Sorry , my mistake. Thank for clear up Matt.

Here are the duty cycle scope-shots from 1kHz to 16kHz.

Going to try and plot these and find the actual curve created by the VIC Driver circuit.

I will do the same. Mine is different.Matt can you switch back to the SM components. In using the first version of this driver and I can go up to at lease 20khz. We need to make sure our voltage control dose not change the outcome. ~Russ

Quote from ~Russ on January 14th, 2017, 11:13 AM

I will do the same. Mine is different.Matt can you switch back to the SM components. In using the first version of this driver and I can go up to at lease 20khz. We need to make sure our voltage control dose not change the outcome. ~Russ

So you think using the LM338 for the voltage control is changing the duty cycle?   Not impossible I guess.  I'll have to try it and see.

Anyway, here's my data and frequency plot.  Duty cycle is perfectly linear.  You can see pretty clearly where the off-time frequency enters the megahertz range.  You can also see where the on-time frequency has a maximum shift near the middle of the range.  The trick now is to comprehend what this data is really telling us.

I want to be sure. Otherwise will never know. I'll also check with my other voltage regulator. It might also have some effect. ~Russ

My question now is:

Do we tune the VIC & WFC to the driver or take a chance on trying to tune the driver to the VIC & WFC ?

Quote from Matt Watts on January 14th, 2017, 02:46 PM

My question now is:

Do we tune the VIC & WFC to the driver or take a chance on trying to tune the driver to the VIC & WFC ?

Tune the VIC & WFC

for now...

if we cant get it to work but think we know why... then we can change it .

however, allways keep the circuit the same , so we are only trying to tune one part of the system.

as soon as some one else tries to do it and they need to cant get it to work....

~Russ

Okay, so the voltage control change back to the original method Stan has does nothing for changing the cutoff frequency, but there is something that does.  See below.  Now my question is, what should it be?

My gut feeling is this should be a tuning parameter with a 1k minimum and a 10k pot to zero-in-on the characteristics of the VIC & WFC.

Notice Stan has something there too, but placed just before the TIP120.  My guess this resistor was bundled in the nest of wires in the VIC cage.  I haven't seen any reference to what its value should be and if I was going to hide a really important tuning variable, that's where I'd hide it.

I think you definitely need fix duty cycle ,imagine that the car has an ignition that is drifting it certainly would not be good

Quote from Ris on January 15th, 2017, 12:33 AM

I think you definitely need fix duty cycle ,imagine that the car has an ignition that is drifting it certainly would not be good

its not what is needed, its what was...

Matt,

according to the cards... theirs nothing there.
according to don's hands on's disassembly... theirs nothing there.
so unless you have photo x-ray vision :) i'm not so sure there's anything there...

it is kinda a nice way to change that curve !!?? hummm

so now its the 2n222... yours is an A version... ill look at mine, but i think its not the A version... not sure tho. will look ( later today... 12:55am)

~Russ