Variable volt SNUS box - my second mod complete

[McDude]

Are you thinking of the PTN4050 boost? For the boost circuits I do use caps, although I don't see much difference with or without - for the regulator, there's no caps recommended in the schematic/data-sheet so I didn't add any I've measured output with and without load and have observed zero "bouncing" - the voltage is constant/steady under both conditions.

Need to correct myself here - gotta stop writing this stuff half asleep. The datasheet for the PTR08100 does call for caps, but I chose not to use them because the voltage is completely stable. I've been playing with three different test circuits - a 5v linear regulated, a boost (4050) and the variable voltage (created each test circuit before creating any mods) and got them a bit mixed up in my response. The 4050 output "bounces" around wildy IMHO so yeah would definately use caps on that, the PTR08100 though seems completely stable. With a tactile switch and moving the multimeter female jack down further (there's a little bit of room), a couple caps could be added in there, but I just didn't see a need.

 

[squirrel64]

I was up late too ..... Thanks so much for your replies and help

 

[McDude]

Here's a layout diagram that would include caps - untested of course, but pretty straight forward. Just had to move where the PCB is "cut" on the input (source) pin's row.

 

[WillyB]

I just noticed this.

Are you thinking of the PTN4050 boost? For the boost circuits I do use caps, although I don't see much difference with or without - for the regulator, there's no caps recommended in the schematic/data-sheet so I didn't add any I've measured output with and without load and have observed zero "bouncing" - the voltage is constant/steady under both conditions.

From the datasheet:

Input Capacitor (Required)

The PTR08100W requires a minimum input capacitance of 100mF. The ripple current rating of the electrolytic capacitor must be at least 750mArms. An optional 22-mF X5R/X7R ceramic capacitor is recommended to reduce the RMS ripple current. Table 3 includes a preferred list of capacitors by vendor.

And FWIW this one from the datasheet's recommended list is quite cheap. A tad large if space is at a premium though.

EEU-FC1V181 Panasonic Electronic Components Aluminum Electrolytic Capacitors - Leaded

 

[McDude]

Yup, corrected myself. Just ran a test as well (almost burned up an atty to make sure LOL). With a multimeter on the device, no load - dialed to 4.99 volts - the device put out 4.99 volts without even a .01v "hiccup" for a total of 1 full minute. Under load the exact same result with a small, expected, voltage drop due to the load - observed in 4 second intervals while keeping my last atty wet. So, yeah - the datasheet calls for the caps, but for our applications I don't see any "evidence" that they are actually required. I debated on redesign, but if I can't see even a .01v fluxuation, then there just isn't any real need IMHO - plus the caps are just big and without need, why bother with losing teh real estate.

 

[theECB]

great work!!!!

 

[Shan B]

And they do have them at RS, although I can't vouch for the quality.

The one's @ RS are actually a little better quality than the one's from MV. There are also one's you can pickup at futurlec.com part #PSPST01 which are similar to both above, but not sure on quality. I ordered some and will post back if they are glitchy or have any difference in quality between RS and MV. I also picked up 5 green mom. ones from the bay for 2.25, but I lost the whole pack the day I got them, LOL.

 

[McDude]

Score - I just stumbled on this today on ebay and snatched it up - 50 classic looking SNUS cans for $20 bucks, crazy cheap and they don't have the very ugly gum disease warning. Not so "vibrant" looking, but classic. Looking forward to making some of these with multimeters to go with. Planning on using the UCC283T-Adj and UCC383T-Adj for the new ones as those are far cheaper than the PTR08100.

50 Camel Snus Mellow Collectible Tin Cans - eBay (item 380278281242 end time Jan-02-11 09:24:03 PST)

 

[Vapenstein]

@McDude I probably have at least a dozen of these tins in my locker at work. I can make as many as you'd like, given enough time. Tell you what, they're all yours, I'll just need one of those mods in return

 

[McDude]

@McDude I probably have at least a dozen of these tins in my locker at work. I can make as many as you'd like, given enough time. Tell you what, they're all yours, I'll just need one of those mods in return

That'd be cool, but I'm out of regulators unfortunately until mid-end of January when TI gets the 283/383's back in stock (sigh). If you happen to have the regulator, then we can work something out.

 

[benjayman2]

Awesome mod

 

[sgtdisturbed47]

I've been using that same battery holder (9v connector) for my mods for a little while now. Much easier to work with than bare connectors that have to be glued into place.

I also don't use caps, even though TI says that it's required.

 

[breaktru]

I would think the caps would be necessary to filter any AC fluctuation from rectifying AC to DC, but using pure DC from a battery, filtering would be unnecessary. This is just my opinion. Now lets hear from an expert....

 

[McDude]

On the caps thing, I'm not sure if this matters, but I couldn't observe any oddities in power-up either. I'm using the inhibit pin, rather than simply cutting off and restoring power to the device, so I would think the device remains powered up and the curve steadies out - no clue if that's correct. Without any observable or measurable (with my limited equipment) effect of not having the caps, I just can't see adding them because "I'm supposed to".

 

[Jetmec]

Big Blues post on the ever cool VV uses the TI PTR08100W and here is his take on the caps. (The reason TI suggests the caps is really because this chip is meant to power delicate equipment. The output cap is really there to make sure there is no AC ripple (unsteady voltage) going to the load ....something an atty really does not care about because it is acting like a resistor.
The input cap's main reason for being there is to filter out any ripple going to the chip (there is no AC in a battery). The second reason for the input cap is to take the "shock" off the chip when you first turn it on (like when you hit the fire button).
In a mod we hit the fire switch a lot. I did talk to a TI engineer and after he heard what I was using it for...... I was told that "TI still recommended that I use both chips", you understand he had to say that BUT, if I wanted to go "outside" of the specs.... The output is needed less than the input for our application.
The way we are using it in a e-cig.... the input will help to extend the "life" of the chip by taking the shock off the chip.)
He does not use the inhibit leg of the chip, so it is getting powered on each time the fire switch is hit.

 

[McDude]

That makes total sense because what you get in the mA range is very "dirty" power, but in the 1+Amp range feeding an analog device (a heating coil certainly isn't a discreet unit) the benefits/requirement of the caps simply isn't there. If the output was to feed more sensitive gear, discreet or otherwise, then yeah definitely. I just hate doing stuff "because I'm supposed to" without empirical need for the application - cleaning up the power signature at the mA level just isn't necessary for burning juice and I would imagine that using the inhibit would lessen any shock to the battery - although - the caps really don't serve that purpose, they're to de3al with the "feedback" quiecent (spelling) power, not buffering/protecting the source necessarily, I kinda question that as a valid point for an input cap. With the huge drain a 100uF cap isn't really providing that kind of "protection" for the battery, it's evident at the mA scale perhaps, but for larger scale/analog burning I'm dubious.