Mosfet for VV mod?

[Madshock]

Hi guys,

Need help on this, I have this Power MOSFET - Power MOSFET Transistor - CSD16325Q5C - TI.com

It doesnt work on my VV and im thinking it is most likely because im feeding 8.4V on freshly charged 3.7 batts. based on the data sheet i think it seems it doesnt take more then 8V.

Am i right on the reasoning for this? if so, do any of you know which Mosfet is suitable for a VV mod?

Thanks in advance!

 

[givesuhe11]

Hi guys,

Need help on this, I have this Power MOSFET - Power MOSFET Transistor - CSD16325Q5C - TI.com

It doesnt work on my VV and im thinking it is most likely because im feeding 8.4V on freshly charged 3.7 batts. based on the data sheet i think it seems it doesnt take more then 8V.

Am i right on the reasoning for this? if so, do any of you know which Mosfet is suitable for a VV mod?

Thanks in advance!

I used that mosfet in both of these and they work fine... u must have someting wired wrong... have u tried it on a breadboard to make sure u have it soldered right? Thats what I did numerous times till I had the microscopic connections made right for sure... its too hard to see on the 18650 box but that exact mosfet is there right below the switch on the right side. In the 18350 box, its under the evercool circuit. Those mosfets work great! If you still want to try a different mosfet, IRLZ34N works too... they can be found on ebay or I've got 3 to trade if ya got something to trade for.

 

[WillyB]

Hi guys,

Need help on this, I have this Power MOSFET - Power MOSFET Transistor - CSD16325Q5C - TI.com

It doesnt work on my VV and im thinking it is most likely because im feeding 8.4V on freshly charged 3.7 batts. based on the data sheet i think it seems it doesnt take more then 8V.

For anyone to actually help you a few details are needed. Wouldn't hurt to know what reg you are using, where in the circuit, and how you've wired it and where and what value resistor are you using.

It doesnt work on my VV and im thinking it is most likely because im feeding 8.4V on freshly charged 3.7 batts. based on the data sheet i think it seems it doesnt take more then 8V.

That would depend on how you implemented the mosfet, post a schematic.

 

[o4_srt]

I used that mosfet in both of these and they work fine... u must have someting wired wrong... have u tried it on a breadboard to make sure u have it soldered right? Thats what I did numerous times till I had the microscopic connections made right for sure... its too hard to see on the 18650 box but that exact mosfet is there right below the switch on the right side. In the 18350 box, its under the evercool circuit. Those mosfets work great! If you still want to try a different mosfet, IRLZ34N works too... they can be found on ebay or I've got 3 to trade if ya got something to trade for.

Someone made some purchases at radioshack.....I have a similar mod in each of those boxes, using their rare-earth magnets to fasten the lid as well. I also removed the screw posts from opposite corners to make room.

 

[Madshock]

For anyone to actually help you a few details are needed. Wouldn't hurt to know what reg you are using, where in the circuit, and how you've wired it and where and what value resistor are you using.

That would depend on how you implemented the mosfet, post a schematic.

Maybe i got the schematics wrong for the Mosfet part. Im using the schematics that Big Blue posted and added the Mosfet before the main power connection.. For the mosfet im using a 100M this could be where i screwed up soldering sinces its so tiny. For now i ended up using a normal switch for the mod. Not really good at drawing a schematic.. the mod works for the normal switch so im pretty sure the fault does not lie in the PTR8100WRD connections.

Can i request a schematic or guide on how to add the Mosfet into BB VV schematics?

 

[WillyB]

Maybe i got the schematics wrong for the Mosfet part. Im using the schematics that Big Blue posted and added the Mosfet before the main power connection.. For the mosfet im using a 100M this could be where i screwed up soldering sinces its so tiny. For now i ended up using a normal switch for the mod. Not really good at drawing a schematic.. the mod works for the normal switch so im pretty sure the fault does not lie in the PTR8100WRD connections.

Remember that the mosfet will be switching the NEGATIVE, hopefully that's the leg you have it on.

No way would I attempt to use the tiny 8 pin mosfet you have, not due to it's fitness but that package takes a deft touch, good eyes, and some quick soldering. It's just so much easier to use a 3 pin TO-220 package. There are many that will work in the $1 to $3 range. Just as long as the Gate Threshold Voltage is 2.5V or less.

Here's bigblue's original schematic, I altered it a bit in hopes of making it clearer.

As far as the resistor value he's showing 47k, in the past following Nuck's example I've used 10k which worked fine. The higher ohms like big's will put a lower current demand on the switch.

 

[o4_srt]

Remember that the mosfet will be switching the NEGATIVE, hopefully that's the leg you have it on.

No way would I attempt to use the tiny 8 pin mosfet you have, not due to it's fitness but that package takes a deft touch, good eyes, and some quick soldering. It's just so much easier to use a 3 pin TO-220 package. There are many that will work in the $1 to $3 range. Just as long as the Gate Threshold Voltage is 2.5V or less.

Here's bigblue's original schematic, I altered it a bit in hopes of making it clearer.

As far as the resistor value he's showing 47k, in the past following Nuck's example I've used 10k which worked fine. The higher ohms like big's will put a lower current demand on the switch.

the problem with this is, in my experience, the PTR08100W, and other regulators (LM317, LM 350's) still produce an output with a floating ground.

 

[WillyB]

Well in this configuration the reg is on and using a very small amount of current due to Drain-to-Source Leakage, but this seems to be measured in micro amps. Is this what you are referring to?

I think if we were using the chips inhibit pin we could talk about Quiescent Current which is that amount of current consumed from a power source by a component or group of components in a circuit when the circuit is in its powered but non-operating/off state.

The 4 pin Fairchild reg lists Quiescent Current at 10mA, not really signicant.

 

[o4_srt]

Well in this configuration the reg is on and using a very small amount of current due to Drain-to-Source Leakage, but this seems to be measured in micro amps. Is this what you are referring to?

I think if we were using the chips inhibit pin we could talk about Quiescent Current which is that amount of current consumed from a power source by a component or group of components in a circuit when the circuit is in its powered but non-operating/off state.

The 4 pin Fairchild reg lists Quiescent Current at 10mA, not really signicant.

by produce an output, i meant, several volts, enough to fire an atty. This has happened to me several times when trying to implement a MOSFET on the ground of a regulator.

10 mA is significant when dealing with battery life, enough to discharge a set of batteries overnight if the device is accidentally left on.

 

[givesuhe11]

Maybe i got the schematics wrong for the Mosfet part. Im using the schematics that Big Blue posted and added the Mosfet before the main power connection.. For the mosfet im using a 100M this could be where i screwed up soldering sinces its so tiny. For now i ended up using a normal switch for the mod. Not really good at drawing a schematic.. the mod works for the normal switch so im pretty sure the fault does not lie in the PTR8100WRD connections.
Can i request a schematic or guide on how to add the Mosfet into BB VV schematics?

I used the same schematic bigblue posted on post #121 right here http://www.e-cigarette-forum.com/fo...rcool-variable-voltage-mod-4.html#post1933903 (unaltered of course) with the mosfet circuit integrated with this same TI mosfet and it works. It's easy to be misled, it's not too hard to solder these and solder them right. Here's some pics that may or may not help, all depends on who's quick to critique them.
I use the words "top" "side" and "bottom" because... well because its the top, side, and bottom according to the pdf and I don't critique or argue with the pdf very often, ok, I never argue with the pdf. I pre-tin all leads on the resistor and the top (source) and bottom (drain) pads on the mosfet and the pin on the gate. Keep this in mind as you continue.

Solder a 47kohm resistor to the top of the mosfet theres a big pad there for doing so, solder with the lead overlapping like in this pic:

then bend the other side lead down and rest it on the gate pin, now if you pre-tinned, all you do is touch it a couple times with your solder point and it tins up. then double the lead back on itself.

turn it over and take a piece of resistor lead (saved from another project), and solder it to the pre-tinned drain pad on the bottom.

then a piece of shrink tube over the entire chip with leads exposed and you can stick this mosfet with new improved extended leads anywhere you want!

not so bad... not so hard. I hope this helped.

Someone made some purchases at radioshack.....I have a similar mod in each of those boxes, using their rare-earth magnets to fasten the lid as well. I also removed the screw posts from opposite corners to make room.

Yes, I got those at RS... busted... but wait till you see the cool new box I just ordered... I should get them mon/tues, Ill post pics when I make the mod with it.

 

[Madshock]

the problem with this is, in my experience, the PTR08100W, and other regulators (LM317, LM 350's) still produce an output with a floating ground.

Wow Willy, i think this is exactly what i did. Now i wonder where it got wrong. I used a multimeter on the mosfet i have with the Surface mount resistor and its not shorted so it should work fine.. and 100M should work? guess ill have to wait till i have the time to make another one. Now waiting for the 9LED flashlights from DX and my modding will continue. I wonder if size of the FL permits a VV. Otherwise ill use the 383T regulator on it.

Question, without any complicated connections on the PTR8100 chip. Its on fixed 5V?

 

[givesuhe11]

just to show the difference if anyone is trying to cram a bunch of stuff into some mod and needs all the room they can get and you want to use a micro switch... hmmmmmmmmmm

fwiw, if anyone cant do the solder job on the TI mosfet and wants me to, I will send you one already soldered with a resistor of your choice (if I have it, which I should), IF you promise to send me the same TI back mosfet unused, you can get 5 of the TI mosfets as a free samples on the TI.com website, I will of course test it when it leaves here so it'll work as long as you dont mistreat it and handle it too roughly.

Question, without any complicated connections on the PTR8100 chip. Its on fixed 5V?

you have to put the caps on or the voltage fluctuates all over the place, but with just the caps and a 220ohm resistor shorted on the 3 and the 5 pin (?) then its full 5.5v

 

[WillyB]

... 10 mA is significant when dealing with battery life, enough to discharge a set of batteries overnight if the device is accidentally left on.

Maybe but that's a datasheet figure so I assume anyone using the standard MadVapes 4 pin schematic (which is probably quite a few) is dealing with it.

 

[o4_srt]

Maybe but that's a datasheet figure so I assume anyone using the standard MadVapes 4 pin schematic (which is probably quite a few) is dealing with it.

im sure they are.

but some of us want more efficiency.....the joys of DIY

 

[WillyB]

.... and 100M should work? guess ill have to wait till i have the time to make another one. Now waiting for the 9LED flashlights from DX and my modding will continue. I wonder if size of the FL permits a VV. Otherwise ill use the 383T regulator on it.

Question, without any complicated connections on the PTR8100 chip. Its on fixed 5V?

I'd opt for a much smaller value. 20k to 50k... not M. Don't ask me why but I've never seen examples that use such a value. Maybe that's the problem.

I don't know what your vaping experience is but true 5V can rather strong and hard on atties. I'm a Joye atty user and find 5V much to harsh. 4.2 to 4.6V is a a nice range.

You will need at least one resistor across pins 3 (GND) and 5 (ADJ) to set volts.

Here's some values, note these will vary a bit.

In general I'd shoot for around 300Ω for about 4.5V.

Here's the chart, ignore the decimal.

 

[Madshock]

Hmm, i got the 100M idea from Scubabatdan in this thread and i just realised its a value only if i use a touch switch, so most likely that is the problem! Due diligence neglected! . I'll drop this idea and use a 47k/ 4.7k or maybe a 4.7M SMD instead and try it on the next mod!

I vape on 4.5 and found it to be to my liking in my previous VV attempt. so yea, i felt that 5V is a little to harsh as well. That 1st VV mod i did died a few weeks back and i had no idea what happened to it.. it produces the voltage on the meter but doesn't fire up my atty (tried it with 3 working atties) didn't bother to find out the reason though as i had spare chips and boxes lying around =)

Just realised my settings at on 5v on the dot without load right now. i guess the voltage preference gets higher as we vape ( for some people at least) LOL

 

[Madshock]

redundant post. =) deleted

 

[WillyB]

Hmm, i got the 100M idea from Scubabatdan in this thread and i just realised its a value only if i use a touch switch, so most likely that is the problem! Due diligence neglected! . I'll drop this idea and use a 47k/ 4.7k or maybe a 4.7M SMD instead and try it on the next mod!

Just realised my settings at on 5v on the dot without load right now. i guess the voltage preference gets higher as we vape ( for some people at least) LOL

No! Stay within 10k o 47k, not 4.7k or 4.7M.

And if you want small why not just use the chip's inhibit with a nice NC switch, you'll be accomplishing the same thing without all the fuss.

Like small?

Grayhill - 30-2 - Switches - Sensors, Switches & Relays - Allied Electronics

 

[Madshock]

No! Stay within 10k o 47k, not 4.7k or 4.7M.

And if you want small why not just use the chip's inhibit with a nice NC switch, you'll be accomplishing the same thing without all the fuss.

Like small?

Grayhill - 30-2 - Switches - Sensors, Switches & Relays - Allied Electronics

Noted!! haha.. thank you WillyB for preventing a potential disaster!

Is there somewhere i can get a schematics for the easy way out? >.< Never dealt with N/C switches before.

 

[o4_srt]

Noted!! haha.. thank you WillyB for preventing a potential disaster!

Is there somewhere i can get a schematics for the easy way out? >.< Never dealt with N/C switches before.

N/C switch is exactly like a N/O switch, except it is normally closed.

Just put it in series with the inhibit pin to ground, no different than putting a N/O switch from the batteries to the input pin.