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Great little MOSFET PWM controller.
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#21 (permalink)      8/11/2015 10:20:26 AM US Central   quote/reply + tips
wuwei.ap
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NurseJ, that could work...

But I am cheap. :P

I figure I can use some silicone glue smeared into a 1mm thick sheet and cut to shape.

It's all the components, they add up in cost quickly, so if I can fabricate, I will.
#22 (permalink)      8/11/2015 12:33:08 PM US Central   quote/reply + tips
hexxed
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+2 details
Plastic case why? As long as you keep the batteries and uninsulated wire from touching the case it'll be fine.

As for keeping it tidy, you don't have to use the same wire to connect to the board and 510, I use solid 13G for the negative side and stranded for the 510 positive for strain relief. Then 28G for the signalling, I mean this board comes with 36ish gauge kynar wire, I left some of in on on my prototype, excuse the horrific positive wire soldering, I assembled the box in less than an hour to take on holiday!



Attach the battery negative to the switch, then the board negative from that contact, and pin 3 on the IC to the other side of the switch. In this you can see where most of the wires go, the black one holding the hot glue back connects to the dual 13Gs going to the MOSFET source pin. Someone told me I wouldn't even be able to get a MOSFET in there!

Here's a series one but disregard the wire colours, the wire up the left side (which goes into the switch and comes out red!) is actually the board's positive, the extra master switch is there just cause it fitted!





Wuwei.ap, that board looks cool, but the only reason I'm using this one is for the adjustable pulse width modulation really, straight up unregulated just doesn't cut it for me!
And that board you linked is gonna reduce the power output, it says 3.6V constant, so it's regulating the voltage down, by PWM, which means it'll switch your MOSFET on and off really quickly and give a lower average power!
#23 (permalink)      8/11/2015 7:45:16 PM US Central   quote/reply + tips
wuwei.ap
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I'm assuming you can use the wires supplied on the controller side of the circuit and something like 26 gauge on the power side for my application.

What differentiates between this board and the linked eGo T? I know that in all voltage modes on the X6, except for blue (high), it uses some form of voltage regulation. On high it seems to deliver whatever the battery can deliver. Would it make a difference using an unregulated eGo board, on power?

I'm not an expert on this dark magic. :P

Wouldn't the X6 also do the same thing on efficiency?
#24 (permalink)      8/12/2015 12:41:52 AM US Central   quote/reply + tips
wuwei.ap
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I'm wondering if an RC circuit on the output of a constant voltage board would stop the switching while also giving PWM efficiency?

The link is about arduinos, but the link in the latter part of it and the explanation is the relevant part.

RC

It's two extra components. I figure that these ego boards are plentiful and some have nice features that could be exploited in mods.
#25 (permalink)      8/12/2015 10:51:34 AM US Central   quote/reply + tips
NurseJ
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wuwei.ap wrote:

I'm wondering if an RC circuit on the output of a constant voltage board would stop the switching while also giving PWM efficiency?

The link is about arduinos, but the link in the latter part of it and the explanation is the relevant part.

RC

It's two extra components. I figure that these ego boards are plentiful and some have nice features that could be exploited in mods.



wouldn't a capacitor smooth out the current to the mosfet enough to get a stable vape? hexxed used a mosfet with something like 20000pf in an earlier post

#26 (permalink)      8/12/2015 11:19:04 AM US Central   quote/reply + tips
wuwei.ap
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I think what it would do is smooth out the voltage so there are no longer pulses switching the MOSFET on/off. All the RC part needs to do is give more than 2.5v for that MOSFET at the gate for it to function like a switch. I am presuming that a constant voltage eGo board is always switching though and in a range that is effective for the RC throughout the battery discharge cycle.

I don't quite know what the capacitance of a MOSFET affects. :P
#27 (permalink)      8/12/2015 11:56:15 AM US Central   quote/reply + tips
hexxed
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No capacitor, 'smoothing' out the vape is pointless, it doesn't need smoothing at all, if you really think you can notice it switching at a few thousand hertz then you're either a superhuman freak or you're imagining things.
The 'switching' is what controls the external MOSFET, so it's definitely required! You could RC the output of that, but I would bet a blue screwdriver you couldn't tell the difference in a blind test.

The capacitance I referred to previously is inside the gate of the MOSFET, it has nothing to do with the output side! I only mentioned it because it's the only load on the board, about 300mA, and that's why the short protection won't work.

You likely need to give alot more than 2.5V to the MOSFET gate unless you want to fry it! The way this board works is Pulse Width Modulation, it turns the output on and off thousands of times per second, with a duty cycle (switched on time) of roughly 60% for red and about 80% for purple, when it's switched on, so is the external MOSFET, when it's switched off, so is the external MOSFET.

The problem you'll have with non adjustable boards is that they use PWM too, but aim to give the equivalent of 3.6V or 3.5V out, battery sag with high drain will throw them off quite a lot, and the output is unreliable so just building a coil for 3.5V won't always work as you expect.
#28 (permalink)      8/12/2015 12:01:26 PM US Central   quote/reply + tips
hexxed
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You could use 26 gauge, depends on your amperage requirements, you'd be good for up to about 3 amps, 13 gauge you're good for up to 35 amps. That is being conservative though, you can probably exceed those ratings by 50% since box mods have short wire runs which are only used for pulses rather than continuous.

www.powerstream.com/Wire_Size.htm
#29 (permalink)      8/12/2015 12:11:43 PM US Central   quote/reply + tips
hexxed
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Yes you could use an RC filter so that the output is a constant voltage to turn on the MOSFET constantly using those other boards, but there are probably much better ways to use these boards alongside a simple unregulated circuit such as locating them in the circuit parallel to the firing circuit with a separate button, or using bipolar junction transistors or a couple of P and N channel FETs to trigger the board alongside the firing mechanism.

There's no efficiency to be gained by chopping up the gate signal with a PWM then smoothing it back out, you just make it less efficient and make it more likely you'll burn out the FET, their resistance is increased the lower the gate voltage is.
#30 (permalink)      8/12/2015 12:22:13 PM US Central   quote/reply + tips
NurseJ
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It's really great having experienced posters to help! Thank you hexxed. Btw quick question, would using pwm at the gate cause the mosfet to turn on and off at the drain side as well? If it does, won't it make the output voltage oscillate as well making the average voltage lower than the voltage from the battery? Sorry if I post stupid questions
#31 (permalink)      8/12/2015 2:10:21 PM US Central   quote/reply + tips
JPBel
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@NurseJ.
The output will be about the same as the input signal.
If it is chopped, you will not have the full battery power.



Something to consider if you want a variable output.

-PWM-ing a mosfet gate make it be in its ohmic region more often, resulting in more heat generated in the mosfet, the higher the frequency the more impact it will have.

-The resistance value used to turn off the mosfet also have an effect on the heat generated in the mosfet when it is PWM-ed.
A too high value will make the mosfet stay in its ohmic region for longer at each cycles, if it even have the time to turn off.
The mosfet turn off resistance can actually be used to smooth out the gate voltage as it is basicaly creating a rc filter with the gate capacitance, depending on the mosfet, a small additional capacitor might be require to do this.
For fast switching, the capacitance at the gate need to be as small as possible, selecting the right mosfet for the job is a must.
A too low value will drain a lot of current just to turn the mosfet on, affecting the voltage at the gate too.