MOSFET Safety

[Fidola13]

I purchased an unregulated Asmodus Pumper 18. It has a mosfet and some safety protections. I’ve been reading as much as I can on mosfets. Most is over my head but in regards to vape mods I’m understanding that it acts as the switch to complete the circuit instead of the mechanical switch. If it detects a short it won’t fire. Do I have that right?

Soooo how reliable are these mosfets and is there anything else I should know before proceeding?

Thanks

sara

 

[Punk In Drublic]

The Pumper actually employs a microcontroller as seen within DJLsb review video. And according to the spec sheet from Asmodus this offers reverse polarity protection, low voltage cut off, a 10 second fire cut off, short circuit protection and temperature sensors that will shut down the device should the board (not batteries) reach a certain temperature.

It also looks to offer a low level of regulation. Looking at DJLsb’s output charts we can see the voltage changes in accordance to the resistance. So if your battery is at 3.7 volts, you are not receiving that 3.7 (or there about) volts at your coil. Your output is still based on resistance but looks like there are some voltage regulation going on.

 

[Fidola13]

I watched his video earlier but couldn’t understand the charts. Thank for taking the time to research this for me.

sara

 

[gpjoe]

Yes, a mosfet works like a high current switch. With a mech mod you need heavy duty contacts to support high current. If you want to use a light duty push button switch on a mod, you need a mosfet (or a circuit board) to do the heavy lifting. When you push the fire button on a mosfet mod, it turns on the mosfet which delivers the current to the atomizer. The high current never flows through the fire button/switch it merely turns the mosfet on and off.

Edit:

...and I don't think the mosfet will fire if the battery is reversed. As far as current limits with a mosfet, that depends on the current capability of the mosfet itself. A manufacturer of vaping mods should specify the max current that his mod will handle safely, or at least specify a minimum coil resistance to ensure that the user doesn't over-drive the device.

 

[Baditude]

If looking for a layer of safety in a mechanical mod, you might consider one of these.

Question directed to @Mooch

 

[gpjoe]

oops

 

[DaveP]

Oh, and I don't think the mosfet will fire if the battery is reversed. As far as current limits with a mosfet, that depends on the current capability of the mosfet itself. A manufacturer of vaping mods should specify the max current that his mod will handle safely, or at least specify a minimum coil resistance to ensure that the user doesn't over-drive the device.

You are right. It only conducts in one direction. It's chief application is a high current NPN switch. When not conducting its P layer is switched to ground, preventing false triggers.

A high amp reverse biased diode in the positive power input line would achieve backup for double protection from reverse bias battery insertion. That's described, but not really clear in the link I posted.

Power MOSFET - Wikipedia

 

[Fidola13]

Is there a difference between a mosfet and a “chip” or the same thing. I guess I wondering how a mosfet provided the same safety features that are listed here for the Luna:

 

[RadiusNick]

i don't use mechs or mosfets but remember seeing this guys experience with them:

 

[diagrammatiks]

This is not a squonker. It is also not a mech.

.

People use the term mosfet incorrectly sometimes.

The mosfet is literally just a single transistor. All it can do is act as a switch and provide maybe some element of protection by blowing like a fuse if it over currented.

The luna and the wismec luxotic mf have mosfets in addition to additional circuitry. They are really unregulated mods.

 

[Punk In Drublic]

This is not a squonker. It is also not a mech.

Maybe not a squonker in the terms of squeezing a bottle to feed juice, but it is a bottom feed device.

@Fidola13 – both the Luna and Pumper 18 use the same chipset. Was able to find these specs on VaporDNA’s site.

• UL-80-JX Chipset

• Power Output Based on Current Battery State

• 80W Maximum Output

• 27A Output Current

• 3.3v to 4.2V Output Voltage

• 0.1 to 3 ohm Atomizer Range

 

[TheTinMan]

I guess I wondering how a mosfet provided the same safety features that are listed here for the Luna:

Your main protections come from an ARM chip made by ST Microelectronics. A very reputable company for many decades.

Is there a difference between a mosfet and a “chip” or the same thin

Yes, there is a difference. Pretty much as @diagrammatiks described.