Go Down

Topic: Which mosfet to use with 4 TEC1-12709 peltiers (Arduino MEGA 2560 board) (Read 739 times) previous topic - next topic

As the title says really,

I'm going to powering 4 peltiers (TEC1-12709 136.8W 12V 9A TEC) and I need to know what MOSFET type to use. I'm quite inexperienced with electronics so if you know a mosfet and model number I'd be super appreciative!

ProjectSpotter

MarkT

In series or in parallel?  Using PWM?  If so what frequency?  Higher speeds of PWM would
really need a MOSFET driver chip to get fast switching.

If you want to drive the MOSFET directly from an Arduino you _must_ get a logic-level FET.

What maximum current are you needing and what's the power supply(see my first question)?  You need to calculate
the power dissipation in the FET using I-squared-R (ignore the nominal current rating of a MOSFET,
its only applicable if using extreme cooling measures).

[ I won't respond to messages, use the forum please ]


In series or in parallel?  Using PWM?  If so what frequency?  Higher speeds of PWM would
really need a MOSFET driver chip to get fast switching.

If you want to drive the MOSFET directly from an Arduino you _must_ get a logic-level FET.

What maximum current are you needing and what's the power supply(see my first question)?  You need to calculate
the power dissipation in the FET using I-squared-R (ignore the nominal current rating of a MOSFET,
its only applicable if using extreme cooling measures).




Some of this has gone a bit over my head, this one of my first projects so apologies for my ignorance  :smiley-red:

The peltiers will be in Parallel, I don't know if I would be using PWM (should I use PWM?). Frequency wise I'm not sure.

Maximum current would be 28A, the power supply would be a max of 550W but in reality the power draw will be closer to 335W.

MarkT

OK, so you need a very low Rds(on) device - heat dissipation is I-squared-R, so if the device were 10 milliohm that
would be 8W dissipated when on, which would need a reasonable amount of cooling (something like a chipset
heatsink and fan perhaps?).  If you got a 3 milliohm device you'd run a lot cooler or need less heatsinking.

I've used an IRLS3036 in the past, its logic level, has 60V rating and 2 milliohm.  However its surface-mount only.

I'd recommend trying to get a device with Vds voltage rating of 20V or more, about 5 milliohm Rds(on) or thereabouts
and logic-level - TO220 package is probably easiest to heatsink (remember the drain terminal is also connected electrically
to the tab, so you need an insulating heat-conducting pad between package and heat-sink.

Another approach is to parallel a couple of devices to get half the Rds(on) figure - then 10 to 15 milliohm devices
would be more feasible.
[ I won't respond to messages, use the forum please ]


OK, so you need a very low Rds(on) device - heat dissipation is I-squared-R, so if the device were 10 milliohm that
would be 8W dissipated when on, which would need a reasonable amount of cooling (something like a chipset
heatsink and fan perhaps?).  If you got a 3 milliohm device you'd run a lot cooler or need less heatsinking.

I've used an IRLS3036 in the past, its logic level, has 60V rating and 2 milliohm.  However its surface-mount only.

I'd recommend trying to get a device with Vds voltage rating of 20V or more, about 5 milliohm Rds(on) or thereabouts
and logic-level - TO220 package is probably easiest to heatsink (remember the drain terminal is also connected electrically
to the tab, so you need an insulating heat-conducting pad between package and heat-sink.

Another approach is to parallel a couple of devices to get half the Rds(on) figure - then 10 to 15 milliohm devices
would be more feasible.


Ok awesome, thanks for the help. Just to check so if I did a 2 x 2 series/ parallel then I would only need a mosfet rated for a 30V and 19A max correct?

Go Up
 


Please enter a valid email to subscribe

Confirm your email address

We need to confirm your email address.
To complete the subscription, please click the link in the email we just sent you.

Thank you for subscribing!

Arduino
via Egeo 16
Torino, 10131
Italy