7Amp Heater and PWM using MOSFET

Other Hardware Motors, Mechanics, Power and CNC
1

Hello everyone,

I'm working on a project that controls 12Vdc 7Amp silicon heater pad using MOSFET.
I tried HA210N06 MOSFET with a heatsink but it doesn't work correctly, the heater doesn't get hot but the MOSFET is getting very hot, I tried another lower amper heater it's work but also not get very hot with a 100% duty cycle as I connect it directly to the power supply.

I'm using dual output power supply 5v for microcontroller and 12v 15A for the heater.
PWM frequency is 500hz.
I'm using pic 18f4685 and programming with MikroC.

The circuit is attached.

my question is this MOSFET could work correctly but I have some connections problem or coding problem?

Thank you.

Heater.jpg

2

The HA210N06 is not logic level and needs 10 to 12V on the gate to turn fully on.

If you want to drive a MOSFET direct from 5V logic it must be logic-level.

To quote the top of the datasheet:

RDS(ON)= 4mΩ (Max)@ VGS=10V

That means 10V is the minimum gate drive voltage it is guaranteed to work at.

3

Thanks Mark,

get it, can you please recommend a MOSFET for this application? or what is the characteristic for it?..

i'm new using MOSFET so please help me to done this project.

4

There are many MOSFETs out there, thousands and thousands. In a TO220 package
though logic-level are less common than for surface mount packages, but any good
component supplier will have a parametric search engine.

You need to decide on the specifications you need, principally heat dissipation.

For 7A and 0.25W max dissipation the Rds(on) needs to be 5 mΩ or less - this will run fairly cool.
For 7A and 1W max disssipation, the Rds(on) can be upto 20mΩ - much hotter unless a heatsink.
power = I-squared-R

And it must be logic level, ie that Rds(on) figure at Vgs=4.5V

For a 12V circuit a max drain voltage of 25 or 30V will be plenty.