Finally, after some years i took arduino back from the shelf!
Í'm doing a thermoelectric fridge. For temperature control i wanna use PID on arduino to control the output power from this SZBK07 DC 300W 20A CC CV Constant Current Adjustable Step-Down Converter based on MOSFET IRFB3607.
My plan is to remove the current limiting pot and use a PWM pin from arduino to reproduce the pot voltage range. I'm assuming this pot is "controling" the gate, and therefore, the current lmit, right?
I'm not an expert on datasheets but i think this is the range based on the IRFB3607 datasheet.
I'm not an expert on datasheets but i think this is the range based on the IRFB3607 datasheet.
No this is the voltage below which the FET is off. This changes from individual device to device but will always be between those two voltages.
My plan is to remove the current limiting pot and use a PWM pin from arduino to reproduce the pot voltage range. I'm assuming this pot is "controling" the gate, and therefore, the current lmit, right?
I doubt it.
Can’t see the images because that site wants to infect my iPad with tracking cookies, which is why we ask you to post images on a particular way. We hide this information from people by putting it in a post that is fixed at the top of each and every forum section. Quite cool eh. We hide them in plain sight and nobody ever sees them.
herbschwarz:
It is much more difficult to do than that!
Herb
Could you elaborate on why please?
Would a digital pot work better? The goal is to control the buck converter output with the arduino but the simpler the better. Thanks!
Grumpy_Mike:
No this is the voltage below which the FET is off. This changes from individual device to device but will always be between those two voltages.
I doubt it.
Can’t see the images because that site wants to infect my iPad with tracking cookies, which is why we ask you to post images on a particular way. We hide this information from people by putting it in a post that is fixed at the top of each and every forum section. Quite cool eh. We hide them in plain sight and nobody ever sees them.
Fixed!
I can always measure that regulation voltage range with multimeter, it should be be within arduino output range, i guess.
Also attached the datasheet of the MOSFET. Thanks!
I have found this on instructables, it some how does what i'm looking for but it's controlling the voltage instead of current. The module uses a LM25116 buck controller. Apparently the current limiting function is controlled by the charge going on the feedback pin. To make things easier, assuming i know that the pot is a 10k multiturn, can't i just change it for a digital potentiometer with same characteristics? thanks!
If not probably i will go with controlling the voltage instead.
Drop the idea of controlling the current or the voltage. It's NOT trival to do so with a buck converter.
What you do want to do is control the power. And for that there IS an easy way. Simply add a transistor (I would use a MOSFET) that's capable of driving the load (peltier element). Now simply PWM that transistor
