Serge and spike protection to controller board

Thread Starter

ep.hobbyiest

Joined Aug 26, 2014
181
i have developed a small board that has a controller and a 16x2 display. I am powering up the board using external smps power supply.
I want to add serge protection, so that my system will be protected from any time of serge or spikes.
One option is i can use fuse but i want to know what else option i can use along with fuse.
 

Thread Starter

ep.hobbyiest

Joined Aug 26, 2014
181
The right place for surge and spike protection is at the AC input of the SMPS. Are you asking how to provide those things at the input to your MCU device?
i want to add it before power supply section (before smps).


I usually add Tranzorbs and Polyswitches.
Sure, i will check on this.
How about following component. I never used but i saw it was used in some boards.

1617798073289.png
 

dendad

Joined Feb 20, 2016
3,781
MOVs (Metal Oxide Varistors) are good too, and I've used them as well. Sometimes with the other 2.
And they are available in quite large power ratings, so that may be a consideration.
A unidirectional Tranzorb gives the reverse polarity protection, so that is my main choice if room is a problem.
Have a look at the Morsun isolated RS485 driver data sheet...
https://www.mornsun-power.com/html/pdf/TD5(3)01M485+.html
Page 3 has an application circuit that included good transient protection.
 
Provided the external SMPS is a purchased one: add a "overvoltage protection adapter" between wall outlet and SMPS.
These usually come with MOVs plus come with MOVs plus gas discharge tube plus fuse plus "adapter operational" indicator.
Just as one example (sorry - my language is German):
https://www.amazon.de/Brennenstuhl-...8TMF4VCMSDX&psc=1&refRID=J1YJPMT4F8TMF4VCMSDX

As you can see: these devices are not too expensive. Other flavors (e.g. 1 filter plus several outlets) are available. Just make sure that your PE line is in good condition as these adapters to some extend rely on the function of the PE line.
 
Really don't understand why it is a problem if you are using a decent power supply and some basic protection on your controller board.
An Arduino Uno board will have an onboard linear regulator and the usual capacitor protection on the power lines.
I think they have a polyfuse as well.
There used to be controller board that went under the name of Ruggeduino or similar and the accompanying article went through every aspect or power, input, output etc protection. It was supposed to be bombproof.
You could also have a look at the industrial version of Arduino to see what protection that has.
 
Just to share my experiences, I repair a lot of mid-90s vintage Ford instrument clusters and am starting to find a few MOV failures. Unfortunately, the MOV failures have resulted in hard shorts to ground, which usually results in burned out traces. A 30 year lifespan is pretty good, but I sure don't like the failure mode I am seeing, I use TVSs to protect my automotive accessory products.
 
Just to share my experiences, I repair a lot of mid-90s vintage Ford instrument clusters and am starting to find a few MOV failures. Unfortunately, the MOV failures have resulted in hard shorts to ground, which usually results in burned out traces. A 30 year lifespan is pretty good, but I sure don't like the failure mode I am seeing, I use TVSs to protect my automotive accessory products.
That is the normal failure mode for a MOV.
 
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