Electronics > Projects, Designs, and Technical Stuff
5VDC project, 110VDC overvoltage protection
Bouteille:
--- Quote from: nick_d on January 16, 2019, 10:49:21 pm ---Why don't you build it and do some tests and let us know how it goes?
--- End quote ---
Will do ! I just ordered some (Littelfuse TRF600 160ma).
I thought PTCs (thanks for the correct term) have been very common parts used in many systems, and I expected a ton of comments about them. But I am maybe wrong.
Is this something relatively new or confidential (or useless) ?
I preferred to ask advice before placing order but hey... time for experimentation ! :)
Zero999:
PTC resistors are very slow. Nowhere quick enough to protect a semiconductor device. They're used for protecting cable, motors, transformers etc. which are big things with a large thermal time constant.
Bouteille:
--- Quote from: Zero999 on January 17, 2019, 01:25:20 pm ---PTC resistors are very slow. Nowhere quick enough to protect a semiconductor device. They're used for protecting cable, motors, transformers etc. which are big things with a large thermal time constant.
--- End quote ---
Hence the Zener for clamping. It dissipates power and waits for the PTC to save its life. Almost romantic ;D
Not realistic though ?
TrickyNekro:
I know that might come as a bit of shameless self promotion, but have a look here.
https://www.eevblog.com/forum/oshw/openservocan-(-for-hobby-standard-size-servos)/
Look at the input protection side of the project (in the .pdf).
Replace the MOSFETs with high voltage ones and the regulator with a HV variant with enough cooling.
You can not got wrong like this. You got reverse voltage protection and possibly also over voltage protection with some modding.
The circuit is not new by the way, I´ve seen it used in many laptop designs, take it as you want it and mod it accordingly.
Sure building this circuit is more expensive than a polyfuse but I guess you ain´t making a cheap product either.
Cheers!
Bouteille:
Thank you ! That looks more advanced than what I can handle yet but I'll come back to it as soon as I feel more confortable with basics.
I'm still a beginner (started by programming pics and loved it) and I wanted to believe I could stick to something very simple, but it looks like I'm gonna have to put some more efforts into it.
I tried to read/watch introduction about individual components but when it's time to assemble them and get something done, I feel stupido :)
I thought I'll be able to get something done after watching Dave's Zener video but apparently... not yet ;D
--- Quote from: TrickyNekro on January 17, 2019, 01:45:02 pm ---Sure building this circuit is more expensive than a polyfuse but I guess you ain´t making a cheap product either.
--- End quote ---
Actually the device will not be that expensive, basically just a pic microcontroller...
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