I was researching protection circuits for a upcoming project for my car. When I ran across this blog . It's very short so I copied the whole thing here. The suppliers of automotive electronic devices are competing these days to lower the cost of theirs designs. This is a sample of rather expensive…

They look reasonable. Similar stuff <a href="https://www.google.com/search?tbs=simg:CAESgAIJoadhUauKip4a9AELELCMpwgaOQo3CAQSE8cENqofui6fIvI8oD-VC8M00RQaGnzKGW5uUDIBnsgk0q8aIrwCVhmGEKKaGAtqIAUwBAwLEI6u_1ggaCgoICAESBMiid28MCxCd7cEJGpUBChsKCHZlcnRpY2Fs2qWI9gMLCgkvYS80aGgzcDAKGwoIbGFuZ3VhZ2XapYj2AwsKCS9qLzJzaF95NAodCgpob3Jpem9udGFs2qWI9gMLCgkvYS8ybXF2emMKFgoDZG902qWI9gMLCgkvbS8wMjdjdGcKIgoPY2lyY3VpdCBkaWFncmFt2qWI9gMLCgkvbS8wMnNzeXAM&sxsrf=AJOqlzUHETWBwfsLPZ-O61HKWzLKDDnKQQ:1674413968607&q=load+dump+protection+circuit+automotive&tbm=isch&sa=X&ved=2ahUKEwjF4biO7tv8AhXgAjQIHa1tCNUQ7Al6BAgMEAo&biw=1112&bih=794&dpr=2" rel="noopener nofollow ugc">here

[image] LarryD: Similar stuff <a href="https://www.google.com/search?tbs=simg:CAESgAIJoadhUauKip4a9AELELCMpwgaOQo3CAQSE8cENqofui6fIvI8oD-VC8M00RQaGnzKGW5uUDIBnsgk0q8aIrwCVhmGEKKaGAtqIAUwBAwLEI6u_1ggaCgoICAESBMiid28MCxCd7cEJGpUBChsKCHZlcnRpY2Fs2qWI9gMLCgkvYS80aGgzcDAKGwoIbGFuZ3VhZ2XapYj2AwsKCS9qLzJzaF95NAodCgpob3Jpem9udGFs2qWI9gMLCgkvYS8ybXF2emMKFgoDZG902qWI9gMLCgkvbS8wMjdjdGcKIgoPY2lyY3VpdCBkaWFncmFt2qWI9gMLCgkvbS8wMnNzeXAM&sxsrf=AJOqlzUHETWBwfsLPZ-O61HKWzLKDDnKQQ:1674413968607&q=load+dump+protection+circuit+automotive&tbm=isch&sa=X&ved=2ahUKEwjF4biO7tv8AhXgAjQIHa1tCNUQ7Al6BAgMEAo&biw=1112&bih=794&dpr=2" rel="noopener nofollow ugc">here [image] jremington: Randomly chosen overview (one of many such). Yes, Those are similar to the first circuit. My question is regarding the bottom circuit about which they claim

I don't see how the lowest down of those circuits protects from a 125V load dump spike.

As suggested adding a TVS should be included. In the past, I have included ferrite beads in the current paths.

Hi, [image] If that is the cars 12V battery that starts the engine, the negative of the battery will already be connected to starter gnd. That circuit will simply "fix" a polarity error, not stop or signal it, bad karma. What is "cranking protection". Keeping the battery negative above car gnd…

Hi, @TomGeorge Thank you for your reply, but that is not the circuit in question. The blog I referenced in the OP was posted by a company that I believe does electronics testing for the Automotive industry. As such I would think they know a bit about the subject. They suggest that that this circu…

No, it does not. A suitable TVS diode costs less than $1. Add one, as advised in other, more serious publications.

[image] jremington: Add one, as advised in other, more serious publications. I intend to but was just curious since I would think a person/place that actually does " Automotive EMC Testing for Electronic Modules" for the Automotive industry would be quite serious and quite unlikely to publish…

[image] Hutkikz: The blog I referenced in the OP was posted by a company that I believe does electronics testing for the Automotive industry. To me, that looks like some random person's blog. The person seems to go by the name of "Christian". There might well be some useful information in it…

Automotive Protection Circuit

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jremington January 22, 2023, 7:11pm 3

Those circuits lack high current transient voltage suppression, needed to handle the occasional >100V spikes in automotive electrical systems.

Randomly chosen overview (one of many such).

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Automotive Protection Circuit

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