Efficient, quiet current limiting noob help please!
I'm looking for an affordable, efficient, low-RFI way to limit ~14.5VDC current between my car's power port and a secondary system. I've considered a constant current buck-boost converter, but I'm afraid that will cause too much RFI. A dim bulb limiter seems like it would be quiet, but I'm worried about the heat and efficiency. What other options are there?
I've had problems in the past with buck converters wrecking VHF radio performance. Now that I'm getting into HF, it's even worse, so I'm loathe to put any investment into a buck/boost converter. If I understand it correctly, current limiting resistors will be extremely clean, but will cause significant voltage drop and heat. A dim bulb tester would be more efficient at low draws, but I'm concerned that if it were to go full-power, the heat (at something in the neighborhood of 100W) could be bad for automotive carpeting and/or my safety and my insurance premiums. I have very poor understanding of linear current limiting circuits, current limiting diodes, etc. Is that were I need to go, or is there another, simpler solution?
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Is it okay if the current limiter completely disconnects the load from the 14.5VDC supply when overcurrent is detected? And then it stays disconnected forever, until the human operator presses the RESET button. How would that be?
Justinicus [OP] 1 points · Mar 2020
No, I would like the secondary system to be able to pull as hard as it likes and be limited to a safe current level without breaking the circuit, as it were.
Justinicus [OP] 1 points · Mar 2020
Something like the constant current function of a lab power supply would be ideal. My first thought was a CC buck/boost -- cheap, efficient, easily obtainable on eBay. But the RFI is very problematic. I couldn't find a linear equivalent, at least not with my electronics vocabulary!