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Thread: Single vs. Multiple +12V rails: The splitting of the +12V rail

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    In my sample it is PS232S.

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    Hmm. Can you check the resistance of the referent current resistor for the chip? It's a resistor connected to pin 6 of the PS232S. It is the sixth pin down, on the left side of the half-circle key notch on the package. The other lead of the resistor should be grounded directly.
    Careful what you wish for... You just might get it.

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    I'll get to it a bit later.
    Last edited by rafal_iB_PL; 04-30-2011 at 02:24 PM.

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    Post under post as it didn't refresh, please merge.

    Anyway, checked it. It's R412 according to traces (BTW I was careless reading part numbers first time - it is PS231S, but it matters little, as Iref is still on pin 6, according to a data sheet). Anyway I had to wait for a while, as there apparently is a cap in circuit.

    Value measured is 1 kOhm.
    Last edited by rafal_iB_PL; 04-30-2011 at 03:32 PM.

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    That's a pretty low, it would put the referent current in the mA range. Perhaps that's why OCP doesn't trip? What's the resistance on the previous and next pin (5 and 7)? Should be pretty high, in the 10s of kOhm range, since the ref. current is so high...
    Careful what you wish for... You just might get it.

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    Nevermind that last measurement <facepalm> checked the wrong one.

    All three measured resistors (pin 5, 7 and 10) are in 200-250 Ohm range. Pin 6 has much higher resistor - 52,5 kOhm - all in all close values to those mentioned in data sheet with trip point @20A.

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    Default What if I just need the Amps

    Thanks for the nice article and breakdown of what's important for almost 99% of users out there. I found myself reading this forum even 5 years after it was written because I have a scenario where I'd want to use a computer PSU to supply current to a 1000W LiPo battery charger (for use with R/C batteries). Simply because I have a couple of these 600/800W supplies lying around(2 single rail, 1 multi). However, what I'm apprehensive about is ... how would I go about selecting a connector that could source like 30A @12V and which ones would be a good/bad choice?

    Hoping I'm not resurrecting a thread that's supposed to be silent

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    Is the actual draw of the charger 1000W? I find that a little difficult to believe. The 1000W might refer to something else.

    I mean, my experience with +12V chargers is automotive, but even those charge @ 40A. Anything more than that and the cables are hot to the touch after about 15 minutes.

    Even the big garage chargers on a cart (like the kind you buy off a Mac truck, etc.) only do 30A for "rapid charge". When they advertise 300A, they're just talking about jump start mode. It's only 300A for a few seconds. Long enough to turn over the car.
    Last edited by Jon Gerow; 12-06-2011 at 08:14 PM.

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    You could simply use several connectors, or rather several different wires from several different connector cables. The most current any one connector is stated to be able to transfer is 32A @ 12V, and that is the EPS12V connector. The pins it uses are specced at 11A each, and 18AWG wires can carry 8A safely without melting the insulation. If thicker gauge is used, you could go for the whole 11A per wire pair, so you could actually get 44A off of just the EPS12V, assuming it isn't OCP-limited at the PSU side.
    Careful what you wish for... You just might get it.

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    Could anyone stop this thread ? it is pointless the only conclusion is:
    -1 rail is better
    - many rails - safer

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