EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: lukaq on April 22, 2015, 06:32:01 am
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Hey,
I have a problem, i'm not too sure how to make outputs share current, I was able to get voltage tracking, but channels don't want to source the same current, one is what it is, other is around 0
For voltage track, you have A6 os slave connected to +, S+, A10 and GND
Slave still has +, S+ and A10 shorted, A7 floating as is A8
I can't connect S+ master to S+ slave, since slave will sink some current
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When doing parallel connection, it is common for one supply to source all current, until it reaches the current limit, when the other one will start to source the excess. This is because one will have a slightly higher output voltage that the other (even if set to the same voltage). This causes the slightly lower one to completely turn off since the output voltage is higher, even if only slightly, than it is trying to maintain. When the first one goes to current limited mode, its voltage will drop, and the second one will begin to source current.
If you really want to share current equally, then you can use ballast resistors between each supply and the load. Even just a long cable (2+ meters) can do well enough. Don't connect one supply to the other one, then one set of cables from it to the load; connect each supply to the load through its own cables, and make those cables the same for each supply. The accuracy of the current sharing will depend on how precisely the output voltages and the cables (or resistors) are matched.
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Sure, this all makes sense. But what I have seen (could be because i didn't fully connect it right or something) is, that one channel (primary) hit current limit driving led and other channel did nothing to output any current (even sink 10-20mA from the first one)