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parallel bipolar supply

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Full Member level 3
May 10, 2010
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Good morning,
I should make a parallel of two +/- 30Vdc bipolar power supplies for the lighting of LEDs that indicate the polarity of the source.
The figure shows the basic scheme in the two working modes with positive and negative polarity.


However, I need an external circuit that can decouple the two generators so that a failure on one does not affect the operation of the other. Furthermore, the polarity change occurs in a non-synchronous way in a time of a few seconds and the load should not switch off during this time.
Unbalanced absorption is not a problem.

I thought of a circuit of the type in the figure


but I have some doubts about the functioning especially in the change of polarity and in the influence of one on the other in case of failure.

I would like to ask you for advice.

Thank you. Let me know.

It seems as though each supply can be reversed, correct? And you wish led's to indicate polarity? Then consider putting 2 led's in anti-parallel, close as possible to each supply. 4 led's are required.

Because 30V is liable to overcome an led's reverse breakdown voltage, add a plain diode in series with each led.
2k to 3k Ohms is reasonable for the safety resistors. (240 ohms results in overmuch Amperes.)

What is the wanted result when one supply is connected "positive" and the other "negative"?
in general they should change polarity together because they receive the same sign change command. however they could be asynchronous of a few seconds in the polarity change.

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