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Unread 07-04-2013, 09:12
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Ether Ether is offline
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Re: 2 19VDC laptop chargers in series

Quote:
Originally Posted by jason701802 View Post
Isolated switching power supplies (which A/C supplied switching power supplies usually are) can easily be and are regularly hooked in series. The supply will never be sinking current, current will always be going out the (+) terminal and in the (-) terminal. To be safe, reverse biased diodes should be connected to each output so that if one power supply comes on more quickly, it will not apply reverse voltage to the other. See here: http://www.acopian.com/acopianPowerS...y.aspx?nsId=17
In other words, the diodes are there to prevent Supply A from trying to push forward current through Supply B (via the load), when Supply B is not ready.

That's essentially what I said in my earlier post, except I expressed it in terms of Supply B being in the "off" switching state, rather than not having powered up yet.

Can someone explain what aspect of the supply's output circuitry does not like having a voltage applied across it... said voltage being of opposite polarity so that said voltage is attempting to push current through the supply in the forward direction (as would be the case we are discussing with the two supplies in series)?



Last edited by Ether : 07-04-2013 at 10:47. Reason: typo & remove some pronouns for clarity