Quote:
Originally Posted by MrBungle
If you are charging batteries there’s no reverse protection diode so when the DC source collapses during a mains transient or power failure it’ll blow the pass transistor and driver up. Very common problem with Farnell supplies. The two I’ve had go through had diodes added.
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I've seen it happen on another supply, Glassman 50A SMPSU. This one had an overvoltage protection circuit with a crowbar and was charging a large capacity car battery. All was well until someone knocked out the plug on the back for remote settings, and with this plug out the OVP trip was reduced to 0V and tripped. The crowbar device would have coped with discharging the supplies own caps and the current from the supply itself. It couldn't cope with trying to pull the voltage of the battery down and expired spectacularly. A diode was added in the leads after that.