How does the current limit work?

The current limit is there to protect the Power supply or DC/DC converter to be over loaded producing excess heat. At short circuits the unit would fail. Most of Polyamp DC/DC converters have what is called a rectangular current limit, which means the current is constant at current limit but the output voltage decrease quickly towards zero volt. We set the current limit at +5% above the nominal rated output current. Other types of current limits are fold forward where the current increase at the same time the voltage drops to zero. To be regarded as fold forward the current increase is higher than 15% than nominal as it will affect the dimensioning of feeder cables. A third type is fold-back which decreade the current at the same time decreasing the voltage. Usually the reach a level where the unit is reset in start mode. PM50/PM80 have this kind of current limit.

Last Updated on Monday, 04 January 2010 08:52