"kony" wrote in message

On Sat, 30 Aug 2003 01:59:03 GMT, "Vanguard"
wrote:


If the voltage drops on the input side but you still have the same
power demands on the output side and where you must maintain the
same voltage requirements with the same demand for current, how does
the power supply make up for the deficiency in input voltage?

Switching opwer supplies monitor output voltage. They typically
maintain the same switching frequency but as output drops, there will
be increase in the duration of the "on" cycle to keep the voltage up.
So, whether the input changes or the load changes, or both, the
appropriate duration of on-cycle will change, up until the limits of
the heat dissipation (longer on cycle generates more heat) or voltage
drop below minimal allowed, generally due to inadequate sized
transformer per load applied.


Dave

And that means more current is drawn on the input side, right?

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