Converter In-Rush Thermistors etc, UPDATE -4
UPDATE on 17 Nov, Update 2 on 22 Nov, Update 3 on 16 Jan 14, Update 4 on 19 Oct 14. --------------- In a recent thread there was mention of how you can wreck your gizmo (in my case a converter) ...
Forum Discussion
Salvo wrote:
The caps are feeding the constant power converter. As soon as input voltage goes up, current demand is reduced. There is no current surge.
On the other hand, during power-up, the converter does not turn on until the cap voltage (I'm guessing) is at least 120V. The requirement for current turn-on surge protection is still there.
Sal
Charging of the input filter caps is totally separate from the converter that is attached to them downstream. You could have *nothing* attached beyond the bridge and caps, and you would still get a large surge at turn on (assuming no inrush protection), just from the filter caps charging. Surely you know this, so I'm not sure why we're debating it. To quote you from your later post:
"Once you turn on the ac power there's a huge inrush of current into the capacitor as it charges up to about 170Vdc. That current needs to be tamed. That's the function of the NTC thermistor."
