Electronics > Power & Renewable Energy

Laptop brick running off DC 300V?

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ocset:
What is the name of the PFC controller on there?
But anyway, it should  work fine....it will just think that its an extremely low frequency mains!!
No PFC controller  "checks for AC"...unless its controlled by a custom micro that does  check for this.

I guess you could increase the speed of the feedback loop of the PFC to make it work a bit better....then again, no point if you dont have highly transient loads.

ejeffrey:

--- Quote from: station240 on May 27, 2021, 01:55:10 pm ---
--- Quote from: elektrinis on May 23, 2021, 02:04:20 pm ---I want to ask if anyone has investigated this - can any laptop brick, and any modern PSU for that, run off DC 300V source instead of AC 230V? Since most of modern PSUs have an initial PFC stage, which is just a rectifier with boost converter, it kinda should? But is there any kind of protection, checking for AC? Anyone know of a "DC-ready" study, where they check how many modern devices will actually run off DC?

--- End quote ---

I've done this experiment with a small 100W PC power supply that has PFC.
Only changes I made (mostly for efficiency) were:
1) Remove the bridge rectifier (-1.2V from 240VAC = 0.5% losses).
2) Remove the AC input common mode chokes (clearly designed for AC mains)
3) Remove the X2 filter capacitor and parallel discharge resistor (again designed for AC frequencies)
4) Add a fat 400V capacitor to the input. (for noise/peak current reasons)
Worked fine on as little as 60V DC.

--- End quote ---

Note that when you unplug this the input jack will be live with 300V and a big capacitor to back it up.  Leave the diode in unless you are hard wiring it or have a connector with no exposed metal.

David Hess:

--- Quote from: ejeffrey on June 12, 2021, 07:29:24 pm ---Note that when you unplug this the input jack will be live with 300V and a big capacitor to back it up.  Leave the diode in unless you are hard wiring it or have a connector with no exposed metal.
--- End quote ---

And the PFC circuit already has a suitably sized input capacitor which will work fine in a DC application.

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