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Old 10-21-2021, 12:21 PM   #6
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Default Re: AC / DC ADAPTER upgrade?

Originally Posted by bohaboha View Post
Hi Thanks tester272001 and momaka. so if i have an adapter that has higher curent or 2amps with lower voltage it would be easier to increase the voltage instead? Is it right?
Maybe, maybe not.
As eccerr0r pointed out above, you can tweak the voltage a little bit, but don't expect to go too far beyond what it was designed for.

Depending on the topology of the adapter, I think 10-15% would be a realistic voltage tweaking limit for continuous-mode topology adapters (ones with an output inductor), and possibly 20-30% with flyback/ discontinuous topology (no output inductor), provided the manufacturer left enough headroom in the latter.

Of course, always consider this: you cannot increase the voltage or the current too much, because the total power output equals voltage times current. Again, the primary side is usually power-limited. Therefore, like eccerr0r pointed out in his example, don't expect to turn something like a 24V 2 Amp adapter into a 36V 2 Amp adapter. Essentially, that's trying to turn a 48-Watt (2 Amps @ 24V) power adapter into a 72 Watt power adapter (2 Amps @ 36V). In some rare cases, if the transformer and the primary switching device(s) can handle it, and if you make proper modifications on the primary side to raise the power limit... maybe you might be able to do that. But again, there are a lot of factors involved here, so it's not a simple question. Generally speaking, though, modifying a flyback / discontinuous topology power supply/ adapter is easier to get higher voltages out, especially if the adapter doesn't have APFC circuit and is rated to accept full range input (95 to 240V AC.) With such adapters, if you run it solely on 220/230/240V AC, you may be able to get that higher voltage output or a good deal above what the adapter is rated for.

Last edited by momaka; 10-21-2021 at 12:26 PM..
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