Yes it is amazing how much power can come out of those ridiculously small and completely sealed wall warts. I think there is a chance for very efficient very small power amps somewhere, maybe battery operated boom boxes or something. These gan amps have been around quite a while, I wonder where have they been used.
When they switch faster, the transformer can be smaller, and since less current needs to be transferred each time, so can the capacitor(s)!
I bought a 45 watt GaN USB-C power supply when they were being hyped.
I'd never seen a new power supply technology for run of the mill stuff.
They said "Efficient GaN"
I expected efficiency - I don't know why I believed them, I must've been tired.
Anyway, when I got home and plugged it into my knock-off kill-a-watt, wall outlet power metering device...
When charging my Samsung android at the fast, not super-fast rate (the speed you'd get using one of the bundled chargers Samsung
used to include when you spent a grand on a phone...) 17.2-17.3 watts were drawn. With the 10 year old "not advertised as efficient" standard Samsung? 17.6 watts!
Here's the best part... The power factor... Long story short, the power factor the power company likes represent current being drawn proportionally to the voltage, and always being drawn (for 100% f the waveform). Now, if you're drawing 20 watts, but only from the peaks half of the waveform, well, your power factor drops to 0.5, and you get billed for 40 watts!
So the Samsung charger's power factor? 0.78
The GaN charger's power factor? Varies, but at 17.2 watts, it's
below 0.5...
I don't even have to do the math! The 0.46 vs 0.78 power factor DWARFS the 0.4 watt ,........
Calculation time: 17.6/17.2 = 102.3% more watts
17.6W * 1/0.78 = 22.6W (up approx. 28%)
17.2W * 1/0.46 = 37.4W (up approx. 217%)
Samsung charger uses ~2.3% watts with a 28% multiplier for how those watts are used
GaN charger uses +0.0% watts with a 217% multiplier for how those watts are used
The cost to charge the phone with the new, supposedly "efficient" GaN charger is 65.5% higher.
Why?
Because when you take only from the top of the waveform (say the top 50%), it's just as hard to generate that power as if you took that same amount for 100% of the time. What ends up happening is, because a lot of devices operate like this (less and less electronic power supplies as time goes on), the top of the, originally, sine wave, is lopped off, and the part immediately surrounding it, becomes a little wider. This is not enough to cause much of a problem for most stuff. Some transformers buzz more, some fans hum more, some things are a little bit less effic=ieh=n yeah.
Fun fax about Jan