I just bought a new USB PSU from AliExpress [1]. I got this to reduce the clutter in my bedroom, I charge my laptop, PineTime, and a few phones at the same time and a single PSU with lots of ports makes it easier. Also I bought a couple of really short USB-C cables as it’s been proven by both real life tests and mathematical modelling that shorter cables get tangled less. This power supply is based on Gallium Nitride (GaN) [2] technology which makes it efficient and cool.

One thing I only learned about after that purchase is the new USB PPS standard (see the USB Wikipedia page for details [3]). The PPS (Programmable Power Supply) standard allows (quoting Wikipedia) “allowing a voltage range of 3.3 to 21 V in 20 mV steps, and a current specified in 50 mA steps, to facilitate constant-voltage and constant-current charging”. What this means in practice (when phones support it which for me will probably be 2029 or something) is that the phone could receive power exactly matching the voltage needed for the battery and not have any voltage conversion inside the phone. Phones are designed to stop charging at a certain temperature, this probably doesn’t concern people in places like Northern Europe but in Australia it can be an issue. Removing the heat dissipation from inefficiencies in voltage change circuitry means the phone will be cooler when charging and can charge at a higher rate.

There is a “Certified USB Fast Charger” logo for chargers which do this, but it seems that at the moment they just include “PPS” in the feature list. So I highly recommend that GaN and PPS be on your feature list for your next USB PSU, but failing that the 240W PSU I bought for $36 was a good deal.

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