3 ms·

Thanks for the previous work. I was most interested in your prose about the old, recalled Apple charger, where design suggested to you someone at Apple was told

Thanks for the previous work. I was most interested in your prose about the old, recalled Apple charger, where design suggested to you someone at Apple was told ~“be sure these never can come out again.” Most of the action in chargers right now is in 30 watt USB-C. Everyone wants the fasted charge possible. New iPhones can apparently consume 22 watts plus (via usb-c to lightning and macs and iPads (I believe) can pull the full 30 over an appropriate usb-c. As a result, when shopping for USB-C chargers, or power strips containing USB-C, I study the supply carefully to make sure they provide this or if not I’ll be happy enough consuming a standard wall plug with a 30W adapter. These adapters seem to have shrunk in the past two years due to GaN, or Galium Nitride instead of silicon. (I have not read what this means exactly but it is in the marketing copy) One of the bigger electronics accessory names was the first, but now you see no-name brands offering GaN as well. To my knowledge, Apple has not introduced GaN-based power adapters but I could be wrong. Regardless, it would be very interesting to read a study of yours of 30W chargers in this class. For example, this no name brand is selling two for $20, a very low price point: https://www.amazon.com/dp/B098J6LN4Q/ https://www.amazon.com/dp/B098J6LN4Q/ Versus Anker and the other big names which have similar, higher priced versions. I’m presuming the cheap one linked above is likely to set my home on fire. But maybe not? You would be the one to speculate. I’d be happy to fund a portion of the purchases needed for such an article. My email is in my profile.

londons_explore 5y ago
GaN is a type of MOSFET, which is the high power transistor at the core of all modern power supplies. By choosing GaN, the MOSFET can be switched quicker without wasting too much energy as heat. That in turn means all other components (capacitors, inductors) can be made smaller in the same ratio. The end result is modern GaN technologies allow someone to make a 30 watt power supply in the same physical space that a 5 watt power supply from 2005 took.
- baybal2 5y ago
  GaN-FET is not necessarily a MOS-FET strictly speaking. > By choosing GaN, the MOSFET can be switched quicker without wasting too much energy as heat. That in turn means all other components (capacitors, inductors) can be made smaller in the same ratio. Faster switching frequency of the whole circuit is not necessarily an attribute of the material. There are silicon ICs with high switching frequencies for things like powering CPUs, and GPUs. They are of course physically bigger, and a bit less efficient. What GaN switches put on the table is having a single transistor being able to do this, and thus allowing much simpler circuits, basically a drop in replacement for existing silicon devices.
- amelius 5y ago
  GaN is also the technology which enables class-D amplifiers, by the way (where you need fast switching and large output power as well).

londons_explore 5y ago

GaN is a type of MOSFET, which is the high power transistor at the core of all modern power supplies. By choosing GaN, the MOSFET can be switched quicker without wasting too much energy as heat. That in turn means all other components (capacitors, inductors) can be made smaller in the same ratio. The end result is modern GaN technologies allow someone to make a 30 watt power supply in the same physical space that a 5 watt power supply from 2005 took.

baybal2 5y ago
GaN-FET is not necessarily a MOS-FET strictly speaking. > By choosing GaN, the MOSFET can be switched quicker without wasting too much energy as heat. That in turn means all other components (capacitors, inductors) can be made smaller in the same ratio. Faster switching frequency of the whole circuit is not necessarily an attribute of the material. There are silicon ICs with high switching frequencies for things like powering CPUs, and GPUs. They are of course physically bigger, and a bit less efficient. What GaN switches put on the table is having a single transistor being able to do this, and thus allowing much simpler circuits, basically a drop in replacement for existing silicon devices.
amelius 5y ago
GaN is also the technology which enables class-D amplifiers, by the way (where you need fast switching and large output power as well).