4 ms·
Inductors are large, expensive, hot, and unreliable.
by addaon 11mo ago
Inductors are large, expensive, hot, and unreliable.
- bsder 11mo agoNot on modern high-frequency switchers. GaN stuff can be 99%+ efficiency. The frequencies are multiple MHz which shrinks the inductors significantly--sometimes allowing PCB based coils (See Anker 120W teardowns).
- throwaway31131 11mo agoI’m with you, I’m not sure the volume or cost would be less once you factor in capacitors that are high enough quality for the application. The datasheet mentions low profile a lot. That does make sense as one can make a flat, high quality, capacitor. Making a flat high quality inductor is harder and probably more expensive and likely consumes more volume overall. I can imagine some applications where being flat is important, like the back of a panel.
- addaon 11mo agoI'm a huge fan of GaN (see the current front page discussion of LiDAR), but 99% at 500 W at 12 V is hard. 3 milliohm in the inductor will eat up 100% of your budget, without accounting for any switching losses. Like most Linear parts, the LTC7820 is impressive, fits a niche, and is too expensive for most applications -- but when you need it, it's good to know it's there.
- namibj 11mo agoYeah 120W is table stakes. Also Anker wall adapters are insulated that's worse for efficiency. Integer ratios can be done with GaN and class 1 ceramics and stray inductance to charge the GaN drain, so they only experience ZVS (they don't need ZCS). Use a resonant gate drive. Efficiencies around 99.8% are feasible for a doubler/halver based on the "3L FC buck" topology, in the 10~30 MHz range.