Inside Apple’s USB Power Adapters

If you own an iPhone, you most likely are in possession of Apple’s 5W USB power adapter, a great little contraption that charges your iPhone via a wall outlet using your normal USB cable. From the face of it, it’s a fairly elementary device. It simply takes alternating current from the wall and turns it into five watts of five volt power.

However, according to Ken Shirriff (who recently tore open one of these power adapters), the circuitry is “surprisingly complex and innovative.”

Shirriff conducted an exhaustive analysis of the 5W iPhone charger and posted about it on his blog. He found out some pretty amazing things about Apple’s tiny USB wall charger. For those that are knowledgeable about circuitry and the like, you’ll find Shirriff’s writeup to be both extremely informative and interesting (with circuit diagrams drawn out even), but for those who just want to know why the damn thing costs a whopping $30, Shirriff has this to say:

Apple’s power adapter is clearly a high-quality power supply designed to produce carefully filtered power. Apple has obviously gone to extra effort to reduce EMI interference, probably to keep the charger from interfering with the touchscreen. When I opened the charger up, I expected to find a standard design, but I’ve compared the charger to the Samsung charger and several other high-quality industry designs, and Apple goes beyond these designs in several ways.”

Some of the ways that Apple went above and beyond are apparent when looking at the small details. Apple used “super-strong AC prongs,” as well as a “complex over-temperature / over-voltage shutdown circuit.” Overall, Shirriff says that Apple’s 5W USB power adapter packs an impressive amount of complexity into such a small space.

However, Shirriff notes that even though Apple’s 5W USB power adapter is higher quality than most other USB adapters, that doesn’t mean that the $30 price tag is necessarily worth it. He says that Apple’s USB charger probably only uses about a dollar more on parts than other, less-expensive chargers that cost $6-$10. So essentially, Apple is making a huge profit off of each power adapter that they sell.

Image Credit: Alan Levine