I have a battery project that i want to charge via USB at around 300mA.
If just using a wall wart then everything is easypeasy, but I want to make it compatible with a computer as well. What I've done in previous project is use an FTDI chip. When the chip enumerates it requests 500mA and then turns on a FET to supply power to the charging IC it can also detect a wall wart and turn on charging. The FTDI was convenient because I also used it for debugging. Using the FTDI would be overkill for this project.

Q: Is there an IC that will enumerate, request full 500mA, turn on a FET and detect a wall wart with no other frills?

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    \$\begingroup\$ Correct capitalisation is an essential requirement for having your questions treated well. That may not be obvious but it's genuinely true. And, following basic presentation rules is part of the social contract involved in getting good answers, believe it or not. But, you should. In most cases little or no capitalisation correlates closely with poor question quality (really). In your case the question is a good one, the wording is good enough and the English OK - suggesting dictation or laziness :-). \$\endgroup\$ – Russell McMahon Jul 23 '15 at 9:42
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    \$\begingroup\$ This SE question discusses this issue. Best answers are either an ATtiny85 or 'just do it'. Surprisingly even quite 'real' peoiple there say 'just do it'. \$\endgroup\$ – Russell McMahon Jul 23 '15 at 9:46
  • \$\begingroup\$ Even Maxim naughtily say 'just do it' \$\endgroup\$ – Russell McMahon Jul 23 '15 at 9:51
  • \$\begingroup\$ A MAX8895 - self eunumerating charger looks like a useful device BUT probably costs more than the FTDI chip. \$\endgroup\$ – Russell McMahon Jul 23 '15 at 9:57
  • \$\begingroup\$ TI too hard / dear. \$\endgroup\$ – Russell McMahon Jul 23 '15 at 9:59

The FTDI FT230X is the best solution. It balances cost and ease of use. It supports both enumeration and it can detect a dedicated charging device. The chip also has provisions for changing the charge current rate depending on what it is connected to. This is all spelled out in the FTDI app note AN_175 http://www.ftdichip.com/Support/Documents/AppNotes/AN_175_Battery%20Charging%20Over%20USB%20with%20FTEX%20Devices.pdf


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