Input power + battery management

[mslaffin]

Requirements

• Accept power from several inputs
  • USB, 12V wall adapter, Li-ion battery
  • Battery probably something standard (4.2V?)
• Outputs regulated system power
• Indicate battery charge status, output supply good
• configurable to the selected battery

Some features I think are cool

• reporting state of charge, faults, temp, etc.
• integrated buck converters
• fancy charging algos
• efficiency

Here's a few options:

MAX8903 – Basic features shared with many parts, seems like it would work. Doesn’t require external FETs/diodes

LTC4089-3 – more configurable and could also work. More part selection. Maybe overkill.

BQ24180 - Also integrated power FETs, I2C interface

Some relevant things that need to be determined:

• [ ] #5
• [ ] #4
  • charge current
  • float voltage