We are working on a family of products that will
* charger input voltage is 5V (USB OTG type charger)
* potentially use both 4.3 and 4.2V Li-Ion and Li-Poly batteries.
* We would like to charge at 1.5A.
* would like power path management so that we can run system with dead battery, and the battery gets all leftover current for charging.
* system output voltage is 4.5V max
* would like to be able to handle lower input voltages as described (http://bec-systems.com/site/800/how-do-modern-usb-chargers-work)
We have looked at several chargers:
* good: charge voltage is adjustable
* bad: does not have power path management, so it is difficult to run the system 50-450mA load, and charge battery with leftover current.
* good: power path stuff is nice: The DPPM control tries to reach a steady-state condition where the system gets its needed current and the battery is charged with the remaining current.
* bad: only supports 4.2 and 4.36V, which probably won't work with Sanyo UR16650ZT cells (4.3V)