Pow Management IC: Li-Ion 2.8 - 4.2V; Sys Volts: 3.3V

Hi,

I am designing a consumer Li-ion powered system with the following constraints:

1.     The system volts has to be 3.3V
2.     Li-Ion battery charging range is 2.8 - 4.2V
3.     Charging is to be done via a standard USB charger.
4.     All aspects of battery charging - charging profile, safety timers, input current programming etc are expected.
5.     [Desirable] the battery and system is isolated via switch.

I have been searching for "power management ICs" and "Li-ion battery chargers". So far my results have all yielded a battery charger IC only - on battery backup, system volts follow battery volts. I would want an internal buck-boost regulator to provide regulated 3.3V o/p.

A boost regulator will not work since system volts need to be @ 3.3V (and not at 5V)

Thanks!