Sorry to "shock" you, but many handheld (and other) products live beyond the single-digit voltage range of one or two cells. To meet their charging and power-management needs, Linear Technology has introduced the LTC4000, a high-voltage, high-current battery charger which can handle single or multiple stacks. When paired with a point of load (PoL) DC/DC converter, designers will have a complete battery-charger subsystem with inputs and outputs covering 3 to 60V.
The IC includes an "ideal" input diode for low-loss reverse blocking, as well as one in the output path for battery load sharing. It works with various battery chemistries including Li-ion/Polymer, LiFePO4, sealed lead acid (SLA), and nickel hydride, and provides "instant-on" operation despite a heavily discharged battery. It also embodies their proprietary PowerPath topology which preferentially provides power to the system load when input power is limited.
Input and output charge current of the LTC4000 are programmable with ±1% accuracy , while float voltage is accurate to ±0.2% at room temperature and ±1% over the operating range of -40 to +125⁰C. Other features include user-selectable time or C/X current termination; temperature-qualified charging using an external NTC thermistor; automatic recharge, C/10 trickle charge for deeply discharged cells, and bad-battery detection.
Package, price, and availability: The LTC4000 is housed in a 28-lead QFN package (4×5×0.75 mm high) and a 28-lead SSOP package. It is available immediately, priced at $3.95 each (1000 pieces).
For more information, contact Linear Technology or http://www.linear.com/product/LTC4000 .