Linear Technology’s LTC4020 power manager and multi-chemistry battery charger can efficiently transfer power from various scources to a system power-supply rail and battery. The device feature ±0.5% charge voltage regulation and operates across a 4.5- to 55-V input voltage range. Output voltage ranges up to 55 V. Coupled with three selectable termination algorithms, the controller can handle a variety of battery-stack voltages and chemistries. Moreover, a step-up/step-down dc-dc controller enables operation with battery voltages above, below, or equal to the input voltage. A PowerPath topology reduces the voltage range required by downstream system components to that of the expected battery-voltage range, rather than the full extent of the input-voltage source. Instant-on operation ensures system load power with a fully discharged battery. PowerPath also preferentially provides power to the system load when input power is limited. There are three pin-selectable charging profiles: a constant-current/constant-voltage (CC/CV) charge characteristic with C/10 or timed termination for lithium-based battery systems (Li-ion, Li-polymer, and LiFePO4); constant-current (CC) characteristic with timed termination for charging supercapacitors or trickle-charging nickel-based batteries; and a four-step, three-stage lead-acid charge profile for lead-acid batteries. Packaging is a 38-pin, 5- by 7- by 0.75-mm QFN.