The LTC4020 is an advanced high-voltage power manager and multi-chemistry battery charger controller designed to efficiently transfer power from a variety of input sources to a system power supply rail and to charge a battery. The device offers precision charge current regulation, ±0.5% charge voltage regulation and operates across a wide 4.5V to 55V input voltage range. Its output voltage range of up to 55V, charge currents to 20A, and three selectable termination algorithms, makes the LTC4020 usable with a wide variety of battery stack voltages and chemistries. The LTC4020 contains a step-up/step-down DC/DC controller, enabling operation with battery voltages that are above, below, or equal to the input voltage.