Controller Charges Lithium Packs

A highly integrated, low-cost controller for charge and end-of-charge control of single- or dual-cell lithium-ion battery packs used in handheld communications and computing products, the LM3620 is rated at 1.2% regulation accuracy to precisely control charge voltage from a current-limited dc-to-dc switching or linear charger. Housed in a SOT23-5, the LM3620 requires only four inexpensive external components to perform the charge-control function. An external PNP or PMOS transistor controlled by the LM3620 provides a charge current to the battery from an external dc power source.