Lithium-ion batteries have emerged as a common energy-storage
device in many energy-harvesting applications. For engineers,
maximizing battery performance and lifecycle requires use of
battery charging circuitry able to account for the specialized
characteristics of Li-ion cells. Engineers can cost-effectively
build in Li-ion-charging functionality using available ICs from
manufacturers including Analog Devices, Diodes Inc., Fairchild
Semiconductor, Fujitsu Semiconductor, Intersil, Linear
Technology, Maxim Integrated, Micrel, Microchip Technology, and
Texas Instruments. Unlike many other battery technologies, Li-
ion cells require a charging profile maintained within a tight
envelope. An undercharged Li-ion battery simply cannot provide
its full rated energy output. On the other hand, charging
circuits cannot afford to push Li-ion battery voltage above
recommended limits or apply charging currents that exceed
manufacturer-recommended levels. In either case, application of
overvoltage or excessive charging curr