Design Of A Linear Li-ion Battery Charger With Dynamic Compensation

As portable electrical applicances become more widespread,Li-ion batteries,known as the"heart"of electrical applicances,have gained much more attention than before. Because Li-ion batteries have less weight,smaller size and higher available energy densities than its counterparts in the battery system (such as NiCd,NiMH),they are very suitable for portable electrical applicances. Recent market research reveals that within a few years,Li-ion batteries will be the leading role in the battery market. So it's well worth doing research on the design of the battery chargers.This thesis presents the design of a linear constant-current and constant-voltage battery charger with AutoComp,which is ideal for single Li-ion batteries. It only needs several external components to construct a charging system with the battery charger. It has better than 1% voltage regulation accuracy and the regulation current can be preset with the programmed external resistor. With AutoComp technique,the charger cancel the battery's internal impedance's effect on the battery pack. When the battery's voltage falls bellow the preset recharge threshold,the charger will recharge the battery automatically. When the power is removed from the system,the charger will enter into the sleep mode to gain a low quiescent current.The project is fabricated with the Jazz's BiCMOS BCD05 process,the simulation has shown that the circuit works well and every electrical characteristic meets the specification of the battery charger.