3

ICS1708

New, over-discharged, and batteries out of long term storage may exhibit an initial high impedance conditions in response to charging, as

shown in Figure 2. Unless dealt with, this high impedance condition can cause a voltage peak and -

charge cycle that can appear to be the response of an already full battery. To manage this condition, the ICS1708 applies a

SoftStart

conditioning charge.

Figure 2: High impedance voltage spike at the beginning of charge

The

alleviates the voltage peak and the -

Figure 3, by extending the current pulse on every cycle until the pulse is about 1.1 seconds in duration. The initial current pulse is

approximately 200ms. The CMN indicator is a continuous active low during the

Figure 3: Cycle-to-cycle increase of the

Initial Pulse

Width

cycle time

cycle time

cycle time

Initial Pulse

Width

Initial Pulse

Width

increment

time

2 x increment

time