ICS1708ST datasheet(3/16 Pages) ETC

3 / 16 page

ICS1708

SoftStart Conditioning Charge

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 -

∆V condition at the beginning of the

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

SoftStart charge eases batteries into the fast charge stage by gradually increasing the duty cycle of the charge. The gradual increase

alleviates the voltage peak and the -

∆V condition. The duty cycle of the applied current is increased to the fast charge rate, as shown in

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

SoftStart conditioning stage.

Figure 3: Cycle-to-cycle increase of the

SoftStart current pulse widths

Initial Pulse

Width

cycle time

Initial Pulse

Width

Initial Pulse

Width

increment

time

2 x increment

time

ICS1708ST 数据表(PDF) 3 Page - List of Unclassifed Manufacturers