BQ24901_13 Datasheet, PDF (11/18 Pages) Texas Instruments – OFFLNE APPLICATIONS

bq24901
APPLICATION INFORMATION
SLUS527 – DECEMBER 2002
Current Regulation Ramp-Up and Ramp-Down
Both current regulation loops ramp up and down when transitioning from pre-charge to fast charge, and when
going in and out of fault/suspend mode where the LDO needs to be turned hard on or off. Figure 5 demonstrates
the typical stepping ramp.
300
275
Pre-Charge
250
Fastcharge
225
Pre-Charge
200
Regulator
Reference
150
125
100
75
Fastcharge
Regulator
50
Reference
25
0
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
tCHG – Time – ms
Step Count
Figure 5. Typical Current Regulation Ramp From/To Pre-Charge/Fastcharge
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