bq24901

SLUS527 – DECEMBER 2002

11

www.ti.com

APPLICATION INFORMATION

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.

0

0

300

150

10

20

50

200

250

50

25

75

100

125

225

275

30

40

60

70

515

25

35

45

55

65

75

13

5

11

7

9

13

15

2

4

6

8

10

12

14

tCHG – Time – ms

Step Count

Pre-Charge

Regulator

Reference

Pre-Charge

Fastcharge

Fastcharge

Regulator

Reference

Figure 5. Typical Current Regulation Ramp From/To Pre-Charge/Fastcharge