Datasheet

0
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
100
1000
10000
I -
SET
W
I -OutputCurrent- A
O
I InternalClampRange
OUT
I Short
Fault
Range
SET
NonRestricted
Operating Area
I Programmed
OUT
min
max
I Clampmin-max
OUT
I Faultmin-max
OUT
Drive
Logic
V
CC
To
ISET2
R1
R2
ToISET2
V
CC
Q1
Q2
Drive
Logic
R1Divider
setto0.9V
Whichisthe
FloatVoltage
OR
bq24090, bq24091
bq24092, bq24093
SLUS968A –JANUARY 2010–REVISED FEBRUARY 2010 www.ti.com
Figure 23. Programmed/Clamped Out Current
PRE_TERM – Pre-Charge and Termination Programmable Threshold
Pre-Term is used to program both the pre-charge current and the termination current threshold. The pre-charge
current level is a factor of two higher than the termination current level. The termination can be set between 5%
and 50% of the programmed output current level set by ISET. If left floating the termination and pre-charge are
set internally at 10/20% respectively. The pre-charge-to-fast-charge, V
lowv
threshold is set to 2.5V.
R
PRE-TERM
= %Term × K
TERM
= %Pre-CHG × K
PRE-CHG
(2) (2)
Where:
%Term is the percent of fast charge current where termination occurs;
%Pre-CHG is the percent of fast charge current that is desired during precharge;
K
TERM
and K
PRE-CHG
are gain factors found in the electrical specifications.
ISET2
Is a 3-state input and programs the Input Current Limit/Regulation Threshold. A low will program a regulated fast
charge current via the ISET resistor and is the maximum allowed input/output current for any ISET2 setting, Float
will program a 100mA Current limit and High will program a 500mA Current limit.
Below are two configurations for driving the 3-state ISET2 pin:
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