Datasheet

Disabling Temperature Sensing
Temperature sensing can be disabled by placing a 10k
Ω
resistor between TS and BAT- and a 10k
Ω
resistor be-
tween TS and V
CC
. See Figures 8 and 9.
Maximum Time-Out
Maximum Time-Out period (t
MTO)
is programmed from
1 to 24 hours by an R-C network on the TM pin (see Fig
-
ure 10) per the following equation:
tRC
MTO =∗∗500
(5)
where R is in ohms, C is in Farads, and t
MTO
is in hours.
The recommended value for C is 0.1µF.
The MTO timer is reset at the beginning of fast charge.
If the MTO timer expires during the voltage regulation
phase, fast charging terminates and the bq2954 enters
the Charge Complete state. If the conditioning phase
continues for time equal to t
QT
(MTO/4) and the battery
potential does not reach V
MIN
, the bq2954 enters the
fault state and terminates charge. See Table 3. If the
MTO timer expires during the current-regulation phase
(V
BAT
never reaches V
REG
), fast charging is terminated,
and the bq2954 enters the fault state.
11
bq2954
FGbq295404LS.eps
SNS
LPD1
bq2954
7
13
V
CC
12
BAT -
V
SS
R
SNS
RT2
RT1
V
SS
V
CC
TS
8
t
NTC
Thermistor
RT
Low-Side Sense Mode
Figure 8. Low-Side Temperature Sensing
FGbq295404HS.eps
LPD1
bq2954
13
V
CC
12
BAT -
V
SS
RT2
RT1
V
SS
V
CC
TS
SNS
8
7
NTC
Thermistor
R
CSEL
High-Side Sense Mode
Figure 9. High-Side Temperature Sensing
TM
FGbq295405.eps
V
CC
V
SS
bq2954
12
13
1
V
SS
V
CC
C
R
Figure 10. R-C Network/Setting MTO