Datasheet

4
bq2954
Power-On
Reset
Fault
CHG = 0
Mod = 0 No Action
Latch DSEL/CSEL Inputs
Latch DSEL/CSEL Inputs
FGbg295401.eps
V
CC
"Up"
S01
S02
S03a
S03b
VO LTAG E
REGULATION
CURRENT
REGULATION
CONDITIONING
QUALIFICATION
DONE
Full Charge
Indication
I
SNS
= I
MIN
Temp Not Hot andV
BAT
V
RCHG
1s Hold Time after V
BAT
< V
RCHG
V
BAT
V
RCHG
V
BAT
> V
HCO
Volt Fault
V
BAT
> V
HCO
Volt Fault
V
BAT
> V
HCO
or T = MTO
Volt or Time Fault
T = MTO/25
Time Fault
Temp Not Valid
Temp Valid
Temp Not Valid
Temp Not Valid
Temp Not Valid
V
BAT
< 0.8V Reset Faults
0.8V > V
BAT
> V
HCO
Hold Time
Hold-off Faults
CHG = 0
Battst = 1
I
SNS
= I
MAX:
V
BAT
V
REG
T MTO
Hold Time
CHG = 1
V
BAT
< V
MIN:
I
SNS
= I
MAX/
10
Hold Time
CHG = 1
V
BAT
= V
REG: I
MAX
>
I
SNS
> I
TRMN
T MTO
CHG = 1
V
BAT
> V
RCHG
Hold-off MOD
V
RCHG
< V
BAT
< V
HCO
CHG = 1
V
HCO
< V
BAT
>0.8V
Reset MTO
V
BAT
V
MIN
Reset MTO
V
BAT
= V
REG
T = MTO
I
SNS
= I
TRM
Temp Hot
Battery Removal
Volt or
Time Fault
S04
<
<
<
<
<
>
V
BAT
Voltages:
V
RCHG
= 1.92V 0.5V
V
MIN
= 1.50V 0.5V
V
REG
= 2.05V
V
HCO
= 2.30V
Volt Fault: When V
BAT
> V
HCO
Time Fault: When T = MTO/4 in State S02 or T = MTO in S03a
Hold Time: A V
HCO
Fault or State charge held off for 0.740s to 1.12s
Figure 2. bq2954 Charge Algorithm