SC908 Datasheet, PDF (22/30 Pages) Semtech Corporation – Power Management IC for Single-Cell Li-Ion Devices

SC908
Applications Information (continued)
The fault modes signaled by FLTB are:
• input over-voltage
• battery NTC temperature out of range
• pre-charge timeout.
• charger-only over-temperature (low OT, post-
termination only)
When any of these conditions occurs the FLTB output goes
low; otherwise it remains high impedance.
The LBATB output is active when the battery voltage is
below the low-battery warning voltage, V_WARN, if the charg-
ing adapter is absent. If CPB and CHRGB outputs are both
active, LBATB indicates when the charger is in precharge
mode. However, LBATB and FLTB active together always
Status Pins
Output State
(on = low)
Table 3 — Status Output State, Charging Adapter Present
Conditions
Adapter
Voltage
(mutually
exclusive)
Battery
Voltage
(mutually
exclusive)
EN_NTC
(mutually
exclusive)
Charging State,
Charging Faults
(Internal signals)
Description
and
Comments
on = open drain output driver is active
off = output is not active
T = listed condition is true
F = listed condition is false
- = don’t care
Blank = mutually exclusive with another condition
on off off off
T
T
T
- - - - _{F VVAD valid, Charger Disable/Reset OR}
F - - F FFF
Charging Done (Die Temperature OK)
on off off on
T
T
T
T
V valid and Low Battery Warning,
VAD
- - - - F Charger Disable/Reset OR
Charge Cycle Pending (about to begin)
on off on off
T
on off on on
T
- -F
T-
V valid,
VAD
F - - F Battery Temperature Fault OR
T
T
Charger Over-Temp Fault (Die Temp > T
)
CHRGR_OT
T
- ---
V_VAD valid, Low Battery Detected, with either
T - ---
Charger Disable/Reset OR
T
F Battery Temperature Fault OR
T
T -FF
Charger Over-Temp Fault OR
F - - - T--
BAT short-to-ground
on on off off
T
on on off on
T
on on on off
T
on on on on
T
- -F
T
- -F
T
- -F
T
T
T
V valid, Pre-termination Charging,
- F F T F ^VAD
Battery Voltage > V_DET
F F T T F ^{VVAD valid, Pre-Charging (trickle charging),}
Battery Voltage > V
DET
V valid, Pre-Charging with Charger Over-Temp
T F T T F ^VAD
Fault, Battery Voltage > V
DET
V valid, Battery Voltage < V
- F - T F ^VAD
DET
Pre-Charging or Pre-Termination Charging
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