LTC4110
9
4110fb
ACPb (Pin 13):
AC Present Status Digital Output. Open-
Drain N-MOSFET output is asserted low when the main
supply is present as detected by the DCDIV pin and internal
DCIN UVLO.
V
DIS
(Pin 14):
Battery Discharge Voltage Limit During
Backup Program Input. Battery threshold voltage at which
backup mode will terminate by turning off the isolation
P-MOSFET with the BATID pin. Adjustable from external
resistor string biased from V
REF
pin. For default threshold
connect to GND pin.
V
CAL
(Pin 15):
Battery Voltage Limit During Calibra-
tion Program Input.
Battery threshold voltage at which
calibration will terminate. Adjustable from external resistor
string biased from V
REF
pin. For default threshold connect
to GND pin.
V
CHG
(Pin 16):
Battery Float Voltage Program Input. Trims
the fl oat voltage during charging. Programmed from
external resistor string biased from V
REF
pin. Connect to
GND for default fl oat voltage.
V
REF
(Pin 17):
Voltage Reference Output and Timing Pro-
gramming Input. Provides a typical virtual reference of 1.220V
(V
REF
) for an external resistor divider tied between this pin and
GND that programs the V
CHG
, V
CAL
and V
DIS
pin functions.
Total resistance from V
REF
to GND, along with the capacitor
on the timer pin, programs the charge time. Voltage refer-
ence output remains active in all modes except shutdown.
Load current must be between 10μA and 25μA.
TIMER (Pin 18):
Charge Timing Input. A capacitor con-
nected between TIMER and GND along with the resistance
connected from V
REF
to GND programs the charge time
intervals.
TYPE (Pin 19):
Refer to Table 8.
THA (Pin 20):
SafetySignal Force/Sense Pin to Smart
Battery and Force Pin to Lead Acid Battery Thermistor.
See description of operation for more detail. The maxi-
mum allowed combined capacitance on THA, THB and
SafetySignal is 1nF. For lead acid battery applications the
maximum capacitance on the THA pin is 50pF.
THB (Pin 21):
SafetySignal Force/Sense Pin to Smart
Battery and Sense Pin to Lead Acid Battery Thermistor.
See description of operation for more detail. The maxi-
mum allowed combined capacitance on THA, THB and
SafetySignal is 1nF.
I
PCC
(Pin 22):
Battery Preconditioning Charge Current
Program Input. Programs the battery current during
preconditioning or wakeup charging. Programmed from
external resistor to GND.
I
CAL
(Pin 23):
Battery Discharge Current During Calibration
Program Input. Programs the constant discharge current at
the battery during calibration. Programmed from external
resistor to GND.
I
CHG
(Pin 24):
Battery Current During Charge Program Input.
Programs the battery current while constant-current bulk
charging. Programmed from external resistor to GND.
I
TH
(Pin 25):
Control Signal of the Current Mode PWM. AC
compensates control loop. Higher I
TH
voltage corresponds
to higher charging current.
CSP (Pin 26):
Current Sense Positive Input. This pin and
the CSN pin measure voltage across the external current
sense resistor to control battery current during charging
and calibration.
CSN (Pin 27):
Current Sense Negative Input. This pin and
the CSP pin measure voltage across the external current
sense resistor to control battery current during charging
and calibration.
SGND (Pin 28):
Signal Ground Reference Input. This pin
should be Kelvin connected to the fl yback current sense
resistor and to the battery return.
I
SENSE
(Pin 29):
Current Sense Input. Senses current in
the fl yback transformer by monitoring voltage across the
external current sense resistor. This pin should be Kelvin-
connected to the resistor.
SELC (Pin 30):
Refer to Table 8.
PIN FUNCTIONS
