Datasheet LTC4110 (Analog Devices) - 9

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