LTC4110EUHF LINER [Linear Technology], LTC4110EUHF Datasheet - Page 18

• Manufacturer Part Number: LTC4110EUHF
• Description: Battery Backup System Manager
• Manufacturer: LINER [Linear Technology]

LTC4110
OPERATION
SMBUS WAKE-UP CHARGE STATE
The battery will be charged with a fi xed “wake-up” current
regardless of previous ChargingCurrent() and Charging-
Voltage() register values during wake-up charging. The cur-
rent is identical to the preconditioning charge current which
is programmed with an external resistor through the I
pin. The wake-up timer has the same period as t
typically 175sec (see t
The following conditions must be met to allow wake-up
charge of the battery:
• The SafetySignal must be RES_COLD, RES_IDEAL, or
• AC must be present. This is qualifi ed by DCDIV > V
• Wake-up charge initiates if a battery does not write
The following conditions will terminate the wake-up charge
state and end charge attempts, unless otherwise noted.
• The t
• The SafetySignal is registering RES_HOT. The state
• The SafetySignal is registering RES_OR. The state
• The LTC4110 will leave the wake-up charge state and
• The AC power is no longer present (DCDIV < V
• The ALARM_INHIBITED becomes set in the
18
RES_UR.
+ V
non-zero values to ChargingCurrent() and Chargin-
Voltage() registers when AC power is applied and a
battery is present or when AC is present and a battery
is subsequently connected.
the SafetySignal is RES_COLD or RES_UR. The state
machine will go to the SMBus OFF state. The CHG_FLT
bit is not set.
machine will go to the SMBus OFF state.
machine will go to the reset state.
go into the SMBus preconditioning charge state if the
ChargingCurrent() AND ChargingVoltage() registers
have been written to non-zero values.
DCIN below UVLO). The state machine will go to the
reset state.
ChargerStatus() register. The state machine will go to
the SMBus OFF state.
ACH
TIMEOUT
and DCIN above UVLO.
period is reached (see t
TIMEOUT
).
TIMEOUT
TIMEOUT
) when
AC
PCC
AC
or
,
• CHARGE_INHIBIT is set in the BBuControl() register.
• There is insuffi cient DCIN voltage to charge the battery
• The CAL_START bit in the BBuControl() register is set.
• Writing a zero value to either the ChargingVoltage() or
• RESET_TO_ZERO is set in the BBuControl() register.
SMBUS PRECONDITIONING CHARGE STATE
During the SMBus preconditioning charge state, the charger
will be operating in the preconditioning charge current
limit. The following conditions must be met in order to
allow SMBus preconditioning charge to start:
• The ChargingVoltage() AND ChargingCurrent() registers
• The SafetySignal must be RES_COLD, RES_IDEAL, or
• AC must be present and suffi cient. This is qualifi ed by
The following conditions will affect the SMBus precondi-
tioning charge state as specifi ed below:
•
must be written to non-zero values. The LTC4110 will
not directly report the status of these registers. The
battery needs only write one pair of ChargingVoltage()
and ChargingCurrent() registers to stay in this state. The
t
ing charge state.
RES_UR.
DCDIV > V
Charge is stopped, however, the wake-up timer is not
paused. Clearing CHARGE_INHIBIT will enable the
LTC4110 to resume charging.
as determined by the internal UVLO. This causes the
state machine to enter the reset state and stop all charge
activity. The LTC4110 will resume wake-up charging when
there is suffi cient DCIN voltage to charge the battery.
Charge is stopped and the LTC4110 enters the calibra-
tion state.
ChargingCurrent() register. The state machine will go
to the SMBus OFF state.
Charge is stopped; the SMBus OFF State is entered.
TIMEOUT
The SafetySignal is registering RES_HOT. Charge is
stopped; the SMBus OFF state is entered.
timer is not operational in SMBus precondition-
AC
+ V
ACH
and DCIN > UVLO.
4110fa