LTC4100EGPBF LINER [Linear Technology], LTC4100EGPBF Datasheet - Page 17

• Manufacturer Part Number: LTC4100EGPBF
• Description: Smart Battery Charger Controller
• Manufacturer: LINER [Linear Technology]

OPERATION
9. There is insuffi cient DCIN voltage to charge the battery.
Controlled Charging Algorithm Overview
The following conditions must be met in order to allow
controlled charging to start on the LTC4100:
1. The ChargingVoltage() AND ChargingCurrent() function
2. The SafetySignal must be RES_COLD, RES_IDEAL, or
3. AC must be present. This is qualifi ed by DCDIV >
The following conditions will stop the controlled charging
algorithm and will cause the battery charger controller to
stop charging:
1. The ChargingCurrent() AND ChargingVoltage() functions
2. The SafetySignal is registering RES_OR.
3. The SafetySignal is registering RES_HOT.
4. The AC power is no longer present. (DCDIV < V
5. ALARM_INHIBITED is set in the ChargerStatus()
The LTC4100 will resume wake-up charging when there
is suffi cient DCIN voltage to charge the battery. This
condition will not reset the T
must be written to non-zero values.
RES_UR.
V
have not been written for T
function.
C
ACP
SS
.
R
R
1.13k
R
54.9k
SafetySignal
THA
THB
Figure 4. SafetySignal Decoder Block
THA
THB
16
15
V
V
DD
DD
THA_SELB
THB_SELB
TIMEOUT
TIMEOUT
SafetySignal
CONTROL
LATCH
.
MUX
REF
timer.
HI_REF
LO_REF
RES_OR
RES_COLD
RES_H0T
RES_UR
ACP
+
+
–
–
)
TH_LO
TH_HI
4100 F04
6. INHIBIT_CHARGE is set in the ChargerMode() function.
7. RESET_TO_ZERO is set in the ChargerMode() function.
8. CHGEN pin is pulled low by an external device. The
9. Insuffi cient DCIN voltage to charge the battery. The
10. Writing a zero value to ChargingVoltage() function.
11. Writing a zero value to ChargingCurrent() function.
The SafetySignal Decoder Block
This block measures the resistance of the SafetySignal and
features high noise immunity at critical trip points. The low
power standby mode supports only battery presence SMB
charger reporting requirements when AC is not present.
The SafetySignal decoder is shown in Figure 4. The value
of R
Clearing INHIBIT_CHARGE will cause the LTC4100 to
resume charging using the previous ChargingVoltage()
AND ChargingCurrent() function values.
LTC4100 will resume charging using the previous
ChargingVoltage() AND ChargingCurrent() function
values, if the CHGEN pin is released by the external
device.
LTC4100 will resume charging using the previous
ChargingVoltage() AND ChargingCurrent() function
values, when there is suffi cient DCIN voltage to charge
the battery.
Figure 5. Simplifi ed V
V
THA
LIM
R
VLIM
is 1.13k and R
14
33k
12.5k
12.5k
25k
25k
25k
V
DD
LIM
THB
Circuit Concept (I
+
–
+
–
is 54.9k.
+
–
+
–
AC_PRESENT
ENCODER
LTC4100
LIM
is Similar)
4
V
LIM
17
4100 F05
[3:0]
4100fb