LTC4015_15 Datasheet, PDF (26/76 Pages) Linear Technology – Multichemistry Buck Battery Charger Controller with Digital Telemetry System

LTC4015
Operation
LiFePO₄ Charging Parameters
Table 7 shows LiFePO₄ charging parameters. For LiFePO₄
programmable, defaults values are shown. Bold parameters
are I²C programmable in LiFePO₄ programmable mode
only. ICHARGE_TARGET and VCHARGE_SETTING values
are at 25°C when JEITA is enabled. Shown in Table 8 are
the LiFePO₄ programmable I²C configurable charging
parameters. Shown in Figure 4 is the LiFePO₄ fixed fast
charge charging profile.
Table 7. LiFePO₄ Charging Parameters
CHARGING
ALGORITHM
ICHARGE_
TARGET
V_ABSORB,
MAX_
ABSORB_
TIME IN
MINUTES
LiFePO₄ Programmable
LiFePO₄ Standard
Charge
LiFePO₄ Fast Charge
32mV/
R_SNSB1
32mV/
R_SNSB1
32mV/
R_SNSB1
No Absorb
Phase
No Absorb
Phase
3.8, 15
V_CHARGE
CV
(PER CELL) TIMER
TERM
3.60¹
Yes
3.60¹
Yes
3.60¹
Yes
MAX CV
TIME
1 Hour
1 Hour
1 Hour
C/x TERM C/x
JEITA MAX CHARGE
THRESH
TIME
No
10%
Y
No
–
Y
No
10%
Y
(Absorb)
18 Hrs
18 Hrs
18 Hrs
1: When JEITA is enabled ICHARGE_TARGET and VCHARGE_SETTING are overridden and controlled by the JEITA temperature qualified charging
algorithm.
Table 8. LiFePO₄ Programmable I²C Configurable Parameters
PROGRAMMABLE MODE
PARAMETER
ICHARGE_TARGET¹
VABSORB_DELTA
RANGE BITS RESOLUTION
1mV to
5 1mV/R_SNSB
32mV/R_SNSB
0V to 0.4V 5
12.5mV
MAX_ABSORB_TIME
VCHARGE_SETTING¹
0 to 65535 16 1 Second
3.4125V to 5
3.8V/Cell
12.5mV
MAX_CV_TIME
0 to 65535 16 1 Second
en_jeita
0,1
1 1 = Enable
en_c_over_x_term
0,1
1 1 = Enable
C_OVER_X_THRESHOLD
MAX_CHARGE_TIME
0mV to
16
32mV/R_SNSB
0 to 65535 16
1.465µV/
R_SNSB
1 Second
LiFePO₄_RECHARGE_THRESHOLD 0 to 4.2V/Cell 16
Notes
192.26µV
1: When JEITA is enabled ICHARGE_TARGET and VCHARGE_SETTING
are overridden and controlled by the JEITA temperature qualified
charging algorithm.
TEXT INDICATES VALUES REPORTED IN REGISTERS:
CHARGER_STATE/CHARGE_STATUS
4.5
ABSORB/CC
4.0
CC_CV/CV
CV TIMER TERMINATION
AFTER ONE HOUR IN
CC_CV/CV PHASE
12
3.5
3.0
9
ABSORB/CV
V_BAT
2.5
I_CHG
2.0
6
1.5
1.0
3
0.5
0
0
0
5 10 15 20 25 30
TIME (min)
4015 F04
Figure 4. LiFePO₄ Fast Charge Charging Profile
4015f
26
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