BQ40Z60_16 Datasheet, PDF (24/47 Pages) Texas Instruments – Programmable Battery Management Unit

bq40z60
SLUSAW3C – DECEMBER 2014 – REVISED JULY 2015
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Feature Description (continued)
9.3.3 Charge Controller Details
The charge controller, under control from the fuel gauge's processor, provides autonomous control over the
charging of the battery pack. The controller uses a 1-MHz buck architecture using external FETs driven by
internal gate drivers. The charge voltage and current can be adjusted via data flash values to account for the
temperature and voltage of the battery cells, allowing for a JEITA type charge profile. The voltage and current
may also be directly written to the charge controller from an external host, allowing for a user-defined charging
profile. The charger runs in Narrow Voltage DC, that is, the output voltage of the charger will only exceed the
battery voltage by a small amount; by contrast, a charger that does not run in Narrow Voltage DC mode will
output the adapter voltage to the system.
The charger is designed to enable the system to continue to run while the battery is charged. If the system
requires more current than the charger is able to provide, the battery supplements the current to the system. The
charger can support an external precharge FET, allowing the VSYS to remain above a minimum voltage needed
for the system to operate.
The charger supports precharge, constant current/constant voltage, and termination, as shown below. The
voltage and current thresholds for precharge and termination are controlled by data flash values. Refer to the
bq40z60 Technical Reference Manual (SLUUA04) for more information.
Pre Constant
Charge Current
Constant
Voltage
Termination
ICHG
IBAT
IPRECHG /
ITERM
0mA
Termination Detect
VPRECHG
Current Loop
Voltage Loop
VSYS
VBAT
V_SYS = V_BAT + I_BAT · (R_BAT+R_SNS)
CHGR
Figure 5. Normal Charge Profile
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