BQ24161B_15 Datasheet, PDF (17/52 Pages) Texas Instruments – bq2416xx 2.5A, Dual-Input, Single-Cell Switched-Mode Li-Ion Battery Charger with Power Path Management and I2C Interface

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bq24160, bq24160A, bq24161
bq24161B, bq24163, bq24168
SLUSAO0F – NOVEMBER 2011 – REVISED JULY 2014
Feature Description (continued)
When the CE bit is a 0 and a valid source is connected to IN or USB, the buck converter starts up using soft-
start. A charge cycle is initiated 64ms after the buck converter iniates startup. When V_BAT is high enough that
V_SYS > V_SYS(REG), the battery FET is turned on and the SYS output is connected to BAT. If the SYS voltage falls
to V_SYS(REG), it is regulated to that point to maintain the system output even with a deeply discharged or absent
battery. In this mode, the SYS output voltage is regulated by the buck converter and the battery FET linearly
regulates the charge current into the battery. The current from the supply is shared between charging the battery
and powering the system load at SYS. The dynamic power-path management (DPPM) circuitry of the bq2416xx
monitors the current limits continuously, and if the SYS voltage falls to the V_MINSYS voltage, it adjusts charge
current to maintain the minimum system voltage and supply the load on SYS. If the charge current is reduced to
zero and the load increases further, the bq2416xx enters battery-supplement mode. During supplement mode,
the battery FET is turned on and the battery supplements the system load.
When an input is connected with no battery attached and termination enabled, the startup process proceeds as
normal until the termination deglitch times out. After this, the bq2416xx enters battery detection and waits for a
battery to be connected. Once a battery is connected and passes battery detection, a new charge cycle begins.
Once the battery is applied, the HZMODE bit or CD pin must be toggled before writing the BATREG to a higher
voltage and beginning a new charge cycle. Failure to do this can result in SYS unexpectedly regulating to 15%
above V_BATREG.
2000 mA
1800 mA
I_SYS
800 mA
0 mA
1500 mA
I_{IN ~850 mA}
0 mA
1A
I_BAT
0 mA
-200 mA
V_SYS(REG)
V_MINSYS
V_OUT
~3.1V
DPPM loop active
Supplement
Mode
Figure 11. Example DPPM Response (V_Supply=5V, V_BAT = 3.1V, 1.5A Input Current Limit)
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