Datasheet

bq24160, bq24160A
bq24161, bq24161B
bq24163, bq24168
www.ti.com SLUSAO0E –NOVEMBER 2011–REVISED NOVEMBER 2013
Once the battery is charged enough so that the system voltage begins to rise above V
SYS(REG)
, the battery FET is
turned on fully and the battery is charged with the full programmed charge current set by the I
2
C interface,
I
CHARGE
. The slew rate for the fast-charge current is controlled to minimize current and voltage overshoot during
transients. The charge current is regulated to I
CHARGE
until the battery is charged to the regulation voltage. Once
the battery voltage is close to the regulation voltage, V
BATREG
, the charge current is tapered down as shown in
Figure 22 while the SYS output remains connected to the battery. The voltage-regulation feedback occurs by
monitoring the battery-pack voltage between the BAT and PGND pins. The bq2416x is a fixed single-cell voltage
version, with adjustable regulation voltage (3.5V to 4.44V), programmed using the I
2
C interface.
The bq2416x monitors the charging current during the voltage-regulation phase. Once the termination threshold,
I
TERM
, is detected and the battery voltage is above the recharge threshold, the bq2416x terminates charge, turns
off the battery charging FET and enters battery detection. The system output is regulated to the V
SYS(REG)
and
supports the full current available from the input and the battery supplement mode is available. (See the Dynamic
Power Path Management section for more details.) The termination current level is programmable. To disable the
charge current termination, the host sets the charge termination bit (TE) of charge control register to 0, refer to
I
2
C section for details.
A new charge cycle is initiated when one of the following conditions is detected:
1. The battery voltage falls below the V
BATREG
-V
RCH
threshold.
2. V
SUPPLY
toggle
3. CE bit toggle or RESET bit is set
4. HI-Z bit toggle
Battery Detection
When termination conditions are met, a battery detection cycle is started. During battery detection, I
DETECT
is
pulled from V
BAT
for t
DETECT
to verify there is a battery. If the battery voltage remains above V
DETECT
for the full
duration of t
DETECT
, a battery is determined to present and the IC enters “Charge Done”. If V
BAT
falls below
V
DETECT
, a “Battery Not Present” fault is signaled and battery detection continues. The next cycle of battery
detection, the bq2416x turns on I
BATSHORT
for t
DETECT
. If V
BAT
rises to V
DETECT
, the current source is turned offand
after t
DETECT
, the battery detection continues through another current sink cycle. Battery detection continues
until charge is disabled or a battery is detected. Once a battery is detected, the fault status clears and a new
charge cycle begins. Battery detection is not run when termination is disabled.
Dynamic Power Path Management (DPPM)
The bq2416x features a SYS output that powers the external system load connected to the battery. This output is
active whenever a source is connected to IN, USB or BAT. The following sections discuss the behavior of SYS
with a source connected to the supply or a battery source only.
Input Source Connected
When a valid input source is connected, the buck converter turns on to power the load on SYS. The STAT/INT
pin outputs a 128µs interrupt pulse to alert the host that an input has been connected. The FAULT bits indicate a
normal condition, and the Supply Status register indicates that a new supply is connected. The CE bit (bit 1) in
the control register (0x02) indicates whether a charge cycle is initiated. By default, the bq2416x (CE=0) enables
a charge cycle when a valid input source is connected. When the CE bit is '1' and a valid input source is
connected, the battery FET is turned off and the SYS output is regulated to the V
SYS(REG)
programmed by the
V
BATREG
threshold in the I
2
C register. A charge cycle is initiated when the CE bit is written to a 0 value (cleared).
When the CE bit is a 0 and a valid source is connected to IN or USB, the buck converter starts up and a charge
cycle is initiated. 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-
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