BQ25120A Datasheet, PDF (21/67 Pages) Texas Instruments – Low IQ Highly Integrated Battery Charge Management Solution for Wearables and IoT

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VREF
90 % VB
S0
-2 % BAT TAP
-4 % BAT TAP
-6 % BAT TAP
-8 % BAT TAP
-10 % BAT TAP
S1
80 % VB
S2
70 % VB
S3
bq25120A
SLUSD08 – MAY 2017
D
E
C
O
D
E
R
60 % VB
VB = 0. 8 VBAT
Figure 17. Voltage Battery Monitor
9.3.5 Sleep Mode
The device enters the low-power sleep mode if the voltage IN falls below the sleep-mode entry threshold and V_IN
is higher than the undervoltage lockout threshold. In sleep mode, the input is isolated from the connected battery.
This feature prevents draining the battery during the absence of V_IN. When V_IN < V_(BAT) + V_SLP, the device turns
the battery discharge FET on, sends a 128-µs pulse on the INT output, and the FAULT bits of the register are
update over I²C. Once V_IN > V_(BAT) + V_SLP, the device initiates a new charge cycle. The FAULT bits are not
cleared until they are read over I²C and the sleep condition no longer exists. It is not recommended to do a
battery connection or plug in when V_UVLO< VIN < V_BAT + V_SLP as it may cause higher quiescent current to be
drained form the battery.
9.3.6 Input Voltage Based Dynamic Power Management (V_IN(DPM))
During the normal charging process, if the input power source is not able to support the programmed or default
charging current and System load, the supply voltage decreases. Once the supply approaches V_IN(DPM), the input
DPM current and voltage loops will reduce the input current through the blocking FETs, to prevent the further
drop of the supply. The V_IN(DPM) threshold is programmable through the I²C register from 4.2 V to 4.9 V in 100-
mV steps. It can be disabled completely as well. When the device enters this mode, the charge current may be
lower than the set value and the VINDPM_STAT bit is set. If the 2X timer is set, the safety timer is extended
while V_IN(DPM) is active. Additionally, termination is disabled. Note that in a condition where the battery is
connected while V_UVLO<V_IN < V_IN(DPM), the VINDPM loop will prevent the battery from being charged and PMID
will be powered from BAT.
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