BQ24262_15 Datasheet, PDF (16/56 Pages) Texas Instruments – bq2426x 3-A, 30-V, Host-Controlled Single-Input, Single-Cell Switched-Mode Li-Ion Battery Charger With Power-Path Management and USB-OTG Support

Not Recommended for New Designs : bq24260, bq24261
bq24260, bq24261, bq24261M, bq24262
SLUSBU4D – DECEMBER 2013 – REVISED APRIL 2015
www.ti.com
9.3 Feature Description
The bq24260/1/1M/2 is a highly integrated single-cell Li-Ion battery charger and system power path management
device that supports operation from either a USB port or wall adapter supply. The power path feature allows the
bq24260/1/1M/2 to power the system from a high efficiency DC-DC converter while simultaneously and
independently charging the battery. The power path also permits the battery to supplement the system current
requirements when the adapter cannot. Many features are programmable using the I²C interface. To support
USB OTG applications, the bq24260/1/1M/2 is configurable to boost the battery voltage to 5 V and supply up to 1
A at the input. The battery is charged with three phases: precharge, constant current and constant voltage.
Thermal regulation prevents the die temperature from exceeding 125°C. Additionally, a JEITA compatible battery
pack thermistor monitoring input (TS) is included to prevent the battery from charging outside of its safe
temperature range.
Device Functional Modes explains these features in detail.
9.4 Device Functional Modes
9.4.1 High Impedance Mode
High Impedance mode (Hi-Z mode) is the low quiescent current state for the bq24260/1/1M/2. During Hi-Z mode,
the buck converter is off, and the battery FET and BGATE are on. SYS is powered by BAT. The bq24260/1/1M/2
is in Hi-Z mode when V_IN < V_UVLO, the HZ_MODE bit in the I²C is '1' or the CD terminal is driven high. Hi-Z mode
resets the safety timer.
The bq24260/1/1M/2 contains a CD input that is used to disable the IC and place the bq24260/1/1M/2 into high-
impedance mode. Drive CD low to enable the bq24260/1/1M/2 and enter normal operation. Drive CD high to
disable charge and place the bq24260/1/1M/2 into high-impedance mode. CD is internally pulled down to PGND
with a 100-kΩ resistor. When exiting Hi-Z mode, charging resumes in approximately 110 ms.
9.4.2 Battery Only Connected
When the battery is connected with no input source, the battery FET is turned on. After the battery rises above
V_BATUVLO and the deglitch time, t_DGL(BAT), the SYS output starts to rise. In this mode, the current is not regulated;
however, there is a short-circuit current limit. If the short-circuit limit (I_LIM(DISCHG)) is reached for the deglitch time
(t_DGL(SC)), the battery FET is turned off for the recovery time (t_REC(SC)). After the recovery time, the battery FET is
turned on to test and see if the short has been removed. If it has not, the FET turns off and the process repeats
until the short is removed. This process protects the internal FET from overcurrent. If an external FET is used
for discharge, the body diode prevents the load on SYS from being disconnected from the battery and t_DGL(BAT) is
not applicable.
9.4.3 Input Connected
9.4.3.1 Input Voltage Protection in Charge Mode
9.4.3.1.1 Sleep Mode
The bq24260/1/1M/2 enters the low-power sleep mode if the voltage on V_IN falls below sleep-mode entry
threshold, V_BAT+V_SLP, and V_IN is higher than the undervoltage lockout threshold, V_UVLO. In sleep mode, the input
is isolated from the battery. This feature prevents draining the battery during the absence of V_IN. When V_IN <
V_BAT+ V_SLP, the bq24260/1/1M/2 turns off the PWM converter, turns the battery FET and BGATE on, sends a
single 128-μs pulse on the STAT and INT outputs and the STATx and FAULT_x bits of the status registers are
updated in the I²C. Once V_IN > V_BAT+ V_SLP, the STATx bits are cleared and the device initiates a new charge
cycle. The FAULT_x bits are not cleared until they are read in the I²C and the sleep condition no longer exists.
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