Datasheet

bq24190, bq24192
bq24192I, bq24193
SLUSAW5A –JANUARY 2012–REVISED OCTOBER 2012 www.ti.com
Termination when REG02[0] = 1
When REG02[0] is HIGH to reduce the charging current by 80%, the charging current could be less than the
termination current. The charger device termination function should be disabled. When the battery is charged to
fully capacity, the host disables charging through CE pin or REG01[5:4].
Termination when REG05[6] = 1
Usually the STAT bit indicates charging complete when the charging current falls below termination threshold.
Write REG05[6]=1 to enable an early “charge done” indication on STAT pin. The STAT pin goes high when the
charge current reduces below 800mA. The charging cycle is still on-going until the current falls below the
termination threshold.
Charging Safety Timer
The bq24190, bq24192, bq24192I, bq24193 has safety timer to prevent extended charging cycle due to
abnormal battery conditions.
In default mode, the device keeps charging the battery with 5-hour fast charging safety timer regardless of
REG05[2:1] default value. At the end of the 5 hours, the EN_HIZ (REG00[7]) is set to signal the buck converter
stops and the system load is supplied by the battery. The EN_HIZ bit can be cleared to restart the buck
converter.
In host mode, the device keeps charging the battery until the fast charging safety timer expired. The duration of
safety timer can be set by the REG05[2:1] bits (default = 8 hours). At the end of safety timer, the EN_HIZ
(REG00[7]) is cleared to signal the buck converter continues to operation to supply system load.
The safety timer is 1 hour when the battery is below BATLOWV threshold. The user can program fast charge
safety timer through I
2
C (REG05[2:1]). When safety timer expires, the fault register REG09[5:4] goes 11 and an
INT is asserted to the host. The safety timer feature can be disabled via I2C (REG05[3]).
The following actions restart the safety timer:
• At the beginning of a new charging cycle
• Toggle the CE pin HIGH to LOW to HIGH (charge enable)
• Write REG01[5:4] from 00 to 01 (charge enable)
• Write REG05[3] from 0 to 1 (safety timer enable)
• Write REG01[7] to 1 (software reset)
During input voltage/current regulation or thermal regulation, the safety timer counts at half clock rate since the
actual charge current is likely to be below the register setting. For example, if the charger is in input current
regulation (IINDPM) throughout the whole charging cycle, and the safety time is set to 5 hours, the safety timer
will expire in 10 hours. This feature can be disabled by writing 0 to REG07[6].
USB Timer when Charging from USB100mA Source
The total charging time in default mode from USB100mA source is limited by a 45-min max timer. At the end of
the timer, the device stops the converter and goes to HIZ.
Host Mode and Default Mode
The bq24190, bq24192, bq24192I, bq24193 is a host controlled device, but it can operate in default mode
without host management. In default mode, bq24190, bq24192, bq24192I, bq24193 can be used as an
autonomous charger with no host or with host in sleep.
When the charger is in default mode, REG09[7] is HIGH. When the charger is in host mode, REG09[7] is LOW.
After power-on-reset, the device starts in watchdog timer expiration state, or default mode. All the registers are in
the default settings.
Any write command to bq24190, bq24192, bq24192I, bq24193 transitions the device from default mode to host
mode. All the device parameters can be programmed by the host. To keep the device in host mode, the host has
to reset the watchdog timer by writing 1 to REG01[6] before the watchdog timer expires (REG05[5:4]), or disable
watchdog timer by setting REG05[5:4]=11.
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Product Folder Links: bq24190 bq24192 bq24192I bq24193