STBC02 Datasheet, PDF (33/39 Pages) STMicroelectronics – Automatic power path management

STBC02
8.8
Floating voltage adjustment
Operation description
The STBC02 features a floating voltage adjustment, controlled via SWIRE, allowing the
battery floating voltage (four steps of 50 mV each) to be changed. Due to multiple battery
charging processes and the aging of the battery, the floating voltage of the battery can
change and be reduced. The floating voltage adjustment feature brings the floating voltage
level back to the original nominal value. For safety reasons, the battery voltage overcharge
threshold level (VOCHG) is linked to any floating voltage set. By default this feature is
disabled and moreover, as no state is stored in any memory, every shutdown or shipping
mode event resets the floating voltage at the default value.
8.9
Input overcurrent protection
When the STBC02 is powered off from a valid input voltage source, a current limitation
circuit prevents the input current from increasing in an uncontrolled manner in case of
excessive load. In fact, when VSYS is lower than VILIMSCTH, the input current is limited so to
have a reduced power dissipation. As soon as VSYS increases over VILIMSCTH, the input
current limit value is increased to IINLIM.
8.10
SYS short-circuit protection, LDO current limitation
In battery mode condition, if a short-circuit on the SYS pin happens, the STBC02 is turned
off (no deglitch). This short-circuit protection occurs until the SYS voltage drops below
VSCSYS.
If the LDO output is in a short-circuit condition, the maximum delivered current is limited
to ISC.
8.11
IN overvoltage protection
Should the input voltage source temporarily be VIN>VINOVP (for example due to a poorly
regulated voltage source), then the STBC02 is powered off from the battery, thus any load
connected to SYS is protected.
As soon as the input voltage source goes back within a valid input range
(VUVLO<VIN<VINOVP), the STBC02 is then powered off again from VIN.
8.12
Shutdown mode
A proper SWIRE sequence forces the STBC02 to enter in shutdown mode (low power); the
current sunk from the battery is reduced to less than 50 nA. Both SYS and LDO pins are
not supplied. Normal operating condition is restored either by connecting a valid input
voltage source (VUVLO<VIN<VINOVP) for at least tPW-VIN or by connecting the WAKE-UP pin to
VBAT for at least tPW-WA.
8.13
Watchdog function
The watchdog function can be enabled by SWIRE commands (#27 enabled, #26 disabled).
The watchdog pulse is generated on nRESET pin.
8.14
Thermal shutdown
The STBC02 is fully protected against overheating. During the charging process, if a
TWRN< TSD temperature level is detected, a warning is signaled via the CHG output
(toggling at 14.2 Hz).When in this condition, the programmed IPRE and IFAST are temporary
halved. In case of a further temperature increase (up to TSD) the STBC02 turns off, thus
stopping the charging process. This condition is latched and normal operation can be
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