TPS658621A_1 Datasheet, PDF (44/107 Pages) Texas Instruments – Advanced Power Management Unit

TPS658621A
SLVSA58 – DECEMBER 2009
www.ti.com
When the LDO mode is set, termination is disabled, all safety timers are held in reset, and the battery
discharge switch is disabled. The BAT pin voltage will regulate to V_O(BATREG) when all the following
conditions are true: the charger is enabled (VIN_CHG > V_O(BATREG)) and input power is present (AC or
USB input power detected). Under these conditions the BAT pin voltage will be regulated to the charge
voltage V_O(BATREG) if the charger current loops are not active.
The charger current limit loop will still be enabled, and the current that can be supplied by the BAT pin in
LDO mode will be dependent on the BAT pin voltage, as shown in Table 3-10.
Table 3-10. Battery Charge Current
BAT PIN VOLTAGE
< V_LOWBAT
> V_LOWBAT
BATTERY CHARGE CURRENT
I_O(PRECHG)
I_O(BAT)
In LDO mode, both the thermal loop and DPPM loop are also enabled. These loops, when active, limit the
current available at the BAT pin. The BAT pin voltage will collapse if the charge current available is lower
than the current required to run subsystems connected to the BAT pin.
The battery tracking function is disabled when the thermistor is not detected; the BAT pin will, as a result,
track the SM2 output voltage when V(SM2) is set below V_O(BATREG).
3.32 CHARGER CONTROL LOGIC AND OPERATING MODES
The charger control logic monitors system parameters and control signals to define when the charger is
enabled. The table below lists the charger operating modes. Note that when the charger is set to OFF all
timers are reset. The charge is enabled by setting bit CHGON to 1 in register CHG2.
The timer fault and termination detection events are latched internally to the charger control logic, and
after that the charger is set to OFF. The only way to reset a timer fault and termination detection is to start
a new charge cycle.
Table 3-11. Charger Mode Control
TPS658621A INPUT POWER
MODE
DETECTED
UVLO
NOT UVLO
X
NO
YES
YES
YES
YES
YES
YES
YES
YES
SM2
MODE ⁽¹⁾
X
X
OFF
ON
ON
ON
ON
ON
ON
ON
CHARGER
THSHUT
DETECTED
X
X
X
YES
NO
NO
NO
NO
NO
NO
CHARGE
ENABLED
X
X
X
X
NO
YES
YES
YES
YES
YES
CHARGE
SUSPEND
CMD
X
X
X
X
X
NO
NO
NO
YES
NO
TIMER
FAULT
DETECTED
X
X
X
X
X
NO
YES
X
NO
NO
PACK
TEMP
FAULT
X
X
X
X
X
NO
X
X
X
YES
TERM
DETECTED
X
X
X
X
X
NO
X
YES
NO
NO
(1) When SM2 is not configured as the charger pre-regulator the SM2 mode does not affect the charger mode.
CHARGER
MODE
OFF
OFF
OFF
OFF
OFF
ON
OFF
OFF
SUSPEND
SUSPEND
3.33 CHARGE SUSPEND
The charge may be suspended anytime by setting CHSUSP to 1 in register CHG1 or when the pack
temperature is out of range and I²C control bit TSBYP is 0. This will disable the charger stage and hold
the safety timers at their current count. Normal operation resumes when a temperature fault is not
detected.
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