TPS658620 Datasheet, PDF (44/104 Pages) Texas Instruments – Advanced Power Management Unit

TPS658620
Advanced Power Management Unit
SLVS993 – OCTOBER 2009
www.ti.com
The termination detection is internally deglitched by T_DGL(TERM) , 25ms typ. When the charge current drops
below the internal termination threshold for t > T_DGL(TERM), the bit ITERM is set to 1 in the status register
STAT, indicating that termination was detected. ITERM is not affected by the state of TERMOFF control
bit, and it will always report the charge current status. If the termination is enabled (TERMOFF cleared to
0) and termination is detected, the charge cycle ends and the charger is turned off.
CHARGE CURRENT
BELOW TERMINATION
THRESHOLD
NO
YES
YES
YES
YES
YES
Table 3-12. Termination Detection Conditions
DPM OR DPPM OR
THERMAL LOOP
ACTIVE
X
X
X
X
YES
NO
CHARGER MODE
X
OFF
SUSPEND
ON
ON
ON
TERMINATION
DETECTION ENABLED
VIA I²C
X
X
X
NO
YES
YES
TERMINATION
DETECTED,
I(BAT) < I_TERM
NO
NO
NO
NO
NO
YES
The termination detection is latched and it will be reset only when a new charge cycle starts.
The I²C charge status bits in the STAT2 register only indicate DONE state when termination is detected.
3.35 STARTING A NEW CHARGE CYCLE
A new charge cycle will start only if the voltage on the BAT pin falls below the V_(RCH) threshold for a time
longer than T_DGL(RCH), 25ms (typ). A new charge cycle also starts when bit CHGON (CHG1 register)
changes from 0 to 1, or if both AC and USB input power are removed and then one or both are
re-inserted.
After termination is detected a new battery pack insertion detection will not start a new charge cycle, even
if V(BAT) < V_(RCH).
3.36 PRE-CHARGE SAFETY TIMER
The TPS658620 activates an internal safety timer during the battery pre-conditioning phase. The
pre-charge safety timer value is set internally to a fixed value, T_PRECHG, 30 min or 60 min typ, selectable
via I²C. The pre-charge safety timer is disabled when the termination is disabled via I²C (bit
TERMOFF=HI, register CHG1) or when CHTMREN=0 at the I²C register CHG2.
When the charger is in suspend mode the pre-charge safety timer is put on hold (i.e., charge safety timer
is not reset). Normal operation resumes when the charger exits the suspend mode. If V(BAT) does not
reach the internal voltage threshold V_(PRECHG) within the pre-charge timer period a fault condition is
detected and the charger is turned off.
3.37 CHARGE SAFETY TIMER
As a safety mechanism the TPS658620 has a user-selectable timer that measures the total fast charge
time. This timer (charge safety timer) is started at the end of the pre-conditioning period. The following
values are available: 4, 5, 6, 8 hours, selectable via I²C register CHG1 bits CHGTMR. The charge safety
timer is kept in reset mode when CHTMREN=0 at the I²C register CHG2. The charge safety timer is
disabled when TERMOFF=1, in register CHG1. When the charger is in suspend mode, set via I²C register
CHG_CONFIG bit CHGON or set by a pack temperature fault, the charge safety timer is put on hold (i.e.,
charge safety timer is not reset). Normal operation resumes when the charger exits the suspend mode. If
charge termination is not reached within the timer period a fault condition is detected, and the charger is
turned off.
44
DETAILED DESCRIPTION
Submit Documentation Feedback