ISL78610 Datasheet, PDF (47/98 Pages) Intersil Corporation – Multi-Cell Li-Ion Battery Manager

ISL78610
TABLE 17. BALANCE, SLEEP, WAKE, WATCHDOG TIMER OPERATION
RECEIVE SLEEP COMMAND
OPERATING WATCHDOG
IN
TIMER
ALL BALANCE MODES
WATCHDOG TIMES OUT
ALL BALANCE MODES
RECEIVE WAKE COMMAND
MANUAL BALANCE TIMED BALANCE AUTO BALANCE
Normal
Off
Stop balancing
N/A
N/A
N/A
N/A
Mode
Device enters the Sleep mode.
On
Stop balancing.
Stop balancing.
N/A
N/A
N/A
Device enters the Sleep mode. Device enters the Sleep mode.
Set the WDTM bit when the
Set the WDTM bit.
watchdog timer expires.
Sleep Mode N/A N/A
N/A
Resume Balancing Resume Balancing, Resume Balancing
Balance time
with Auto Balance
reduced by the settings suspended
time spent in Sleep during Sleep
If the watchdog timer is active during manual balance and the
device receives the Sleep command, then balancing stops
immediately and the device goes into Sleep mode, but the WDTM
bit is set when the watchdog timer expires (see Table 17).
The ISL78610 has a watchdog timer function that protects the
battery from excess discharge due to balancing. In the event that
communications is lost the watchdog begins a count down. If the
timeout value is exceeded while the part is in Manual Balance
mode all balancing ceases and the device goes into Sleep mode.
See Table 17.
If the device was performing a manual balance operation prior to
a Sleep command, then receiving a Wake command resumes
balancing.
Timed Balance Mode
In Timed Balance mode, the host microcontroller specifies which
cell is balanced and sets a balance time-out period. Balancing
starts by control of the microcontroller and stops at the end of a
time-out period (or by command from the microcontroller.)
To set up a timed balance operation:
• Set the Balance mode bits to ‘10’ for “Timed”
• Set the Balance Status Pointer to zero
• Set bits in the Balance Status register to program the cells to
be balanced (e.g., to balance cells 7 and 10, set BAL7 and
BAL10 bits to 1)
• Set the balance on time. The balance on time is
programmable in 20 second intervals from 20 seconds to 42.5
minutes using BTM[6:0] bits. See Table 18.
• Enable balancing, either by setting the BEN bit in the Balance
Setup register or by sending a Balance Enable command.
When BEN is reasserted, or when a new Balance Enable
command is received, balancing resumes, using the full time
specified by the BTM[6:0] bits.
• Disable balancing either by resetting the BEN bit or by sending
a Balance Inhibit command. Resetting BEN stops the
balancing functions and resets the timer values.
• When the balance timeout period is met, the End Of Balance
(EOB) bit in the Device Setup register is set and BEN is reset.
TABLE 18. WATCHDOG/BALANCE TIME REGISTER
REGISTER BITS
13 12 11 10 9 8 7
BTM6 BTM5 BTM4 BTM3 BTM2 BTM1 BTM0
BALANCE TIME
(MINUTES)
0000000
Disabled
0000001
0.33
0000010
0.67
0000011
1.00
•••
-
1111101
41.67
1111110
42.00
1111111
42.33
Timed Balance mode cannot operate while the ISL78610 is in
Sleep mode. If the watchdog timer is off and the Sleep command
is received during Manual balance, then balancing stops
immediately and the device goes into Sleep mode.
If the watchdog timer is active during Timed balance and the
device receives the Sleep command, then balancing stops
immediately and the device goes into Sleep mode, but the WDTM
bit is set when the watchdog timer expires (see Table 17).
If the watchdog timeout value is exceeded while the part is in
Manual Balance mode all balancing ceases and the device goes
into Sleep mode (see Table 17).
If the device was performing a Timed balance operation prior to a
Sleep command, then receiving a Wake command resumes
balancing. However, the balance timer continues during the
Sleep mode, so if the Balance timer expires before a Wake
command, then Balance will not resume until the host
microcontroller starts another balance cycle.
Auto Balance Mode
In Auto Balance mode, the host microcontroller specifies an
amount of charge to be removed from each cell to be balanced.
Balancing starts by control of the microcontroller and stops when
all cells have had the specified charge removed (or by command
from the microcontroller.)
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FN8830.1
June 16, 2016