Datasheet

LTC1760
30
1760fa
Power Reporting for Batteries Being Calibrated
AC_PRESENT CALIBRATE_BAT2 CALIBRATE_BAT1 POWERED_BY_BAT(4:1)
1 0 0 0000b
1 1 1 0001b
1 1 0 0010b
*States not shown are not allowed
Power Reporting as a Function of Battery Presence
AC_PRESENT PRESENT_BAT2 PRESENT_BAT1 POWERED_BY_BAT(4:1)
1 X X 0000b
0 0 0 0000b
0 0 1 0001b
0 1 0 0010b
0 1 1 0011b
Power Reporting with AC_PRESENT Low and both Batteries
Present, as a Function of Power Alarms.
AC_PRESENT
BATTERY 2
POWER ALARM
(NOTE 1)
BATTERY 1
POWER ALARM
(NOTE 1) POWERED_BY_BAT(4:1)
0 0 0 0011b
0 0 1 0010b
0 1 0 0001b
0 1 1 0011b
1 X X 0000b
Note 1: A power alarm means that ALARM() has returned
TERMINATE_DISCHARGE=1 or FULLY_DISCHARGED_ALARM=1
Power Reporting When
BatterySystemStateCont(POWER_NOT_GOOD) is High
and the LTC1760 has Autonomously Entered 3-Diode Mode
AC_PRESENT PRESENT_BAT2 PRESENT_BAT1 POWERED_BY_BAT(4:1)
0 0 0 0000b
0 0 1 0001b
0 1 0 0010b
0 1 1 0011b
1 0 0 0000b
1 0 1 0000b
1 1 0 0000b
1 1 1 0000b
OPERATION
2. A battery issues a TERMINATE_DISCHARGE alarm and
AC_PRESENT is low. The LTC1760 will select the other
battery to power the system.
3. A battery issues a TERMINATE_DISCHARGE alarm,
AC_PRESENT is low, and the other battery is not present
or has previously issued an alarm. The LTC1760 will au-
tonomously try to restore power by entering 3-Diode mode.
The 3-Diode mode will ignore TERMINATE_DISCHARGE
and FULLY_DISCHARGED alarms.
4.3 Power-By Algorithm When a Battery is Being
Calibrated
During battery calibration, the battery being calibrated is
the only device powering the system. This will be reflected
in the reported POWER_BY[4:1] bits. See “Section 5” for
more information on battery calibration.
4.4 Power-By Reporting
The following tables illustrate how BatterySystem
State(POWER_BY_BAT[4:1]) interprets PowerPath
conditions.
5 Battery Calibration (Conditioning)
Calibration allows the SMBus Host to fully discharge
a battery for conditioning purposes. The SMBus Host
may determine the battery to be discharged or allow the
LTC1760 to choose based on the batteries’ request to
be conditioned.
5.1 Selecting a Battery to be Calibrated
Option 1) SMBus Host chooses battery to be calibrated
using BatterySystemStateCont(CALIBRATE_BAT[4:1])
Allowed values:
0001b: Set CALIBRATE_BAT1. Only has an effect if Bat-
tery 1 BatteryMode(CONDITION_FLAG) is high . May
not be updated if a calibration is in progress.
0010b: Set CALIBRATE_BAT2. Only has an effect if
Battery 2 BatteryMode(CONDITION_FLAG) is high. May
not be updated if a calibration is in progress.