ltc1760 Linear Technology Corporation, ltc1760 Datasheet - Page 28

• Manufacturer Part Number: ltc1760
• Description: Dual Smart Battery System Manager
• Manufacturer: Linear Technology Corporation

OPERATIO
LTC1760
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:
Option 2) SMBus Host allows LTC1760 to choose battery
to be calibrated.
BatterySystemStateCont(CALIBRATE_BAT[4:1]) = 'b0000.
See previous option.
The LTC1760 determines that the battery requires calibra-
tion by reading BatteryMode(CONDITION_FLAG). This
flag is cached in the LTC1760. The LTC1760 sets
BatterySystemStateCont(CALIBRATE_REQUEST) high.
The LTC1760 will always select the battery that is request-
ing calibration. If both batteries are requesting calibration,
the LTC1760 will select Battery 1. If neither battery is
requesting calibration, then calibration cannot occur.
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'b0001: Set CALIBRATE_BAT1. Only has an effect if
Battery 1 BatteryMode(CONDITION_FLAG) is high .
May not be updated if a calibration is in progress.
'b0010: 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.
'b0000: Clears CALIBRATE_BAT1 and
CALIBRATE_BAT2 and allows LTC1760 to chose. Power
on reset default. May not be updated if a calibration is
in progress.
U
5.2 Initiating Calibration of Selected Battery
The SMBus Host initiates a calibration by writing to
BatterySystemStateCont(CALIBRATE). Follow rules of the
previous section to preserve battery intended for calibra-
tion. The SMBus Host must only set the calibration bit
once per calibration.
The LTC1760 will discharge the selected battery as long as
the calibration is in progress (CALIBRATE high). Updates
to the cached BatteryMode(CONDITION_FLAG) will be
inhibited while CALIBRATE is asserted. This means that
discharge of the battery will continue even if the battery
clears the CONDITION_FLAG.
5.3 Terminating Calibration of Selected Battery
Calibration will end when CALIBRATE is cleared. CALI-
BRATE will be cleared when:
The LTC1760 will attempt to initiate a charge cycle after the
discharge cycle is completed.
• AC is removed.
• The battery being calibrated is removed. When the
• BatterySystemStateCont(POWER_NOT_GOOD) is
• The battery sets Alarm Warning
• The battery sets Alarm Warning
• A zero is written to the CALIBRATE bit.
battery being calibrated is removed, the LTC1760
will automatically calibrate the other battery if it is
requesting calibration.
high.
(TERMINATE_DISCHARGE) high.
(FULLY_DISCHARGED) high.
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