Datasheet

DS2775/DS2776/DS2777/DS2778
2-Cell, Stand-Alone, Li+ Fuel-Gauge IC with
Protector and Optional SHA-1 Authentication
26 ______________________________________________________________________________________
Status Register Format
The Status register contains bits that report the device status. All bits are set internally. The CHGTF, AEF, SEF, and
LEARNF bits are read-only.
Status Register (01h)
Bit 7: Charge-Termination Flag (CHGTF). CHGTF is set to indicate that the average of the voltages on V
IN1
and
V
IN2
and the Average Current register values have persisted above the VCHG and below the IMIN thresholds suffi-
ciently long enough to detect a fully charged condition. CHGTF is cleared when RARC is less than 90%. CHGTF is
read-only.
Bit 6: Active-Empty Flag (AEF). AEF is set to indicate that the battery is at or below the active-empty point. AEF is
set when the average of the voltages on V
IN1
and V
IN2
is less than the VAE threshold. AEF is cleared when RARC is
greater than 5%. AEF is read-only.
Bit 5: Standby-Empty Flag (SEF). SEF is set to indicate RSRC is less than 10%. SEF is cleared when RSRC is
greater than 15%. SEF is read-only.
Bit 4: Learn Flag (LEARNF). LEARNF indicates that the current-charge cycle can be used to learn the battery
capacity. LEARNF is set when the active-empty point is detected. This occurs when the average of the voltages on
V
IN1
and V
IN2
drops below the VAE threshold and the two previous current register values were negative and
greater in magnitude than the IAE threshold. See the
Active-Empty Point Detect section for additional information.
LEARNF is cleared when any of the following occur:
1) Learn cycle completes (CHGTF set).
2) Current register value becomes negative indicating discharge current flow.
3) ACR = 0.
4) ACR value is written or recalled from EEPROM.
5) Sleep mode is entered.
LEARNF is read-only.
Bit 3 to 0: Reserved.
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
CHGTF AEF SEF LEARNF X X X X