
DS2782: Stand-Alone Fuel Gauge IC 
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When an empty condition is detected (
AEF
 or 
LEARNF
 set), the ACR adjustment is conditional. If 
AEF
 is set and 
LEARNF
 is not, then the Active Empty Point was not detected and the battery is likely below the Active Empty 
capacity of the model. The ACR is set to the Active Empty model value only if it is greater than the Active Empty 
model value. If 
LEARNF
 is set, then the battery is at the Active Empty Point and the ACR is set to the Active Empty 
model value. 
Full Detect 
Full detection occurs when the Voltage (VOLT) readings remain continuously above the VCHG threshold for the 
period between two Average Current (IAVG) readings, where both IAVG readings are below IMIN. The two 
consecutive IAVG readings must also be positive and non-zero. This ensures that removing the battery from the 
charger does not result in a false detection of full. Full Detect sets the Charge to Full (
CHGTF
) bit in the Status 
register. 
Active Empty Point Detect 
Active Empty Point detection occurs when the Voltage register drops below the VAE threshold and the two 
previous Current readings are above IAE. This captures the event of the battery reaching the Active Empty point. 
Note that the two previous Current readings must be negative and greater in magnitude than IAE, that is, a larger 
discharge current than specified by the IAE threshold. Qualifying the Voltage level with the discharge rate ensures 
that the Active Empty point is not detected at loads much lighter than those used to construct the model. Also, 
Active Empty must not be detected when a deep discharge at a very light load is followed by a load greater than 
IAE. Either case would cause a learn cycle on the following charge to full to include part of the Standby capacity in 
the measurement of the Active capacity. Active Empty detection sets the Learn Flag (
LEARNF
) bit in the Status 
register. 
RESULT  REGISTERS 
The DS2782 processes measurement and cell characteristics on a 3.5s interval and yields seven result registers. 
The result registers are sufficient for direct display to the user in most applications. The host system can produce 
customized values for system use, or user display by combining measurement, result and User EEPROM values. 
FULL(T) [ ]:
 The Full capacity of the battery at the present temperature is reported normalized to the 40°C Full 
value. This 15-bit value reflects the cell model Full value at the given temperature. FULL(T) reports values between 
100% and 50% with a resolution of 61ppm (precisely 2
). Though the register format permits values greater than 
100%, the register value is clamped to a maximum value of 100%. 
Active Empty, AE(T) [ ]:
 The Active Empty capacity of the battery at the present temperature is reported 
normalized to the 40°C Full value. This 13-bit value reflects the cell model Active Empty at the given temperature. 
AE(T) reports values between 0% and 49.8% with a resolution of 61ppm (precisely 2
-14
). 
Standby Empty, SE(T) [ ]:
 The Standby Empty capacity of the battery at the present temperature is reported 
normalized to the 40°C Full value. This 13-bit value reflects the cell model Standby Empty value at the current 
temperature. SE(T) reports values between 0% and 49.8% with a resolution of 61ppm (precisely 2
). 
Remaining Active Absolute Capacity (RAAC) [mAh]:
 RAAC reports the capacity available under the current 
temperature conditions at the Active Empty discharge rate (IAE) to the Active Empty point in absolute units of milli-
amp-hours. RAAC is 16 bits. 
Remaining Standby Absolute Capacity (RSAC) [mAh]:
 RSAC reports the capacity available under the current 
temperature conditions at the Standby Empty discharge rate (ISE) to the Standby Empty point capacity in absolute 
units of milli-amp-hours. RSAC is 16 bits. 
Remaining Active Relative Capacity (RARC) [%]:
 RARC reports the capacity available under the current 
temperature conditions at the Active Empty discharge rate (IAE) to the Active Empty point in relative units of 
percent. RARC is 8 bits. 
Remaining Standby Relative Capacity (RSRC) [%]:
 RSRC reports the capacity available under the current 
temperature conditions at the Standby Empty discharge rate (ISE) to the Standby Empty point capacity in relative 
units of percent. RSRC is 8 bits.