DS2780 Maxim Integrated Products, DS2780 Datasheet - Page 10

• Manufacturer Part Number: DS2780
• Description: Stand-Alone Fuel Gauge IC
• Manufacturer: Maxim Integrated Products

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Figure 8. Fractional/Low Accumulated Current Register Format, ACRL
ACCUMULATION BIAS
The Accumulation Bias register (AB) allows an arbitrary bias to be introduced into the current-accumulation
process. The AB can be used to account for currents that do not flow through the sense resistor, estimate currents
too small to measure, estimate battery self-discharge or correct for static offset of the individual DS2780 device.
The AB register allows a user programmed constant positive or negative polarity bias to be included in the current
accumulation process. The user-programmed two’s compliment value, with bit weighting the same as the current
register, is added to the ACR once per current conversion cycle. The AB value is loaded on power-up from
EEPROM memory. The format of the AB register is shown in Figure 9.
Figure 9. Accumulation Bias Register Formats
ACRL
“X”: reserved
MSb
2
11
2
10
MSB—Address 12h
2
±409.6mVh
9
6.25mVh
VSNS
VSNS
VSS -
VSS -
2
8
AB
2
7
312.5mAh
±20.48Ah
“S”: sign bit
MSb
2
20mW
20mW
S
6
2
2
5
6
LSb
ACR RANGE
2
2
4
5
416.7mAh
±27.30Ah
ACR LSb
10 of 27
Address 61h
15mW
15mW
2
4
Units:
MSb
2
R
R
2
3
3
SNS
SNS
±40.96Ah
2
2
625mAh
10mW
10mW
1.5625mV/Rsns
2
2
2
LSB—Address 13h
2
1
1
EE
LSb
DS2780 Stand-Alone Fuel Gauge IC
2
2
0
0
1.250mAh
±81.92Ah
5mW
5mW
X
Units:1.526nVHr/R
X
Read Only
X
LSb
X
SNS