Datasheet

DS2781
10 of 31
update the internal offset correction factor. Current measurement and accumulation begins with the second
conversion following a write to the ACR. Writing ACR clears the fractional values in ACRL. The Format of the ACR
register is shown in Figure 8, and the format of ACRL is shown in Figure 9.
In order to preserve the ACR value in case of power loss, the ACR value is backed up to EEPROM. The ACR
value is recovered from EEPROM on power-up. See the Memory Map in Table 2 for specific address location and
backup frequency.
Figure 8. Accumulated Current Register Format, ACR
ACR
R/W & EE
MSB—Address 10h LSB—Address 11h
2
15
2
14
2
13
2
12
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
MSb LSb MSb LSb
Units: 6.25μVh/Rsns
Figure 9. Fractional/Low Accumulated Current Register Format, ACRL
ACRL
Read Only
MSB—Address 12h LSB—Address 13h
2
11
2
10
2
9
2
8
2
7
2
6
2
5
2
4
2
3
2
2
2
1
2
0
X X X X
MSb LSb MSb LSb
“X”: reserved Units:1.526nVHr/R
SNS
ACR LSb
R
SNS
V
SS
- V
SNS
20mΩ 15mΩ 10mΩ 5mΩ
6.25μVh 312.5μAh 416.7μAh 625μAh
1.250mAh
ACR RANGE
R
SNS
V
SS
- V
SNS
20mΩ 15mΩ 10mΩ 5mΩ
409.6mVh 20.48Ah 27.30Ah 40.96Ah 81.92Ah