BQ2040_15 Datasheet, PDF (25/36 Pages) Texas Instruments – Gas Gauge IC With SMBus Interface

Not Recommended For New Designs
bq2040
Table 10. Example Register Contents (Continued)
Description
EEPROM
Address
EEPROM
Hex
Contents
Low High Low High
Byte Byte Byte Byte
Example
Values
Notes
Digital filter
0x4d
96
0.30mV
Used to set the digital magnitude filter as described in
Table 2.
Current integra-
tion gain¹
0x4e
40 0
3.2/0.05
Represents the following: 3.2/sense resistor in ohms.
It is used by the bq2040 to scale the measured voltage
values on the SR pin in mA and mAh. This register
also compensates for variations in the reported sense
resistor value.
Self-discharge rate 0x4f
2d
0.25%
This packed field is the two’s complement of (52.73/x)
where x is the desired self-discharge rate per day (%)
at room temperature.
Voltage gain¹
0x56 0x57 17 07
Voltage gain is packed as two units. For example, (R4
7.09
+ R5)/R4 = 7.09 would be stored as: whole number
stored in 0x57 as 7 and the decimal component stored
in 0x56 as 256 x 0.09 = 23(= 17h).
Reserved
0x58 0x59 00 00
0
Should be programmed to 0.
EDVF charging
current
0x5a 0x5b 64
00
100mA Contains the desired charge current below EDVF.
End of discharge
voltage 1
0x5c 0x5d
20
d1
12000mV
The value programmed is the two’s complement of the
threshold voltage in mV.
End-of-discharge
voltage final
0x5e 0x5f
40
d4
11200mV
The value programmed is the two’s complement of the
threshold voltage in mV.
Full charge
capacity
0x60 0x61 d0 07 2000mA This value sets the initial estimated pack capacity.
∆t step
0x62
0f
20s
The ∆t step for ∆T/∆t termination equals
320 - (byte value ∗ 20).
Hold-off time
0x63
00
320s hold-off The hold-off time is 320 - (byte value ∗ 20).
EEPROM check 2 0x64
b5
181
Must be equal to 0xb5.
Reserved
0x65 0x7f
NA
Not currently used by the bq2040.
Note:
1. Can be adjusted to calibrate the battery pack.
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