
EEPROM Programming
The following sections describes the function of each
EEPROM location and how thedata is tobestored.
Fundamental Parameters
Sense Resistor Value
Two factors are used to scale the current related mea-
surements. The 16-bit
 ADC Sense Resistor Gain
 value
in E E 0x68–0x69 scales Current() to mA.
ADC Sense Resistor Gain
 from its nominal value pro-
vides a method to calibrate the current readings for sys-
tem errors and the sense resistor value (R
S
) . The nomi-
nal valueis set by
Adjusting
ADC SenseResistor Gain
625
(Rs)
(4)
The 16-bit
 VFC Sense Resistor Gain
 in EE 0x6a–0x6b
scales each VFC interrupt to mAh.
 VFC Sense Resistor
Gain
 is based on the resistance of the series sense resis-
tor. The following formula computes a nominal or start-
ing value for
 VFC SenseResistor Gain
 from the sense re-
sistor value.
VFC SenseResistor Gain
409.6
(Rs)
(5)
Sense resistor values are limited to the range of 0.00916
to0.100
.
Digital Filter
The desired digital filter threshold, VDF (
μ
V), is set by
calculating thevaluestored in
 Digital Filter
 EE 0x52.
Digital Filter
2250
VDF
(6)
Cell Characteristics
Battery Pack Capacity and Voltage
Pack capacity is programmed in mAh units to
 Pack Ca-
pacity
 in EE 0x3a–0x3b and
 Last Measured Discharge
in
EE 0x38–0x39. In mAh mode, the bq2060 copies
 Pack
Capacity
 to DesignCapacity(). In mWh mode, the bq2060
multiplies
 Pack C apacity
 by
 Design Voltage
 E E
0x12–0x13 to calculate DesignCapacity() scaled to
10mWh.
 Design Voltage
is stored in mV.
Last Measured Discharge
 is modified over the course of
pack usage to reflect cell aging under the particular use
conditions.
The bq2060 updates
 Last Measured Dis-
charge
 in mAh after a capacity learning cycle. The
bq2060 uses the
 Last Measured Discharge
 value to cal-
culateFullChargeCapacity() in mAh or 10mWh mode.
EDV Thresholds and Near Full Percentage
The bq2060 uses three pack voltage thresholds to pro-
vide voltage-based warnings of low battery capacity.
The bq2060 uses the values stored in EEPROM for the
EDV0, EDV1, and EDV2 values or calculates the three
thresholds from a base value and the temperature, ca-
pacity, and rate adjustment factors stored in EEPROM.
If EDV compensation is disabled then EDV0, EDV1, and
EDV2 are stored directly in mV in EE 0x72–0x73, EE
0x74–0x75, and EE 0x78–0x79, respectively.
For capacity correction at E DV2,
 Battery Low %
 E E
0x54 can be set at a desired state-of-charge,
STATEOFCHARGE%, in the range of 5 to 20%. Typical
values for STATEOFCHARGE% are 7–12% representing
7 –12% capacity.
Battery Low %
 = STATEOFCHARGE%
 
 2.56
(7)
The bq2060 updates FCC if a qualified discharge occurs
from a near-full threshold to E DV 2. T he desired
near-full threshold window, NFW (mAh), is programmed
in
 Near Full
 in EE 0x55.
Near Full
 =NFW
2
(8)
EDV Discharge Rate and Temperature
Compensation
If EDV compensation is enabled, the bq2060 calculates
battery voltage to determine EDV0, EDV1, EDV2 as a
function of EDV, battery capacity, temperature, and dis-
charge load The general equation for EDV0, EDV1, and
EDV2 calculation is
(9)
EDV0,1,2
 =
 EMF
 
 F
BL
 - |
I
LOAD
|
 
 R0
 
 F
TZ
 F
CY
where
EMF is a no-load battery voltage that is higher than
the highest EDV threshold that is computed. EMF is
programmed in mV in
 EMF/ EDV1
 EE 0x74–0x75.
I
LOAD
is thecurrent dischargeload.
F
BL
 is the factor that adjusts the EDV voltage for bat-
tery capacity and temperature to match the no-load
characteristics of thebattery.
F
BL
 = f ( C0, C + C1, T )
(10)
where
32
bq2060