Texas Instruments Evaluation Module for BQ76925 Analog Front End for 3 to 6 Series Lithium-Ion Cells BQ76925EVM BQ76925EVM Datenbogen
Produktcode
BQ76925EVM
1317
VCOUT
4.018
-
æ
ö
ç
÷
è
ø
(
)
V REF
VCOUT
VC6
GC
+ VC6_OFFSET_CORR
0.001
1 + VC6_GAIN_CORR
0.001
G
æ
ö
´
´
´
´
ç
÷
è
ø
(
)
V REF
VCOUT
VC5
GC
+ VC5_OFFSET_CORR
0.001
1 + VC5_GAIN_CORR
0.001
G
æ
ö
´
´
´
´
ç
÷
è
ø
(
)
V REF
VCOUT
VC4
GC
+ VC4_OFFSET_CORR
0.001
1 + VC4_GAIN_CORR
0.001
G
æ
ö
´
´
´
´
ç
÷
è
ø
(
)
V REF
VCOUT
VC3
GC
+ VC3_OFFSET_CORR
0.001
1 + VC3_GAIN_CORR
0.001
G
æ
ö
´
´
´
´
ç
÷
è
ø
(
)
V REF
VCOUT
VC2
GC
+ VC2_OFFSET_CORR
0.001
1 + VC2_GAIN_CORR
0.001
G
æ
ö
´
´
´
´
ç
÷
è
ø
(
)
V REF
VCOUT
VC1
GC
+ VC1_OFFSET_CORR
0.001
1 + VC1_GAIN_CORR
0.001
G
æ
ö
´
´
´
´
ç
÷
è
ø
(
)
VREF
NOMINAL
VREF_OFFSET_CORR
0.001
GC
= 1 + VREF_GAIN_CORR
0.001 +
VREF
´
´
Control Panel Demonstration
12. Delay 40
µ
s, get A/D Counts for VC2.
13. Set VCOUT to Read VC1.
14. Delay 40
14. Delay 40
µ
s, get A/D Counts for VC1.
15. Set VIOUT to read SENSEP (SENSEN for first 5 s of polling).
16. Delay 40
16. Delay 40
µ
s, get A/D Counts for Current.
17. Get A/D Count for THERM.
5.4
VCOUT Readings
VCOUT is a multiplexed output, and up to seven measurement results can be displayed. These millivolt
values are converted to Corrected Measurements on the home screen using the equations in
values are converted to Corrected Measurements on the home screen using the equations in
Table 16. Formulas to Convert VCOUT to either
°
C or mV
Display
Function
Formula to convert VCOUT reading to Cell Voltage or Temperature
Units
Name
Tint
Internal Temp.
°
C
VC6
Cell 6
mV
VC5
Cell 5
mV
VC4
Cell 4
mV
VC3
Cell 3
mV
VC2
Cell 2
mV
VC1
Cell 1
mV
In
, GC
REF
is defined as
(1)
And, G
VCOUT
must be set to 0.6 for the bq76925EVM.
The VCn in
is the millivolt reading shown in the measurement window.
5.5
VIOUT Readings
The VIOUT readings are shown in millivolts and labeled as SENSEP and SENSEN. The SENSEN
readings are done with I_AMP_CAL set to zero and are only taken in the first 5 seconds of polling while
the VIOUT signal level stabilizes. After that time, SENSEN is not updated. The SENSEP readings are
done with I_AMP_CAL set to one thereafter and are done continuously until polling is stopped.
readings are done with I_AMP_CAL set to zero and are only taken in the first 5 seconds of polling while
the VIOUT signal level stabilizes. After that time, SENSEN is not updated. The SENSEP readings are
done with I_AMP_CAL set to one thereafter and are done continuously until polling is stopped.
This measurement technique results in an approximate 5-s delay before the current measurement
stabilizes.
stabilizes.
5.6
Auto Control
Two checkboxes are in the Analog Output Section: Auto Control VCOUT during poll and Auto Control
VIOUT during poll, checked by default. The Auto Control VCOUT During Poll means that all six-cell
voltage inputs are read during polling. The Auto Control VIOUT During Poll means that the current is read
during polling. Note that these checkboxes do not turn the Voltage and Current Amplifier circuits on/off.
VIOUT during poll, checked by default. The Auto Control VCOUT During Poll means that all six-cell
voltage inputs are read during polling. The Auto Control VIOUT During Poll means that the current is read
during polling. Note that these checkboxes do not turn the Voltage and Current Amplifier circuits on/off.
23
SLUU514
–
July 2011
bq76925EVM Evaluation Module
Copyright
©
2011, Texas Instruments Incorporated