Datasheet

1317 VCOUT
4.018
-
æ ö
ç ÷
è ø
( )
VREF
VCOUT
VC6 GC + VC6_OFFSET_CORR 0.001
1 + VC6_GAIN_CORR 0.001
G
æ ö
´ ´
´ ´
ç ÷
è ø
( )
VREF
VCOUT
VC5 GC + VC5_OFFSET_CORR 0.001
1 + VC5_GAIN_CORR 0.001
G
æ ö
´ ´
´ ´
ç ÷
è ø
( )
VREF
VCOUT
VC4 GC + VC4_OFFSET_CORR 0.001
1 + VC4_GAIN_CORR 0.001
G
æ ö
´ ´
´ ´
ç ÷
è ø
( )
VREF
VCOUT
VC3 GC + VC3_OFFSET_CORR 0.001
1 + VC3_GAIN_CORR 0.001
G
æ ö
´ ´
´ ´
ç ÷
è ø
( )
VREF
VCOUT
VC2 GC + VC2_OFFSET_CORR 0.001
1 + VC2_GAIN_CORR 0.001
G
æ ö
´ ´
´ ´
ç ÷
è ø
( )
VREF
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
´
´
www.ti.com Control Panel Demonstration
12. Delay 40 µs, get A/D Counts for VC2.
13. Set VCOUT to Read VC1.
14. Delay 40 µs, get A/D Counts for VC1.
15. Set VIOUT to read SENSEP (SENSEN for first 5 s of polling).
16. Delay 40 µs, 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 Table 16.
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 Table 16, GC
REF
is defined as
(1)
And, G
VCOUT
must be set to 0.6 for the bq76925EVM.
The VCn in Table 16 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.
This measurement technique results in an approximate 5-s delay before the current measurement
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.
23
SLUU514–July 2011 bq76925EVM Evaluation Module
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