9
Calibration Screen
9.1
How to Calibrate
9.2
To Calibrate the bq20z40
9.3
Board Offset Calibration
9.4
Pack Voltage Calibration
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Calibration Screen
The bq20z40 must be calibrated using power supplies or a power supply and cell simulation resistors (200
Ω
to 1000
Ω
each) before cells are attached. Before the bq20z40 is calibrated:
•
Connect and measure a 2-A current source from 1N (-) and Pack- (+) to calibrate without using the
FETs (calibration using the FETs is not recommended).
•
Measure the pack voltage from Batt+ to Batt- (total of cell voltages).
•
Measure the temperature of the pack.
•
Whether the foregoing steps are necessary depends on the type of calibration being performed.
Select the types of calibration to be performed.
Enter the measured values for the types selected (Except for
CC Offset Calibration
).
If
Voltage Calibration
is selected, enter the number of cells on the pack.
If
Temperature Calibration
is selected, select the sensor that is to be calibrated.
If the current source is connected between 1N and Pack-, then select the
Off (Bypassed)
check box in the
FET Control
section.
Press the
Calibrate Part
button.
This performs the offset calibration for the current offset of the board.
Remove any current source, load, or external voltage from the PACK terminals.
Press the
Software Board Offset Calibration
button.
This calibrates the voltage at the AFE Pack pin.
Ensure that
Voltage Calibration
has been performed for the pack. If
Voltage Calibration
is not performed,
then
Pack Voltage Calibration
calibrates incorrectly.
Remove load/external voltage applied between Pack+ and Pack-.
Press the
Pack Voltage
button to calibrate.
SLUU320C – January 2009 – Revised June 2009
bq20z40EVM-001 SBS 1.1 Impedance Track™Technology
13
Enabled Battery Management Solution EVM