Texas Instruments bq2060AEVM-001, Руководство пользователя

Страница: 30 / 35

Calibration of a bq2060A Based Module Using the EV2200-60 Software
5-10
5.5 Calibration of a bq2060A Based Module Using the EV2200-60 Software
The VFC Offset tab is used in the calibration routine. The VFC Offset screen
offers a simple-to-use interface for calibrating the Offset of the VFC. Two
different types of offset can be selected.
Figure 5−9.
VFC Offset Screen
Default VFC Offset: To select this offset method, click on | Start Calibration |.
This method appies an internal short (inside the bq2060A) across the sense
resistor. With the sense resistor shorted inside the bq2060A, there is less
chance that an external current can cause a poor offset calculation. If the
circuit board induces a slight offset, then it is not compensated for with this
method.
Alternate VFC Offset: To select this offset method, click on | Start Alternate
Calibration |. This method does not apply an internal short across the sense
resistor. Care must be taken that no current is flowing through the sense
resistor. If there is current, the bq2060A applies this current to its calculations,
resulting in an inaccurate VFC offset. With no short across the sense resistor,
this method compensates for board offset as long as no current is flowing.
Once calibration is started, the Calibration Started Field displays the time
when the calibration was initiated. The Elapsed Time continually updates the
amount of time in minutes since the calibration began.
To abort the offset attempt, click on | Abort |. This halts the offset calculation
process and stores a value of 0x003800 in to the EEPROM.
If this module is installed on a pack where VCC will be present to the bq2060A
after disconnecting from the EV2200, then you can click | Continue Calibration
Offline | and the bq2060A automatically finishes the calibration and stores the