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See table for reduced cell configuration
4 cells shown
Short VC4 to VC3
Remove R5
Short C4 to C3
(optional with cells and R5 removed)
With cells, open switches to avoid
draining cells
If connecting cells confirm operation
before connecting. Use all appropriate
fusing, insulation, isolation and shielding
necessary for safe operation. Board has
exposed contacts. Do not leave
unattended
bq76920 Circuit Module Use
25
SLVU924D – March 2014 – Revised November 2018
Copyright © 2014–2018, Texas Instruments Incorporated
bq76920 Evaluation Module User's Guide
Figure 19. Example Connection With 4 Cells
When using external balancing with P-channel MOSFETs, such as on the bq76930 and bq76940 EVMs,
the inrush current for a cell can momentarily turn on the balance FET causing the next cell input below to
rise. This can continue down the stack. Connecting C0 on the board by closing the C0 dip switch during
cell connection can reduce stress on the VC0 input of the AFE. Open the switch after cell connection for
sensing at the cell.
6.5
Connecting to a Host
After initial operation of the AFE with the bq76940/bq76930/bq76920 software, it may be desirable to
operate the board connected to a microcontroller board. J12 could be used to connect to the
microcontroller board. No voltages should be applied to the gauge terminals. Alternately, the
microcontroller is connected to the signal test points or J8 and the ALERT test point. The bq76920
installed on the EVM is a 2.5V ouput device. Be sure the MCU will operate at 2.5V or provide separate
power for the MCU and shift the level of the interface signals if needed. Pull-ups may not be required on
the EVM if they are provided on the MCU. Although it was developed for 10 cells,
implements
an example host for the bq76930 family member of the AFE using the MSP430. The code is available for
the TI Design and may be a helpful reference in development of a host system.