The BQ76922 registers must be configured to enable
most protections, select the monitored cells, and enable the protection FETs on the
EVM. This quick start section does not describe current protection settings. Once
registers are configured, the values may be written to One Time Programmable memory
(OTP) for use on the next reset of the device, but since that is a permanent change
it is not part of this quick start procedure. Preproduction sample configuration may
differ from the production data sheet, check the documents provided with the
samples. This quick start assumes a new EVM without OTP configuration settings. If
your board has a part with configuration stored in OTP refer to the Section 4 and Section 5.
These steps describe quick connection of the BQ76922 EVM to demonstrate operation of the AFE portion of the EVM. For more detailed descriptions, refer to other sections of the user guide.
Install the interface shunts to the INT positions.
Attach the on board communication adapter USB connector to the PC using USB cable.
Connect a 0-V DC power supply capable of 250 mA minimum between the BAT- and CELL5 terminals and adjust to approximately 18 V.
Press and release the WAKE switch.
Start the BQStudio software. The GUI should open with a register display. Click on the Scan button to enable repeated update of the display. The power supply may be adjusted within range of the part to observe voltage changes in the GUI register display.
Select the Data memory button in the BQStudio window.
Select the Settings button and set the Enabled Protections A CUV bit. Writing
to the data memory after setting the bit.
In the Commands panel click on the FET_EN button.
In the Registers view, click on the Scan icon so that the registers update
periodically. Observe that the DSG_FET and CHG_FET bits in the FET Status
register of the BIT Registers section are on and that the Stack voltage and the
Pack pin voltage registers in the Registers section are approximately equal.
The SLEEPCHG bit is enabled by default, if the SLEEP status is set CHG_FET will
be off. Click the SLEEP_DISABLE command button. Measure the PACK voltage on
the board if desired.
Adjust the supply voltage to approximately 22 V. In the registers view observe
that the COV bit turns on, the CHG_FET bit goes off, and the Pack pin voltage
drops to approximately 0.3 V below the Stack voltage.
Adjust the supply voltage to approximately 12 V. In the registers view observe
that the CUV bit turns on, the DSG_FET bit goes off, and the Pack pin voltage
drops to approximately 0 V.
Make other adjustments as desired, for evaluation. See other sections of this user guide for details of operation.
When complete with this quick start demonstration, exit BQStudio software and turn off the power supply.
Refer to other sections of this user guide for additional details.