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threshold, the SHUTDOWN mode sequence is automatically initiated. The shutdown based on cell voltage does
not apply to cell input pins being used to measure interconnect.
While the BQ769142 device is in NORMAL mode or SLEEP mode, the device can also be configured to enter
SHUTDOWN mode if the internal temperature measurement exceeds a programmed temperature threshold for a
programmed delay.
When the SHUTDOWN mode sequence is initiated by subcommand or the RST_SHUT pin driven high for 1
second, the device waits for a delay then disables the protection FETs. After the delay from when the sequence
begins, the device enters SHUTDOWN mode. However, if the voltage on the LD pin is still above the V
level, shutdown will be delayed until the voltage on LD falls below that level.
While the device is in SHUTDOWN mode, ≈5 voltage is provided at the TS2 pin with high source impedance. If
the TS2 pin is pulled low, such as by a switch to VSS, or if a voltage is applied at the LD pin above V
(such as when a charger is attached in series FET configuration), the device exits SHUTDOWN mode.
If a thermistor is attached from the TS2 pin to VSS, this may prevent the device from fully entering
SHUTDOWN mode.
As a countermeasure to avoid an unintentional wake from SHUTDOWN mode when putting the BQ769142
device into long-term storage, the device can be configured to automatically reenter SHUTDOWN mode after a
programmed number of minutes.
The BQ769142 device performs periodic memory integrity checks and forces a watchdog reset if any corruption
is detected. To avoid a cycle of resets in the case of a memory fault, the device enters SHUTDOWN mode rather
than reset if a memory error is detected within a programmed number of seconds after a watchdog reset has
occurred.
When the device is wakened from SHUTDOWN, it generally requires approximately 200 ms–300 ms for the
internal circuitry to power up, load settings from OTP memory, perform initial measurements, evaluate those
relative to enabled protections, then to enable FETs if conditions allow. This can be much longer, depending on
settings.
The BQ769142 device integrates a hardware overtemperature detection circuit, which determines when the die
temperature passes an excessive temperature of approximately 120°C. If this detector triggers, the device
automatically begins the sequence to enter SHUTDOWN mode if this functionality is enabled through
configuration.
13.6 CONFIG_UPDATE Mode
The BQ769142 device uses a special CONFIG_UPDATE mode to make changes to the data memory settings. If
changes were made to the data memory settings while the firmware was in normal operation, it could result in an
unexpected operation or consequences if settings used by the firmware changed in the midst of operation. When
changes to the data memory settings are needed (which generally should only be done on the customer
manufacturing line or in an offline condition), the host should put the device into CONFIG_UPDATE mode,
modify settings as required, then exit CONFIG_UPDATE mode. See the BQ769142 Technical Reference Manual
(SLUUCF2)
for more details.
When in CONFIG_UPDATE mode, the device stops normal firmware operation and stops all measurements and
protection monitoring. The host can then make changes to data memory settings (either writing registers directly
into RAM, or instructing the device to program the RAM data into OTP). After changes are complete, the host
then exits CONFIG_UPDATE mode, at which point the device restarts normal firmware operation using the new
data memory settings.
14 Serial Communications Interface
14.1 Serial Communications Overview
The BQ769142 device integrates three serial communication interfaces—an I
and 400-kHz modes with an optional CRC check, an SPI bus with an optional CRC check, and a single-wire
HDQ interface. The default configuration for the BQ769142 device is I
Copyright © 2021 Texas Instruments Incorporated
Note
Product Folder Links:
BQ769142
SLUSE91A – SEPTEMBER 2020 – REVISED FEBRUARY 2021
2
C bus, which supports 100-kHz
2
C mode, while other versions of the
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BQ769142
WAKEONLD
WAKEONLD
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