BQ33100_15 Datasheet, PDF (22/67 Pages) Texas Instruments – Super Capacitor Manager

bq33100
SLUS987B – JANUARY 2011 – REVISED DECEMBER 2015
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Additionally, the bq33100 periodically validates its read and write communications with the integrated AFE. If
either a read or write verify fails, an internal AFE_Fail_Counter is incremented. If the AFE_Fail_Counter reaches
AFE Fail Limit, the bq33100 sets the [AFE_C] flag in SafetyStatus. An AFE communication fault condition can
also be declared if, after a full reset, the initial gain and offset values read from the AFE cannot be verified.
These values are A to D readings of the integrated AFE VCx signal. The integrated AFE offset values are verified
by reading the values twice and confirming that the readings are within acceptable limits. The maximum number
of read retries, if offset and gain value verification fails and [AFE_C] fault is declared, is set in AFE Fail Limit If
the AFE Fail Limit is set to 0, this feature is disabled.
8.3.5.11 Data Flash Fault (DFF)
The bq33100 can detect if the data flash is not operating correctly. A permanent failure is reported when either:
(i) After a full reset the instruction flash checksum does not verify; (ii) if any data flash write does not verify; or (iii)
if any data flash erase does not verify
When a data flash fault is detected then the [DFF] flag in SafetyStatus is set.
8.3.5.12 FAULT Indication (FAULT Pin)
The bq33100 provides the status of the safety detection through SafetyStatus. To provide an extra indication of a
fault state ( SafetyStatus ≠ 0x00) the bq33100 will set the FAULT pin (pin 15) if the corresponding SafetyStatus
bit is set in Fault.
8.3.6 Communications
The bq33100 uses SMBus v1.1 for host communications although an SMBus slave can be communicated with
through an I²C master.
8.3.6.1 SMBus On and Off State
The bq33100 detects a SMBus off state when SCL and SDA are logic-low for ≥ 2 seconds. Clearing this state
requires either SCL or SDA to transition high. Within 1 ms, the communication bus is available.
8.3.7 Security (Enables and Disables Features)
There are two levels of secured operation within the bq33100, Sealed and Unsealed. To switch between the
levels, different operations are needed with different codes.
1.Unsealed to Sealed — The use of the Seal command instructs the bq33100 to limit access to the SBS
functions and data flash space and sets the [SS] flag. In sealed mode, available standard SBS functions have
access per the Smart Battery Data Specification (SBS). Extended SBS Functions and data flash are not
accessible. Once in sealed mode, the part can never permanently return to Unsealed mode.
2. Sealed to Unsealed — Instructs the bq33100 to extend access to the SBS and data flash space and clears the
[SS] flag. In unsealed mode, all data, SBS, and DF have read and write access. Unsealing is a 2 step command
performed by writing the 1st word of the UnSealKey to ManufacturerAccess followed by the second word of the
UnSealKey to ManufacturerAccess. The unseal key can be read and changed through the extended SBS block
command UnSealKey when in Unsealed Mode. To return to the Sealed mode, either a hardware reset is needed,
or the ManufacturerAccess Seal command is needed.
8.3.8 Measurement System Calibration
The bq33100 does not require calibration, but can be calibrated for improved measurement accuracy.
8.3.8.1 Coulomb Counter Deadband
The bq33100 does not accumulate charge or discharge for monitoring when the current input is below the
Deadband threshold which must be set sufficiently high to prevent false signal detection with no charge or
discharge flowing through the sense resistor.
8.3.8.2 Auto Calibration
The bq33100 provides an auto-calibration feature to cancel the voltage offset error across SRP and SRN for
maximum charge measurement accuracy. The bq33100 performs auto-calibration when the SMBus lines stay
low continuously for a minimum of 5 s and Temperature is within bounds of 5°C and 45°C.
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