BQ4050 Datasheet, PDF (26/53 Pages) Texas Instruments – CEDV Gas Gauge and Protection Solution

bq4050
SLUSC67A – MARCH 2016 – REVISED MARCH 2016
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Feature Description (continued)
7.3.6 Battery Parameter Measurements
7.3.6.1 Charge and Discharge Counting
The bq4050 uses an integrating delta-sigma analog-to-digital converter (ADC) for current measurement, and a
second delta-sigma ADC for individual cell and battery voltage and temperature measurement.
The integrating delta-sigma ADC measures the charge/discharge flow of the battery by measuring the voltage
drop across a small-value sense resistor between the SRP and SRN terminals. The integrating ADC measures
bipolar signals from –0.1 V to 0.1 V. The bq4050 detects charge activity when V_SR = V_(SRP) – V_(SRN) is positive,
and discharge activity when V_SR = V_(SRP) – V_(SRN) is negative. The bq4050 continuously integrates the signal over
time, using an internal counter. The fundamental rate of the counter is 0.26 nVh.
7.3.7 Battery Trip Point (BTP)
Required for WIN8 OS, the battery trip point (BTP) feature indicates when the RSOC of a battery pack has
depleted to a certain value set in a DF register. This feature allows a host to program two capacity-based
thresholds that govern the triggering of a BTP interrupt on the BTP_INT pin and the setting or clearing of the
OperationStatus[BTP_INT] on the basis of RemainingCapacity().
An internal weak pull-up is applied when the BTP feature is active. Depending on the system design, an external
pull-up may be required to put on the BTP_INT pin. See Electrical Characteristics: PRES, BTP_INT, DISP for
details.
7.3.8 Lifetime Data Logging Features
The bq4050 offers lifetime data logging for several critical battery parameters. The following parameters are
updated every 10 hours if a difference is detected between values in RAM and data flash:
• Maximum and Minimum Cell Voltages
• Maximum Delta Cell Voltage
• Maximum Charge Current
• Maximum Discharge Current
• Maximum Average Discharge Current
• Maximum Average Discharge Power
• Maximum and Minimum Cell Temperature
• Maximum Delta Cell Temperature
• Maximum and Minimum Internal Sensor Temperature
• Maximum FET Temperature
• Number of Safety Events Occurrences and the Last Cycle of the Occurrence
• Number of Valid Charge Termination and the Last Cycle of the Valid Charge Termination
• Number of Shutdown Events
• Cell Balancing Time for Each Cell
(This data is updated every 2 hours if a difference is detected.)
• Total FW Runtime and Time Spent in Each Temperature Range
(This data is updated every 2 hours if a difference is detected.)
7.3.9 Authentication
The bq4050 supports authentication by the host using SHA-1.
7.3.10 LED Display
The bq4050 can drive a 3-, 4-, or 5- segment LED display for remaining capacity indication and/or a permanent
fail (PF) error code indication.
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