BQ4050 Datasheet, PDF (27/53 Pages) Texas Instruments – CEDV Gas Gauge and Protection Solution

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bq4050
SLUSC67A – MARCH 2016 – REVISED MARCH 2016
Feature Description (continued)
7.3.11 Voltage
The bq4050 updates the individual series cell voltages at 0.25-second intervals. The internal ADC of the bq4050
measures the voltage, and scales and calibrates it appropriately. This data is also used to calculate the
impedance of the cell for the CEDV gas gauging.
7.3.12 Current
The bq4050 uses the SRP and SRN inputs to measure and calculate the battery charge and discharge current
using a 1-mΩ to 3-mΩ typ. sense resistor.
7.3.13 Temperature
The bq4050 has an internal temperature sensor and inputs for four external temperature sensors. All five
temperature sensor options can be individually enabled and configured for cell or FET temperature usage. Two
configurable thermistor models are provided to allow the monitoring of cell temperature in addition to FET
temperature, which use a different thermistor profile.
7.3.14 Communications
The bq4050 uses SMBus v1.1 with MASTER mode and packet error checking (PEC) options per the SBS
specification.
7.3.14.1 SMBus On and Off State
The bq4050 detects an SMBus off state when SMBC and SMBD are low for two or more seconds. Clearing this
state requires that either SMBC or SMBD transition high. The communication bus will resume activity within
1 ms.
7.3.14.2 SBS Commands
See the bq4050 Technical Reference Manual (SLUUAQ3) for further details.
7.4 Device Functional Modes
The bq4050 supports three power modes to reduce power consumption:
• In NORMAL mode, the bq4050 performs measurements, calculations, protection decisions, and data updates
in 250-ms intervals. Between these intervals, the bq4050 is in a reduced power stage.
• In SLEEP mode, the bq4050 performs measurements, calculations, protection decisions, and data updates in
adjustable time intervals. Between these intervals, the bq4050 is in a reduced power stage. The bq4050 has
a wake function that enables exit from SLEEP mode when current flow or failure is detected.
• In SHUTDOWN mode, the bq4050 is completely disabled.
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