8.3.24 Charge Control Features

This device supports charge control features, such as:

• Reports charging voltage and charging current based on the active temperature range—JEITA temperature

ranges T1, T2, T3, T4, T5, and T6

• Provides more complex charging profiles, including sub-ranges within a standard temperature range

• Reports the appropriate charging current required for constant current charging and the appropriate charging

voltage needed for constant voltage charging to a smart charger, using the bus communication interface

• Selects the chemical state-of-charge of each battery cell using the Impedance Track method, and reduces

the voltage difference between cells when cell balancing multiple cells in a series

• Provides pre-charging/zero-volt charging

• Employs charge inhibit and charge suspend if battery pack temperature is out of programmed range

• Reports charging faults and indicates charge status via charge and discharge alarms

8.3.25 Authentication

This device supports security by:

• Authentication by the host using the SHA-1 method

• The gas gauge requires SHA-1 authentication before the device can be unsealed or allow full access.

8.4 Device Functional Modes

This device supports three modes, but the current consumption varies, based on firmware control of certain

functions and modes of operation:

• NORMAL mode: In this mode, the device performs measurements, calculations, protections, and data

updates every 250-ms intervals. Between these intervals, the device is operating in a reduced power stage to

minimize total average current consumption.

• SLEEP mode: In this mode, the device performs measurements, calculations, protections, and data updates

in adjustable time intervals. Between these intervals, the device is operating in a reduced power stage to

minimize total average current consumption.

• SHUTDOWN mode: The device is completely disabled.

8.4.1 Lifetime Logging Features

The device supports data logging of several key parameters for warranty and analysis:

• Maximum and minimum cell temperature

• Maximum current in CHARGE or DISCHARGE mode

• Maximum and minimum cell voltages

8.4.2 Configuration

The device supports accurate data measurements and data logging of several key parameters.

8.4.2.1 Coulomb Counting

The device uses an integrating delta-sigma analog-to-digital converter (ADC) for current measurement. The ADC

measures charge/discharge flow of the battery by measuring the voltage across a very small external sense

resistor. The integrating ADC measures a bipolar signal from a range of –100 mV to 100 mV, with a positive

value when V(SRP) – V(SRN), indicating charge current and a negative value indicating discharge current. The

integration method uses a continuous timer and internal counter, which has a rate of 0.65 nVh.

8.4.2.2 Cell Voltage Measurements

The BQ28Z610-R1 measures the individual cell voltages at 250-ms intervals using an ADC. This measured

value is internally scaled for the ADC and is calibrated to reduce any errors due to offsets. This data is also used

for calculating the impedance of the individual cell for Impedance Track gas gauging.

www.ti.com

BQ28Z610-R1

SLUSE07B – JANUARY 2020 – REVISED JANUARY 2022

Copyright © 2022 Texas Instruments Incorporated

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Product Folder Links: BQ28Z610-R1