• To enable the internal temperature and the external temperature sensors: Set Settings:Configuration:

Temperature Enable: Bit 0 (TSInt) = 1 for the internal sensor; set Bit 1 (TS1) = 1 for the external sensor.

9.2.3 Calibration Process

The calibration of current, voltage, and temperature readings is accessible by writing 0xF081 or 0xF082 to

ManufacturerAccess(). A detailed procedure is included in the BQ27Z561-R1 Technical Reference Manual

(SLUUBY5) in the Calibration section. The description allows for calibration of cell voltage measurement offset,

battery voltage, current calibration, coulomb counter offset, PCB offset, CC gain/capacity gain, and temperature

measurement for both internal and external sensors.

9.2.4 Gauging Data Updates

When a battery pack enabled with the BQ27Z561-R1 gas gauge is cycled, the value of FullChargeCapacity()

updates several times, including the onset of charge or discharge, charge termination, temperature delta,

resistance updates during discharge, and relaxation. Figure 9-3 shows actual battery voltage, load current,

and FullChargeCapacity() when some of those updates occur during a single application cycle.

Update points from the plot include:

• Charge termination at 7900 s

• Relaxation at 9900 s

• Resistance update at 11500 s

9.2.4.1 Application Curve

Figure 9-3. Full Charge Capacity Tracking (X-Axis Is Seconds)

10 Power Supply Requirements

The only power supply is the BAT pin, which is connected to the positive terminal of the battery. The input

voltage for the BAT pin will have a minimum of 2 V to a maximum of 5 V.

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BQ27Z561-R1

SLUSDH5B – MARCH 2019 – REVISED DECEMBER 2022

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