8.3 Feature Description

8.3.1 Battery Parameter Measurements

The BQ28Z610-R1 device measures cell voltage and current simultaneously, and measures temperature to

calculate the information related to remaining capacity, full charge capacity, state-of-health, and other gauging

parameters.

8.3.1.1 BQ28Z610-R1 Processor

The BQ28Z610-R1 device uses a custom TI-proprietary processor design that features a Harvard architecture

and operates at frequencies up to 4.2 MHz. Using an adaptive, three-stage instruction pipeline, the BQ28Z610-

R1 processor supports variable instruction length of 8, 16, or 24 bits.

8.3.2 Coulomb Counter (CC)

The first ADC is an integrating converter designed specifically for coulomb counting. The converter resolution is

a function of its full-scale range and number of bits, yielding a 3.74-µV resolution.

8.3.3 CC Digital Filter

The CC digital filter generates a 16-bit conversion value from the delta-sigma CC front-end. Its FIR filter uses

the LFO clock output, which allows it to stop the HFO clock during conversions. New conversions are available

every 250 ms while CCTL[CC_ON] = 1. Proper use of this peripheral requires turning on the CC modulator in the

AFE.

8.3.4 ADC Multiplexer

The ADC multiplexer provides selectable connections to the VCx inputs, TS1 inputs, internal temperature

sensor, internal reference voltages, internal 1.8-V regulator, PACK input, and VSS ground reference input. In

addition, the multiplexer can independently enable the TS1 input connection to the internal thermistor biasing

circuitry, and enables the user to short the multiplexer inputs for test and calibration purposes.

8.3.5 Analog-to-Digital Converter (ADC)

The second ADC is a 16-bit delta-sigma converter designed for general-purpose measurements. The ADC

automatically scales the input voltage range during sampling based on channel selection. The converter

resolution is a function of its full-scale range and number of bits, yielding a 38-µV resolution. The default

conversion time of the ADC is 31.25 ms, but is user-configurable down to 1.95 ms. Decreasing the conversion

time presents a tradeoff between conversion speed and accuracy, as the resolution decreases for faster

conversion times.

8.3.6 ADC Digital Filter

The ADC digital filter generates a 24-bit conversion result from the delta-sigma ADC front end. Its FIR filter uses

the LFO clock, which allows it to stop the HFO clock during conversions. The ADC digital filter is capable of

providing two 24-bit results: one result from the delta-sigma ADC front-end and a second synchronous result

from the delta-sigma CC front-end.

8.3.7 Internal Temperature Sensor

An internal temperature sensor is available on the BQ28Z610-R1 device to reduce the cost, power, and size of

the external components necessary to measure temperature. It is available for connection to the ADC using the

multiplexer, and is ideal for quickly determining pack temperature under a variety of operating conditions.

8.3.8 External Temperature Sensor Support

The TS1 input is enabled with an internal 18-kΩ (Typ.) linearization pull-up resistor to support the use of a

10-kΩ (25°C) NTC external thermistor, such as the Semitec 103AT-2. The NTC thermistor should be connected

between VSS and the individual TS1 pin. The analog measurement is then taken via the ADC through its input

multiplexer. If a different thermistor type is required, then changes to configurations may be required.

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