BQ35100 Datasheet, PDF (9/26 Pages) Texas Instruments – Lithium Primary Battery Fuel Gauge

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7 Detailed Description
bq35100
SLUSCM6A – JUNE 2016 – REVISED JULY 2016
7.1 Overview
The bq35100 Battery Monitor provides gas gauging for Lithium Thionyl Chloride (LiSOCl2) and Lithium
Manganese Dioxide (LiMnO2) primary batteries without requiring any forced discharge of the battery. The
lithium primary gas gauging function uses voltage, current, and temperature data to provide State-Of-Health
(SOH) and End-Of-Service (EOS) data.
7.2 Functional Block Diagram
REGIN
GE
REG25
2.5-V LDO
+
Power Mgmt
Oscillator
System Clock
SDA
I2C
Communications
SCL
Gauging
Algorithm
ADC
Coulomb
Counter
Divider
Temp
Sensor
Peripherals
BAT
VIN
TS
SRP
SRN
VEN
ALERT
Data
Memory
Program
Memory
NC VSS
Copyright © 2016, Texas Instruments Incorporated
7.3 Feature Description
7.3.1 Basic Measurement Systems
7.3.1.1 Voltage
The device measures the BAT input, which is scaled by the internal translation network, through the ADC. The
translation gain function is determined by a calibration process.
In systems where the battery voltage is greater than V_IN(BAT) MAX (for example, 2-series cell or more), then an
external voltage scaling circuit is required. The firmware then scales this <1 V value to reflect an average cell
value and then again by the number of series cells to reflect the full battery voltage value.
7.3.1.2 Temperature
The device can measure temperature through an integrated temperature sensor or an external NTC thermistor.
Only one source can be used and the selection is made by setting Operation Config A [TEMPS] appropriately.
The resulting measured temperature is available through the Temperature() command. The internal temperature
sensor result is also available through the InternalTemperature() command.
Copyright © 2016, Texas Instruments Incorporated
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