This document describes the method of using the STC3100 battery monitor to implement gas gauge applications. The STC3100 is a new device that includes battery monitoring features (voltage, current, and temperature) and a Coulomb counter to implement a gas gauge system in existing or future applications.
The document describes the STC3100, a device designed for measuring battery voltage, current, and temperature to calculate state-of-charge (SoC) and remaining operating time. It is intended for one-cell Li-ion battery applications in handheld electronics like mobile phones and navigation devices.
The guide details the hardware setup, including connections for an external sense resistor and optional ESD protection. It also explains the software implementation required to control the device via I2C, specifically focusing on enabling the Coulomb counter and reading charge data from specific registers.
The Reg resistor is used to sense the current flowing into or from the battery, and its value must be selected so the voltage drop does not exceed +/-80 mV.
The device can operate from an internal oscillator or use an external RTC signal. An external square wave signal provides higher accuracy than the internal oscillator.
To convert the current code into milliamperes, you must multiply the code by 11.77 and divide by the value of the external sense resistor (Rsense) in milli-ohms.