Demonstration circuit 1496C-A features the LTC2941, a battery gas gauge that measures battery charge and discharge with an external sense resistor (100mΩ sense resistor included), yielding a maximum current measurement of 500mA (±50mV current sense voltage range). The sense resistor can be changed; however the software only accepts sense resistors between 0.1mΩ to 5Ω. The 2.7V to 5.5V operating range is perfectly suited for single cell Li-Ion batteries.
A precision analog coulomb counter integrates current through the sense resistor between the battery’s positive terminal and the load or charger. The measured charge is stored in internal registers accessible via the on-board SMBus/I2C interface.