Demonstration circuit 1496C-B features the LTC2942, a battery gas gauge that measures battery charge and discharge, battery voltage and chip temperature. The demo board includes an external 100mΩ (default) sense resistor for 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 LTC2942 adds battery voltage and on-chip temperature measurement with an internal 14-bit No Latency ΔΣ™ ADC. The three measured quantities (charge, voltage and temperature) are stored in internal registers accessible via the on-board SMBus/I2C interface.