CMOS battery fuel gauges cut power consumption and system cost

The LC709201F, LC709202F and LC709203F provide measurements of the remaining power level of one-cell Li-ion batteries used in portable electronics such as smartphones, tablets and digital cameras. ON claims the devices reduce component count and system cost by eliminating the need for a current sensing resistor. The modules are optimised to reduce measurement errors to below ±5% (for LC709201F and LC709202F) or below ± 2.8% (LC709203F) by employing a correction technology to ascertain temperature and voltage. Low current consumption minimises the drain on battery power helping to extend time between charging cycles. This is enhanced further on the LC709202F and LC709203F by a sub 0.2µA power saving sleep mode feature. The LC709203F also has a 2µA ECO Mode. Key features of the LC709201F include an I2C interface and communications pin, plus further pins for battery temperature reading control, analogue voltage input for battery temperature, reset, test and power supply. The LC709202F and LC709203F add an alert function - which is configurable on the LC709203F - to indicate low relative state of charge and battery voltage, as well as external alarm/interrupt for low battery warning.