5μA System-Side Single Cell Fuel Gauge

The RT9427 Li-Ion/Li-Polymer battery fuel gauge is a microcontroller peripheral that provides fuel gauging for single-cell battery packs. The RT9427 resides within the system's main board and manages a non- removable battery or removable battery pack.The RT9427 reports StateOfCharge, StateOfHealth, FullChargeCapacity, TimeToEmpty and CycleCount based on the Voltaic Gauge with Current Sensing (VGCS) algorithm by using the voltage difference between battery voltage and OCV to calculate the increasing or decreasing SOC, with current sensing compensation to report battery SOC.The Voltaic Gauge with Current Sensing algorithm can support smoothly SOC tracking and does not accumulate error over time and with current changes. That is an advantage compared to coulomb counter which suffer from SOC drift caused by current sense error and battery self-discharge.The RT9427 provides a complete battery status monitor with an interrupt alarm function. It can actively alert the host processor when conditions of battery overvoltage, undervoltage, or over-temperature conditions during charging or discharging. This is especially useful for high C-rate battery charging applications, as it can measure battery voltage using a Kelvin sense connection to eliminate the IR drop effect for an optimal charging profile and safety. Additional useful alarm functions include under SOC alert, SOC Change and battery presence status change.The RT9427 is available in WDFN-10L 2x2.5 (FC) and WL-CSP-9B 1.68x1.81 (BSC) packages. The recommended junction temperature range is -40°C to 125°C, and the ambient temperature range is -40°C to 85°C.