BATTERY FUEL GAUGES USING FET SEGMENT CONTROL TO INCREASE LOW CURRENT MEASUREMENT ACCURACY

摘要

The circuit includes a battery FET coupled between the electronic system and the battery such that current from the battery flows to the electronic system through a battery field-effect transistor (FET). The replica FET couples the battery to the current sense circuit. One of the battery FET and the replica FET includes a plurality of parallel FET segments having separate control terminals. The logic block provides a plurality of switch control signals based on system state inputs. The switching circuit receives the switch control signals and selectively couples the separate control terminals of the FET segments to either the first reference voltage terminal or the second reference voltage terminal to independently turn on or off each FET segment. The current sensing circuit provides a voltage representative of the current flowing through the replica FET.