Systems and Methods of Accurate Control of Battery Pre-charge Current

摘要

Systems and methods for accurate control of battery pre-charge current use external charge FET external discharge FET for accurate control of battery pre-charge current. A low Vforward diode or other component and series resistor form a parallel path around the discharge FET. It is preferable for the component to have a voltage drop significantly less than that of the parasitic diode in the FET when carrying current in one direction and substantially higher voltage drop in the other direction. During a pre-charge condition, the discharge FET is turned off, and a servo amplifier monitors the voltage across the series resistor. The servo amplifier controls the gate of the charge FET such that a desired current is flowing from the charger to the battery.