BATTERY BALANCING FOR MULTI-BATTERY SYSTEMS

A closed loop control system actively regulates the battery current paths of physically separated circuits so that the current is approximately the same for each of the circuits regardless of the various system loads. The closed loop control system modulates the current paths by either modulating a high side transistor used to independently limit each battery's current path or by modulating a DC/DC converter's output voltage to independently boost each battery's current path. The closed loop control system is also designed to handle undervoltage lockout (UVLO) situations when one of the batteries is nearing empty to tilt the power balance in the chance that there is an existing battery charge mismatch to support system load bursts and to turn off the circuit when the system current draw is exceptionally low. A tilting circuit also identifies and discharges the battery with the higher charge until the charge states are substantially equal.