An improved arrangement for detecting DC current leakage in implanted devices is disclosed. Currents are monitored, so that any unexpected imbalance indicates that a fault condition has occurred. The principle of the system is that if everything working correctly, the same current should be flowing into the tissue from VDDH-ELEC as is passing out of the tissue into VSS_ELEC. Any difference is indicative of current flowing into or out of the tissue from unknown paths, which is indicative of some fault. This replaces routine monitoring for specific faults.
