Spinal cord stimulator system

A wireless charger system for inductively charging a rechargeable battery of an implantable pulse generator (IPG) implanted in a human body, the wireless charger system comprising:

• a charging coil adapted to be wirelessly coupled to a receiving coil of the IPG to charge the rechargeable battery, wherein the charging coil is backed by a ferrite plate;
• a reflected impedance sensor coupled to the charging coil to detect a reflected impedance of the charging coil;
• an end-of-charge (EOC) circuit coupled to the reflected impedance sensor, the EOC circuit adapted to continuously monitor the reflected impedance from the reflected impedance sensor and determine the end of charge when a predetermined pattern of the reflected impedance corresponding to an EOC signal from the IPG is received;
• and
• a feedback closed loop control configured to reduce losses in the wireless charger system during recharging.