ARCHITECTURES FOR AN IMPLANTABLE MEDICAL DEVICE SYSTEM HAVING DAISY-CHAINED ELECTRODE-DRIVE INTEGRATED CIRCUITS

Architectures for an implantable neurostimulator system having a plurality of electrode-driver integrated circuits (ICs) in provided. Electrodes from either or both ICs can be chosen to provide stimulation, and one of the IC acts as the master while the other acts as the slave. A parallel bus operating in accordance with a communication protocol couples the ICs, and certain functional blocks not needed in the slave are disabled. Stimulation parameters are loaded via the bus into each IC, and a stimulation enable command is issued on the bus to ensure simultaneous stimulation from the electrodes on both ICs. Clocking strategies are also disclosed to allow clocking of the master and slave ICs to be independently controlled, and to ensure that relevant internal and bus clocks used in the system are synchronized.