Implantable medical device with exposed generator

A method of manufacturing an implantable medical device that is implantable in and electrically connected to a biological tissue for transmission of an electrical signal between the implantable medical device and the biological tissue, the implantable medical device including a control assembly and an energy storage device that provides power to the control assembly, the method comprising:

• electrically connecting a first electrode of the energy storage device to an internal component of the energy storage device;
• enclosing the internal component with an outer housing;
• electrically connecting a first control electrode and a second control electrode to a control component of the control assembly, the control component being supported by a circuit board;
• inserting a spacer that abuts an inner surface of the control case with projections and receives an end of the circuit board within a recess, wherein the spacer maintains the circuit board and the control component in a substantially fixed position relative to the control case;
• enclosing the control component with a control housing;
• electrically connecting the control component and the control housing via the second control electrode;
• electrically connecting the first control electrode and the first electrode of the energy storage device;
• mechanically coupling and electrically connecting the control case and the outer case, leaving an outer surface of the outer case and an outer surface of the control case exposed to an area outside the implantable medical device.

An implantable cardiac device that is implantable in a biological tissue comprising:

• a lead that is operatively connected to a cardiac tissue;
• a battery with a cathode, an anode, a cylindrical outer case that encloses the anode and the cathode, and a first electrode that is electrically insulated from the outer case, one of the anode and the cathode electrically connected to the outer case, and the other of the anode and the cathode electrically connected to the first electrode;
• and
• a control assembly disposed between the lead and the battery, the control assembly including a control component, a cylindrical control case that encloses the control component, a first control electrode electrically connecting the control component and the first electrode of the battery, and a second control electrode electrically connecting the control case and the control component, the control case being mechanically and electrically connected to the outer case of the battery, the first electrode and the first control electrode having an opposite electrical charge from the outer case, the control case, and the second control electrode, the battery providing power to the control component to control transmission of an electrical signal between the implantable medical device and the cardiac tissue, an outer surface of the outer case and an outer surface of the control case being exposed to the biological material, wherein the control component is supported by a circuit board, the control assembly further including a spacer that abuts the inner surface of the control case, the spacer supporting the circuit board to maintain the circuit board and the control component substantially in a fixed position relative to the control case, and wherein the spacer includes a plurality of projections that abut the inner surface of the control case and wherein the spacer includes a recess that receives an end of the circuit board.