Abstract: Disclosed herein is a resistance welding system for welding a ribbon to a bond site of a bond surface. The system includes a welding header, a bond header, a ribbon dispenser, a cutter, and a support surface. The welding header includes a resistance welding tip. The bond header includes a bond foot displaceable relative to the bond surface. The bond foot includes a welding aperture. The ribbon dispenser feeds the ribbon to the bond foot. The support surface is configured to support the bond surface. The bond foot is configured to press the ribbon against the bond site of the bond surface, which is thereby forced against the support surface. With the ribbon so pressed against the bond site, the system is configured to cause the welding tip to enter the welding aperture to resistance weld the ribbon to the bond site of the bond surface.

Abstract: The implantable medical device is provided with typically equal portions of both random access memory (RAM) and read only memory (ROM) and a virtual memory space is defined equal to the amount of memory in one of the memory devices. In a specific example, the RAM and ROM provide 256 K of memory each, with the virtual memory space also set to 256 K. A zone control register is provided which specifies, for each of a set of predetermined zones within the virtual memory space, whether memory access commands are to be routed to RAM or ROM. Control bits within the zone control register may be reset to permit portions of memory to be remapped from one memory device to the other. By providing RAM and ROM each typically equal in size to the virtual memory space, software for use in the device may be tested and debugged using RAM then transferred to ROM for use in production devices.

Abstract: A circuit within an implantable cardiac stimulation device monitors impedance of an electrode configuration including first and second electrodes in electrical contact with a heart. The circuit is within the implantable cardiac stimulation device which applies stimulation pulses having a current and a voltage magnitude across the electrode configuration. The circuit that monitors impedance of an electrode configuration provides an impedance digital output proportional to the ratio of a stimulation pulse voltage and current.

Abstract: The implantable medical device is provided with typically equal portions of both random access memory (RAM) and read only memory (ROM) and a virtual memory space is defined equal to the amount of memory in one of the memory devices. In a specific example, the RAM and ROM provide 256K of memory each, with the virtual memory space also set to 256K. A zone control register is provided which specifies, for each of a set of predetermined zones within the virtual memory space, whether memory access commands are to be routed to RAM or ROM. Control bits within the zone control register may be reset to permit portions of memory to be remapped from one memory device to the other. By providing RAM and ROM each typically equal in size to the virtual memory space, software for use in the device may be tested and debugged using RAM then transferred to ROM for use in production devices.

Abstract: An implantable cardiac stimulation device that has automatic functions in each of two different sets of microprocessor operating code. Following implantation, a first mode of operation executes a first set of operating code, stored primarily in RAM, and performs software error detection. Upon detection of an error, the microprocessor is caused to enter a second (backup) mode of operation, where it executes a second set of operating code, which is retained in read-only memory (ROM). Thus, in the unlikely event of error detection, the implantable device is still fully functional in its second mode to provide automaticity, e.g., to select therapies for different heart condition and provide rate-responsive pacing that tracks physiological requirements. If an error is detected in the second mode, than a third mode of operation (e.g., fixed-rate VVI pacing) is enabled.