Isolation of Logic Circuits
Original Publication Date: 1984-Sep-01
Included in the Prior Art Database: 2005-Feb-05
In a battery backed-up pluggable CMOS RAM cartridge, a battery 1 is utilized as a power source when the RAM cartridge is unplugged from its machine. When a memory device 2 and a non-memory device 3 of the cartridge have a common ground, as is required when the cartridge is plugged into the machine, the battery 1 has to provide drain current for both the memory device 2 and the non-memory device 3. Because the current drain through the non-memory device 3 is about the same as the current drain through the memory device 2 in a CMOS RAM, the battery 1 would have to be sized to provide a standby current drain of two times that required solely for the memory device 2.