|
|
Multiple-valued logic has in the last few decades been proposed as a possible alternative to binary logic. Whereas binary logic is limited to only two states, "true" and "false", multiple-valued logic (MVL) replaces these with finitely or infinitely numbers of values. A MVL system is defined as a system operating on a higher radix than two. A radix-n set has n elements, (0, 1, ...., n-1). The feasibility of MVL depends on the availability of the devices constructed for MVL operations. The devices should be able to switch between the different logical levels, and preferably be less complex than the binary counterparts. The multiple-input FG transistors can be used to simplify the design of multiple-valued logic. The initial charge on the floating-gates may vary significantly and therefore impose a very severe inaccuracy unless we apply some form of initialization. By recharging of the semi-floating-gate (SFG) we do not only avoid the problems linked to programming or initializing of the floating gates, but we convert the non-volatile floating gates to semi-floating-gates. The control of the actual floating gate charges in terms of predictable long term charge restoration becomes easier. The SFG is not influenced by a random FG charge distortion due to a periodic or frequent charge restoration or reset. The recharge of the SFGs is accomplished by a local recharge transistor or a pass gate temporarily connecting the output to the floating gate of a gate.
|