Patent ID: 7847595

Claim:
An input circuit for delivering N pieces of plural-bit signals each comprised of a signal of a plurality of bits, based on input data, said input circuit comprising: N pieces of control signal preservation/output circuits, which are provided one by one corresponding to the plural-bit signals, for delivering the input data as it is when a trigger signal to said control signal preservation/output circuits is at a first level, and holding the previously delivered output data when the trigger signal to said control signal preservation/output circuits is at a second level different from the first level, thereby enabling switching and preservation of the plural-bit signals; and a controlled circuit selector circuit for setting the trigger signal for S pieces of said control signal preservation/output circuits to the first level, and setting the trigger signal for the rest (N-S) pieces of the control signal preservation/output circuits to the second level, wherein a group of input signals are supplied in common to said N pieces of the control signal preservation/output circuits, corresponding to the input data, and wherein said each control signal preservation/output circuit comprises: a selector circuit for setting only one bit of an S-bit output signal to the first level in accordance with the value of a supplied decode signal; a gating circuit applied with an output of said selector circuit for delivering the output of said selector circuit as it is when the trigger signal applied to said control signal preservation/output circuit is at the first level, and setting all the outputs to the second level when the trigger signal is at the second level; and a number of latch circuits equal to the number of bits of the plural-bit signal, each for delivering input data as it is when the trigger signal is at the first level, and holding the output data when the trigger signal is at the second level, wherein the group of input signals are supplied to input terminals of said latch circuits in parallel.