Incrementer with common precharge enable and carry-in signal

摘要

A MOSFET incrementer circuit is disclosed which is adapted for use in conjunction with a clocked register for incrementing the binary value stored within the register. Each stage of the register has an input terminal which is used to determine whether or not the binary value stored in the particular stage is to be toggled. Each of the input terminals is precharged to a high level which corresponds to the no-increment mode of operation. After the input terminals are initially precharged, the input terminal of the least significant stage is driven to a low level to perform an increment. A plurality of series-coupled MOSFET devices are controlled according to output signals provided by each of the register stages for selectively coupling the low level present at the input terminal of the least significant stage to the input terminals of subsequent stages. When a low level is presented to the input terminal of a stage of the register, the binary value stored within the particular stage is toggled when the register is clocked, thereby causing the value stored within the register to be incremented. A common signal is used to initially precharge the voltage at each of the input terminals as well as to select an increment operation.