Segmented Group-Inversion Coding for Parallel Links

A new segmented group-inversion coding is proposed to achieve current balancing in single-ended parallel data transmission. With minimal increase in number of pins, the proposed coding reduces the difference between the number of ZEROs and ONEs to only 0 or 2. Since the proposed coding is a simple inversion-or-not transformation of pre-defined groups of binary data, it can be implemented with greatly simplified logic circuits. Generalization for the optimum grouping is also presented. A transmitter with 16-bit link was designed for verification. The proposed coding scheme is suitable for gigabit parallel links to reduce the simultaneous switching noise