Low power and low area or high throughput single-ended bus and I/O protocols

Low power, low area and high data throughput strategies using large or relatively large swing for single-ended buses and I/Os are addressed. Four protocols are presented, combining swing-reduction with charge-recycling. Protocols 1 and 2 use V_dd/2 swing with three signal levels while protocols 3 and 4 use V_dd/3 swing with four signal levels. Their average power reducing factors are 2.5, 3.2, 4.7 and 4.3 (>5.5 for large loads) respectively. Protocol 3 merges two buses or I/Os into a single one while retaining the transmission capacity of two, an improvement factor of 2 either in bus number or in data throughput