Lookahead-based adaptive voltage scheme for energy-efficient on-chip interconnect links

This paper presents a novel adaptive voltage scheme based on a lookahead circuit that checks the transmitter buffer for data transitions. The advanced knowledge of incoming data patterns is used to adjust the link swing voltage, improving delay and energy performance. In the presented example system, a transition detection circuit is used to check the transmitter buffer for rising transitions (dasia0psila in cycle t, dasia1psila in cycle t+1). When a rising transition is detected, a higher supply voltage is applied to the driver for a small portion of the clock cycle to boost the rising edge delay, improving link performance. A lower voltage is used for all other transmissions, improving the delay performance of falling edge transitions and the link energy dissipation. For a 1 GHz link frequency, the proposed approach improves energy dissipation by 45% compared to a traditional two-inverter buffer. An energy savings of up to 15% is achieved compared to a previously proposed dual-voltage scheme.