Approximate Voltage Regulation for Energy Efficient Error Tolerable Applications

The primary objective of on-chip voltage regulation is to achieve the best possible output quality. In a centralized on- chip voltage regulation scheme with a single voltage regulator, the transient voltage droop can be reduced faster transient response as compared to off-chip voltage regulation. To further improve the quality of the generated supply voltage, a distributed on-chip voltage regulation scheme with many localized voltage regulators can be implemented to improve the transient performance and reduce static IR drop. In this work, approximate voltage regulation is investigated to investigate a trade-off between designing a voltage regulator that can achieve the best possible transient and steady state performance or one with just enough output quality. Approximate voltage regulation can fill the niche design space for energy efficient error tolerable applications for both centralized and distribution on-chip voltage regulation cases. Leveraging the error tolerance of the load circuitry, more than 26% current efficiency savings have been achieved with a digital low-dropout regulator.