Abstract—Theuseofdynamicallyadjustablepowersuppliesas
amethodtolowerpowerdissipationinDSPisanalyzed.Power
canbereducedsubstantiallywithoutsacri?cingperformancein
?xed-throughputapplicationsbyslowingtheclockandlowering
supplyvoltageinsteadofidlingwhencomputationalworkload
varies.Thiscanyieldatypicalpowersavingsof30–50%.If
latencycanbetolerated,bufferingdataandaveragingprocessing
ratecanyieldpowerreductionsof anorderofmagnitude insome
applications.Continuousvariationofthesupplyvoltagecanbe
approximatedbyverycrudequantizationanddithering:afour-
levelcontrollerissuf?cienttogetwithinafewpercentofthe
optimalpowersavings.Signi?cantsavingsarepossibleonlyifthe
voltagecanbechangedonthesametimescaleasthevariations
inworkload.Achiphasbeenfabricatedandtestedtoverify
theclosed-loopfunctionalityofavariablevoltagesystem.The
controllertakesonly0.4mm2
anddrawsamaximumof1mW
at2Vwitha40MHzclock.Thecontrolframeworkdeveloped
isapplicabletogenericDSPapplications.
IndexTerms—Low-powerDSP,variablesupplyvoltage,work-
loadaveraging.