| 摘要 |
PURPOSE: A self refresh device is provided to reduce power consumption owing to refresh and to realize low power by selectively using a refresh cycle proper for element characteristic. CONSTITUTION: Several signals of drain terminals(pu,pd) in PMOS/NMOS(p-channel/n-channel metal oxide semiconductor) transistors(MP0,MN0) are converted owing to variable resistance depending on fuse blowing. The converted signals are transmitted to gate terminals of each PMOS/NMOS transistor(MP1-MPn,MN1-MNn) to change the amount of electric currents. The amount of currents flowing into inverters(IV1-IVn) is changed by changing the potential of source terminals(pu_a,pd_a) of the inverters. The signals are fed back to the input terminal of an inverter(IV1) from the odd numbers of inverters. At the same time, an oscillation cycle is changed through the variation of delay amount of each inverter owing to the changed currents to form pulse signals having various cycles depending on each different resistance value of variable resistance.
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