DRAM with total self refresh and control circuit

摘要

Internally refreshing one or more DRAM arrays without requiring additional external command signals. Scheduling of either refresh cycles and/or read/write access cycles uses an arbitration and selection circuit that receives a refresh request input signal from an independent oscillator and a row access select RAS input signal. A wordline address multiplexer provides either internally-provided refresh or externally-provided row-line address signals to a wordline decoder. A refresh row counter uses a token status signal for activating only one refresh row counter at a time. Instantaneous refresh power is controlled by controlling the number of cells in each DRAM block. An arbitration and control system includes an address transition block with a delay for resolving metastability, a refresh control block, a RAS control block, and an arbitration circuit that temporarily stores unselected requests.