Dual-Threshold Approximate Write for PCM in Video Applications

As an emerging non-volatile memory technology,phase change memory（PCM）is promising as an alternative to DRAM.For PCM used in video applications,given that luminance data are more critical than chrominance data,this paper proposes a significance-aware dual-threshold approximate write scheme to reduce its write traffic and extend its lifetime.This scheme first designates different threshold registers and selects different thresholds for luminance data and chrominance data.Next it compares the chosen threshold with the absolute difference between new data and old data.If the absolute difference doesn’t exceed the threshold,the write operations are disabled.Otherwise,only the updated bits are written.Experimental results show that the proposed method can effectively reduce the write operations of PCM with a low hardware overhead.In addition,it has the flexibility to make a trade-off between write traffic reduction and video quality.