An instruction buffering apparatus is disclosed. Each resultant class is clustered into a plurality of segments to build a code-book for the respective class using a modified K-means clustering process which dynamically adjusts the size and centroid of each segment during each iteration in the modified K-means clustering process. A latch miss detection circuit outputs a latch miss detection signal indicating presenceabsence of a latch miss generation according to the test pattern and a delay shift clock. The charging profiles are provided to the universal charger device.