Patent ID: 7233300

Claim:
An apparatus for displaying gray scales of a plasma display panel (PDP), by which gray scales are displayed by arranging a plurality of sub-fields having brightness weights in the order of time and the number of sub-fields is determined according to an average signal level (ASL) of video data, the apparatus comprising: an automatic power controller for detecting an ASL in each field of video data; first and second memories for storing the video data in even frames and odd frames; a sub-field generator for mapping the video data output from the automatic power controller according to the number of sub-fields that is determined by the ASL detected by the automatic power controller, generating corresponding gray scale data, and selectively storing the gray scale data in the first and second memories; an address data generator for generating address data corresponding to the gray scale data output from the sub-field generator and applying the address data to the PDP; an ASL controller for comparing the number of sub-fields that are determined by the ASL in a current field from the automatic power controller with the number of sub-fields that are determined by the ASL in a previous field from the automatic power controller, and controlling the output number of sub-fields; and a sustain scan pulse generator for receiving the number of sub-fields that is controlled by and output from the ASL controller, generating corresponding sustain pulses and scan pulses, and applying the sustain pulses and scan pulses to the PDP, wherein the sub-field generator maps the video data of the current field according to the number of sub-fields that is determined by the ASL of the previous field video data, and stores the video data of the current field in either the first memory or the second memory, and wherein the ASL controller compares the number of sub-fields corresponding to the ASL of the current field with the number of sub-fields corresponding to the ASL of the previous field, outputs the number of sub-fields corresponding to the ASL of the current field to the sustain scan pulse generator when the number of sub-fields corresponding to the ASL of the previous field is equal to the number of sub-fields corresponding to the ASL of the current field, and outputs the number of sub-fields corresponding to the ASL of the previous field to the sustain scan pulse generator when the number of sub-fields corresponding to the ASL of the previous field is different from the number of sub-fields corresponding to the ASL of the current field.