Patent ID: 7589581

Claim:
A binary bidirectional trimming circuit, comprising: a first resistor set having 4 resistors in parallel connected and a first fuse bridged two ends thereto provide one trimming step; a second resistor set having 2 resistors in series connected and a second fuse bridged two ends thereto provide eight trimming steps; a third resistor set having 2 resistors in parallel connected and a third fuse bridged two ends thereto provide two trimming steps; a fourth resistor set having 1 resistor and a fourth fuse bridged two ends thereto provide four trimming steps; a first loading resistor; a second loading resistor; and wherein all of said resistors have the same resistance except both of said loading resistors, and still said first loading resistor, and said second resistor set are in series connected to constitute a first set and said second loading resistor, said first resistor set, said third resistor set, said fourth resistor set are in series connected in any predetermined order to constitute a second set having at most seven trimming steps, furthermore, a connection node between said first set and said second set, which are in series connected, is chosen as an output terminal.