US Patent 7843374 Priority encoder

A priority encoder encodes an (N+1)-bit thermometer code, where N indicates a natural number. A plurality of selectors are arranged in a matrix of M rows and (N+1) columns, where M indicates a natural number, and select one of signals at first and second input terminals (1,0) in accordance with the value of a signal input to the control terminal. An output signal from the selector in the i-th row and (j−1)th column is input to the first input terminal of the selector in the i-th row and j-th column (1≦i≦M, 2≦j≦N+1), a predetermined value of 1 or 0 is input to the second input terminal of the selector in the i-th row and j-th column, and the j-th significant bit of the thermometer code is input to the control terminal of the selector in the i-th row and j-th column.