Accumulation circuit having a round-off function

A method of accumulating input data in an accumulation circuit, comprising the steps of:

• (a) selecting an initial value representing a predetermined shift number for rounding off accumulated data in an initial cycle;
• (b) adding the initial value to a first input value in the initial cycle to produce an accumulated value;
• and
• (c) adding a second input value to the accumulated value.

An accumulation circuit for accumulating input data, comprising:

• an accumulator storing accumulated data;
• a selection circuit, operatively connected to said accumulator, and selectively outputting one of the accumulated data and a predetermined initial value, said selection circuit selecting the initial value when an initialization signal is input thereto;
• an adder, operatively connected to said accumulator and said selection circuit, and summing the input data and an output of said selection circuit, and outputting a result to said accumulator;
• a shifter, operatively connected to said accumulator, shifting-right bit positions of the accumulated data by a predetermined shift number, input to said shifter, for rounding off said accumulated data to obtain rounded-off data;
• the initial value representing said predetermined shift number, and having logic "1" in a 1/2 LSB position of the rounded-off data and has logic "0" in all bit positions other than said 1/2 LSB position;
• a shift number register for storing the predetermined shift number;
• and
• a decoder for decoding the shift number to generate said initial value.