Multiply-accumulate operation device, multiply-accumulate operation circuit, multiply-accumulate operation system, and multiply-accumulate operation method

A multiply-accumulate operation method, comprising:

• inputting pulse signals having pulse widths corresponding to input values to a plurality of input lines;
• generating, on a basis of the pulse signals input to each of the plurality of input lines, charges corresponding to multiplication values obtained by multiplying the input values by weight values;
• accumulating a sum of the generated charges corresponding to the multiplication values in an accumulation unit;
• charging the accumulation unit in which a sum of the charges corresponding to the multiplication values is accumulated at a charging speed associated with an accumulation state of the accumulation unit;
• and
• outputting a multiply-accumulate signal representing a sum of the multiplication values by executing threshold determination using a threshold value associated with the accumulation state of the accumulation unit on a voltage held by the accumulation unit after the charging is started, wherein
• the charging speed and the threshold value are set on a basis of an effective maximum value and an effective minimum value of the sum of the charges corresponding to the multiplication values, and
• the effective maximum value and the effective minimum value are obtained from an estimation result of the sum of the charges corresponding to the multiplication values accumulated by the accumulation unit.

A multiply-accumulate operation device that executes a multiply-accumulate operation with an analog circuit, comprising:

• a plurality of input lines, pulse signals having pulse widths corresponding to input values being input to the plurality of input lines;
• a plurality of multiplication circuits that generates, on a basis of the pulse signals input to each of the plurality of input lines, charges corresponding to multiplication values obtained by multiplying the input values by weight values;
• an accumulation circuit that accumulates a sum of the charges corresponding to the multiplication values generated by each of the plurality of multiplication circuits;
• a charging circuit that charges, at a charging speed associated with an accumulation state of the accumulation circuit, the accumulation circuit in which the sum of the charges corresponding to the multiplication values have been accumulated;
• and
• an output circuit that outputs a multiply-accumulate signal representing a sum of the multiplication values by executing threshold determination using a threshold value associated with the accumulation state of the accumulation circuit on a voltage held by the accumulation circuit after the charging by the charging circuit is started, wherein
• the charging speed and the threshold value are set on a basis of an effective maximum value and an effective minimum value of the sum of the charges corresponding to the multiplication values, and
• the effective maximum value and the effective minimum value are obtained from an estimation result of the sum of the charges corresponding to the multiplication values accumulated by the accumulation circuit.

A multiply-accumulate operation device that executes a multiply-accumulate operation with an analog circuit, comprising:

• a plurality of input lines, pulse signals having pulse widths corresponding to input values being input to the plurality of input lines;
• a plurality of multiplication circuits that generates, on a basis of the pulse signals input to each of the plurality of input lines, charges corresponding to multiplication values obtained by multiplying the input values by weight values;
• an accumulation circuit that accumulates a sum of the charges corresponding to the multiplication values generated by each of the plurality of multiplication circuits;
• a charging circuit that charges, at a charging speed associated with an accumulation state of the accumulation circuit, the accumulation circuit in which the sum of the charges corresponding to the multiplication values have been accumulated;
• and
• an output circuit that outputs a multiply-accumulate signal representing a sum of the multiplication values by executing threshold determination using a threshold value associated with the accumulation state of the accumulation circuit on a voltage held by the accumulation circuit after the charging by the charging circuit is started, wherein
• the pulse signals are respectively input to each of the plurality of input lines within an input period having a predetermined length,
• the charging circuit starts the charging after the input period is ended, and
• the output circuit outputs the multiply-accumulate signal on a basis of timing at which the voltage held by the accumulation circuit increases or decreases over the threshold value within an output period having a predetermined length, and
• the pulse signals respectively have a pulse width corresponding to a period from timing corresponding to the input value in the input period to end timing of the input period.