Multiply-accumulate operation device

A multiply-accumulate operation device performs a series of processing by using an analog circuit, the series of processing including causing each of N electric signals being given to correspond to each of loads, multiplying each of values of the electric signals by each of values of the loads corresponding to the electric signals to obtain N multiplied values, and deriving a sum of the N multiplied values,

• the analog circuit including
• N+ first output means that cause each of N+ electric signals being given in a predetermined period T1 to correspond to each of positive loads and output electric charges respectively, each of the electric charges having a size depending on each of values of the electric signals and each of values of the positive loads corresponding to the electric signals,
• a first capture-and-storage means to which the N+ first output means are connected in parallel and in which the electric charges output from each of the N first output means are stored,
• (N−N+) second output means that cause each of (N−N+) electric signals being given in the period T1 to correspond to each of absolute values of negative loads and output electric charges respectively, each of the electric charges having a size depending on each of values of the electric signals and each of the absolute values of the negative loads corresponding to the electric signals,
• a second capture-and-storage means to which the (N−N+) second output means are connected in parallel and in which the electric charges output from each of the (N−N+) second output means are stored, and
• a multiply-accumulate deriving means calculating a first multiply-accumulate value when detecting that a voltage held in the first capture-and-storage means reaches a preset first threshold, calculating a second multiply-accumulate value when detecting that a voltage held in the second capture-and-storage means reaches a preset second threshold, and obtaining the sum of the N multiplied values by subtracting the second multiply-accumulate value from the first multiply-accumulate value, the first multiply-accumulate value being a sum of N+ multiplied values obtained by multiplying each of the positive loads corresponding to the N+ electric signals by each of the values of the N+ electric signals respectively, the second multiply-accumulate value being a sum of (N−N+) multiplied values obtained by multiplying each of the absolute values of the negative loads corresponding to the (N−N+) electric signals by each of the values of the (N−N+) electric signals respectively,
• characterized in that
• the first threshold has a size proportional to a product of a sum of the N+ positive loads and a length of the period T1,
• the second threshold has a size proportional to a product of a sum of the absolute values of the (N−N+) negative loads and the length of the period T1, and
• the multiply-accumulate operation device derives the first multiply-accumulate value and the second multiply-accumulate value in a period T2 having the same length as the length of the period T1 after the period T1,
• wherein the N is a natural number that is two or more, and the N+ is a natural number that is the N or less.