To suppress power consumption by sequentially holding digital voltage signal with registers, holding a plurality of coefficients of one bit, which correspond to the registers, in a shift register, calculating the exclusive OR of the digital voltage signals and the coefficients and converting the total sum of outputs into an analog current signal.
In the analog addition circuit ADD of a current type, the four-bit outputs of exclusive OR circuits XOR1-XORn are inputted to the gates of switches T11-T14,..., Tn1-Tn4. When outputs are in high levels, the switches are closed. Constant current sources I11-I14,..., In1-In4 connected to the drains of the respective switches supply the current of a current value corresponding to the weight of the bit connected to the switch. When the switch is closed, the currents are supplied to the source of the switch connected to a common output terminal and the total sum of the currents flowing in the respective switches is outputted as Aout.
SHU TERUHEI
SUZUKI KUNIHIKO
