Matsushita Electric Industrial Co., Ltd.

Akira Matzuzawa

Michihiro Inoue

In a serial-type A/D converter utilizing folding circuit cells connected in cascade, the cell has a differential type input and a differential type output, and a comparator included in the cell switches over current paths in the cell to establish a folding characteristic. An input potential difference is converted into a current difference by a pair of transistors having the emitters interconnected through a resistor, and the current difference is further converted into a pair of differential output voltages by a load circuit having a pair of series connections each including a resistor, a diode and a transistor having its base connected with another resistor, so that the non-linear characteristic and gain can be corrected. A current switching circuit is switched by the comparator for discriminating the polarity of the input potential difference to switch over current paths for the paired transistors or to alternately operate voltage level shifting circuits associated with a pair of output terminals, thereby establishing the folding characteristic with high accuracy.

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Neyagawa, Japan

Akira Matzuzawa