D-a converter circuit

Abstract

Abstract PURPOSE:To improve the non-linearity of a D-A conversion characteristic generated with a current unbalance due to the on-resistance of a MOS switch by adopting a constitution to connect a MOS single switch to be always in an on-condition in series to a resistance R of an R-2R resistance ladder circuit. CONSTITUTION:For eliminating the influences of the on-resistances of dual switches C1, C1'...Cn and Cn' composed of the MOS transistors, a resistance 2R is divided into resistances having two resistance values R, and a switch VDD by the MOS transistor which is always in the on-condition and, simultaneously, whose on-resistance is equal to the on-resistances of the switched C1, C1'...Cn and Cn' is connected in series to each of two among three resistances R. To the other one, the on-resistances of the MOS dual switches C1, C1'...Cn and Cn' are supplied. When the on-resistance of the switch by the MOS transistor is made into an (r), the resistance to see the right and the resistance to see the below from the connecting point An are made equally into 2R+2r, and a synthetic resistance to simultaneously see the right and below from the connecting point An is made into R+r. A feedback resistance Rf of an arithmetic amplifier 62 is made into R+r.

Inventors

• 👤 Hiroshi Asazawa
• 👤 浅澤　博

Bibliographic Details