Patent ID: 8004291

Claim:
A bioelectric impedance measuring circuit for applying a current to an organism and measuring a bioelectric impedance of the organism, the bioelectric impedance measuring circuit comprising: a pseudo-sine wave generating circuit for generating a pseudo-sine wave based on an input square wave; a voltage/current converting circuit for outputting current to the organism in correspondence with the pseudo-sine wave generated by the pseudo-sine wave generating circuit; and a processing circuit for generating the square wave and supplying the square wave to the pseudo-sine wave generating circuit and measuring the bioelectric impedance based on a voltage output from the voltage/current converting circuit; wherein the pseudo-sine wave generating circuit is included in a semiconductor integrated circuit; wherein the pseudo-sine wave generating circuit includes: a plurality of serially connected resistors for dividing voltage from a power source, a plurality of switching devices for outputting a voltage divided by the plurality of resistors, each of the plural switching devices has a source connected to a connecting point connecting a pair of the plural resistors, and a controller for sequentially switching on the plurality of switching devices based on the square wave.