CMOS temperature compensated logarithmic converter based on master–slave control

A logarithmic converter employing the proposed temperature compensating method based on a master-slave control is presented. With the help of a raised master-slave circuit, the proportional to absolute temperature (PTAT) coefficient of the logarithmic converter is compensated by that of the PTAT current in the bandgap reference, which makes the CMOS implementation of the logarithmic converter employing no external component possible. The logarithmic converter provides a 45 dB linear range with <; 3 dB error as the temperature varies from 0 to 90°C.