Patent ID: 6777999
Filing Date: 2004-08-17
Classification: H03G

Abstract:
An exponential conversion circuit comprising:a first voltage conversion circuit for converting first and second reference input voltages to first and second differential output voltages on the basis of a first gain control signal; a first exponential conversion device for creating a first output current which changes exponentially with respect to the first differential output voltage; a second exponential conversion device for creating a second output current which changes exponentially with respect to the second differential output voltage; a current comparison circuit for changing the first gain control signal in accordance with a ratio of the first and the second output currents; a second voltage conversion circuit for converting a control input voltage and the first reference input voltage into third and fourth differential output voltages, respectively, on the basis of a first gain control signal; and a third exponential conversion device for creating a third output current which changes exponentially with respect to the third and the fourth differential output voltages.