| 摘要 |
PURPOSE:To provide the logarithmic conversion circuit with a small scale circuit so as to suppress an output more than a logarithmic function for the signal of a fine area. CONSTITUTION:An input signal A is amplified by differential amplifier circuits 11 and 12 in first and next steps and an output step amplifier circuit 13 and turned to an output signal B, and an operating current 11 of the differential amplifier circuit 11 in the first step is controlled by a detection signal B' of this output signal B. Thus, logarithmic conversion is while suppressing the fine area. The scale is just made possible for the feedback part of the conventional circuit. |
