Reduction of Power Supply Voltage for the CMOS Exponentiation Conversion IC Effectively Utilizing Weak Inversion Operation

In order to compensate the non-linear characteristics in many kinds of electronic devices, the exponentiation conversion circuit that can change the power exponent to any value has been proposed. The exponentiation conversion circuit multiplies the logarithmically converted input signal by the power exponent value to perform exponential conversion. As a result, we can obtain the power function characteristic of the power exponent value. In this paper, we proposed a transconductance circuit that can increase the voltage gain, which decreases with lower power supply voltage. By parallelizing the input and output signal voltage windows with the transconductance circuit, the maximum exponent value was secured to be 2.9, which is equivalent to the conventional value, furthermore the signal dynamic range was 42.7 dB in simulation results. By evaluating its prototype IC with 0.6 µm CMOS process, we confirmed the signal dynamic range was 30.0 dB and maximum power exponent value was 3.4.