A Low-Power CMOS Current-Mode True RMS-to-DC Converter

Abstract

This paper presents a low-power CMOS current-mode true RMS-to-DC converter based on the translinear principle of CMOS operating in a saturation region. The technique used for the design of the realization scheme was the implicit computation method. Its main conversion circuit structure consisted of a two-quadrant squaring circuit and a low-pass filter circuit. The circuit can be used with both positive and negative input signals. Simulation results were examined using the HSPICE program with model 0.18 µm BSIM3V3 level 49 TSMC CMOS process parameters. It was found that the circuit features could operate well in a wide input range (500 nA-100 µA), with low supply voltage (1.8 V), low power dissipation (0.15 µW), and a high bandwidth (50 MHz); and the error of conversion accuracy was less than 1%, well in agreement with theory.