A low-voltage low-power CMOS weak inversion true rms-to-dc converter

A true RMS-to-DC converter based on the explicit computation technique is proposed in this paper. The design technique utilizes translinear principle circuit to realize current mode absolute-value, squarer, averaging and square root circuit. The circuit employs CMOS transistors operating in weak inversion region, and features very low power (<;1 uW), low supply voltage (0.8 V) and wide input dynamic range (0.5 nA to 500 nA) with the error less than 2%. Simulation results by HSPICE show high performance of the circuit and confirm the validity of the proposed design technique.