Simple Diode-Less Active RMS Detector Using Special Analog Multipliers

Active root mean square (RMS) diode-less detectors are common analog blocks suitable for various signal processing and communication applications. This brief introduces a new and simple type of this detector suitable for high-speed applications up to several tens of MHz. The circuit was designed with special analog multipliers (MLTs) fabricated in
$0.18 ~\mu \text{m}$
CMOS process having power consumption 3.5 mW only at supply voltage 1.8 V. It actually utilizes two MLTs and one external grounded capacitor. The operationability of the RMS detector was verified by a set of experimental measurements and the obtained features were compared with recent solutions including also peak detectors. For this purpose, signals with various waveforms and amplitudes in a range from 5 mV up to 500 mV were used. Good correspondence between theory and real measurements were observed for signals with frequency up to 40 MHz.