Simple VCO with negative voltage-frequency relation

A simple voltage controlled oscillator (VCO) with negative voltage-frequency (V-F) relation is presented in this paper. The realization technique is based on the use of commercial available devices to generate tunable sawtooth and square wave signals. Decreasing the control voltage linearly increases the output oscillation frequency. The proposed VCO consists of operational transconductance amplifiers (OTAs) and an RS Flip Flop. Experimental results showing the circuit performances are agreed with the expected values. The usefulness of the proposed circuit is demonstrated through application example with reducing the output ripple waveforms of a buck converter.