Methods, algorithms, architectures, circuits, and/or systems for increasing voltage controlled oscillator (VCO) operational frequency ranges are disclosed. In one embodiment, a VCO can include 2n+1 transconductors configured to provide an oscillating signal, where n≧1; a selectable supply voltage coupled to each of the transconductors, where a frequency range of the oscillating signal is related to the selectable supply voltage; and an adjustable input voltage, where a frequency of the VCO depends on a value of the adjustable input voltage. Also, the VCO may include a voltage regulator configured to provide the supply voltage and/or a selecting circuit configured to select a reference voltage (e.g., from the voltage regulator can produce the supply voltage). Embodiments of the present invention can advantageously provide a cost effective approach for enhancing VCO frequency ranges from a singly VCO, suitable for phase-locked loop (PLL) applications.