Patent ID: 6911869

Claim:
A voltage controlled oscillator (VCO) receiving positive and negative control voltages on which an oscillation frequency of a signal is based, the VCO comprising: a storage capacitor linearly charged by a constant charge current and linearly discharged by a constant discharge current; a comparator comparing a voltage on the storage capacitor to upper and lower threshold voltages, wherein an output of the comparator drops to a negative saturation voltage when the storage capacitor voltage exceeds one of the upper and lower threshold voltages and rises to a positive saturation voltage when the storage capacitor voltage exceeds the other of the upper and lower threshold voltages; a constant charge current source injecting constant charge current to the storage capacitor when the comparator output rises to one of the positive and negative saturation voltages; and a constant discharge current source draining constant discharge current from the storage capacitor when the comparator output drops to the other of the positive and negative saturation voltages.