Patent ID: 6734742
Filing Date: 2004-05-11
Classification: H03K,H03L

Abstract:
A voltage controlled oscillator (VCO) capable of receiving a +V(IN) control voltage and a âˆ’V(IN) control voltage and outputting a VCO output signal having a frequency of oscillation determined by said +V(IN) control voltage and said âˆ’V(IN) control voltage, said VCO comprising:a storage capacitor capable of being charged linearly by a constant charge current and discharged linearly by a constant discharge current; a comparator capable of comparing a voltage on said storage capacitor to an upper threshold voltage and a lower threshold voltage, wherein an output of said comparator drops to a negative saturation voltage (âˆ’V(SAT)) when said storage capacitor voltage rises above said upper threshold voltage and said comparator output rises to a positive saturation voltage (+V(SAT)) when said storage capacitor voltage drops below said lower threshold voltage; a constant charge current source capable of injecting said constant charge current to said storage capacitor when said comparator output rises to said positive saturation voltage; and a constant discharge current source capable of draining said constant discharge current from said storage capacitor when said comparator output drops to said negative saturation voltage.