Patent ID: 6407644
Filing Date: 2002-06-18
Classification: H03K

Abstract:
A voltage controlled oscillator having an output frequency that is controlled by incrementing an input voltage of the oscillator, comprising:a variable frequency oscillator, whose oscillating frequency is controlled by an input signal; and a control device operative to generate the input signal for controlling the variable frequency oscillator such that an incremental change of the input voltage changes the output frequency by &Dgr;F hertz when the input voltage is equal to or less than a predetermined threshold voltage, and for controlling the variable frequency oscillator such that the incremental change of the input voltage changes the output frequency by more than &Dgr;F hertz, when the input voltage exceeds a predetermined threshold voltage, the control device comprising: a first voltage/current converter in which an output current changes in response to the change of the input voltage; and a second voltage/current converter in which the output current changes in response to the change of the input voltage, when the input voltage exceeds the predetermined threshold voltage; wherein the variable frequency oscillator is controlled by the currents from the first and the second voltage/current converters; and wherein the second voltage/current converter is a voltage/current converter having a variable threshold voltage.