Patent ID: 6617933
Filing Date: 2003-09-09
Classification: H03L

Abstract:
A voltage-controlled oscillating circuit receiving supply of a power source voltage to operate comprising:a voltage generating circuit setting a voltage level of a bias voltage according to a control voltage being different from said power source voltage inputted from the outside, said voltage generating circuit including an operational amplifier, which is an amplifier of a single stage configuration, and receiving supply of said power source voltage to operate, said operational amplifier having first and second input terminals, wherein one of said first and second input terminals is electrically coupled with said control voltage, and an output terminal outputting said bias voltage, and said voltage generating circuit further including a) a feedback portion coupled between said output terminal and another one of said first and second input terminals and b) a non-inverting amplifier circuit using said operational amplifier receiving supply of said power source voltage to operate; and a ring oscillator circuit generating a clock having a frequency corresponding to said bias voltage, and having an odd-number of inverters, interconnected in a closed ring, and each inverter receiving supply of said bias voltage to operate, wherein each of said inverters includes a p-channel MOS transistor receiving said bias voltage at its source electrode.