Patent ID: 8890627

Claim:
A voltage controlled oscillator generating an oscillation signal according to a first control signal, comprising: a control signal adjuster, receiving the first control signal and generating a second control signal and a third control signal according to the first control signal, wherein the second control signal is generated to be higher than a voltage level of the first control signal and the third control signal is generated to be higher than a voltage level of the second control signal; and a plurality of delay cells, ring-connected and controlled by the first, the second, and the third control signals to generate the oscillation signal, wherein each delay cell comprises: a first set of current generation transistors, wherein each transistor provides a control terminal to receive the first control signal; a second set of current generation transistors, wherein each transistor provides a control terminal to receive the second control signal; and a third set of current generation transistors, wherein each transistor provides a control terminal to receive the third control signal.