Voltage controlled oscillator and control method thereof
AssigneeMediatek Inc.
InventorsChao-Ching Hung, Po-Chun Huang, Yu-Li Hsueh
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Abstract
A voltage-controlled oscillator for generating oscillation signals at two output terminals includes an inductor coupled between the two output terminals, a capacitor coupled between the two output terminals, two P-type transistors, coupled between a supply voltage and the two output terminals, two N-type transistors coupled between a ground voltage and the two output terminals, and a control circuit. The control circuit is coupled to the inductor, and is arranged to control a current flowing through the two P-type transistors and the inductor by controlling a voltage of the inductor.
Claims18
A voltage-controlled oscillator for generating oscillation signals at two output terminals, comprising:
- an inductor coupled between the two output terminals;
- a capacitor coupled between the two output terminals;
- two P-type transistors, coupled between a supply voltage and the two output terminals;
- two N-type transistors, coupled between a ground voltage and the two output terminals;
- and
- a control circuit, coupled to the inductor, for controlling a current flowing through the two P-type transistors and the inductor;
- wherein when the voltage-controlled oscillator generates the oscillation signals, each P-type transistor is controlled to have different currents by setting different DC voltages at the corresponding output terminal.
A voltage-controlled oscillator for generating oscillation signals at two output terminals, comprising:
- an inductor coupled between the two output terminals;
- a capacitor coupled between the two output terminals;
- two P-type transistors, coupled between a supply voltage and the two output terminals;
- two N-type transistors, coupled between a ground voltage and the two output terminals, wherein drain electrodes of the two N-type transistors are coupled to drain electrodes of the two P-type transistors via the two output terminals, respectively;
- and
- a control circuit, coupled to the inductor, for turning on or off the two N-type transistors.
A method for controlling a voltage controlled oscillator, comprising:
- when the voltage controlled oscillator is in a start-up stage, controlling the voltage controlled oscillator to operate as a P-type voltage controlled oscillator;
- and
- when the voltage controlled oscillator is in a normal stage following the start-up stage, controlling the voltage controlled oscillator to operate as a PN-type voltage controlled oscillator;
- wherein the voltage controlled oscillator comprises an inductor, a capacitor, two P-type transistors and two N-type transistors, and the step of controlling the voltage controlled oscillator to operate as the P-type voltage controlled oscillator or the PN-type voltage-controlled oscillator comprises:
- when the voltage controlled oscillator is in the start-up stage, turning off the two N-type transistors to make the voltage controlled oscillator to operate as the P-type voltage controlled oscillator;
- and
- when the voltage controlled oscillator is in the normal stage following the start-up stage, turning on the N-type transistors to make the voltage controlled oscillator to operate as the PN-type voltage controlled oscillator.
Dependencies are inferred from the claim text.