VCO CIRCUIT AND FREQUENCY SYNTHESIZER

Title:

VCO CIRCUIT AND FREQUENCY SYNTHESIZER

Document Type and Number:

Japanese Patent JP2015154394

Kind Code:

A

Abstract:

PROBLEM TO BE SOLVED: To improve a phase noise, and to quickly stabilize the amplitude of an oscillation signal.SOLUTION: A VCO circuit includes: a current source; an oscillation core part; an amplitude detection part; a current control part; a low-pass filter; and a switch. The current source supplies bias currents having a value corresponding to a current control signal. The oscillation core part performs an oscillating operation by using the bias currents, and outputs an oscillation signal. The amplitude detection part outputs a detection voltage corresponding to the amplitude of the oscillation signal. The current control part outputs a control signal to make the detection voltage equal to a reference voltage. The low-pass filter supplies the current control signal obtained by filtering the control signal to the current source. The switch is connected in parallel with the low-pass filter.

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Inventors:

SHOJI TAKASHI
MASUOKA HIDEAKI

Application Number:

JP2014028467A

Publication Date:

August 24, 2015

Filing Date:

February 18, 2014

Export Citation:

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Assignee:

TOSHIBA CORP

International Classes:

H03L7/099

Attorney, Agent or Firm:

Hirohito Katsunuma
Takeshi Sekine
Akaoka Akira
Katsumi Ozawa

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