US 7,443,252 B2Granted

Calibration circuit and operation method for voltage-controlled oscillator

AssigneeNovatek Microelectronics Corp.

InventorsYih-Min Tu, Yuan-Tung Peng, Ping-Hsun Hsieh, Min-Chieh Hsu

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Abstract

A calibration circuit for voltage-controlled oscillator (VCO) includes a calibration bias generator, a VCO, a detection unit, a micro control unit, an adjuster unit, a phase-locked loop (PLL) unit, a control voltage detection unit, and a control switch set. The calibration bias generator outputs a first control voltage. The VCO outputs an oscillation frequency according to the first control voltage. The detection unit detects the oscillation frequency and outputs the detection result signal to the micro control unit. The micro control unit outputs an adjust signal according to the detection result signal. The adjuster unit receives the adjust signal voltage and adjusts the oscillation frequency output from the VCO according to the adjust signal voltage. The PLL unit outputs a second control voltage to the VCO. The control voltage detection unit outputs voltage-detection signal to the micro control unit, which outputs the adjust signal according to the voltage-detection signal.

Claims15

Dependent claims

A calibration circuit for voltage-controlled oscillator (VCO), comprising:

a control unit, with an output terminal outputting a first control voltage;
a voltage-controlled oscillator, with a first input terminal receiving the first control voltage and outputting an oscillation frequency from its output terminal according to the first control voltage;
a detection unit for detecting the oscillation frequency and outputting a detection result signal;
a micro control unit, receiving the detection result signal and outputting an adjust signal according to the detection result signal;
an adjuster unit for receiving the adjust signal and outputting a voltage-adjusting signal to a second input terminal of the VCO according to the adjust signal so as to adjust the oscillation frequency output from the VCO;
a phase-locked loop (PLL) unit, with an input terminal receiving the oscillation frequency and outputting a second control voltage to the first input terminal of the VCO according to the oscillation frequency;
a control voltage, detection unit, with an input terminal receiving the second control voltage and outputting a voltage-detection signal to the micro control unit according to the second control voltage, wherein the micro control unit outputs the adjust signal according to the voltage-detection signal;
and
a control switch set coupled to the output terminal of the PLL unit, the input terminal of the control voltage detection unit, the output terminal of the control unit, and the first input terminal of the VCO to control the connection between each of the units.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 11/309,129Filed 26 Jun 2006
Priority: TW 94134932 A6 Oct 2005
Published: US 2007/0080751 A112 Apr 2007
Granted: 28 Oct 2008
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H03L 7/099
Details of the phase-locked loop: concerning mainly the controlled oscillator of the loop
H03L 7/113
For assuring initial synchronisation or for broadening the capture range: using frequency discriminator
H03L 7/18
Indirect frequency synthesis, i.e. generating a desired one of a number of predetermined frequencies using a frequency- or phase-locked loop:…
H03L 7/0891
The phase or frequency detector generating up-down pulses: the up-down pulses controlling source and sink current generators, e.g. a charge pump