US 7,609,123 B2Granted

Direct modulation type voltage-controlled oscillator using MOS varicap

AssigneePanasonic Corporation

InventorMasakatsu Maeda

Life of this patent

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Abstract

Transistors M11 and M12 are cross-coupled to each other so as to form a negative resistance circuit. First and second variable capacitor sections 10 and 20 are connected in parallel with an inductor circuit so as to form a parallel resonant circuit. A first reference voltage Vref1 and a control voltage VT1 corresponding to a carrier wave component are fed to both terminals, respectively, of each of variable capacitors VC11 and VC12 included in the first variable capacitor section 10. A second reference voltage Vref2 and a control voltage VT2 corresponding to a modulated wave component are fed to both terminals, respectively, of each of variable capacitors VC21 and VC22 included in the second variable capacitor section 20. A DC control section 30 includes a resistance R31 interposed between the second reference voltage Vref2 and a common connection point of resistances R21 and R22, and a capacitor C31 for feeding only an AC component included in the modulated wave component to the common connection point of the resistances R21 and R22. Thus, a DC voltage, on which the AC component included in the modulated wave component is superimposed, is changed from a certain DC bias to a DC bias of the second reference voltage Vref2.

Claims6

Dependent claims

A direct modulation type voltage-controlled oscillator for oscillating a signal in which a carrier wave component is modulated by a modulated wave component, the direct modulation type voltage-controlled oscillator comprising:

a first variable capacitor section having a first terminal and a second terminal, the first variable capacitor section including a variable capacitor whose capacitance value varies in accordance with a potential difference between a control voltage, corresponding to the carrier wave component, which is fed to the first terminal and a first reference voltage applied to the second terminal;
a second variable capacitor section having a first terminal and a second terminal, the second variable capacitor section including a variable capacitor whose capacitance value varies in accordance with a potential difference between a control voltage, corresponding to the modulated wave component, which is fed to the first terminal and a second reference voltage applied to the second terminal;
and
a voltage setting section operable to set the control voltage corresponding to the modulated wave component based on the second reference voltage,
wherein the voltage setting section includes:
an offset circuit operable to detect an intermediate capacitance value in the second variable capacitor section and to generate, based on the second reference voltage, a third reference voltage corresponding to the intermediate capacitance value;
a resistance located between the offset circuit and the first terminal of the second variable capacitor section, the third reference voltage passing through the resistance prior to being received at the first terminal of the second variable capacitor section;
and
a capacitor located before the first terminal of the second variable capacitor section, the capacitor being operable to pass only an AC component included in the modulated wave component to the first terminal of the second variable capacitor section.

6 more elements

a first variable capacitor section having a first terminal and a second terminal, the first variable capacitor section including a variable capacitor whose capacitance value varies in accordance with a potential difference between a control voltage, corresponding to the carrier wave component, which is fed to the first terminal and a first reference voltage applied to the second terminal;
a second variable capacitor section having a first terminal and a second terminal, the second variable capacitor section including a variable capacitor whose capacitance value varies in accordance with a potential difference between a control voltage, corresponding to the modulated wave component, which is fed to the first terminal and a second reference voltage applied to the second terminal;
and
a voltage setting section operable to set the control voltage corresponding to the modulated wave component which is differentially inputted, based on the second reference voltage.

1 more element

Dependencies are inferred from the claim text.

Facts

Application: 11/953,345Filed 10 Dec 2007 · us provisional application
Priority: 12 Dec 2006
Published: US 2008/0150648 A126 Jun 2008
Granted: 27 Oct 2009
Term ends: Not estimatedThe source records don’t support an estimate.

Classification6 codes

H03C 3/225
The element being a semiconductor diode, e.g. varicap diode: using field effect transistors
H03B 5/1215
The amplifier comprising a pair of transistors, wherein an output terminal of each being connected to an input terminal of the other, e.g. a…
H03B 5/1228
Active element in amplifier being semiconductor device: the amplifier comprising one or more field effect transistors
H03B 5/1253
The means comprising transistors used to provide a variable capacitance: the transistors being field-effect transistors

Family

Application60/874,278Us provisional application · filed 12 Dec 2006
US 2008/0150648 A1Pre-grant publication · published 26 Jun 2008
US 7,609,123 B2This patent

From the US filing history. Foreign family members aren’t listed.

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