KR20140072996A - Active inductor and oscillator using the same - Google Patents

Active inductor and oscillator using the same Download PDF

Info

Publication number
KR20140072996A
KR20140072996A KR1020120140447A KR20120140447A KR20140072996A KR 20140072996 A KR20140072996 A KR 20140072996A KR 1020120140447 A KR1020120140447 A KR 1020120140447A KR 20120140447 A KR20120140447 A KR 20120140447A KR 20140072996 A KR20140072996 A KR 20140072996A
Authority
KR
South Korea
Prior art keywords
node
inductor
transistor
oscillator
active inductor
Prior art date
Application number
KR1020120140447A
Other languages
Korean (ko)
Inventor
유태근
Original Assignee
한국전자통신연구원
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 한국전자통신연구원 filed Critical 한국전자통신연구원
Priority to KR1020120140447A priority Critical patent/KR20140072996A/en
Publication of KR20140072996A publication Critical patent/KR20140072996A/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1206—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device using multiple transistors for amplification
    • H03B5/1212—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device using multiple transistors for amplification 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 cross coupled pair
    • H03B5/1215—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device using multiple transistors for amplification 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 cross coupled pair the current source or degeneration circuit being in common to both transistors of the pair, e.g. a cross-coupled long-tailed pair
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B5/00—Generation of oscillations using amplifier with regenerative feedback from output to input
    • H03B5/08—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance
    • H03B5/12—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device
    • H03B5/1228—Generation of oscillations using amplifier with regenerative feedback from output to input with frequency-determining element comprising lumped inductance and capacitance active element in amplifier being semiconductor device the amplifier comprising one or more field effect transistors
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03B—GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS
    • H03B2200/00—Indexing scheme relating to details of oscillators covered by H03B
    • H03B2200/003—Circuit elements of oscillators
    • H03B2200/0058—Circuit elements of oscillators with particular transconductance characteristics, e.g. an operational transconductance amplifier

Landscapes

  • Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)

Abstract

Disclosed are an active inductor and an oscillator using the same. the active inductor includes a first current source connected between a source voltage and a first node; a first transistor of which a drain is connected to the first node and a source is connected to a second node; a second current source connected between the second node and an earthing terminal; a second transistor of which the source is connected to the power voltage and the drain is connected to the second node; and a feedback resistance connected between the first node and a gate of the second transistor. Therefore, the present invention expands a frequency changing ranged and reduces a chip area. The present invention also can be designed in a low voltage.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an active inductor and an oscillator using the same,

The present invention relates to an oscillator, and more particularly, to an oscillator using an active inductor and an active inductor that can be applied to a low power supply voltage, reduce a chip area, and extend a frequency variable range.

An inductor is a device that induces a voltage corresponding to a change in current, and recently, a function of varying the value of an inductor in various fields is required. For example, the inductor can be used to adjust the operating frequency range to a voltage controlled oscillator (VCO) that performs the function of adjusting the frequency bandwidth of the transmission and reception signals in the communication system, and in the high-performance radar system, May be used for the phase shifter constituting the phase shifter.

Meanwhile, since most of the oscillators manufactured by the semiconductor integrated circuit process have a large circuit size due to the integration of the passive inductors, the area of the whole chip is increased and thus the manufacturing cost is increased .

In addition, since the conventional oscillators are configured to vary the frequency by using a capacitor, there is a disadvantage that the frequency variable range is narrow. In order to overcome such disadvantages, attempts have been made to use active inductors for oscillators. However, since most of the chips are manufactured to operate at a low power, it is difficult to apply an active inductor to a lower power supply voltage.

SUMMARY OF THE INVENTION An object of the present invention is to provide an active inductor capable of operating at a low power supply voltage and having a wide frequency variable range and reducing the area of a chip.

Another object of the present invention is to provide an oscillator using the active inductor.

According to an aspect of the present invention, there is provided an active inductor including: a first current source connected between a power supply voltage and a first node; a drain connected to the first node; A second transistor connected between the second node and the ground terminal, a second transistor having a source connected to the power supply voltage and a drain connected to the second node, and a second transistor coupled between the first node and the second transistor, And a feedback resistor connected between the gates of the transistors.

According to the oscillator using the active inductor as described above, the passive inductor included in the conventional oscillator can be replaced with an active inductor having a high Q value and operating at a low voltage, thereby reducing the total chip area occupied by the oscillator, Can be easily applied to the required circuit.

In addition, it is possible to extend the frequency variable range by varying the inductance value of the active inductor by varying the feedback resistance and / or the bias current of the active inductor.

1 is a circuit diagram showing an active inductor according to an embodiment of the present invention.
2 is a circuit diagram showing an example in which the active inductor shown in Fig. 1 is applied to an oscillator.
3 is a circuit diagram showing a configuration of an oscillator using an active inductor according to an embodiment of the present invention.

While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail.

It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

The terminology used in this application is used only to describe a specific embodiment and is not intended to limit the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In the present application, the terms "comprises" or "having" and the like are used to specify that there is a feature, a number, a step, an operation, an element, a component or a combination thereof described in the specification, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Terms such as those defined in commonly used dictionaries should be interpreted as having a meaning consistent with the meaning in the context of the relevant art and are to be interpreted in an ideal or overly formal sense unless explicitly defined in the present application Do not.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In order to facilitate the understanding of the present invention, the same reference numerals are used for the same constituent elements in the drawings and redundant explanations for the same constituent elements are omitted.

Recently, various RF (Radio Frequency) devices have been implemented using CMOS technology in accordance with the development of CMOS (Complementary Metal-Oxide Semiconductor) process technology. In particular, studies for integrating inductors essential for RF circuit design have been actively conducted.

In the conventional method, a spiral structure of a multilayer is used as a method of integrating the inductors, or an inductor having a Q factor in the range of 3 to 10 using a substrate having a high resistivity, Respectively.

On the other hand, in the current RF integrated circuit, spiral inductors are integrated and used mainly on a silicon substrate. However, in the CMOS process, there is a problem that inductance having a sufficiently large Q value can not be realized due to loss of the substrate.

In addition, a spiral inductor integrated in a CMOS process has a disadvantage in that the manufacturing cost is increased because it occupies a wide chip area. In order to overcome such disadvantages, an active inductor using a CMOS device has been proposed.

The active CMOS inductor has a relatively small chip area, high Q value, and variable inductance when compared to a spiral inductor integrated on a silicon substrate. However, since active CMOS inductors use active devices, they have a limitation in operating frequency, a high noise figure, and a drawback that DC power is consumed.

In order to overcome the disadvantages of the conventional active CMOS inductor as described above, in the present invention, a feedback resistor is applied to the active inductor, so that the active inductor has a higher Q value than the conventional active CMOS inductor, The present invention provides an oscillator using an active inductor, which is applied to an oscillator using a conventional passive inductor.

1 is a circuit diagram showing an active inductor according to an embodiment of the present invention. FIG. 1 (a) shows an active inductor circuit, and FIG. 1 (b) And shows an equivalent circuit of the inductor circuit.

1, the active inductor 100 includes a first current source I1 connected between a power source voltage VDD and a first node N1, a second current source I2 connected between a drain of the first node N1 A second current source I2 connected between a second node N2 and a ground terminal GND and a second current source I2 connected between the second node N2 and a source And a gate connected to the drain of the first transistor M1 and the gate of the second transistor M2. The second transistor M2 is connected between the first node N1 and the second node N2, And a connected feedback resistor (R f ).

The active inductor circuit shown in Fig. 1 (a) has an equivalent inductance L eq , an equivalent capacitance C eq , an equivalent resistance R eq and a loss resistance R s as shown in Fig. 1 (b) The equivalent inductance L eq , the equivalent capacitance C eq , the equivalent resistance R eq , and the loss resistance R s of the equivalent circuit can be expressed by Equation 1 .

Figure pat00001

In Equation 1, C gs1 means the capacitance between the gate and the source of the first transistor (M1) and, C gs2 means a capacitance between the gate and the source of the second transistor (M2). G ds1 means the drain-to-source conductance of the first transistor M1, and g m1 and g m2 mean the transconductance of the first and second transistors M1 and M2, respectively.

Further, g o1 and g o2 denote the output conductances of the first and second transistors M1 and M2, respectively, and r o2 denotes the output resistance of the second transistor M2.

On the other hand, the oscillation frequency of the active inductor 100 shown in FIG. 1 is obtained by resonance of the inductor L and the capacitor C as shown in Equation (2).

Figure pat00002

In Equation (2), C p denotes the parasitic capacitance of the source of the first transistor M 1 and the drain of the second transistor M 2 corresponding to the oscillation node, C gs 2 denotes the gate of the second transistor M 2, Means the capacitance between the electrodes.

The transconductances g m1 and g m2 and the feedback resistance R f of the parameters shown in the equation (2) can be adjusted, and the resonance frequency can be changed by adjusting the parameter values.

As shown in FIG. 1, the active inductor 100 according to an exemplary embodiment of the present invention includes a transistor, a feedback resistor, and a current source. Therefore, the active inductor 100 can operate at a low voltage and reduce the chip area in actual implementation.

2 is a circuit diagram showing an example in which the active inductor shown in Fig. 1 is applied to an oscillator.

2 (a) shows a conventional oscillator circuit using a passive inductor, and FIG. 2 (b) shows an active inductor 100 according to an embodiment of the present invention shown in FIG. Lt; / RTI >

2, a conventional oscillator includes a first inductor L1 and a second inductor L2 connected between a power supply voltage VDD and a third node N3 and a fourth node N4, A capacitor C1 connected between the third node N3 and the fourth node N4; a drain connected to the third node N3; a gate connected to the fourth node N4; A fourth transistor M4 having a drain connected to the fourth node N4 and a gate connected to the third node N3 and a source connected to the ground terminal GND, .

As shown in FIG. 2A, in the integrated oscillator using the conventional passive inductors (i.e., L1 and L2), the inductors L1 and L2 occupy most of the entire area of the oscillator. Therefore, there is a limitation in reducing the overall chip size of the oscillator due to the passive inductors L1 and L2, which raises the problem of increasing the price.

However, when the first inductor L1 and the second inductor L2 included in the conventional oscillator are replaced with the active inductor 200 according to an embodiment of the present invention, the area of the chip is relatively reduced It can be remarkably reduced, and it is possible to secure price competitiveness.

When the active inductor 200 of the present invention is applied to a conventional oscillator, the bias of the first and / or second transistors M1 and M2 through g m1 and / or g m2 as shown in Equation (2) It is possible to change the inductance value of the active inductor 200 by adjusting the current or adjusting the value of the feedback resistor R f to change the inductance of the variable inductance of the variable inductance It is possible to design an oscillator having a certain range.

3 is a circuit diagram showing a configuration of an oscillator using an active inductor according to an embodiment of the present invention.

Referring to FIG. 3, the oscillator 300 according to an embodiment of the present invention includes a first active inductor 100a and a second active inductor 100b. Here, the first and second active inductors 100a and 100b have the same configuration and function as those of the active inductor 100 shown in FIG. 1 (a), and thus detailed description thereof will be omitted to avoid redundancy.

More specifically, the oscillator 300 includes a first active inductor 100a connected between the power supply voltage VDD and the fifth node N5, a second active inductor 100b connected between the power supply voltage VDD and the sixth node N6, A capacitor C2 connected between the fifth node N5 and the sixth node N6; a drain connected to the fifth node N5; a gate connected to the sixth node N6; A fifth transistor M5 having a source connected to the ground terminal GND and a sixth transistor M5 having a drain connected to the sixth node N6 and a gate connected to the fifth node N5 and a source connected to the ground terminal GND, And a transistor M6.

The first active inductor 100a and the second active inductor 100b and the capacitor C2 generate oscillation signals V out + and V out- with a variable frequency through LC resonance. In addition, cross-linked (cross-coupled), the fifth transistor (M5) and a sixth transistor (M6) is an oscillator (300) to offset the loss of the resonator 300 by using a negative transconductance (negative transconductance, g m) is Thereby providing a stable output signal.

As shown in FIG. 3, an oscillator using an active inductor according to an embodiment of the present invention replaces a passive inductor included in a conventional oscillator with an active inductor having a high Q value and operating at a low voltage, And it can be easily applied to a circuit in which a low power supply voltage is required.

In addition, a conventional oscillator has a narrow frequency variable range by varying the oscillation frequency through a capacitor and a varactor, while an oscillator using an active inductor according to an embodiment of the present invention has a feedback resistance and / or a bias current And the inductance value of the active inductor is varied to expand the frequency variable range.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined in the appended claims. It will be possible.

100, 100a, 100b: active inductor 300: oscillator
C1, C2: Capacitor GND: Ground terminal
I1: first current source I2: second current source
L1: first inductor L2: second inductor
M1: first transistor M2: second transistor
M3: third transistor M4: fourth transistor
M5: fifth transistor M6: sixth transistor
N1: first node N2: second node
N3: third node N4: fourth node
N5: fifth node N6: sixth node
R f : Feedback resistor VDD: Supply voltage

Claims (1)

A first current source connected between the power supply voltage and the first node;
A first transistor having a drain connected to the first node and a source connected to the second node;
A second current source coupled between the second node and a ground terminal;
A second transistor having a source connected to the power supply voltage and a drain connected to the second node; And
And a feedback resistor coupled between the first node and the gate of the second transistor.
KR1020120140447A 2012-12-05 2012-12-05 Active inductor and oscillator using the same KR20140072996A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
KR1020120140447A KR20140072996A (en) 2012-12-05 2012-12-05 Active inductor and oscillator using the same

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020120140447A KR20140072996A (en) 2012-12-05 2012-12-05 Active inductor and oscillator using the same

Publications (1)

Publication Number Publication Date
KR20140072996A true KR20140072996A (en) 2014-06-16

Family

ID=51126645

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020120140447A KR20140072996A (en) 2012-12-05 2012-12-05 Active inductor and oscillator using the same

Country Status (1)

Country Link
KR (1) KR20140072996A (en)

Similar Documents

Publication Publication Date Title
US7920030B2 (en) Multi-phase voltage-control oscillator
US10425038B2 (en) LC-tank oscillator having intrinsic low-pass filter
US9070510B2 (en) Frequency tuning and step control of a digitally controlled oscillator
JP3892383B2 (en) Voltage controlled oscillator
US8098109B2 (en) Differential varactor circuit for a voltage controlled oscillator
US8143960B2 (en) Voltage controlled oscillator with multi-tap inductor
US9281779B2 (en) Structure for an inductor-capacitor voltage-controlled oscillator
US20080315964A1 (en) Voltage controlled oscillator using tunable active inductor
Ben Hammadi et al. RF and microwave reconfigurable bandpass filter design using optimized active inductor circuit
US20130009715A1 (en) Inductance-capacitance (lc) oscillator
KR101043668B1 (en) Active inductor
TWI485975B (en) Apparatus for digitally controlling capacitance
JP6158732B2 (en) Circuit, voltage controlled oscillator and oscillation frequency control system
JP4669130B2 (en) Oscillator
US9240754B2 (en) Frequency fine tuning
KR20170034306A (en) Apparatus for and method of fine capacitance tuning for high resolution digitally controlled oscillator
Ebrahimzadeh et al. A new active inductor and its application to wide tuning range LC oscillator
Ghorbel et al. A subthreshold low-power CMOS LC-VCO with high immunity to PVT variations
WO2017126241A1 (en) Variable capacitance circuit, oscillator circuit, and method of controlling variable capacitance circuit
Hammadi et al. Design of wide-tuning high-Q differential active inductor for multistandard applications
KR20140072996A (en) Active inductor and oscillator using the same
Ghadiri et al. A dual-band CMOS VCO for automotive radar using a new negative resistance circuitry
Beigizadeh et al. A low power tunable inductor based on active capacitor with negative resistance
Maheshwari et al. Design & optimization of switched capacitor array based differential CMOS LC VCO for wide band application
Son et al. A Widely Tunable K-band Voltage-Controlled Oscillator

Legal Events

Date Code Title Description
E902 Notification of reason for refusal
E601 Decision to refuse application