KR101503505B1 - wide-band voltage controlled oscillator using transformer coupling and resonance mode switching - Google Patents
wide-band voltage controlled oscillator using transformer coupling and resonance mode switching Download PDFInfo
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- KR101503505B1 KR101503505B1 KR1020130101912A KR20130101912A KR101503505B1 KR 101503505 B1 KR101503505 B1 KR 101503505B1 KR 1020130101912 A KR1020130101912 A KR 1020130101912A KR 20130101912 A KR20130101912 A KR 20130101912A KR 101503505 B1 KR101503505 B1 KR 101503505B1
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- 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
- 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
-
- 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
- H03B5/1296—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 feedback circuit comprising a transformer
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Inductance-Capacitance Distribution Constants And Capacitance-Resistance Oscillators (AREA)
Abstract
A wideband voltage controlled oscillator using transformer coupling and resonant mode switching is disclosed. The voltage controlled oscillator according to an embodiment of the present invention can operate at low power through cross coupling of a current reuse structure and a transformer, and supports a multi-band and multi-mode communication environment by using a resonance mode switching technique.
Description
The present invention relates to a voltage controlled oscillator.
Generally, a voltage controlled oscillator (VCO) refers to an oscillator that adjusts a frequency by changing a capacitance of a variable capacitor by a voltage control. When designing a VCO, most LC tanks are used by using inductors and capacitor banks. Recently, the effect of reducing the area can be obtained by using only one inductor number through the differential inductor.
Fig. 1 is a circuit diagram of a general
1, the
In the current wireless communication field, not only analog transceivers but also digital RF transceivers and ultimately SDR (Software Defined Radio) transceivers are evolving. One of the directions that these transceivers are seeking is to support multi-band and multi-mode. One of the most difficult parts for this is the frequency synthesizer, which must be designed to be wideband to cover all frequency ranges. To solve this problem, there is a method of using a plurality of voltage-controlled oscillators per frequency, but in this case, the area and the power consumption of the oscillator increase rapidly. Therefore, a multi-band and multimode voltage-controlled oscillator that operates with low power and small area is required.
According to one embodiment, a wideband voltage controlled oscillator using transformer coupling and resonant mode switching is proposed to support multi-band and multi-mode communication environments.
A voltage-controlled oscillator according to an embodiment includes a resonance circuit including a transformer for replacing an inductor and a plurality of capacitors to generate oscillation frequencies of a plurality of bands, and a plurality of transistors cross-coupled through a transformer, And a negative transconductance circuit that generates a negative transconductance to maintain oscillation. In this case, the transformer has a primary coil connected between the first node and the third node, a secondary coil connected between the second node and the fourth node, and the primary coil and the secondary coil connected to the center tap A plurality of capacitors are connected between the first node and the third node and between the second node and the fourth node with a first capacitor pair having the same capacitance with each other and between the first node and the second node and between the third node and the fourth node, And a second pair of capacitors having capacitances different from those of the first pair of capacitors and having the same capacitance between the nodes.
Wherein the negative transconductance circuit includes a first negative transconductance circuit that generates a first negative transconductance and a second negative transconductance circuit that generates a second negative transconductance and wherein the voltage controlled oscillator is coupled to the center tap of the transformer, The first negative transconductance circuit and the second negative transconductance circuit can each produce a negative transconductance through one current path, as the current reuse structure constitutes one current path through the first negative transconductance circuit and the second negative transconductance circuit.
The first negative transconductance circuit includes a first transistor connected between the other end of the primary coil and the bias current supply end and switching on and off in accordance with a signal applied to one end of the secondary coil, And a second transistor connected between the application terminals and switched on and off according to a signal applied to one end of the primary coil. The second negative transconductance circuit includes a third transistor connected between the power supply voltage application terminal and one end of the primary coil and switched on and off in accordance with a signal applied to the other end of the secondary coil, And a fourth transistor connected between the first coil and the second coil and being switched on and off according to a signal applied to the other end of the primary coil.
The voltage-controlled oscillator further includes a resonance-mode switching circuit that varies the manner of connecting the transconductance to the transformer so as to select a predetermined resonance mode, thereby causing the resonance circuit to generate the oscillation frequency by the selected resonance mode, thereby extending the oscillation frequency can do.
The resonance mode switching circuit can reduce the oscillation frequency by selecting the first resonance mode and increasing the value of the capacitor so that the phase of the oscillation waveform is opposite in each oscillation port of the resonance circuit. Or the resonance mode switching circuit can increase the oscillation frequency by selecting the second resonance mode and decreasing the capacitor value by causing the phase of the oscillation waveform to be in phase with each oscillation port of the resonance circuit. The resonance mode switching circuit can adjust the capacitor value in each mode so that the oscillation frequency in the first resonance mode and the oscillation frequency in the second resonance mode are continuous.
According to an exemplary embodiment, a wideband differential voltage controlled oscillator using a transformer coupling and a resonant mode switching technique can reduce the power consumption while reducing the area of the oscillator by using only a single transformer. Further, by connecting a switch to the center tap of the transformer used in the oscillator, the oscillator can be operated in various frequency bands by adjusting the value of the oscillating trans inductance. Accordingly, it is possible to operate the oscillator in multimode multi-band, and it can be applied to SDR (Software Defined Radio) transceiver as well as various transceiver designs including such oscillators.
1 is a circuit diagram of a general differential voltage controlled oscillator,
2 is a circuit diagram of a voltage-controlled oscillator according to an embodiment of the present invention,
FIG. 3 is a circuit diagram in which the voltage-controlled oscillator of FIG. 2 operates in odd mode,
4 is a circuit diagram in which the voltage-controlled oscillator of FIG. 2 operates in an even mode.
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention of the user, the operator, or the custom. Therefore, the definition should be based on the contents throughout this specification.
2 is a circuit diagram of a voltage controlled oscillator (VCO) 2 according to an embodiment of the present invention.
Referring to FIG. 2, the
The
Hereinafter, the configuration of the
Referring to Figure 2, the
The
In the transformer according to one embodiment, the primary coil 200-1 and the secondary coil 200-2 are connected to each other by a center tap M. The transformer forms one current path using the center tap M and the transconductance is connected to the opposite port of the transformer so that one transformer is divided into four inductors to form four oscillation ports P +, S +, P- , S-), respectively. As described above, when the
The capacitor of the
The second capacitor pair includes a third capacitor Cc 230-1 formed between the first node N1 and the second node N2 and a third capacitor Cc 230-1 formed between the third node N3 and the fourth node N4. The third capacitor Cc 230-1 and the fourth capacitor Cc 230-2 are formed of a first capacitor C 220-1 and a second capacitor C 220-2, -2) and have the same capacitance. The aforementioned capacitors may be a collector diode. The selector diode can vary its oscillation frequency by varying its capacitance according to the control voltage.
The negative transconductance circuit includes a number of transistors cross-coupled through a transformer to create a negative transconductance for maintaining the oscillation of the
The
The transistors M2, M3, M4 and M5 constituting the negative transconductance circuit are cross-coupled through a transformer. In detail, the first negative transconductance circuit 22-1 includes a first transistor M2 and a second transistor M3. At this time, the first transistor M2 is connected between the other end of the primary coil 200-1 of the transformer and the bias current supply terminal Nb, and is switched according to a signal applied to one end of the secondary coil 200-2. And the second transistor M3 is connected between the other end of the secondary coil 200-2 and the bias current supply terminal Nb to switch the primary coil 200-1 according to a signal applied to one end of the primary coil 200-1. Off.
The second negative transconductance circuit 22-2 includes a third transistor M4 and a fourth transistor M5. The third transistor M4 is connected between the power supply voltage terminal Vdd and one end of the primary coil 200-1 and is switched on and off according to a signal applied to the other end of the secondary coil 200-2. The fourth transistor M5 is connected between the power supply voltage terminal Vdd and one end of the secondary coil 200-2 and is switched on and off according to a signal applied to the other end of the primary coil 200-1. As described above, the
The
The
3 is a circuit diagram in which the
3, when entering the odd mode by the resonance mode switching circuit 24-1, the phases of the oscillation waveforms at the oscillation ports are opposite to each other. Therefore, the inductance of the transformer is reduced by the mutual inductance, Has a value obtained by adding C and Cc. As the capacitor increases, the oscillation frequency decreases. Because the inductor is not physically variable to extend the oscillation frequency, the performance of the oscillator is not deteriorated and the DC current is also constant.
4 is a circuit diagram in which the
Referring to FIG. 4, when the resonance mode switching circuit 24-2 enters the even mode, the phase of the oscillation waveform at each oscillation port becomes in phase, so that the inductance of the transformer is increased by mutual inductance, Only C operates. When the capacitor decreases, the oscillation frequency increases.
The oscillation frequency in each mode is determined according to how the capacitor value is set. In order to continuously change the oscillation frequency, it is important how to set the overlapping frequency range in each mode. Four oscillation ports (P +, S +, P-, S-) are formed by connecting one transformer by using a center tap and resonance mode switching circuits 24-1 and 24-2 are connected to the oscillation ports (2) It can operate in multi-mode and multi-band without deterioration in performance.
The embodiments of the present invention have been described above. 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 by the appended claims. Therefore, the disclosed embodiments should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the appended claims rather than by the foregoing description, and all differences within the scope of equivalents thereof should be construed as being included in the present invention.
Claims (5)
A negative transconductance circuit including a plurality of transistors cross-coupled through the transformer to generate a negative transconductance for maintaining oscillation of the resonant circuit; And
A resonance mode switching circuit for changing the manner of connecting the transconductance to the transformer so as to select a predetermined resonance mode, thereby causing the resonance circuit to generate the oscillation frequency by the selected resonance mode, thereby extending the oscillation frequency; / RTI >
The transformer has a primary coil connected between a first node and a third node, a secondary coil connected between a second node and a fourth node, and the primary coil and the secondary coil are connected to a center tap ,
Wherein the plurality of capacitors comprises a first capacitor pair having a capacitance equal to each other between a first node and a third node and between a second node and a fourth node and a second capacitor pair having a capacitance between the first node and the second node, And a second capacitor pair having capacitances different from the first capacitor pair between the nodes and having the same capacitance.
A first negative transconductance circuit generating a first negative transconductance; And
A second negative transconductance circuit for generating a second negative transconductance; / RTI >
Wherein the first negative transconductance circuit and the second negative transconductance circuit each convert the negative transconductance to the one current through the center tap of the transformer so that the voltage controlled oscillator has a current reuse structure that forms a current path through the center tap of the transformer, Pass through the path.
The first resonance mode is selected and the oscillation frequency is decreased by increasing the capacitor value so that the phases of the oscillation waveforms are opposite to each other in the oscillation ports of the resonance circuit, or the second resonance mode is selected, And the oscillation frequency is increased by decreasing the value of the capacitor so that the phase of the oscillation waveform is in phase with the oscillation port.
Wherein the resonance mode includes a first resonance mode and a second resonance mode,
The resonant mode switching circuit includes:
And the capacitor value in each resonance mode is adjusted so that the oscillation frequency in the first resonance mode and the oscillation frequency in the second resonance mode are continuous.
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KR1020130101912A KR101503505B1 (en) | 2013-08-27 | 2013-08-27 | wide-band voltage controlled oscillator using transformer coupling and resonance mode switching |
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KR1020130101912A KR101503505B1 (en) | 2013-08-27 | 2013-08-27 | wide-band voltage controlled oscillator using transformer coupling and resonance mode switching |
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KR101503505B1 true KR101503505B1 (en) | 2015-03-18 |
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WO2021081950A1 (en) | 2019-10-31 | 2021-05-06 | 华为技术有限公司 | Oscillator circuit |
CN115361033B (en) * | 2022-08-18 | 2023-12-19 | 百瑞互联集成电路(上海)有限公司 | Broadband dual-mode voltage-controlled oscillator and radio frequency transceiver |
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KR100952424B1 (en) * | 2008-02-21 | 2010-04-14 | 한국전자통신연구원 | The Differential VCO and quadrature VCO using center-tapped cross-coupling of transformer |
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KR100952424B1 (en) * | 2008-02-21 | 2010-04-14 | 한국전자통신연구원 | The Differential VCO and quadrature VCO using center-tapped cross-coupling of transformer |
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