Broadband dual-mode voltage coupling voltage-controlled oscillator

Abstract

The broadband dual-mode voltage coupling voltage-controlled oscillator comprises two resonance units, and a common inductor is arranged between the two resonance units. The resonance unit comprises a passive LC resonance circuit, a voltage coupling selection circuit and a cross-coupled active circuit; the passive LC resonance circuit comprises inductors and a variable capacitor; the inductors comprise a common inductor L0 and a four-branch inductor L1; the active circuit is used for providing negative resistance required by oscillation, the voltage coupling selection circuit is used for realizing switching of coupling modes, and the passive LC resonance circuit is used for realizing filtering; the two resonance units are subjected to in-phase or anti-phase voltage coupling through a voltage coupling selection circuit. In the invention, the voltage coupling selection circuit is utilized to realize in-phase or reverse-phase coupling between the two oscillators, so that the voltage-controlled oscillator works in an odd-mode or even-mode mode, thereby achieving the characteristics of wide frequency band and low phase noise.

Description

Technical Field

[0001] The invention relates to the field of voltage-controlled oscillators, and in particular to a broadband dual-mode voltage-coupled voltage-controlled oscillator. Background Art

[0002] A voltage controlled oscillator (VCO) is an electronic oscillator whose oscillation frequency is controlled by an input voltage. The applied input voltage determines the instantaneous oscillation frequency. VCOs are used in a variety of applications such as frequency modulation (FM), phase modulation (PM), phase-locked loops, etc.

[0003] With the vigorous development of communication technology, especially the emergence of different communication technologies such as automotive radar, 5G communication, and the Internet of Things in recent years, different communication standards have different requirements for the frequency coverage of frequency sources. The frequency tuning range of the voltage-controlled oscillator (VCO) directly determines the operating frequency supported by the communication system. Therefore, improving the frequency coverage of the VCO can greatly improve the universality and flexibility of the communication system.

[0004] Although multiple VCOs can be used to increase the frequency range traditionally, each VCO is used for a specific frequency band. However, using multiple VCOs will increase the chip area and complexity, and also have a great impact on system reliability, locking time, power consumption, etc. Therefore, it is necessary to provide a wide-band voltage-controlled oscillator with wide applicability. Summary of the invention

[0005] The invention provides a wideband dual-mode voltage-coupled voltage-controlled oscillator, which can greatly broaden the resonant frequency range covered by the VCO by changing the working mode of the resonator inductor.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A wide-band dual-mode voltage-coupled voltage-controlled oscillator includes two resonant units, and a common inductance is provided between the two resonant units;

[0008] Each resonant unit includes a passive LC resonant circuit, a voltage coupling selection circuit and a cross-coupled active circuit; the voltage coupling selection circuit is located between the cross-coupled circuit and the passive LC resonant circuit;

[0009] The passive LC resonant circuit includes an inductor and a variable capacitor, and the inductor includes a common inductor L0 and a four-branch inductor L1;

[0010] The active circuit is used to provide the negative resistance required for oscillation, the voltage coupling selection circuit is used to realize the switching of coupling mode, and the passive LC resonant circuit is used to realize filtering;

[0011] The voltage coupling selection circuit couples the two resonant units with the same phase or opposite phase voltage.

[0012] Further, the voltage coupling selection circuit includes switch selection circuits S1 and S2 for controlling the operating mode of the oscillator, which are respectively composed of 8 PMOS transistors PM3-PM10 and 8 NMOS transistors NM3-NM10;

[0013] The gates of the third PMOS tube and the sixth PMOS tube of the switch selection circuit S1 are connected to the LB control signal, the gates of the fourth PMOS tube and the fifth PMOS tube are connected to the HB control signal, the gates of the seventh PMOS tube and the ninth PMOS tube are connected to the P1 terminal of the four-terminal inductor, and the gates of the eighth PMOS tube and the tenth PMOS tube are connected to the M1 terminal of the four-terminal inductor;

[0014] The source of the third PMOS tube and the source of the fourth PMOS tube of the switch selection circuit S1 are connected together, and the source of the fifth PMOS tube and the source of the sixth PMOS tube are connected together;

[0015] The sources of the seventh PMOS tube and the eighth PMOS tube of the switch selection circuit S1 are connected to the drains of the third PMOS tube and the fourth PMOS tube respectively, the sources of the ninth PMOS tube and the tenth PMOS tube are connected to the drains of the fifth PMOS tube and the sixth PMOS tube respectively, the drains of the seventh PMOS tube and the eighth PMOS tube are connected to the P2 terminal of the four-terminal inductor, and the drains of the ninth PMOS tube and the tenth PMOS tube are connected to the M2 terminal of the four-terminal inductor.

[0016] Further, the gates of the third NMOS tube and the sixth NMOS tube of the switch selection circuit S2 are connected to the HB control signal, the gates of the fourth NMOS tube and the fifth NMOS tube are connected to the LB control signal, the gates of the seventh NMOS tube and the ninth NMOS tube are connected to the P2 terminal of the four-terminal inductor, and the gates of the eighth NMOS tube and the tenth NMOS tube are connected to the M2 terminal of the four-terminal inductor;

[0017] The source of the third NMOS tube and the source of the fourth NMOS tube of the switch selection circuit S2 are connected together, and the source of the fifth NMOS tube and the source of the sixth NMOS tube are connected together;

[0018] The sources of the seventh NMOS tube and the eighth NMOS tube of the switch selection circuit S2 are connected to the drains of the third NMOS tube and the fourth NMOS tube respectively, the sources of the ninth NMOS tube and the tenth NMOS tube are connected to the drains of the fifth NMOS tube and the sixth NMOS tube respectively, the drains of the seventh NMOS tube and the eighth NMOS tube are connected to the P1 terminal of the four-terminal inductor, and the drains of the ninth NMOS tube and the tenth NMOS tube are connected to the M1 terminal of the four-terminal inductor.

[0019] Furthermore, for the switch selection circuits S1 and S2, when the control signal LB is at a high level and HB is at a low level, P1-M1 and P2-M2 are in phase, and the oscillator operates in an even mode state; when the control signal LB is at a low level and HB is at a high level, P1-M2 and P2-M1 are in phase, and the oscillator operates in an odd mode state.

[0020] Furthermore, the two resonant units respectively adopt a PMOS cross-coupled negative resistance circuit and an NMOS cross-coupled negative resistance circuit.

[0021] Furthermore, in the PMOS cross-coupled negative resistance circuit, the gate of the first PMOS tube is connected to the M2 terminal of the four-terminal inductor, and the drain is connected to the source of the third PMOS tube and the fourth PMOS tube; the gate of the second PMOS tube is connected to the P2 terminal of the four-terminal inductor, and the drain is connected to the source of the fifth PMOS tube and the sixth PMOS tube; the source of the first PMOS tube and the second PMOS tube are both connected to the power supply voltage VDD.

[0022] Furthermore, in the NMOS cross-coupled negative resistance circuit, the gate of the first NMOS tube is connected to the M1 terminal of the four-terminal inductor, and the drain is connected to the source of the third NMOS tube and the fourth NMOS tube; the gate of the second NMOS tube is connected to the P1 terminal of the four-terminal inductor, and the drain is connected to the source of the fifth NMOS tube and the sixth NMOS tube; the source of the first NMOS tube and the second NMOS tube are both grounded GND.

[0023] Furthermore, the variable capacitance C of the resonance unit var1 , C var2 , used to adjust the resonant frequency of the oscillator, capacitor C var1 Connected between the P2 and M2 terminals of the four-terminal inductor, the variable capacitor C var2 Connected between the P1 and M1 terminals of the four-terminal inductor, the variable capacitor C var1 and C var2 The size of the voltage V c to control.

[0024] It can be seen from the above technical solution that the broadband dual-mode voltage-coupled voltage-controlled oscillator of the present invention includes two resonant units, the resonant units have a common inductance, and each resonant unit includes an LC resonant circuit, a voltage coupling selection circuit and an active circuit. The voltage coupling selection circuit is used to achieve in-phase or anti-phase coupling between the two oscillators, so that the voltage-controlled oscillator works in odd mode or even mode, thereby achieving the characteristics of broadband and low phase noise.

[0025] Compared with the prior art, the wide-band dual-mode voltage-coupled voltage-controlled oscillator disclosed in the present application includes an odd-mode (high-frequency) working mode and an even-mode (low-frequency) working mode. By changing the working mode of the resonator, the coverage range of the resonant frequency can be greatly broadened. Compared with the traditional inductor switching mode, there is no switch in series with the inductor, which will not affect the quality factor of the resonant circuit; in addition, compared with the traditional capacitor switching mode, the frequency tuning range of the switching inductor is larger.

[0026] The two resonant units respectively use cross-coupled negative resistance circuits of PMOS and NMOS structures, which can reuse current, thereby reducing the operating current by half compared to the single-ended structure and reducing the overall power consumption.

[0027] Specifically, the present invention includes the following beneficial effects:

[0028] 1. Two resonant units are coupled by a common inductor and switched by a mode selection circuit in each unit to achieve a dual-frequency operating mode and expand the operating frequency range of the oscillator.

[0029] 2. The two resonant units 1 and 2 respectively use PMOS and NMOS transistors stacked together to reuse current, thereby reducing the operating current by half. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 A schematic diagram of a voltage-controlled oscillator provided in an embodiment of the present invention;

[0031] Figure 2 A schematic diagram of an inductor layout provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0033] The embodiment of the present invention provides a wide-band dual-mode voltage-coupled voltage-controlled oscillator, which is characterized by adopting two resonant units, with a common inductance connection between the resonant units, and coupling the two resonant units by a coupling selection circuit to couple the same-phase or anti-phase voltage, thereby changing the equivalent inductance value of the resonant circuit and realizing a dual-band working mode.

[0034] The resonance unit includes: a voltage coupling selection circuit, a cross-coupled active circuit and an LC resonance circuit, wherein the LC resonance circuit includes a variable capacitor and an inductor, and the inductor is composed of a common inductor L0 and four-branch inductors L1.

[0035] The switch circuits S1 and S2 are composed of 8 PMOS transistors and 8 NMOS transistors respectively, and are used to control the oscillator working mode, where:

[0036] In the switch selection circuit S1, the gates of the third PMOS tube and the sixth PMOS tube are connected to the LB control signal, the gates of the fourth PMOS tube and the fifth PMOS tube are connected to the HB control signal, the gates of the seventh PMOS tube and the ninth PMOS tube are connected to the P1 terminal of the four-terminal inductor, and the gates of the eighth PMOS tube and the tenth PMOS tube are connected to the M1 terminal of the four-terminal inductor; the source of the third PMOS tube and the source of the fourth PMOS tube are connected together, and the source of the fifth PMOS tube and the source of the sixth PMOS tube are connected together; the source of the seventh PMOS tube and the eighth PMOS tube are respectively connected to the drain of the third PMOS tube and the fourth PMOS tube, the source of the ninth PMOS tube and the tenth PMOS tube are respectively connected to the drain of the fifth PMOS tube and the sixth PMOS tube, the drain of the seventh PMOS tube and the eighth PMOS tube is connected to the P2 terminal of the four-terminal inductor, and the drain of the ninth PMOS tube and the tenth PMOS tube is connected to the M2 terminal of the four-terminal inductor.

[0037] In the switch selection circuit S2, the gates of the third NMOS tube and the sixth NMOS tube are connected to the HB control signal, the gates of the fourth NMOS tube and the fifth NMOS tube are connected to the LB control signal, the gates of the seventh NMOS tube and the ninth NMOS tube are connected to the P2 terminal of the four-terminal inductor, and the gates of the eighth NMOS tube and the tenth NMOS tube are connected to the M2 terminal of the four-terminal inductor; the source of the third NMOS tube and the source of the fourth NMOS tube are connected together, and the source of the fifth NMOS tube and the source of the sixth NMOS tube are connected together; the source of the seventh NMOS tube and the eighth NMOS tube are respectively connected to the drain of the third NMOS tube and the fourth NMOS tube, the source of the ninth NMOS tube and the tenth NMOS tube are respectively connected to the drain of the fifth NMOS tube and the sixth NMOS tube, the drain of the seventh NMOS tube and the eighth NMOS tube is connected to the P1 terminal of the four-terminal inductor, and the drain of the ninth NMOS tube and the tenth NMOS tube is connected to the M1 terminal of the four-terminal inductor.

[0038] When the control signal LB=1, HB=0, P1-M1 and P2-M2 are in phase, and the oscillator works in an even-mode LC resonant circuit.

[0039] When the control signal LB=1, HB=0, the two resonant units work in the same phase mode, that is, the voltage phases at P1 and P2, M2 and M1 are the same, and the oscillator works in the even mode (low frequency) state. At this time, the equivalent inductance values ​​in resonant unit 1 and resonant unit 2 are both L1+L0, so the VCO works in the low frequency band, and the operating frequency ω L for

[0040] When the control signal LB=0, HB=1, the two resonant units work in the anti-phase mode, that is, the voltage phases at P1 and P2, M2 and M1 are opposite, and the oscillator works in the odd mode (high frequency) state. At this time, the equivalent inductance values ​​in the resonant unit 1 and the resonant unit 2 are both L1-L0, so the VCO works in the high frequency band, and the operating frequency is

[0041] It also includes a cross-coupled negative resistance circuit of a PMOS structure and an NMOS structure, which is used to meet the start-up conditions of the resonant circuit. The gate of the first PMOS tube is connected to the M2 terminal of the four-terminal inductor, and the drain is connected to the source of the third PMOS tube and the fourth PMOS tube; the gate of the second PMOS tube is connected to the P2 terminal of the four-terminal inductor, and the drain is connected to the source of the fifth PMOS tube and the sixth PMOS tube; the source of the first PMOS tube and the second PMOS tube are both connected to the power supply voltage VDD; the gate of the first NMOS tube is connected to the M1 terminal of the four-terminal inductor, and the drain is connected to the source of the third NMOS tube and the fourth NMOS tube; the gate of the second NMOS tube is connected to the P1 terminal of the four-terminal inductor, and the drain is connected to the source of the fifth NMOS tube and the sixth NMOS tube; the source of the first NMOS tube and the second NMOS tube are both grounded GND.

[0042] Among them, the variable capacitor C var1 , C var2 , used to adjust the resonant frequency of the oscillator. var1 Connected between the P2 and M2 terminals of the four-terminal inductor, C var2 Connected between the P1 and M1 terminals of the four-terminal inductor, C var1 and C var2 The size of the voltage V c to control.

[0043] The working principle of the embodiment of the present invention is described below with reference to the accompanying drawings:

[0044] Reference Manual Attached Figure 1 The present application provides a wideband dual-mode voltage-coupled voltage-controlled oscillator, including: switch circuits S1 and S2, a cross-coupled negative resistance circuit of a PMOS structure and an NMOS structure, a variable capacitor C var1 , C var2 , inductor circuit.

[0045] The specific working mode of the switch circuits S1 and S2 is to control the inductors P1-M1 and P2-M2 in the oscillator to be in-phase coupled or anti-phase coupled through the LB and HB signals, thereby controlling the output frequency of the oscillator to be low frequency or high frequency. When LB=1 and HB=0, the oscillator is in the even mode working mode, and the four terminals of the inductor P1 and M1, P2 and M2 are in-phase coupled; when LB=0 and HB=1, the oscillator is in the odd mode working mode, and the four terminals of the inductor P1 and M2, P2 and M1 are in-phase coupled.

[0046] The cross-coupled negative resistance circuit of the PMOS structure and the NMOS structure is used to meet the start-up conditions of the resonant circuit. The gates of PM1 and PM2 are respectively connected to the M2 terminal and the P2 terminal of the four-terminal inductor; the gates of NM1 and NM2 are respectively connected to the M1 terminal and the P1 terminal of the four-terminal inductor; the drain of the cross-coupled negative resistance pair is connected to the source of the switch selection circuit; the source of the PMOS cross-coupled negative resistance circuit is connected to the power supply voltage VDD, and the source of the NMOS cross-coupled negative resistance circuit is connected to GND.

[0047] Variable Capacitor C var1 , C var2 , variable capacitor C var1 and C var2 They are connected to the four-terminal inductors P2-M2 and P1-M1 respectively, and the gates of the coupling pairs PM1 and PM2 are cross-connected to C var1 The gates of NM1 and NM2 are connected to the C var2 By changing the control voltage V c To adjust the variable capacitor C var1 , C var2 The size of the oscillator is adjusted to tune the resonant frequency of the oscillator.

[0048] The structure of the four-terminal inductor is as follows Figure 2 As shown, it includes a common inductor L0 and four inductor branches L1. The advantage of this inductor is that it can increase the tuning range without causing additional phase noise.

[0049] From the working principle, according to the different control signals, the oscillator can work in two states: low frequency and high frequency. When the LB signal is 1, P1-M1 and P2-M2 are in phase, L eq becomes larger, the resonant frequency decreases, so that the oscillator works in low-frequency mode. Conversely, when the HB signal is 1, P1-M1 and P2-M2 are inverted, and L eq becomes smaller, the resonant frequency rises, so that the oscillator works in the high frequency mode, thereby increasing the output frequency range of the voltage controlled oscillator.

[0050] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A broadband dual-mode voltage-coupled voltage-controlled oscillator, characterized in that: It includes two resonant units, and there is a common inductance between the two resonant units; Each resonant unit includes a passive LC resonant circuit, a voltage coupling selection circuit and a cross-coupled active circuit; the voltage coupling selection circuit is located between the cross-coupled circuit and the passive LC resonant circuit; The passive LC resonant circuit includes an inductor and a variable capacitor, and the inductor includes a common inductor L0 and a four-branch inductor L1; The active circuit is used to provide the negative resistance required for oscillation, the voltage coupling selection circuit is used to realize the switching of coupling mode, and the passive LC resonant circuit is used to realize filtering; The voltage coupling selection circuit couples the two resonant units with the same phase or opposite phase voltage.

2. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 1, characterized in that: The voltage coupling selection circuit includes switch selection circuits S1 and S2 for controlling the operating mode of the oscillator, which are respectively composed of 8 PMOS transistors PM3-PM10 and 8 NMOS transistors NM3-NM10; The gates of the third PMOS tube and the sixth PMOS tube of the switch selection circuit S1 are connected to the LB control signal, the gates of the fourth PMOS tube and the fifth PMOS tube are connected to the HB control signal, the gates of the seventh PMOS tube and the ninth PMOS tube are connected to the P1 terminal of the four-terminal inductor, and the gates of the eighth PMOS tube and the tenth PMOS tube are connected to the M1 terminal of the four-terminal inductor; The source of the third PMOS tube and the source of the fourth PMOS tube of the switch selection circuit S1 are connected together, and the source of the fifth PMOS tube and the source of the sixth PMOS tube are connected together; The sources of the seventh PMOS tube and the eighth PMOS tube of the switch selection circuit S1 are connected to the drains of the third PMOS tube and the fourth PMOS tube respectively, the sources of the ninth PMOS tube and the tenth PMOS tube are connected to the drains of the fifth PMOS tube and the sixth PMOS tube respectively, the drains of the seventh PMOS tube and the eighth PMOS tube are connected to the P2 terminal of the four-terminal inductor, and the drains of the ninth PMOS tube and the tenth PMOS tube are connected to the M2 terminal of the four-terminal inductor.

3. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 2, characterized in that: The gates of the third NMOS tube and the sixth NMOS tube of the switch selection circuit S2 are connected to the HB control signal, the gates of the fourth NMOS tube and the fifth NMOS tube are connected to the LB control signal, the gates of the seventh NMOS tube and the ninth NMOS tube are connected to the P2 terminal of the four-terminal inductor, and the gates of the eighth NMOS tube and the tenth NMOS tube are connected to the M2 terminal of the four-terminal inductor; The source of the third NMOS tube and the source of the fourth NMOS tube of the switch selection circuit S2 are connected together, and the source of the fifth NMOS tube and the source of the sixth NMOS tube are connected together; The sources of the seventh NMOS tube and the eighth NMOS tube of the switch selection circuit S2 are connected to the drains of the third NMOS tube and the fourth NMOS tube respectively, the sources of the ninth NMOS tube and the tenth NMOS tube are connected to the drains of the fifth NMOS tube and the sixth NMOS tube respectively, the drains of the seventh NMOS tube and the eighth NMOS tube are connected to the P1 terminal of the four-terminal inductor, and the drains of the ninth NMOS tube and the tenth NMOS tube are connected to the M1 terminal of the four-terminal inductor.

4. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 3, characterized in that: For the switch selection circuits S1 and S2, when the control signal LB is at a high level and HB is at a low level, P1-M1 and P2-M2 are in phase, and the oscillator operates in an even mode state; when the control signal LB is at a low level and HB is at a high level, P1-M2 and P2-M1 are in phase, and the oscillator operates in an odd mode state.

5. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 1, characterized in that: The two resonance units respectively adopt a PMOS cross-coupled negative resistance circuit and an NMOS cross-coupled negative resistance circuit.

6. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 1, characterized in that: The PMOS cross-coupled negative resistance circuit, wherein the gate of the first PMOS tube is connected to the M2 terminal of the four-terminal inductor, and the drain is connected to the source of the third PMOS tube and the fourth PMOS tube; The gate of the second PMOS tube is connected to the P2 terminal of the four-terminal inductor, and the drain is connected to the source of the fifth PMOS tube and the sixth PMOS tube; the source of the first PMOS tube and the second PMOS tube are both connected to the power supply voltage VDD.

7. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 1, characterized in that: The NMOS cross-coupled negative resistance circuit, wherein the gate of the first NMOS tube is connected to the M1 terminal of the four-terminal inductor, and the drain is connected to the source of the third NMOS tube and the fourth NMOS tube; the gate of the second NMOS tube is connected to the P1 terminal of the four-terminal inductor, and the drain is connected to the source of the fifth NMOS tube and the sixth NMOS tube; the source of the first NMOS tube and the second NMOS tube are both grounded GND.

8. The broadband dual-mode voltage-coupled voltage-controlled oscillator according to claim 2, characterized in that: The variable capacitance C of the resonant unit var1 , C var2 , used to adjust the resonant frequency of the oscillator, capacitor C var1 Connected between the P2 and M2 terminals of the four-terminal inductor, the variable capacitor C var2 Connected between the P1 and M1 terminals of the four-terminal inductor, the variable capacitor C var1 and C var2 The size of the voltage V c to control.

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