阅读说明：本技术 电感电容器振荡器及相关的双核振荡器 (Inductance capacitor oscillator and related dual-core oscillator ) 是由 黄皓玮 林昂生 邱威豪 于 2021-01-05 设计创作，主要内容包括：本发明公开了一种电感电容器振荡器,包括：第一晶体管和第二晶体管；第一部分第一电感器和第一部分第二电感器,其中,所述第一部分第一电感器的第一端和所述第一部分第二电感器的第一端分别耦合至所述第一晶体管的栅极和所述第二晶体管的栅极；第一部分电容器,耦合在所述第一部分第一电感器的所述第一端和所述第一部分第二电感器的所述第一端之间；第二部分电感器,耦合在所述第一部分第一电感器的第二端和所述第一部分第二电感器的第二端之间；和至少一个第二部分电容器,耦合在所述第一晶体管的漏极端和所述第二晶体管的漏极端。实施本发明实施例可具有更佳的噪声相关性能。(The invention discloses an inductance capacitor oscillator, comprising: a first transistor and a second transistor; a first partial first inductor and a first partial second inductor, wherein a first end of the first partial first inductor and a first end of the first partial second inductor are coupled to a gate of the first transistor and a gate of the second transistor, respectively; a first partial capacitor coupled between the first end of the first partial first inductor and the first end of the first partial second inductor; a second partial inductor coupled between a second end of the first partial first inductor and a second end of the first partial second inductor; and at least one second partial capacitor coupled between a drain terminal of the first transistor and a drain terminal of the second transistor. The embodiment of the invention has better noise correlation performance.)

1. An inductor-capacitor oscillator, comprising:

a first transistor and a second transistor;

a first partial first inductor and a first partial second inductor, wherein a first end of the first partial first inductor and a first end of the first partial second inductor are coupled to a gate of the second transistor and a gate of the first transistor, respectively;

a first partial capacitor coupled between the first end of the first partial first inductor and the first end of the first partial second inductor;

a second partial inductor coupled between a second end of the first partial first inductor and a second end of the first partial second inductor; and

at least one second partial capacitor coupled at a drain terminal of the first transistor and a drain terminal of the second transistor.

2. The inductor-capacitor oscillator of claim 1, wherein at least the first portion of the first inductor, the first portion of the second inductor, the second portion of the inductor, and the first portion of the capacitor form a fundamental resonant tank.

3. The inductor-capacitor oscillator of claim 1, wherein at least the second fractional inductor and the at least one second fractional capacitor form a second harmonic filter to block or attenuate second harmonic signals.

4. The inductive capacitor oscillator of claim 1, wherein said first partial first inductor, said first partial second inductor and said second partial inductor are implemented by continuous metal layers without segmentation.

5. The inductor-capacitor oscillator of claim 1, further comprising:

a third portion first inductor and a third portion second inductor, wherein the third portion first inductor is coupled between the second end of the first portion first inductor and a drain terminal of the first transistor, and the third portion second inductor is coupled between the second end of the first portion second inductor and a drain terminal of the second transistor.

6. The inductive capacitor oscillator of claim 5, wherein at least said second partial inductor, said at least one second partial capacitor, said third partial first inductor and said third partial second inductor form a second harmonic filter to block or attenuate second harmonic signals of the inductive capacitor oscillator.

7. The inductive capacitor oscillator of claim 5, wherein said first portion first inductor, said first portion second inductor, said second portion inductor, said third portion first inductor and said third portion second inductor are implemented with a continuous metal layer without segmentation.

8. The inductor capacitor oscillator of claim 1, wherein the first transistor is a P-type transistor, the second transistor is an N-type transistor, and the first and second terminals of the at least one second partial capacitor are coupled to the first transistor drain terminal and the drain terminal of the second transistor, respectively.

9. The inductor-capacitor oscillator of claim 1, wherein the first transistor and the second transistor are both P-type transistors or the first transistor and the second transistor are both N-type transistors.

10. The inductor-capacitor oscillator of claim 1, further comprising a tail filter coupled to a source terminal of the first transistor and a source terminal of the second transistor.

11. The inductor-capacitor oscillator of claim 1, further comprising a tail filter coupled to a center tap of the second partial inductor.

12. A dual core oscillator, comprising: first and second inductor-capacitor oscillators identical to each other, wherein the first and second inductor-capacitor oscillators respectively include:

a first transistor and a second transistor;

a first partial first inductor and a first partial second inductor, wherein a first end of the first partial first inductor and a first end of the first partial second inductor are coupled to a gate of the second transistor and a gate of the first transistor, respectively;

a first partial capacitor coupled between the first end of the first partial first inductor and the first end of the first partial second inductor;

a second partial inductor coupled between a second end of the first partial first inductor and a second end of the first partial second inductor; and

at least one second partial capacitor coupled between a drain terminal of the first transistor and a drain terminal of the second transistor;

wherein the second portion of the inductor of the first inductive capacitor oscillator is coupled to the second portion of the inductor of the second inductive capacitor oscillator.

13. The dual core oscillator of claim 12 wherein at least the first portion of the first inductor, the first portion of the second inductor, the second portion of the inductor, and the first portion of the capacitor form a fundamental resonant tank.

14. The dual core oscillator of claim 12 wherein at least the second portion of the inductor and the at least one second portion of the capacitor form a second harmonic filter to block or attenuate second harmonic signals.

15. The dual-core oscillator of claim 12, wherein the first portion of the first inductor, the first portion of the second inductor, and the second portion of the inductor in the first inductor-capacitor oscillator, and the first portion of the first inductor in the second inductor-capacitor oscillator, the first portion of the second inductor, and the second portion of the inductor are implemented with a continuous metal layer without segmentation.

16. The dual-core oscillator of claim 12, wherein each of the first inductor-capacitor oscillator and the second inductor-capacitor oscillator further comprises:

a third portion first inductor and a third portion second inductor, wherein the third portion first inductor is coupled between the second end of the first portion first inductor and a drain terminal of the first transistor, and the third portion second inductor is coupled between the second end of the first portion second inductor and a drain terminal of the second transistor.

17. The dual core oscillator of claim 16 wherein at least the second portion of the inductor, the at least one second portion of the capacitor, the third portion of the first inductor and the third portion of the second inductor form a second harmonic filter to block or attenuate second harmonic signals of an inductive capacitor oscillator.

18. The dual-core oscillator of claim 16, wherein the first portion of the first inductor, the first portion of the second inductor, the second portion of the inductor, the third portion of the first inductor, and the third portion of the second inductor in the first inductor-capacitor oscillator, and the first portion of the first inductor, the first portion of the second inductor, the second portion of the inductor, the third portion of the first inductor, and the third portion of the second inductor in the second inductor-capacitor oscillator are implemented with a continuous metal layer without segmentation.

19. The dual-core oscillator of claim 12, wherein the first transistor is a P-type transistor, the second transistor is an N-type transistor, and the first and second ends of the at least one second fractional capacitor are coupled to a drain terminal of the first transistor and a drain terminal of the second transistor, respectively.

20. A dual core oscillator comprising an inductor capacitor oscillator, the inductor capacitor oscillator comprising:

a first transistor and a second transistor; and

a first inductive capacitor loop, the first inductive capacitor loop comprising:

a first transistor and a second transistor;

a first partial first inductor and a first partial second inductor, wherein a first end of the first partial first inductor and a first end of the first partial second inductor are coupled to a gate of the second transistor and a gate of the first transistor, respectively;

a first partial capacitor coupled between the first end of the first partial first inductor and the first end of the first partial second inductor;

a second partial inductor coupled between a second end of the first partial first inductor and a second end of the first partial second inductor;

at least one second partial capacitor coupled between a drain terminal of the first transistor and a drain terminal of the second transistor; and

a second inductive capacitor loop comprising at least one inductor and at least one capacitor;

Wherein the second partial inductor of the first inductive capacitor oscillator is coupled to the at least one inductor of the second inductive capacitor resonator.

Technical Field

The present invention relates to inductor-capacitor (LC) oscillators, and more particularly to LC oscillators with embedded second harmonic (second harmonic) filters and related dual core oscillators.

Background

In general, the oscillator not only generates a fundamental frequency determined by the primary resonant tank (resonant tank), but also generates undesirable second harmonic frequencies that may cause noise up-conversion. In the prior art, additional loops may be used to filter the second harmonic frequency in order to block or attenuate the second harmonic frequency. However, there are still some drawbacks in this architecture. For example, there is poor noise correlation performance.

Therefore, there is a need for a novel LC oscillator architecture that has better noise-related performance (e.g., less phase noise) than the prior art.

Disclosure of Invention

The invention provides an inductance capacitor oscillator and a related dual-core oscillator, which can have better noise correlation performance.

The present invention provides an inductor capacitor oscillator, which may include: a first transistor and a second transistor; a first partial first inductor and a first partial second inductor, wherein a first end of the first partial first inductor and a first end of the first partial second inductor are coupled to a gate of the second transistor and a gate of the first transistor, respectively; a first partial capacitor coupled between the first end of the first partial first inductor and the first end of the first partial second inductor; a second partial inductor coupled between a second end of the first partial first inductor and a second end of the first partial second inductor; and at least one second partial capacitor coupled between a drain terminal of the first transistor and a drain terminal of the second transistor.

The structure of the inductance capacitor oscillator provided by the invention can improve the performance related to noise, thereby obtaining better noise-related performance.

Drawings

Fig. 1A shows a diagram of an inductive-capacitor (LC) oscillator 10 with an embedded second harmonic filter, according to an embodiment of the present invention.

Fig. 1B illustrates a layout diagram of inductors in the LC oscillator 10 shown in fig. 1A, according to an embodiment of the present invention.

Fig. 2 shows a diagram of an LC oscillator 20 according to an embodiment of the present invention.

Fig. 3 shows a diagram of an LC oscillator 30 according to an embodiment of the present invention.

Fig. 4 shows a diagram of an LC oscillator 40 according to an embodiment of the present invention.

Fig. 5 shows a diagram of an LC oscillator 50 according to an embodiment of the present invention.

Fig. 6A shows a diagram of a dual-core oscillator, according to an embodiment of the invention.

Fig. 6B illustrates a layout diagram of inductors in the dual core oscillator shown in fig. 6A, in accordance with an embodiment of the present invention.

Fig. 7A shows a diagram of a dual-core oscillator, according to another embodiment of the invention.

Fig. 7B illustrates a layout diagram of the inductors in the dual core oscillator shown in fig. 7A, in accordance with an embodiment of the present invention.

Detailed Description

Certain terms are used throughout the description and following claims to refer to particular components. As one skilled in the art will appreciate, manufacturers may refer to a component by different names. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. "substantially" means within an acceptable error range, within which a person skilled in the art can solve the technical problem to substantially achieve the technical result. Furthermore, the term "coupled" is intended to include any direct or indirect electrical connection. Thus, if a first device couples to a second device, that connection may be through a direct electrical connection, or through an indirect electrical connection via other devices and connections. The following is a preferred embodiment of the invention for the purpose of illustrating the spirit of the invention and not for the purpose of limiting the scope of the invention, which is defined by the claims.

The following description is of the best embodiments contemplated by the present invention. The description is made for the purpose of illustrating the general principles of the invention and should not be taken in a limiting sense. The scope of the invention should be determined with reference to the claims that follow.

Fig. 1A shows a diagram of an inductive-capacitor (LC) oscillator 10 with an embedded second harmonic filter, according to an embodiment of the present invention. As shown in FIG. 1A, LC oscillator 10 may include a first transistor, such as a P-type transistor (e.g., P-type Metal Oxide Semiconductor Field Effect Transistor (MOSFET)) MP, a second transistor, such as an N-type transistor (e.g., N-type MOSFET) MN, a first portion first inductor (e.g., inductor L)₁₁) First part of a second inductor (e.g. inductor L)₁₂) First part of a capacitor (e.g. capacitor C)₁) A second partial inductor (e.g. capacitor L)₂) And at least one second partial capacitor C₂. Inductor L₁₁First terminal of and inductor L₁₂Are coupled to the gate terminal of the N-type transistor MN and the gate terminal of the P-type transistor MP, respectively. Capacitor C₁Coupled in an inductor L₁₁First terminal of and inductor L₁₂Between the first ends of the first and second ends. Inductor L₂Coupled in an inductor L₁₁Second terminal and inductor L₁₂Between the second ends. At least one second partial capacitor is coupled to the drain terminals of the first transistor and the second transistor. For example, a capacitor C ₂Coupled between the drain terminal of the P-type transistor MP and the drain terminal of the N-type transistor MN. The source terminal of the P-type transistor MP and the source terminal of the N-type transistor MN are coupled to a power supply voltage terminal (e.g., a terminal providing the highest fixed voltage level within the LC oscillator 10) and a ground voltage terminal (e.g., a terminal providing the lowest fixed voltage level within the LC oscillator 10), respectively.

As shown in fig. 1A, LC oscillator 10 may further include a third partial first inductor (e.g., inductor L)₃₁) And a third portion second inductor (e.g.Inductor L₃₂) Wherein the inductor L₃₁Coupled in an inductor L₁₁Between the second terminal of the P-type transistor MP and the drain terminal of the P-type transistor MP, an inductor L₃₂Coupled in an inductor L₁₂And the drain terminal of the N-type transistor MN.

For better illustration, the inductances and capacitances of the respective components are indicated by italics of the same/similar symbols of the respective components. For example, a capacitor C₁And a capacitor C₂Respectively is composed of C₁And C₂Showing the inductor L₁₁And L₁₂Inductance of each of L₁Showing the inductor L₂Is composed of L₂Showing the inductor L₃₁And L₃₂Is composed of L₃Where the symbol "s" may represent a variable associated with frequency and phase. For the inductor L shown in FIG. 1A ₃₁And L₃₂Of at least an inductor L₁₁And L₁₂Inductor L₂And a capacitor C₁Forming a fundamental frequency resonance loop. In detail, the impedance Z at the fundamental frequency fo_in1This can be shown as follows:

furthermore, at least the inductor L₂Capacitor C₂Inductor L₃₁And L₃₂The second harmonic filter is configured to block or attenuate the second harmonic signal of the LC oscillator 10. In detail, the impedance Z at the second harmonic frequency 2fo_in2This can be shown as follows:

in some embodiments, inductor L may be omitted₃₁And L₃₂E.g. inductor L₁₁Second terminal and inductor L₁₂May be directly connected to the drain terminal of the P-type transistor MP and the drain of the N-type transistor MN, respectivelyAnd (4) extreme. In this case, at least the inductor L₂And a capacitor C₂The second harmonic filter is configured to block or attenuate the second harmonic signal. In detail, the inductor L is omitted₃₁And L₃₂Impedance Z in the case of_in2This can be shown as follows:

due to the inductor L₃₁/L₃₂To impedance Z_in1The influence of (2) is not great, and for the sake of brevity, the description is omitted here. The symbol α may represent a positive value, α representing a larger C for a given 2fo₂One factor of multiplication, which is for exemplary purposes only and is not meant to limit the invention.

Generally, preferably, from V ₂To V₁Voltage gain of A_VAs high as possible, wherein the voltage gain A_VThis can be shown as follows:

inductor L₃₁And L₃₂Is to eliminate the control impedance Z_in2And controlling the voltage gain A_VInevitable correlations therebetween. For example, the desired impedance Z_in2As high as possible (more specifically, the desired impedance Z_in2The peak resistance Rp is as high as possible) in order to prevent or attenuate the second harmonic frequency 2 fo. In the absence of the inductor L₃₁And L₃₂In the case of (3), the peak resistance Rp may be as follows:

suppose Q_L＝Q_CWherein Q is_LRepresents an inductor L₂Quality factor of (2), Q_CRepresentative of a capacitor C₂The quality factor of (2). To not change the second harmonicIncreasing Z in the case of a resonant frequency of the filter (e.g. 2fo)_in(more specifically, increase Rp), it is desirable to increase L₂And need to reduce C₂. At the same time, the voltage gain Av will gradually decrease to the cell gain. In the presence of an inductor L₃₁And L₃₂In the case of (3), it is preferable to increase L₃Rather than increasing L₂So as not to sacrifice the voltage gain A_VIncrease the impedance Z in the case of_in2Thereby optimizing the overall performance of the LC oscillator 10.

The LC oscillator 10 shown in fig. 1A can effectively increase the impedance Z at the second harmonic frequency 2fo in comparison with the prior art_in2Thereby improving noise-related performance (e.g., less phase noise) and efficiency (e.g., quality Factor (FOM) related to power consumption, noise, and signal swing). Another advantage of the LC oscillator 10 shown in fig. 1A is that the second harmonic filter tracks the changes caused by the fundamental resonant tank. For example, when the capacitance C ₁When the resonance frequency of the fundamental resonant tank changes and thus decreases accordingly (e.g., fo decreases), the resonance frequency of the second harmonic filter will also decrease, substantially tracking the second harmonic frequency (e.g., tracking 2 fo). In addition, since neither the fundamental resonant tank nor the second harmonic filter is separated by transistors (e.g., P-type transistor MP and N-type transistor MN), the inductor L₁₁，L₁₂，L₂，L₃₁And L₃₂Can be arranged together, more specifically, as shown in FIG. 1B, an inductor L₁₁，L₁₂，L₂，L₃₁And L₃₂May be implemented by a continuous metal layer without segmentation. Even though the inductor L is omitted in some embodiments₃₁And L₃₂Inductor L realized by continuous metal layers without division₁₁，L₁₂And L₂Similar advantages are also provided. In this case, the effects of process variations on the components may be very similar or substantially the same as each other, and thus mismatches (e.g., relative differences) between the components due to process variations may be minimized, which may minimize the sensitivity of performance to process variations.

It should be noted that the first transistor and the second transistor are not limited to using different types of transistors. Fig. 2 shows a diagram of an LC oscillator 20 according to an embodiment of the present invention. LC oscillator 20 is very similar to LC oscillator 10 shown in FIG. 1A, with the primary difference being that the first and second transistors are each implemented as P-type transistors (e.g., MP1 and MP2), with at least one capacitor being implemented as a capacitor C ₂₁And C₂₂Implementation, wherein the source terminals of the P-type transistors MP1 and MP2 are coupled to the supply voltage terminal, capacitor C₂₁A capacitor C coupled between the drain terminal of the P-type transistor MP1 and the ground voltage terminal₂₂Coupled between the drain terminal of the P-type transistor MP2 and a ground voltage terminal. Inductor L₂Is coupled to a ground voltage terminal. The advantages and performance of LC oscillator 20 are similar to those of LC oscillator 10 and, for the sake of brevity, relevant details are not repeated here.

Fig. 3 shows a diagram of an LC oscillator 30 according to an embodiment of the present invention. The LC oscillator 30 is very similar to the LC oscillator 20 shown in fig. 2, with the main difference being that the first and second transistors are implemented by N-type transistors (e.g., MN1 and MN2), wherein the source terminals of the N-type transistors MN1 and MN2 are coupled to a ground voltage terminal, and a capacitor C₂₁A capacitor C coupled between the drain terminal and the supply voltage terminal of the N-type transistor MN1₂₂Coupled between the drain terminal and the supply voltage terminal of the N-type transistor MN2, and an inductor L₂Is coupled to the supply voltage terminal. The advantages and performance of LC oscillator 30 are similar to those of LC oscillator 10 and, for brevity, relevant details are not repeated here.

Since second harmonic filtering is intended to filter common mode currents, any additional filter may be further added on the path through which the common mode current flows to create double second harmonic filtering. More specifically, a tail filter (tail filter) may be added to a path through which the common mode current flows in the LC oscillator 20 shown in fig. 2 or a path through which the common mode current flows in the LC oscillator 30 shown in fig. 3. Taking LC oscillator 20 as an example, a tail filter (e.g., parallel connected inductor L) may be implemented_tailAnd a capacitor C_tail) Source terminals coupled to P-type transistors MP1 and MP2To configure the LC oscillator 40 as shown in fig. 4, for simplicity, the impedance Zcm at the second harmonic frequency 2fo on the common mode signal path of the LC oscillator 40 is_highLabeled as "Zcm_high@2fo ". Similarly, a tail filter (e.g., parallel connected inductors L)_tailAnd a capacitor C_tail) Can be coupled to an inductor L₂To configure the LC oscillator 50 as shown in fig. 5, for simplicity, the impedance Zcm at the second harmonic frequency 2fo on the common mode signal path of the LC oscillator 50_highLabeled as "Zcm_high@2fo ". The phase noise sensitivity of the LC oscillator 40 or 50 associated with the capacitor change may be significantly reduced compared to using only the tail filter. A tail filter may be added to the oscillator 30 by analogy, and thus, a description thereof will not be repeated here for the sake of brevity.

Fig. 6A shows a diagram of a dual-core oscillator 60, according to an embodiment of the invention. In particular, the dual-core oscillator may include a first LC oscillator and a second LC oscillator that are identical to each other. For example, the upper half of the dual-core oscillator 60 may be considered a first LC oscillator and the lower half of the dual-core oscillator 60 may be considered a second LC oscillator, where each of the first and second LC oscillators may be implemented by the LC oscillator 10 shown in fig. 1A, with the second portion of the inductor of the first LC oscillator coupled to the second portion of the inductor of the second LC oscillator. It should be noted that the second part inductor of the first LC-oscillator and the second part inductor of the second LC-oscillator are formed by the inductor L₂₁And L₂₂Implementation of, wherein the inductor L₂₁Is coupled to the inductor L₂₂Is center tapped and the inductor L₂₁And L₂₂All have an inductance L₂. More specifically, inductor L₂₁And inductor L₂₂May be considered as the second partial inductor of the first LC-oscillator, and the inductor L₂₁And inductor L₂₂The combination of the lower parts of (a) may be regarded as a second partial inductor of the second LC-oscillator. Further, as shown in fig. 6B, all inductors (e.g., electricity in the first LC oscillator and the second LC oscillator) Sensor L₁₁/L₁₂And an inductor L₃₁/L₃₂And an inductor L₂₁/L₂₂) May be implemented by a continuous metal layer without segmentation.

In some embodiments, alternative designs of the LC oscillator 10 may be applied to the dual-core oscillator 60, for example the inductor L within the first and second LC oscillators of the dual-core oscillator 60 may be omitted₃₁And L₃₂. Similarly, when the inductor L in the first LC oscillator and the second LC oscillator is omitted₃₁And L₃₂All inductors within the dual-core oscillator 60 (e.g., inductor L in both the first and second LC oscillators)₁₁/L₁₂And an inductor L₂₁/L₂₂) Or by a continuous metal layer without segmentation. With or without inductor L₃₁And L₃₂Reference may be made to the description relating to the embodiment of fig. 1A for design of the dual-core oscillator 60, which will not be described again for the sake of brevity.

In some embodiments, the P-type transistor MP and the N-type transistor MN within the second LC oscillator shown in fig. 6A and 6B may be omitted. For example, as shown in the lower half of the dual core oscillator 70 shown in fig. 7A, the second LC oscillator may be replaced with a second LC tank (e.g., where there are no transistors). Since the only difference between the dual-core oscillator 60 and the dual-core oscillator 70 is whether the P-type transistor MP and the N-type transistor MN are configured in the second LC oscillator, further details of the dual-core oscillator 70 are not repeated for the sake of brevity. Similarly, as shown in fig. 7B, all of the inductors (e.g., inductor L in the first and second LC oscillators) ₁₁/L₁₂And an inductor L₃₁/L₃₂And an inductor L₂₁/L₂₂) Can be realized by a continuous metal layer without division.

Since the dual-core oscillators 60 and 70 are based on the architecture shown in fig. 1A, both dual-core oscillators 60 and 70 have all the advantages of the LC oscillator 10. Furthermore, dual core oscillators 60 and 70 may effectively double the output signal swing/power compared to using a single LC oscillator (e.g., any of LC oscillators 10, 20, 30, 40, and 50), thereby equivalently reducing the overall phase noise (e.g., by 3dB) with unchanged efficiency (e.g., FOM).

Briefly, embodiments of the present invention provide an LC oscillator with an embedded second harmonic filter that combines a fundamental resonant tank and a second harmonic filter into one LC network. The LC oscillator can effectively increase the impedance associated with the second harmonic signal without sacrificing voltage gain, and can minimize the impact of process variations on overall performance since the mismatch of capacitors and inductors can be minimized by appropriate layout as shown in the embodiments. Embodiments of the present invention do not substantially increase the overall cost as compared to the prior art. Therefore, the present invention can improve the overall performance of the LC oscillator without or with less possibility of causing any side effects.

Although the present invention has been described with reference to particular embodiments, 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.