Complementary inverse F-class voltage-controlled oscillator and nested voltage-controlled oscillator thereof

Abstract

The invention discloses a complementary type inverse F-class voltage-controlled oscillator and a nested type voltage-controlled oscillator thereof, and mainly solves the problem that an existing oscillator is large in occupied area or high in cost. The oscillator is composed of two same active cores A1 and A2, each active core internally comprises a pair of complementary NMOS (N-channel Metal Oxide Semiconductor) tube and PMOS (P-channel Metal Oxide Semiconductor) tube, a drain capacitor CD is connected between the drain of the NMOS tube and the drain of the PMOS tube, a grid capacitor CG is connected between the grid of the NMOS tube and the grid of the PMOS tube, and the two active cores are mutually connected through four transformers. According to the complementary type inverse F-type voltage-controlled oscillator, broadband coverage, high performance and low phase noise under high frequency are achieved, inductance nesting is carried out through the basic units, the problem that the occupied area of a multi-core oscillator is too large is greatly solved, the requirements for small size and low cost of a chip are met, and the complementary type inverse F-type voltage-controlled oscillator is suitable for large-scale popularization and application. And in addition, good performance consistency is achieved under the broadband condition.

Description

Technical Field

[0001] The present invention relates to a voltage-controlled oscillator, and more particularly, to a complementary class-F inverse voltage-controlled oscillator and its nested voltage-controlled oscillator. Background Art

[0002] An oscillator is a device that does not require external signal excitation and converts direct current into an alternating current signal output by itself. It has positive feedback and a certain gain to overcome the loss on the circuit feedback path, so it can generate a stable oscillating signal with self-sustaining output. As one of the main classifications of oscillators, a voltage-controlled oscillator is used in modules such as phase-locked loops and clock recovery circuits, and is one of the core modules of wireless communication systems. As shown in Figure 1 (a), an oscillator can be divided into an active circuit and a resonant circuit. The negative resistance generated by the lower active circuit cancels the resistance generated by the resonant circuit and supplements the energy loss in the resonant circuit. Therefore, when the oscillator oscillates stably, it realizes the Figure 1 stable output at the resonant point shown in 0 (b).

[0003] As the heart of the frequency source carrier generation, the oscillator plays an important role in the design of multi-standard systems, and affects the overall performance of the frequency source system in key indicators such as phase noise, FoM (figure of merit of the oscillator), power consumption, area, frequency coverage, and frequency stability. The design of the frequency source architecture also plays a decisive role in aspects such as in-band noise, frequency modulation accuracy, and system complexity. However, in the millimeter-wave band, it is very challenging to build a system that can be configured for different frequency bands and different system requirements, and it often faces the problems of a strict design trade-off between performance and bandwidth and an overly complex frequency source system.

[0004] As shown in Figure 2 is a schematic diagram of an existing switched-inductor LC oscillator. The switched-inductor technology uses switches to select the inductance value, thereby realizing frequency tuning and switching. This method can achieve a relatively wide frequency coverage and has the following advantages: (1) wide frequency coverage; (2) simple design and relatively small occupied area. However, the introduction of the switch on-resistance deteriorates the inductance quality factor, which is more obvious at high frequencies. Therefore, its performance is limited at high frequencies, and the phase noise deteriorates significantly at higher frequencies, making it difficult to be used in high-frequency applications.

[0005] As shown in Figure 3 is a schematic diagram of an existing switched-coupled transformer LC oscillator. The switched-coupled transformer indirectly controls the change of the primary inductance value by introducing a switch on the secondary inductance through coupling, reducing the influence of the switch on-resistance on the quality factor, and it also has a relatively wide frequency modulation range. However, the excessive inductance windings of this oscillator often occupy too large an area, increasing the cost and the design complexity while increasing the cost.

[0006] As Figure 4 shown in the schematic diagram of the existing multi-core switching LC oscillator, this solution designs several oscillators with different frequencies, selects the oscillators operating in different frequency bands for output, so as to achieve wide-frequency coverage while reducing the impact of the switch on the resonant circuit. However, since multiple oscillators are independently designed, different oscillators occupy independent inductor areas, and their areas are often too large, which also brings a series of problems such as increased power consumption and complex circuit design.

[0007] As Figure 5 shown in the schematic diagram of the existing mode-switching LC oscillator, it uses a multi-stage resonator to generate multiple resonant frequencies and selects them through an odd-even mode switching switch. In any mode, the switch only acts on the unwanted resonant frequencies, so the quality factor of the selected mode will not be deteriorated. However, the native performance differences between different modes of the mode-switching oscillator are often large, and the performance consistency is poor. Due to its relatively complex inductive coupling method, some techniques for optimizing phase noise, such as waveform shaping technology, are difficult to be used in the mode-switching oscillator, so its overall performance is also limited. Summary of the Invention

[0008] The purpose of the present invention is to provide a complementary inverse class-F voltage-controlled oscillator and its nested voltage-controlled oscillator, mainly solving the problems of large occupied area or high cost of the existing oscillators.

[0009] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0010] A complementary inverse class-F voltage-controlled oscillator is composed of two identical active cores A1 and A2. Each active core internally contains a pair of complementary NMOS transistors and PMOS transistors. A drain capacitor C is connected between the drains of the NMOS transistor and the PMOS transistor D , and a gate capacitor C is connected between the gates of the NMOS transistor and the PMOS transistor G, the two active cores are interconnected through four transformers; among them, the four transformers are respectively denoted as F1, F2, F3, and F4. The same-name end of the primary winding of transformer F1 is connected to the drain of the NMOS transistor in active core A1, and the same-name end of the secondary winding of transformer F1 is connected to the gate of the PMOS transistor in active core A1; the same-name end of the primary winding of transformer F2 is connected to the drain of the PMOS transistor in active core A1, and the same-name end of the secondary winding of transformer F2 is connected to the gate of the NMOS transistor in active core A1; the same-name end of the primary winding of transformer F3 is connected to the drain of the NMOS transistor in active core A2, and the same-name end of the secondary winding of transformer F3 is connected to the gate of the PMOS transistor in active core A2; the same-name end of the primary winding of transformer F4 is connected to the drain of the PMOS transistor in active core A2, and the same-name end of the secondary winding of transformer F4 is connected to the gate of the NMOS transistor in active core A2; the different-name ends of the primary windings and the different-name ends of the secondary windings of transformers F1 and F4 are correspondingly connected; the different-name ends of the primary windings and the different-name ends of the secondary windings of transformers F2 and F3 are correspondingly connected; a capacitor or a resistor is connected between the different-name end of the primary winding and the different-name end of the secondary winding of transformer F1; a capacitor or a resistor is connected between the different-name end of the primary winding and the different-name end of the secondary winding of transformer F2; a capacitor or a resistor is connected between the different-name end of the secondary winding of transformer F1 and the different-name end of the secondary winding of transformer F2.

[0011] Further, in the present invention, the drain capacitance C D or the gate capacitance C G adopts one or more of a fixed capacitor, a varactor diode, or a switched capacitor.

[0012] Further, in the present invention, the active cores A1 and A2 adopt complementary bipolar junction transistors or complementary metal-oxide-semiconductor field-effect transistors.

[0013] Based on the above structure, the present invention also provides a complementary inverse class-F voltage-controlled oscillator based on inductance nesting, which is made of two complementary inverse class-F voltage-controlled oscillators with different frequencies.

[0014] Further, in the present invention, the two complementary inverse class-F voltage-controlled oscillators with different frequencies are placed orthogonally.

[0015] Further, in the present invention, one of the two complementary inverse class-F voltage-controlled oscillators with different frequencies is designed in an 8-shaped design, and the other is designed in a ring-shaped design, and the two different oscillators are placed vertically.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The complementary inverse class-F voltage-controlled oscillator proposed by the present invention achieves wide-frequency coverage, high performance, and low phase noise at high frequencies. By using basic units for inductance nesting, the problem of excessive area occupation of multi-core oscillators is greatly reduced, meeting the requirements of small chip size and low cost, and having good performance consistency over a wide frequency range.

[0018] (2) The complementary inverse class-F waveform shaping technology adopted by the present invention has a half-sine wave voltage waveform and a square wave current waveform. Waveform shaping is carried out using the second harmonic to reduce the sensitivity of the oscillator phase noise to noise, thereby reducing the phase noise.

[0019] (3) The quality factor of the inductor implemented by the present invention is also relatively high, further reducing the phase noise, improving the overall performance, and being beneficial to high-frequency applications. By placing the power supply layout outside the resonator, the crosstalk of power supply parasitics is reduced.

[0020] (4) Compared with the performance of traditional oscillators, the present invention still has excellent phase noise and good performance consistency while increasing the output frequency range. The present invention has advantages in terms of comprehensive performance and manufacturing cost. Description of the Drawings

[0021] Figure 1 (a) Schematic diagram of an existing oscillator structure.

[0022] Figure 1 (b) Schematic diagram of the resonance point of an existing oscillator.

[0023] Figure 2 Schematic diagram of an existing switched-inductor LC oscillator.

[0024] Figure 3 Schematic diagram of an existing switched-coupled transformer LC oscillator.

[0025] Figure 4 Schematic diagram of an existing multi-core switched LC oscillator.

[0026] Figure 5 Schematic diagram of an existing mode-switching LC oscillator.

[0027] Figure 6 Complementary inverse class-F voltage-controlled oscillator of the present invention.

[0028] Figure 7 Schematic diagrams of operations such as juxtaposition, nesting, and coupling of the class-F voltage-controlled oscillator in the embodiment of the present invention.

[0029] Figure 8 Capacitor implementation form of the complementary inverse class-F voltage-controlled oscillator of the present invention.

[0030] Figure 9 This is the active core implementation form of the complementary inverse class-F voltage-controlled oscillator based on area reuse of the present invention.

[0031] Figure 10 This is the implementation principle of the complementary inverse class-F voltage-controlled oscillator based on inductance nesting of the present invention.

[0032] Figure 11 This is the specific implementation form of the complementary inverse class-F voltage-controlled oscillator based on inductance nesting of the present invention.

[0033] Figure 12 This is the schematic diagram of the inductance nesting technical mechanism in the present invention. Specific embodiments

[0034] The present invention will be further described below in conjunction with the accompanying drawings and embodiments. The implementation manners of the present invention include but are not limited to the following embodiments.

[0035] Embodiment 1

[0036] As Figure 6 shown, a complementary inverse class-F voltage-controlled oscillator disclosed by the present invention is composed of two identical active cores A1 and A2. Each active core internally includes a pair of complementary NMOS transistors and PMOS transistors. A drain capacitor C is connected between the drains of the NMOS transistor and the PMOS transistor D , and a gate capacitor C is connected between the gates of the NMOS transistor and the PMOS transistor G . The two active cores are interconnected through 4 transformers. Among them, the 4 transformers are respectively denoted as F1, F2, F3, and F4. The same-name end of the main winding of transformer F1 (i.e., Figure 6 the L in D ) is connected to the drain of the NMOS transistor in the active core A1, and the secondary winding of transformer F1 (i.e., Figure 6 the L in G)The same-named terminal of () is connected to the gate of the PMOS transistor in the active core A1; the same-named terminal of the primary winding of the transformer F2 is connected to the drain of the PMOS transistor in the active core A1, and the same-named terminal of the secondary winding of the transformer F2 is connected to the gate of the NMOS transistor in the active core A1; the same-named terminal of the primary winding of the transformer F3 is connected to the drain of the NMOS transistor in the active core A2, and the same-named terminal of the secondary winding of the transformer F3 is connected to the gate of the PMOS transistor in the active core A2; the same-named terminal of the primary winding of the transformer F4 is connected to the drain of the PMOS transistor in the active core A2, and the same-named terminal of the secondary winding of the transformer F4 is connected to the gate of the NMOS transistor in the active core A2; the different-named terminals of the primary windings and the different-named terminals of the secondary windings of the transformers F1 and F4 are correspondingly connected; the different-named terminals of the primary windings and the different-named terminals of the secondary windings of the transformers F2 and F3 are correspondingly connected; a capacitor or a resistor is connected between the different-named terminal of the primary winding and the different-named terminal of the secondary winding of the transformer F1; a capacitor or a resistor is connected between the different-named terminal of the primary winding and the different-named terminal of the secondary winding of the transformer F2 (i.e., Figure 6 the components in); a capacitor or a resistor is connected between the different-named terminal of the secondary winding of the transformer F1 and the different-named terminal of the secondary winding of the transformer F2. Compared with the traditional Class-F inverse oscillator, the present design uses a transformer with a co-directional coupling 1:1 turns ratio, which can achieve a high Q value at a relatively high frequency, thereby obtaining better performance and meeting the requirements of high-frequency design.

[0037] It adopts the Class-F inverse waveform shaping technology and uses the second harmonic for waveform shaping, thereby achieving low phase noise and high performance. Figure 6 FIG. shows a schematic structural diagram of a complementary Class-F inverse voltage-controlled oscillator based on area reuse, and this structure forms a basic unit.

[0038] By performing operations such as juxtaposing, nesting, or coupling different basic units, this basic unit can be further utilized to broaden the frequency bandwidth and improve the overall performance, as Figure 7 shown.

[0039] By nesting two voltage-controlled oscillators with different frequencies, the inductors of the two different oscillators share the same area. Compared with the traditional multi-core switching oscillator ( Figure 4 ), the circuit size is greatly reduced and the cost of the chip is lowered. The two oscillators can also be independently optimized. Compared with the traditional mode-switching oscillator ( Figure 5 ), the broadband performance consistency of the oscillator is greatly improved. It meets the requirements of broadband high performance, low phase noise, small chip size, and good performance consistency.

[0040] Embodiment 2

[0041] Based on Embodiment 1, the gate capacitance (C G ) and the drain capacitance (CD ) are respectively connected to both sides of the gate and the drain of the active core, as Figure 8 shown. The output frequency of this oscillator can be adjusted by controlling the changes in the gate capacitance and the drain capacitance. The implementation forms of the capacitance include fixed capacitance, varactor diode, and switched capacitor, etc. By adjusting the number and size of the capacitance groups, different frequency tuning ranges can be achieved, thereby realizing the continuous coverage of the output frequency of the oscillator. By adjusting the ratio of the gate capacitance to the drain capacitance, the accuracy of the frequency of the second harmonic is ensured.

[0042] Embodiment 3

[0043] Based on Embodiment 1, the implementation form of the active core of the complementary inverse class-F voltage-controlled oscillator based on area reuse is as Figure 9 shown. A complementary bipolar junction transistor or a complementary field-effect transistor is used to provide negative resistance, and different active cores can be adopted according to actual situations.

[0044] Embodiment 4

[0045] Based on Embodiment 1, the extended implementation form of the complementary inverse class-F voltage-controlled oscillator based on inductance nesting is as Figure 10 shown. The two oscillators operate at different frequencies. Oscillator A operates at a low frequency, and oscillator B operates at a high frequency, improving the frequency coverage range. The two oscillators with different frequencies are orthogonally placed and have native isolation. Furthermore, the purpose of sharing the same area by the inductors of different oscillators is achieved, reducing the chip size and the cost of the chip. The nesting mechanism is as Figure 12 shown. This figure shows the principle of the inductance nesting technology, which shows the current directions of four different resonance modes and the magnetic field distribution generated in this resonance mode. The magnetic fields generated by the harmonics of different modes of each oscillator do not generate magnetic flux on the other oscillator, thereby realizing the multi-order resonance isolation between different oscillators.

[0046] Figure 11 shows the specific layout implementation form of the complementary inverse class-F voltage-controlled oscillator based on inductance nesting. By designing one of the oscillators in an 8-shaped design and the other in a circular design, and placing the two different oscillators vertically, the two oscillators can work independently and be isolated from each other. Inside the same oscillator, the midpoints of each inductor are connected by resistors to suppress unwanted modes and ensure the stable operation of the oscillator. The power supply layout is placed outside the resonator cavity, simplifying the power supply layout and avoiding the influence of the parasitics of the power supply traces on the resonator cavity of the oscillator. The two oscillators can be independently optimized, and compared with the traditional mode-switching oscillator, the broadband performance consistency of the oscillator is greatly improved. It meets the requirements of broadband high performance, low phase noise, small chip size, and good performance consistency.

[0047] The above embodiments are only one of the preferred embodiments of the present invention and should not be used to limit the protection scope of the present invention. Any modification or polishing that has no substantial meaning made on the main design concept and spirit of the present invention, as long as the technical problems solved are still consistent with those of the present invention, should be included within the protection scope of the present invention.

Claims

1. A complementary inverse class F voltage controlled oscillator, characterized in that: It consists of two identical active cores A1 and A2. Each active core contains a pair of complementary NMOS and PMOS transistors. A drain capacitor C is connected between the drains of the NMOS and PMOS transistors. D , a gate capacitor C is connected between the gates of the NMOS tube and the PMOS tube G , the two active cores are connected to each other through four transformers; the four transformers are respectively denoted as F1, F2, F3, and F4, the same-name end of the main winding of transformer F1 is connected to the drain of the NMOS tube in the active core A1, and the same-name end of the secondary winding of transformer F1 is connected to the gate of the PMOS tube in the active core A1; the same-name end of the main winding of transformer F2 is connected to the drain of the PMOS tube in the active core A1, and the same-name end of the secondary winding of transformer F2 is connected to the gate of the NMOS tube in the active core A1; the same-name end of the main winding of transformer F3 is connected to the drain of the NMOS tube in the active core A2, and the same-name end of the secondary winding of transformer F3 is connected to the gate of the PMOS tube in the active core A2. The gate of the MOS tube is connected; the same-name end of the main winding of the transformer F4 is connected to the drain of the PMOS tube in the active core A2, and the same-name end of the secondary winding of the transformer F4 is connected to the gate of the NMOS tube in the active core A2; the opposite-name ends of the main windings of the transformers F1 and F4 and the opposite-name ends of the secondary windings are connected correspondingly; the opposite-name ends of the main windings of the transformers F2 and F3 and the opposite-name ends of the secondary windings are connected correspondingly; a capacitor or a resistor is connected between the opposite-name end of the main winding of the transformer F1 and the opposite-name end of the secondary winding; a capacitor or a resistor is connected between the opposite-name end of the main winding of the transformer F2 and the opposite-name end of the secondary winding; a capacitor or a resistor is connected between the opposite-name end of the secondary winding of the transformer F1 and the opposite-name end of the secondary winding of the transformer F2.

2. A complementary inverse class-F voltage-controlled oscillator according to claim 1, characterized in that: The drain capacitance C D Or gate capacitance C G One or more of fixed capacitors, variable capacitance diodes or switched capacitors are used.

3. A complementary inverse class-F voltage-controlled oscillator according to claim 2, characterized in that: The active cores A1 and A2 are complementary bijunction transistors or complementary field effect transistors.

4. A complementary inverse class F voltage-controlled oscillator based on inductor nesting, characterized in that: It is made of two complementary inverse class F voltage-controlled oscillators with different frequencies as claimed in claim 3.

5. The complementary inverse class-F voltage-controlled oscillator based on inductor nesting according to claim 4, characterized in that: Two complementary inverse class F voltage controlled oscillators with different frequencies are placed in quadrature.

6. The complementary inverse class-F voltage-controlled oscillator based on inductor nesting according to claim 4, characterized in that: One of the two complementary inverse F-type voltage-controlled oscillators with different frequencies adopts an 8-shaped design, and the other adopts a ring design, and the two different oscillators are placed vertically.

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