Multi-element resonator

Abstract

The invention is a multi-element resonator, and provides a resonant tank including a first capacitor formed on a semiconductor substrate, a first inductor formed on the semiconductor substrate, a second capacitor formed on the semiconductor substrate, and a second inductor formed on the semiconductor substrate. The first capacitor, the first inductor, the second capacitor and the second inductor are connected together in the form of a ring structure, each capacitor is connected between a pair of the inductors, and each inductor is connected between a pair of the capacitors. An amplifier circuit is coupled with the resonant tank and is configured to amplify a signal in the resonant tank.

Description

[0001] This application is a divisional application. The application number of the original application is 201980037281.9, and the original application date is July 9, 2019. The entire contents of the original application are incorporated into this application by reference.

[0002] Cross-application of related applications

[0003] This application claims priority to U.S. non-provisional patent application No. 16 / 029,905, filed on July 9, 2018, entitled “Multi-Element Resonator,” the entire contents of which are incorporated herein by reference. Technical Field

[0004] The present invention generally relates to a circuit including an integrated circuit for communications. Background Art

[0005] Electronic circuits, including those formed as integrated circuits (ICs) on semiconductor substrates, are used in various applications in communication systems. For example, a transmitter circuit may be formed by one or more integrated circuits formed on one or more silicon substrates, and a receiver circuit may be formed by one or more integrated circuits formed on one or more silicon substrates. In general, integrated circuit technology is trending toward smaller feature sizes to make circuits smaller and less expensive. Smaller feature sizes may affect circuits in many ways, and not all circuits scale the same. As feature sizes become smaller, the breakdown voltage of the device becomes lower, which can be overcome by designing for a lower voltage to ensure that the breakdown voltage is not exceeded. The lower voltage may affect IC characteristics, including IC characteristics of transmitter circuits and receiver circuits formed as or by the IC. Summary of the invention

[0006] According to one aspect of the present invention, an oscillator circuit is provided, comprising: a resonant circuit, comprising a first capacitor formed on a semiconductor substrate, a first inductor formed on the semiconductor substrate, a second capacitor formed on the semiconductor substrate, and a second inductor formed on the semiconductor substrate, wherein the first capacitor, the first inductor, the second capacitor, and the second inductor are connected together in the form of a ring structure, wherein each capacitor is connected between a pair of the inductors, and each inductor is connected between a pair of the capacitors; and an amplifier circuit coupled to the resonant circuit and used to amplify the signal in the resonant circuit.

[0007] Optionally, in any of the above aspects, the first inductor and the second inductor are each formed by one or more corresponding portions of metal deposited on the semiconductor substrate.

[0008] Optionally, in any of the above aspects, the first inductor and the second inductor are tapped inductors, each of which has at least one tapped input terminal at a mid-position between the inductor ends.

[0009] Optionally, in any of the above aspects, the amplifier circuit includes a first inverter connected to the tap input terminal of the first inductor and a second inverter connected to the tap input terminal of the second inductor.

[0010] Optionally, in any of the above aspects, the amplifier circuit comprises a first pair of inverters connected across the first inductor and a second pair of inverters connected across the second inductor.

[0011] Optionally, in any of the above aspects, the first capacitor is a variable capacitor, and the capacitance of the variable capacitor is variable within a predetermined range to control the resonant frequency of the oscillator circuit.

[0012] Optionally, in any of the above aspects, the first capacitor includes at least a first capacitive element and a second capacitive element, and one or more switches to modify the capacitance of the first capacitor by discrete amounts according to the connection of the first capacitive element and the second capacitive element.

[0013] Optionally, in any of the above aspects, the first capacitor comprises one or more variable capacitive elements, each of the one or more variable capacitive elements having a respective capacitance that is variable over a continuous range according to an applied voltage.

[0014] Optionally, in any of the above aspects, the oscillator circuit forms a voltage controlled oscillator (VCO) in a phase locked loop (PLL) circuit, and the phase locked loop circuit also includes a feedback loop, a phase detector and a filter.

[0015] Optionally, in any of the above aspects, the phase locked loop (PLL) circuit is used to provide an oscillator signal in a transmitter or a receiver in a user equipment in a communication system.

[0016] Optionally, in any of the above aspects, the oscillator circuit further includes: a third capacitor formed on the semiconductor substrate, a third inductor formed on the semiconductor substrate, a fourth capacitor formed on the semiconductor substrate, and a fourth inductor formed on the semiconductor substrate. The third capacitor, the third inductor, the fourth capacitor, and the fourth inductor are connected together with the first capacitor, the first inductor, the second capacitor, and the second inductor in the form of a ring structure, wherein each capacitor is connected between a pair of the inductors, and each inductor is connected between a pair of the capacitors.

[0017] According to another aspect of the present invention, a method for generating an oscillator signal is provided, the method comprising: receiving an electrical signal from a resonant circuit, the resonant circuit comprising a first capacitor formed on a semiconductor substrate, a first inductor formed on the semiconductor substrate, a second capacitor formed on the semiconductor substrate, and a second inductor formed on the semiconductor substrate. The first capacitor, the first inductor, the second capacitor, and the second inductor are connected in series in the form of a ring structure, wherein each capacitor is connected in series between the inductors, and each inductor is connected in series between the capacitors. The method also comprises: amplifying the electrical signal from the resonant circuit and returning the amplified electrical signal to the resonant circuit to generate the oscillator signal at the resonant frequency of the resonant circuit.

[0018] Optionally, in any of the above aspects, the electrical signal is amplified by one or more pairs of inverters.

[0019] Optionally, in any of the above aspects, the first inductor and the second inductor are tapped inductors, each of which has at least one tap terminal at a mid-position between the inductor ends, and returning the amplified electrical signal to the resonant circuit includes: providing an inverted amplified signal at the tap terminals of the first inductor and the second inductor.

[0020] Optionally, in any of the above aspects, the method further comprises: controlling the capacitance of at least the first capacitor to control the resonant frequency and thereby control the frequency of the oscillator signal.

[0021] Optionally, in any of the above aspects, the method further comprises: acquiring a carrier signal in a transceiver in a communication system from the oscillator signal.

[0022] Optionally, in any of the above aspects, acquiring the carrier signal in the transceiver includes: performing phase comparison and filtering in a phase locked loop (PLL).

[0023] According to another aspect of the present invention, a voltage controlled oscillator (VCO) is provided, the voltage controlled oscillator comprising: a resonant circuit, a first inverter and a second inverter. The resonant circuit comprises: a first capacitor formed on a semiconductor substrate; a second capacitor formed on a semiconductor substrate; a first inductor formed on the semiconductor substrate, the first inductor having a first tap terminal, the first inductor being connected between the first terminal of the first capacitor and the first terminal of the second capacitor; a second inductor formed on the semiconductor substrate, the second inductor having a second tap terminal, the second inductor being connected between the second terminal of the first capacitor and the second terminal of the second capacitor, so that the first capacitor, the first inductor, the second capacitor and the second inductor form a loop. The first inverter has an input terminal connected to the first terminal of the first capacitor and an output terminal connected to the first tap terminal. The second inverter has an input terminal connected to the second terminal of the first capacitor and an output terminal connected to the second tap terminal.

[0024] Optionally, in any of the above aspects, at least one of the first capacitor and the second capacitor is a variable capacitor having a variable capacitance, wherein the variable capacitance is controlled to select a resonant frequency of the resonant tank.

[0025] Optionally, in any of the above aspects, the VCO is connected with a phase detector, a filter and a feedback loop in a phase locked loop (PLL) arrangement to provide an oscillator signal for the transceiver.

[0026] The summary of the invention briefly introduces some concepts, which will be further described in the detailed description. The summary of the invention is not intended to provide the key features or basic features of the subject matter claimed in the patent application, nor is it intended to determine the scope of the subject matter claimed in the patent application. The subject matter claimed in the patent application is not limited to the implementation method that solves any or all problems mentioned in the background technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The various aspects of the present invention are illustrated by way of example and not limitation in the accompanying figures, in which like references indicate similar elements.

[0028] Figure 1 An exemplary wireless network for communicating data is shown;

[0029] Figure 2 Shown in Figure 1Exemplary details of an instance of user equipment (UE) introduced in;

[0030] Figure 3 Shown in Figure 1 Exemplary details of an example of a base station (BS) introduced in;

[0031] Figure 4 Shown included in Figure 2 and Figure 3 Exemplary details of a receiver in a UE or BS are shown;

[0032] Figure 5 Shown included in Figure 2 and Figure 3 Exemplary details of a transmitter in a UE or BS are shown;

[0033] Figure 6 Shown as Figure 4 and Figure 5 Included in the Figure 2 and Figure 3 An example of a PLL in a UE or BS is shown;

[0034] Figure 7A-7F Shown included in Figure 6 Example of a VCO in a PLL;

[0035] Figure 8A-8C shows that it may be included in Figure 7A-7B Example of an LC loop in a VCO;

[0036] Figure 9A-9D shows that it may be included in Figure 7A-7B Another example of an LC loop in a VCO;

[0037] Figures 10A-10D Shows Figure 7A-7B The VCO in the VCO Figure 9A-9D The realization method of LC circuit;

[0038] Figures 11A-11C shows the use of a tapped inductor Figure 7A-7B The implementation method of VCO;

[0039] Fig.12 It shows that Figure 7A-7B A method for implementing an LC loop used in a VCO, wherein the LC loop has two or more capacitors and two or more inductors in a ring structure;

[0040] Fig.13 shows the summary operation Figure 9A-Figure 12 A brief flow chart of various methods of LC circuits and other resonant circuits. DETAILED DESCRIPTION

[0041] The present invention will now be described with reference to the accompanying drawings, which generally relate to a Voltage Controlled Oscillator (VCO) circuit including an inductor-capacitor (LC) resonant tank.

[0042] The resonant tank in an oscillator circuit such as a VCO can be formed by a capacitor and an inductor. In general, as the size of the device decreases, the breakdown voltage becomes smaller, and to avoid breakdown, a lower voltage can be used. However, the lower voltage may cause a decrease in the signal-to-noise ratio (SNR) and a decrease in the quality factor (Q factor) in some circuits, including those used in user equipment in communication systems. In order to maintain the signal-to-noise ratio at a given frequency while reducing the voltage, the capacitor size can be increased while reducing the inductor size. However, this approach is not always feasible. Devices with mismatched sizes may be difficult or impossible to physically connect at a certain scale.

[0043] A resonant circuit formed by a multi-element ring of capacitors and inductors can allow the use of lower voltages while maintaining an acceptable SNR, and while keeping the relative sizes of the capacitors and inductors within an acceptable range. For example, two capacitors and two inductors can be coupled together in an alternating manner to form a ring structure. At the same voltage as a single capacitor, single inductor resonant circuit, this dual capacitor, dual inductor resonant circuit can store approximately twice the energy and can provide a signal with approximately twice the SNR. At half the voltage used by a single capacitor, single inductor resonant circuit, this dual capacitor, dual inductor resonant circuit can store approximately the same amount of energy and can provide a signal with approximately the same SNR, thereby facilitating achieving an acceptable SNR while miniaturizing the device and reducing the voltage.

[0044] It should be understood that the current embodiments of the present invention can be implemented in many different forms, and the scope of the claims should not be interpreted as being limited to the embodiments set forth herein. In fact, these embodiments are provided to make the present invention thorough and complete, and to fully convey the concept of the embodiments of the present invention to those skilled in the art. In fact, the present invention is disclosed to cover substitutes, modifications and equivalents of these embodiments included in the spirit and scope of the present invention disclosed as defined by the appended claims. In addition, in the following detailed description of the current embodiments of the present invention, many specific details are set forth to provide a thorough understanding. However, it should be clear to those of ordinary skill in the art that the current embodiments of the present invention can be practiced without these specific details.

[0045] Figure 1 A wireless network for transmitting data is shown. For example, the communication system 100 includes user equipment 110A-110C, a radio access network (RAN) 120A-120B, a core network 130, a public switched telephone network (PSTN) 140, the Internet 150, and other networks 160. Other or alternative networks include private and public data packet networks, including corporate intranets. Although a certain number of these components or elements are shown in the figure, any number of these components or elements may be included in the system 100.

[0046] In one embodiment, the wireless network may be a fifth generation (5G) network, comprising at least one 5G base station, wherein the 5G base station uses orthogonal frequency-division multiplexing (OFDM) and / or non-OFDM and a transmission time interval (TTI) shorter than 1ms (e.g., 100 microseconds or 200 microseconds) to communicate with a communication device. In general, a base station may also refer to any one of an eNB and a 5G BS (gNB). In addition, the network may further include a network server for processing information received from the communication device via at least one eNB or gNB.

[0047] The system 100 enables multiple wireless users to transmit and receive data and other content. The system 100 may implement one or more channel access methods, such as, but not limited to, code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), or single-carrier FDMA (SC-FDMA).

[0048] User equipment (UE) 110A-110C is used to operate and / or communicate in the system 100. For example, the user equipment 110A-110C is used to send and / or receive wireless signals or wired signals. Each user equipment 110A-110C represents any suitable end-user device, which may include (or may be referred to as): user equipment / equipment, wireless transmission / reception unit (UE), mobile station, fixed or mobile user unit, pager, cellular phone, personal digital assistant (PDA), smart phone, laptop, computer, touch pad, wireless sensor, wearable device or consumer electronic device.

[0049] In the described embodiment, the RAN 120A-120B includes one or more base stations 170A, 170B (collectively referred to as base stations 170). Each base station 170 is used to wirelessly connect to one or more of the UEs 110A, 110B, 110C to enable access to the core network 130, the PSTN 140, the Internet 150 and / or other networks 160. For example, the base station (BS) 170 may include one or more of several well-known devices, such as a base transceiver station (BTS), a Node-B (NodeB), an evolved NodeB (eNB), a next generation (fifth generation) (5G) NodeB (gNB), a home NodeB, a home eNodeB, a site controller, an access point (AP), or a wireless router, or a server, a router, a switch, or a processing entity having a wired network or a wireless network.

[0050] In one embodiment, base station 170A forms part of RAN 120A, which may include other base stations, components and / or devices. Similarly, base station 170B forms part of RAN 120B, which may include other base stations, components and / or devices. Each base station 170 is used to send and / or receive wireless signals within a specific geographic area (sometimes referred to as a "cell"). In some embodiments, multiple-input multiple-output (MIMO) technology may be used, where each cell has multiple transceivers.

[0051] The base station 170 communicates with one or more of the user equipment 110A-110C using wireless communication links over one or more air interfaces (not shown). The air interfaces may utilize any suitable radio access technology.

[0052] It is contemplated that the system 100 may use multiple channel access functions, such as including base station 170 and user equipment 110A-110C for implementing the Long Term Evolution (LTE) wireless communication standard, LTE-Advanced (LTE-A) and / or LTE Multimedia Broadcast Multicast Service (MBMS) scheme. In other embodiments, base station 170 and user equipment 110A-110C are used to implement UMTS, HSPA or HSPA+ standards and protocols. Of course, other multiple access schemes and wireless protocols may also be used.

[0053] The RANs 120A-120B communicate with the core network 130 to provide voice, data, applications, Voice over Internet Protocol (VoIP) or other services to the user equipment 110A-110C. It should be understood that the RANs 120A-120B and / or the core network 130 may communicate directly or indirectly with one or more other RANs (not shown). The core network 130 may also serve as a gateway access to other networks such as the PSTN 140, the Internet 150, and other networks 160. In addition, some or all of the user equipment 110A-110C may include functionality to communicate with different wireless networks over different wireless links using different wireless technologies and / or protocols.

[0054] The RAN 120A-120B may also include millimeter wave and / or microwave access points (APs). The AP may be part of the base station 170 or may be located remotely from the base station 170. The AP may include, but is not limited to, a connection point (mmWCP) or a base station 170 capable of mmW communication (e.g., a mmW base station). The mmW AP may send and receive signals in a frequency range of, for example, from 24 GHz to 100 GHz, but is not required to operate throughout the frequency range. As used herein, the term "base station" is used to refer to a base station and / or a wireless access point.

[0055] Although Figure 1 An example of a communication system is shown, but the Figure 1Various changes may be made. For example, the communication system 100 may include any number of user devices, base stations, networks, or other components in any suitable configuration. It should also be understood that the term "user device" may refer to any type of wireless device that communicates with a wireless network node in a cellular or mobile communication system. Non-limiting examples of user devices are target devices, device-to-device (D2D) user devices, machine-type user devices, or user devices capable of machine-to-machine (M2M) communication, laptops, PDAs, iPads, tablet computers, mobile terminals, smart phones, laptop embedded equipment (laptop embedded equipment, LEE), laptop mounted equipment (laptop mounted equipment, LME), and USB dongles.

[0056] Figure 2 1 shows example details of a UE 110 that can implement methods and teachings according to the present invention. For example, the UE 110 can be a mobile phone, but in other examples can be other devices such as a desktop computer, a laptop computer, a tablet computer, a handheld computing device, an automotive computing device, and / or other computing devices. Figure 2 As shown, the exemplary UE 110 is shown to include at least one transmitter 202, at least one receiver 204, a memory 206, at least one processor 208, and at least one input / output device 212. The processor 208 can implement various processing operations of the UE 110. For example, the processor 208 can perform signal decoding, data processing, power control, input / output processing, or any other operations that enable the UE 110 to operate in the system 100 ( Figure 1 ). The processor 208 may include any suitable processing or computing device for performing one or more operations. For example, the processor 208 may include a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array, or an application specific integrated circuit.

[0057] The transmitter 202 is used to modulate data or other content for transmission via at least one antenna 210. The transmitter 202 may also be used to amplify, filter, and frequency convert RF signals before providing them to the antenna 210 for transmission. The transmitter 202 may include any suitable structure for generating signals for wireless transmission.

[0058] The receiver 204 may be used to demodulate data or other content received by at least one antenna 210. The receiver 204 may also be used to amplify, filter, and frequency convert RF signals received by the antenna 210. The receiver 204 may include any suitable structure for processing wirelessly received signals. The antenna 210 may include any suitable structure for transmitting and / or receiving wireless signals. The same antenna 210 may be used to transmit and receive RF signals, or alternatively, different antennas 210 may be used to transmit and receive signals.

[0059] It should be understood that one or more transmitters 202, one or more receivers 204, and one or more antennas 210 may be used in UE 110. Although shown as separate blocks or components, at least one transmitter 202 and at least one receiver 204 may be combined into a transceiver. Therefore, a single block of a transceiver may be shown instead of showing Figure 2 A separate block for the transmitter 202 and a separate block for the receiver 204 in FIG.

[0060] UE 110 also includes one or more input / output devices 212. Input / output devices 212 facilitate interaction with a user. Each input / output device 212 includes any suitable structure for providing information to a user or receiving information from a user, such as a speaker, microphone, keypad, keyboard, display, or touch screen.

[0061] In addition, the UE 110 includes at least one memory 206. The memory 206 stores instructions and data used, generated, or collected by the UE 110. For example, the memory 206 can store software or firmware instructions executed by one or more processors 208 and data for reducing or eliminating interference in incoming signals. Each memory 206 includes any suitable volatile and / or non-volatile storage and retrieval device. Any suitable type of memory can be used, such as random access memory (RAM), read only memory (ROM), hard disk, optical disk, subscriber identity module (SIM) card, memory stick, secure digital (SD) memory card, etc.

[0062] Figure 3 An exemplary BS 170 is shown that can implement the methods and teachings according to the present invention. Figure 3As shown, BS170 includes at least one processor 308, at least one transmitter 302, at least one receiver 304, one or more antennas 310 and at least one memory 306. Processor 308 implements various processing operations of BS170, such as signal decoding, data processing, power control, input / output processing or any other function. Each processor 308 includes any suitable processing or computing device for performing one or more operations. For example, each processor 308 may include a microprocessor, a microcontroller, a digital signal processor, a field programmable gate array or an application-specific integrated circuit.

[0063] Each transmitter 302 includes any suitable structure for generating signals for wireless transmission to one or more UEs 110 or other devices. Each receiver 304 includes any suitable structure for processing signals wirelessly received from one or more UEs 110 or other devices. Although shown as separate blocks or components, at least one transmitter 302 and at least one receiver 304 can be combined into a transceiver. Each antenna 310 includes any suitable structure for transmitting and / or receiving wireless signals. Although a shared antenna 310 is shown here as being coupled to both a transmitter 302 and a receiver 304, one or more antennas 310 can be coupled to one or more transmitters 302, and one or more separate antennas 310 can be coupled to one or more receivers 304. Each memory 306 includes any suitable volatile and / or non-volatile storage and retrieval device.

[0064] The technology described herein can be implemented using hardware, software, or a combination of hardware and software. The software used is stored on one or more of the above-mentioned processor-readable storage devices to program one or more of the processors to perform the functions described herein. The processor-readable storage device may include a computer-readable medium, such as a volatile and non-volatile medium, a removable and non-removable medium. By way of example and not limitation, a computer-readable medium may include a computer-readable storage medium and a communication medium. A computer-readable storage medium may be implemented in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Examples of computer-readable storage media include RAM, ROM, EEPROM, flash memory or other storage technology, CD-ROM, digital versatile disk (digital versatiledisk, DVD) or other optical disk storage, cassette, magnetic tape, disk storage or other magnetic storage device, or any other medium that can be used to store the desired information and can be accessed by a computer. One or more computer-readable media do not include propagation, modulation, or transient signals.

[0065] Communication media typically embodies computer readable instructions, data structures, program modules or other data in a propagated, modulated or transient data signal (such as a carrier wave or other transmission mechanism), and includes any information delivery medium. The term "modulated data signal" refers to information that sets or changes one or more of its characteristics in a manner that encodes the information in the signal. By way of example and not limitation, communication media include wired media, such as a wired network or a direct wired connection, and wireless media, such as RF and other wireless media. Combinations of the above are also included within the scope of computer readable media.

[0066] In alternative embodiments, some or all of the software may be replaced by dedicated hardware logic components. For example, and not limitation, illustrative types of hardware logic components that may be used include field programmable gate arrays (FPGAs), application-specific integrated circuits (ASICs), application-specific standard products (ASSPs), system-on-a-chip systems (SOCs), complex programmable logic devices (CPLDs), special-purpose computers, etc. In one embodiment, software (stored on a storage device) that implements one or more embodiments is used to program one or more processors. One or more processors may communicate with one or more computer-readable media / storage devices, peripherals, and / or communication interfaces.

[0067] Figure 4 4 shows exemplary details of a receiver 404, which may be a receiver 204 (eg, Figure 2 ) or a receiver 304 included in BS 170 (such as Figure 3 ), but not limited to this. Figure 4, the receiver 404 is shown as including an input terminal 406, at which a radio frequency (RF) signal is received, and therefore, the input terminal 406 may also be referred to as the RF input terminal 406. The RF input terminal 406 may be coupled to an antenna or a coupler, but is not limited thereto. The RF signal received by the RF input terminal 406 is provided to a low noise amplifier (LNA) 408, which may have an adjustable gain. The LNA 408 amplifies the low-power RF signal it receives without significantly reducing the signal-to-noise ratio (SNR) of the signal. The amplified RF signal output by the LNA 408 is provided to a mixer 410. In addition to receiving the amplifier RF signal from the LNA 408, the mixer 410 also receives an oscillator signal from a local oscillator, which in this case is a phase locked loop (PLL) 431. The mixer 410 adjusts the frequency of the amplifier RF signal, for example, from a first frequency to a second frequency lower than the first frequency. More specifically, the mixer 410 can be a down-conversion mixer (DN MIX) that down-converts the amplified RF signal from a relatively high frequency to a baseband frequency, or down-converts to an intermediate frequency (IF) offset from the baseband frequency. Therefore, the oscillator signal from the PLL 431 is used as a carrier signal in the receiver 404.

[0068] Still reference Figure 4, the down-converted RF signal output from the mixer 410 is shown as being provided to a trans-impedance amplifier (TIA) 412. The TIA 412 acts as a current buffer to isolate a multi-feedback (MFB) filter 414 downstream of the TIA 412 from the mixer 410 upstream of the TIA 412. The MBF filter 414 low-pass filters the down-converted RF signal to filter out irrelevant high-frequency signal components, such as high-frequency (HF) noise. The filtered RF signal output from the MBF filter 414 is provided to a variable gain amplifier (VGA) 416, which is used to amplify the RF signal before providing it to an analog-to-digital (A / D) converter 418, which converts the RF signal from an analog signal to a digital signal. The digital signal output from the A / D converter 418 is then provided to a digital filter 420, which performs additional filtering to remove out-of-band signal components and attenuate quantization energy from the A / D converter 418. The filtered digital signal output from the digital filter 420 is then provided to other digital circuits downstream of the digital filter 420. For example, such other digital circuits may include a digital signal processor (DSP), but are not limited thereto. The digital filter 420 may be implemented using the same DSP or different DSPs.

[0069] Figure 5 2 shows exemplary details of a transmitter 502, which may be a transmitter 202 (eg, Figure 2 ) or a transmitter 302 included in BS 170 (as shown Figure 3 ), but not limited to this. Figure 5, the transmitter 502 is shown to include a digital-to-analog (D / A) converter 506, which converts a digital input (e.g., from the processor 208 or the processor 308) into an analog RF signal and provides the RF signal to a low-pass filter 508, which filters the RF signal and provides the filtered RF signal to a mixer 510. In addition to receiving the filtered RF signal from the low-pass filter 508, the mixer 510 also receives a local oscillator signal from the PLL 531 and adjusts the frequency of the RF signal, for example, from a first frequency to a second frequency higher than the first frequency. More specifically, the mixer 510 can be an up-conversion mixer (UP MIX) that up-converts the filtered RF signal from a relatively low frequency (e.g., a baseband frequency, or an intermediate frequency (IF) offset from the baseband frequency) to a relatively high frequency. Therefore, the oscillator signal from the PLL 531 is used as a carrier signal in the transmitter 502. Then, the RF signal from the mixer 510 is amplified by a pre-power amplifier (PPA) 512 and a power amplifier (PA) 514, and filtered by a filter 516 before being provided to an RF output terminal 518 (RFout). For example, the RF output terminal 518 can be coupled to an antenna or a coupler, but is not limited thereto.

[0070] Figure 6 PLL 631 (eg, Figure 4 PLL 431 or Figure 5 Schematic diagram of a PLL 531 of the present invention, which can be used to provide a local oscillator signal for a transmitter (e.g., for transmitter 202 or transmitter 302) or for a receiver (e.g., for a receiver in a user equipment or in a base station, such as receiver 204 or receiver 304) or for any other purpose. PLL 531 can be incorporated into a common IC or a group of ICs with a receiver and / or a transmitter (e.g., receiver 404 and / or transmitter 502), and the receiver and / or transmitter can use, for example, flip chip or metal bump bonding to form a connection to such an IC without using bonding wires. A transmitter, receiver, or transceiver IC can include multiple PLLs to generate oscillator signals, which can be used as a carrier signal, but is not limited to this.

[0071] The PLL 631 includes a phase detector 640, which receives an input signal (e.g., a signal from a master oscillator) and a feedback signal from the output of the PLL 631 through a feedback loop via a frequency divider 642 (depending on the relationship between the input frequency and the output frequency, the frequency divider 642 may be considered optional). The phase detector 640 compares the input frequency and the feedback frequency and generates an output based on the phase comparison, which is provided to a low-pass filter 644. The low-pass filter 644 removes high-frequency noise based on the difference between the input frequency and the feedback frequency to generate a direct current (DC) output. The DC output is provided to a voltage-controlled oscillator VCO 646, which adjusts the frequency of its output signal based on the voltage received from the low-pass filter 644 so as to return its output signal to the frequency of the input signal. Therefore, the phase-locked loop provides an output whose frequency is locked to the input frequency.

[0072] Fig. 7A The implementation of VCO 746 (eg, used in PLL 631) is shown. Figure 6 6) to provide an example of a local oscillator signal for a receiver (e.g., receiver 404) or a transmitter (e.g., transmitter 502). VCO 746 includes a resonant tank 748 and an amplifier 750 coupled to provide an electrical input to the resonant tank and amplify the electrical signal in the resonant tank 748. A control signal 752 (e.g., a DC voltage from a phase detector and a low pass filter in the PLL) is provided to the resonant tank 748 to allow adjustment of the resonant frequency of the tank, thereby adjusting the frequency of the output signal 754. The control signal 752 can change the resonant frequency by changing the characteristics of one or more components of the resonant tank 748. For example, in a resonant tank including a capacitor and an inductor ("LC resonant tank", or simply "LC tank"), the capacitance of the capacitor can be modified according to the control signal (e.g., the capacitor can be a variable capacitor having a variable capacitance that varies according to the control signal).

[0073] In some cases, the LC loop may include an inductor that may be tapped to have more than two terminals. For example, a tapped inductor may include one or more tapped terminals located at an intermediate position between the ends of the inductor (i.e., between the end terminals of the inductor). Figure 7BAn example of a VCO 760 is shown, wherein an LC loop 762 includes a capacitor and a tapped inductor controlled by a control signal 768, the tapped inductor including two tapped terminals in addition to two terminals at either end of the inductor. The end terminals of the inductor of the tapped LC loop 762 can be connected to the input of an amplifier 764, and the tapped terminals of the inductor of the tapped LC loop 762 can be connected to the output of the amplifier 764, and the signal output by one of the output terminals is provided as an output signal 766. This can provide some advantages. For example, the input signal from the LC loop 762 to the amplifier 764 may exceed the power supply voltage limit of the amplifier 764. Since the input voltage represents the energy stored in the tapped LC loop 762, the VCO noise in the VCO 760 may be lower than the VCO noise using a tapless inductor for the same total inductance (i.e., this is because the LC circuit voltage is higher). The tapped inductor can provide a higher SNR and a higher Q value compared to a corresponding tapless inductor of the same size. Since the input voltage of amplifier 764 may exceed the supply rails, the gain of amplifier 764 may be higher for a given power consumption. A detailed description of the use of tapped inductors in VCOs is provided in U.S. Patent Application No. 9,425,737, entitled "Tapped inductor voltage controlled oscillator," which is incorporated herein by reference in its entirety.

[0074] Amplifiers used in VCOs, such as amplifiers 750 and 764, can be single-ended amplifiers or differential amplifiers, and both can be used with tapped inductors or tapless inductors. Single-ended amplifiers have one input and one output, while differential amplifiers have two inputs and two outputs. Both single-ended amplifiers and differential amplifiers can be inverting or non-inverting.

[0075] For example, Figure 7C An example of a VCO 771 is shown that includes a single-ended amplifier 770 connected to a resonant tank 772 that includes a capacitor 774 and a tapless inductor 776 . Fig.7D An example of a VCO 780 is shown that includes a single-ended amplifier 770 connected to a resonant tank 782 that includes a capacitor 774 and a tapped inductor 784 . Fig. 7E An example of a VCO 786 is shown that includes a differential amplifier 788 connected to a resonant tank 772 that includes a capacitor 774 and a tapless inductor 776 . Figure 7FAn example of a VCO 790 is shown that includes a differential amplifier 788 connected to a resonant tank 792 that includes a capacitor 774 and a tapped inductor 794 that has two tapped terminals in this example.

[0076] Fig. 8A 848 that can be used in a VCO, such as the resonant tank 748 of the VCO 746. The LC tank 848 includes a capacitor 850 and an inductor 852 connected in parallel. The capacitor 850 can be a variable capacitor ( Fig. 8A ), which is controlled by a control signal to control the resonant frequency of the LC tank 848. The output terminals 854, 856 of the LC tank 848 can be connected to an amplifier (such as the amplifier 750), and Figure 8B The voltage V between the output terminals 854 and 856 is shown. It can be seen that in this example, the voltage is in the form of a sine wave. The frequency ω of this signal is the resonant frequency of the LC tank 848, and this frequency depends on the inductance (L) and the capacitance (C) according to the following equation:

[0077]

[0078] Generally speaking, the signal-to-noise ratio (SNR) and Q factor of the output signal of an LC loop depend on the energy stored in the loop. The energy depends on capacitance (C), inductance (L), voltage (V), and current (I) according to the following equation:

[0079]

[0080] To increase the energy E and improve the signal strength of the VCO at a fixed supply voltage and fixed frequency, the capacitor can be made larger while the inductor can be made smaller to reduce impedance and facilitate increased current. Similarly, to maintain the same energy and signal strength while reducing the voltage, the inductor can be made smaller while the capacitor can be made larger. Therefore, the relative sizes of the capacitor and inductor in the LC loop can change as the voltage is reduced (for example, to facilitate the realization of a smaller device with a lower breakdown voltage).

[0081] Figure 8CAn example of a physical implementation of an LC loop 848 formed on a semiconductor substrate 860 is shown. An inductor 852 is formed as a metal loop formed on the semiconductor substrate 860, such as deposited in a capping layer, patterned and etched to form the loop shown. The capacitor 850 can be formed by one or more capacitive elements formed by depositing layers of conductive material separated by dielectric layers. Although reducing the inductor size and increasing the capacitor size can operate over a voltage range to provide sufficient SNR, as the size of the components changes, there may be physical limitations in forming connections between components. For example, it may be difficult to form a small enough metal loop and connect it to the terminals of a larger capacitor to achieve high frequencies (e.g., 12 GHz).

[0082] Generally speaking, LC loops such as LC loop 848 store energy and also lose energy. If the energy is added faster than it is lost, the power and amplitude of the signal will increase. As the signal increases, the losses generally increase, so a stable limit cycle occurs where the energy added equals the energy lost. In some cases, the oscillator can start without providing an external stimulus signal because an inductor always has some resistance and the random movement of electrons in such an inductor causes Gaussian noise to be distributed across all frequencies. When the LC loop filters the noise, the LC loop appears as a peak in the noise spectrum at the resonant frequency. When an amplifier is coupled to such an LC loop (e.g., as in Figure 7A-7F ), the amplifier amplifies the peak noise and adds it to the energy of the resonant tank. In this way, the oscillator can be started without any externally provided electrical stimulus (except for the noise present in the components of the LC tank itself). Because the noise is very low, the oscillator usually takes some time to reach its full amplitude. Therefore, in some cases, an electrical input or external stimulus signal is applied to reduce the time required to reach full amplitude. Various aspects of the present technology are applicable to both implementations with such stimulus signals and implementations without such stimulus signals.

[0083] Fig.9A In a schematic manner, an alternative example of a resonant tank, ie an LC tank 948, is shown which may be used in a VCO, for example as Fig. 7ALC circuit 948 includes two capacitors, capacitor 970 and capacitor 972, and two inductors, inductor 974 and inductor 976, in a ring structure, wherein each capacitor is connected between a pair of inductors (i.e., capacitor 970 is connected between inductor 974 and inductor 976, as is capacitor 972), and each inductor is connected between a pair of capacitors (i.e., inductor 974 is connected between capacitor 970 and capacitor 972, as is inductor 976). LC circuit 948 can be considered an example of a multi-element LC circuit or a multi-element resonator.

[0084] LC tank 948 has certain advantages over LC tank 848. For example, when the voltage across the components in LC tank 848 and LC tank 948 is the same and the components are the same size, LC tank 948 can store more energy, thereby providing a higher SNR. The resonant frequency ω of LC tank 948 depends on the inductance (L) of the individual inductors 974, 976 and the capacitance (C) of the individual capacitors 970, 972 according to the following equation:

[0085]

[0086] Therefore, when using components of the same size, the resonant frequency is the same as the resonant frequency of LC tank 848. The energy stored in LC tank 948 is twice the energy E stored in LC tank 848 (i.e., the energy stored in each capacitor and inductor in LC tank 948 is the same as the energy stored in each capacitor and inductor in LC tank 848, and the number of capacitors and inductors in LC tank 948 is twice the number of capacitors and inductors in LC tank 848). This energy 2E depends on capacitance (C), inductance (L), voltage (V), and current (I) according to the following equation:

[0087]

[0088] Thus, for the same voltage, LC tank 948 can store twice as much energy and can improve SNR as LC tank 848. Alternatively, when a lower voltage is used (e.g., using half the voltage to maintain the same energy and SNR), the energy and SNR of LC tank 948 can be maintained at the same level as the energy and SNR of LC tank 848. Various benefits can be obtained by performing certain combinations of improving SNR and reducing voltage.

[0089] Fig. 9B and Fig. 9C Shows Fig.9A The voltage at different positions of the LC loop 948. Fig. 9Bshows a graph of the voltage V1 between the terminal 980 and the terminal 982 versus time, and Fig. 9C A graph of the voltage V2 between the terminal 984 and the terminal 986 versus time is shown. Fig. 9B and Fig. 9C Similar periodic signals are shown out of phase (in this example, 180 degrees out of phase). Voltages V1 and / or V2 may be used to provide an output signal of LC tank 948 (and an output signal of a VCO that includes LC tank 948). In order to allow tuning of LC tank 948, capacitor 970 and / or capacitor 972 may be variable (i.e., configurable to have different capacitances) so that the output of LC tank 948 may be modified (e.g., based on a reference signal in a PLL).

[0090] Fig.9D The semiconductor substrate 960 is formed on the Fig.9A 970, 972. An example of a physical implementation of an LC loop 948 of FIG. 970. Inductor 974 is formed as part of metal on semiconductor substrate 960, such as deposited in a blanket layer, patterned and etched to form the partial loop shown. Inductor 976 is similarly formed as part of metal on semiconductor substrate 960. In one example, the inductor in the LC loop can be formed from a portion of metal that is a half loop (e.g., inductor 974 can form one half of the loop and inductor 976 can form the other half of the loop, wherein a capacitor is provided at the break in the loop). Capacitors 970, 972 can be formed from one or more capacitive elements formed by depositing layers of conductive material separated by dielectric layers.

[0091] One or more amplifiers connected to the components of the LC loop can amplify the signal in the LC loop to add energy to overcome the energy loss of the lossy elements of the LC loop. For an LC loop with a single capacitor and a single inductor in parallel, amplification can be performed across the capacitor and the inductor. In an LC loop with two or more capacitors and two or more inductors (such as LC loop 948), amplification can be performed at different locations and in different configurations as appropriate.

[0092] Fig. 10A Shown include Fig.9A948, wherein an amplifier 1002 is coupled to amplify across an inductor 976 and an amplifier 1004 is coupled to amplify across an inductor 974. The amplifiers 1002, 1004 may be formed by any suitable circuit for amplifying a signal in the LC tank 948. The amplifiers 1002 and 1004 may be collectively considered to be an exemplary implementation of the amplifier 750 of the VCO 746 and may provide an electrical input to the LC tank 948 and amplify the electrical signal to produce an oscillator signal at the resonant frequency of the LC tank 948.

[0093] Fig. 10B An example of an amplifier 1006 is shown, which can be connected to an LC circuit (such as Fig. 10A 1004) (i.e., amplifier 1006 can be used as amplifier 1002 and / or amplifier 1004). Amplifier 1006 is formed by a differential inverter pair consisting of inverter 1008 and inverter 1010 in opposite directions. In this configuration, amplifier 1006 can amplify in both directions on both phases of the signal in LC loop 948.

[0094] Fig. 10C Another example of an amplifier 1012 is shown, which can be connected to an LC circuit (such as Fig. 10A 1004) (i.e., amplifier 1012 can be used as amplifier 1002 and / or amplifier 1004). Amplifier 1012 is formed by inverter 1014. In this configuration, amplifier 1012 amplifies in only one direction on one phase of the signal in LC loop 948.

[0095] The capacitor in the LC loop may be a variable capacitor formed by two or more capacitive elements configurable to vary capacitance. In an LC loop with more than one capacitor, one or more of the capacitors may be a variable capacitor to tune the resonant frequency of the LC loop.

[0096] Fig. 10D A schematic diagram of a variable capacitor (ie, capacitor 1020) is shown, which can be used in an LC loop (eg, Fig. 10A948) (e.g., capacitor 1020 may be used as capacitor 970 and / or capacitor 972). Capacitor 1020 includes a first capacitive element 1022 and a second capacitive element 1024, and a switch 1026 to modify the capacitance of capacitor 1020 by discrete amounts according to the connection of the first capacitive element 1022 and the second capacitive element 1024. Specifically, the first capacitive element 1022 and the second capacitive element 1024 may be inactive (not acting on the capacitance of capacitor 1020) when switch 1026 is open, or may be active (acting on the capacitance of capacitor 1020) when switch 1026 is closed. Fig. 10D Also shown are variable capacitance elements 1028 and variable capacitance elements 1030, each of which has a corresponding capacitance that is variable in a continuous range according to the applied voltage. For example, variable capacitance elements 1028, 1030 can be varactor tubes whose capacitance varies with the applied voltage. Although two variable capacitance elements 1028, 1030 are shown in capacitor 1020, any number of variable capacitance elements can be provided. And although a single switch for controlling the coupling of capacitance elements 1022 and capacitance elements 1024 is shown, it should be understood that variable capacitors can include any number of capacitance elements (e.g., arrays or groups of capacitance elements and switches) in any suitable configuration. Variable capacitors can include capacitance elements (e.g., capacitance elements 1022 and 1024 that can be configured by switches) and / or variable capacitance elements (e.g., variable capacitance elements 1028, 1030) that can be configured to modify capacitance. Switches 1026 and variable capacitance elements can be controlled to change the capacitance of capacitor 1020 in discrete amounts and / or in a continuous range. Switches such as switch 1026 may be formed from any one or more suitable components. For example, one or more transistors may be used as switches that are configurable to connect or disconnect components. Any suitable component that can connect and disconnect circuit nodes may be used as a switch. In this manner, coarse and fine tuning capacitors may be used to precisely adjust the resonant frequency, for example, in response to a voltage from a phase detector in a PLL.

[0097] In an LC loop having two or more capacitors (e.g., capacitors 970 and 972 of LC loop 948), one or more of the capacitors may be variable capacitors. In a symmetrical implementation of LC loop 948, capacitor 970 and capacitor 972 are variable capacitors, e.g., Fig. 10D In this implementation, the amplification may be symmetrical, so that both amplifier 1002 and amplifier 1004 may be Fig. 10B The output voltages V1 and V2 in this configuration can be symmetrical with a phase difference of 180 degrees.

[0098] Although Fig. 10AAn example is shown where amplifiers 1002 and 1004 are connected across inductors 976 and 974, respectively, but other amplifier-to-inductor configurations are possible. For example, some inductors may be tapped inductors that have one or more tapped terminals (in addition to having terminals at either end). A tapped inductor may also be connected to its tap terminals in addition to being connected to its end terminals at the ends of the inductor.

[0099] Fig.11A An example of an inductor 1101 as a tapped inductor is shown. In addition to end terminals 1102 and 1104, the inductor 1101 also includes a tap terminal 1106 connected to a mid-position between the end terminal 1102 and the end terminal 1104. Therefore, in addition to the metal loop 1108 extending between the end terminal 1102 and the end terminal 1104, the inductor 1101 also includes a metal connector 1110, which is connected to the tap terminal 1106 from the mid-position of the metal loop 1108, so that the input or output can be coupled at the mid-position. For example, in some cases, it may be advantageous to couple an amplifier between an end terminal and a tapped input terminal (e.g., between the end terminal 1102 and the tap terminal 1106) so that the input is provided through the tap terminal. The end terminals can be connected to other components, such as capacitors in a ring arrangement such as the LC loop 948.

[0100] Fig. 11B An example of an implementation schematic diagram of a VCO 1100 is shown. The VCO 1100 includes Fig.9A The LC circuit 948 uses Fig.11A The inductor 1101 of the VCO 760 is a tapped inductor, that is, wherein the inductors 974 and 976 of the LC loop 948 are tapped inductors. The inductors 974 and 976 are amplified through the tapped input terminals. Specifically, the amplifier 1002 is connected to the tapped terminal 1112 of the inductor 976, and the amplifier 1004 is connected to the tapped terminal 1114 of the inductor 974. The amplifiers 1002 and 1004 can be collectively regarded as an exemplary implementation of the amplifier 764 of the VCO 760, and can provide an electrical input to the LC loop 948 and amplify the electrical signal in the LC loop 948 to generate an oscillator signal at the resonant frequency of the LC loop 948 (for example, the voltage V1 or V2 can be the oscillator signal).

[0101] Fig. 11CA more detailed example of VCO 1100 is shown (which can be viewed as an example of how VCO 1100 is implemented using specific components including a tapped inductor, an inverter connected to the tap terminal of the tapped inductor, and a variable capacitor). Amplifier 1002 is implemented by a single inverter 1152, the output of which is connected to the tap terminal 1112 of inductor 976. Amplifier 1004 is implemented by a single inverter 1154, the output of which is connected to the tap terminal 1114 of inductor 974. Thus, amplification in VCO 1100 is provided by a pair of differential inverters including inverter 1152 and inverter 1154. Capacitor 970 and capacitor 972 are implemented as variable capacitors, each of which has a capacitance that is variable within a certain range to control the resonant frequency of LC tank 948. Capacitor 972 includes capacitive element 1158 and capacitive element 1160, and switch 1162 to modify the capacitance of capacitor 972 in discrete amounts depending on the connection of capacitive element 1158 and capacitive element 1160. Capacitor 972 includes variable capacitive elements 1164 and 1166, each of which has a corresponding capacitance that is variable over a continuous range depending on the applied voltage. Capacitor 970 may include components similar to those shown in capacitor 972 so that the capacitance of capacitor 970 (from Fig. 11C Components of capacitor 970 are omitted). It can be seen that VCO 1100 provides a simpler implementation than a symmetrical implementation.

[0102] Although the LC loop 948 of the above example is shown as including two capacitors and two inductors in a ring structure, which are arranged in an alternating order (capacitor, inductor, capacitor, inductor), the technology of the present invention is not limited to any particular number of components and can be implemented using more than two inductors and more than two capacitors, such as three capacitors and three inductors, four capacitors and four inductors, five capacitors and five inductors, etc.

[0103] Fig.12An example of an LC loop 1200 is shown, which includes four capacitors 1202, 1204, 1206, and 1208 and four inductors 1212, 1214, 1216, and 1218 connected in a ring structure, wherein each capacitor is connected in series between a pair of inductors, and each inductor is connected in series between a pair of capacitors. For example, capacitor 1202 is connected between inductors 1218 and 1212, capacitor 1204 is connected between inductors 1212 and 1214, and so on, and inductor 1212 is connected between capacitors 1202 and 1204, inductor 1214 is connected between capacitors 1204 and 1206, and so on. This ring structure can be extended to any number of components and is not limited to the two-capacitor, two-inductor example (e.g., LC loop 948) and the four-capacitor, four-inductor example (e.g., LC loop 1200), as shown in the accompanying Fig.12 As shown. It should be understood that the term "ring structure" can refer to two-terminal elements, such as capacitors and inductors, connected in series or cascaded so that one and only one terminal of any one element is connected to one and only one terminal of the next element in the closed loop (the tap terminal is not used to connect with the capacitor, so for the purpose of forming such a connection, the inductor can be regarded as a two-terminal element). One or more of capacitors 1202, 1204, 1206 and 1208 can be variable capacitors to tune the resonant frequency of the LC loop 1200. One or more of inductors 1212, 1214, 1216 and 1218 can be tapped inductors so that an amplifier can be connected to the tap terminal.

[0104] The above circuit can be used in various applications. Fig.13 The simplified flow chart shown in summarizes the method of using a resonant tank (such as LC tank 948 or LC tank 1200). Fig.13 , step 1300 involves providing an electrical input to a resonant tank, the resonant tank comprising a first capacitor, a first inductor, a second capacitor, and a second inductor connected in a ring structure formed on a semiconductor substrate, wherein each capacitor is connected in series between the inductors, and each inductor is connected in series between the capacitors. For example, one or more amplifiers may be connected to the terminals of the resonant tank to provide the electrical input to the resonant tank. Still referring to Fig.13 Step 1302 involves amplifying an electrical signal generated from an electrical input in a resonant tank to generate an oscillator signal at a resonant frequency of the resonant tank. For example, the resonant tank may generate an electrical signal at a resonant frequency, and the amplifier may amplify the electrical signal to generate an oscillator signal (e.g., an oscillator signal of a VCO).

[0105] It should be understood that this theme can be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. In fact, these embodiments are provided to make this theme thorough and complete, and to fully convey this theme to those skilled in the art. In fact, this theme is intended to cover substitutes, modifications and equivalents of these embodiments within the scope and spirit of this theme as defined by the appended claims. In addition, in the following detailed description of this theme, many specific details are set forth to provide a thorough understanding of this theme. However, it will be clear to those of ordinary skill in the art that this theme can be practiced without such specific details.

[0106] The description of the present invention is presented for illustration and description and is not intended to be exhaustive or limited to the present invention in the disclosed form. Various modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the present invention. Various aspects of the present invention are selected and described in order to better explain the principles and practical applications of the present invention and to enable those of ordinary skill in the art to understand the present invention and various modifications suitable for the intended specific use.

[0107] Although the present invention has been described with reference to specific features and embodiments of the present invention, it is apparent that various modifications and combinations may be made without departing from the scope of the present invention. Therefore, the specification and the drawings are only considered as an explanation of the present invention as defined by the appended claims, and are intended to cover any and all modifications, variations, combinations or equivalents falling within the scope of the present invention. Although the subject matter has been described in a language specific to structural features and / or method actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. In fact, the specific features and actions described above are disclosed as example forms of implementing the claims.

Claims

1. A radio frequency integrated circuit, characterized in that: include: Oscillators, including: A resonant circuit, comprising a first capacitor, a first inductor, a second capacitor and a second inductor, wherein the first capacitor, the first inductor, the second capacitor and the second inductor are coupled together in the form of a ring structure, wherein each capacitor is connected between a pair of the inductors, and each inductor is connected between a pair of the capacitors; An amplifier circuit is coupled to the resonant tank.

2. The radio frequency integrated circuit according to claim 1, characterized in that: The first inductor and the second inductor are each formed from one or more respective portions of metal formed on a semiconductor substrate.

3. The radio frequency integrated circuit according to claim 1, characterized in that: The first inductor and the second inductor are tapped inductors each having at least one tapped input terminal at a mid-position between inductor ends.

4. The radio frequency integrated circuit according to claim 1, characterized in that: The amplifier circuit includes a first inverter connected to the tap input terminal of the first inductor, and a second inverter connected to the tap input terminal of the second inductor.

5. The radio frequency integrated circuit according to claim 1, characterized in that: The amplifier circuit includes a first pair of inverters connected across the first inductor, and a second pair of inverters connected across the second inductor.

6. The radio frequency integrated circuit according to claim 1, characterized in that: The first capacitor is a variable capacitor.

7. The radio frequency integrated circuit according to claim 1, characterized in that: The first capacitor includes at least a first capacitive element and a second capacitive element, and one or more switches.

8. The radio frequency integrated circuit according to claim 1, characterized in that: The first capacitor includes one or more variable capacitance elements.

9. The radio frequency integrated circuit according to any one of claims 1 to 8, characterized in that: The radio frequency integrated circuit further comprises a phase-locked loop, and the oscillator circuit forms a voltage-controlled oscillator in the phase-locked loop circuit, wherein the phase-locked loop circuit further comprises a feedback loop, a phase detector and a filter.

10. The radio frequency integrated circuit according to claim 9, characterized in that: The phase-locked loop circuit is used to provide an oscillator signal.

11. The radio frequency integrated circuit according to claim 1, characterized in that: Also includes: A third capacitor, a third inductor, a fourth capacitor and a fourth inductor, wherein the third capacitor, the third inductor, the fourth capacitor and the fourth inductor are coupled together in the form of a ring structure, wherein each capacitor is connected between a pair of the inductors, and each inductor is connected between a pair of the capacitors.

12. The radio frequency integrated circuit according to any one of claims 1 to 11, characterized in that: The radio frequency integrated circuit is a radio frequency transmitter or a radio frequency receiver.

13. A method for generating an oscillation signal, characterized in that: include: Receiving an electrical signal from a resonant circuit using an amplifier circuit, the resonant circuit comprising: a first capacitor formed on a semiconductor substrate, a first inductor formed on the semiconductor substrate, a second capacitor formed on the semiconductor substrate, and a second inductor formed on the semiconductor substrate, the first capacitor, the first inductor, the second capacitor, and the second inductor being connected in series in a ring structure, wherein each capacitor is connected in series between the inductors, and each inductor is connected in series between the capacitors; The electrical signal from the resonant tank is amplified by the amplifier circuit, and the amplified electrical signal is returned to the resonant tank.

14. The method according to claim 13, characterized in that The electrical signal is amplified by one or more pairs of inverters.

15. The method according to any one of claims 13 to 14, characterized in that The first inductor and the second inductor are tapped inductors, each of which has at least one tap terminal at a mid-position between the inductor ends, wherein returning the amplified electrical signal to the resonant circuit includes providing an inverted amplified signal at the tap terminals of the first inductor and the second inductor.

16. The method according to claim 13, characterized in that The method further comprises controlling a capacitance of at least the first capacitor to control the resonant frequency and thereby the frequency of the oscillator signal.

17. The method according to claim 13, characterized in that The method further includes obtaining a carrier signal in a transceiver in a communication system from the oscillator signal.

18. The method according to claim 17, characterized in that Acquiring the carrier signal in the transceiver includes performing phase comparison and filtering in a phase locked loop.

19. A wireless terminal, characterized in that: include: A processor, and a radio frequency integrated circuit as claimed in any one of claims 1 to 12, wherein: The radio frequency integrated circuit is coupled to the processor.

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