114 results about "Negative resistance circuits" patented technology

A voltage-controlled oscillator comprising a resonant circuit and MOS transistors which constitute a negative resistance circuit of a differential structure. The resonant circuit consists of an inductance element and a MOS variable capacitance element connected in parallel therewith. The MOS variable capacitance element is divided into plural pairs connected in parallel with each other. A voltage division circuit generates staircase different-step DC bias voltages to be applied respectively to the gates of the plural divided MOS transistors. The divided MOS variable capacitance elements have a common terminal to which a common control voltage is applied. The resonant circuit is capable of reducing a load on the control voltage generator and improving the characteristics of the voltage-controlled oscillator.

A voltage-controlled oscillator comprising a resonant circuit and MOS transistors which constitute a negative resistance circuit of a differential structure. The resonant circuit consists of an inductance element and a MOS variable capacitance element connected in parallel therewith. The MOS variable capacitance element is divided into plural pairs connected in parallel with each other. A voltage division circuit generates staircase different-step DC bias voltages to be applied respectively to the gates of the plural divided MOS transistors. The divided MOS variable capacitance elements have a common terminal to which a common control voltage is applied. The resonant circuit is capable of reducing a load on the control voltage generator and improving the characteristics of the voltage-controlled oscillator.

A power amplifier utilizes cascode arrangements to achieve target performance levels for a power amplifier, such as the type used in wireless communication devices. A negative resistance circuit is provided for the cascode arrangement such that high gain, or oscillation, is promoted during operation of the power amplifier. In one embodiment, the negative resistance circuit includes cross-coupling transistors. Various features are provided in order to reduce the susceptibility of the power amplifier to voltage breakdown while maintaining good performance.

A voltage controlled oscillator includes a resonant circuit including one or more transformers and a plurality of variable capacitor circuits connected in parallel to the one or more transformers and generating a plurality of oscillation frequencies having multiple phases, and a negative resistance circuit including a plurality of transistors cross-coupled via the one or more transformers and generating negative resistance for maintaining the oscillation of the resonant circuit.

A voltage-controlled oscillator having an inductor circuit, n pieces (n is two or more) of variable capacitance circuit having variable capacitance elements, negative resistance circuits, and reference voltage generation means of generating a reference voltage from a power supply voltage, and wherein a predetermined reference voltage is inputted to some terminals of the variable capacitance elements of the n pieces of variable capacitance circuit, a control voltage is inputted to the other terminals thereof, and of the variable capacitance elements of the n pieces of variable capacitance circuits, the predetermined reference voltage inputted to some terminals of the variable capacitance elements of at least two pieces of the variable capacitance circuit is different.

A voltage controlled oscillator includes a resonator configured to resonate with an initial oscillation frequency during starting period of oscillation and a steady oscillation frequency during a steady state oscillation. The resonator includes a film bulk acoustic resonator having a series resonance frequency higher than the steady oscillation frequency. A negative resistance circuit configured to drive the resonator, has a positive increment for reactance in the steady state oscillation compared with reactance in the starting period.

A voltage-controlled oscillator operates stably over a narrow variation range of a control voltage, including a variable capacitance circuit 12 controllable by voltage, an inductor circuit 11 having inductors, a negative resistance circuit 13, and a capacitance control circuit 14 that outputs a correction voltage. An oscillator circuit is constituted by the variable capacitance circuit 12, the inductor circuit 11, and the negative resistance circuit 13 connected in parallel. The capacitance control circuit 14 controls to correct the capacitance of the variable capacitance circuit 12 with the correction voltage outputted in response to a temperature fluctuation and / or power supply voltage fluctuation in the oscillator circuit.

A voltage-controlled oscillator having an inductor circuit, n pieces (n is two or more) of variable capacitance circuit having variable capacitance elements, negative resistance circuits, and reference voltage generation means of generating a reference voltage from a power supply voltage, and wherein a predetermined reference voltage is inputted to some terminals of the variable capacitance elements of the n pieces of variable capacitance circuit, a control voltage is inputted to the other terminals thereof, and of the variable capacitance elements of the n pieces of variable capacitance circuits, the predetermined reference voltage inputted to some terminals of the variable capacitance elements of at least two pieces of the variable capacitance circuit is different.

The invention relates to a switchable chaotic analog circuit based on a Chua chaotic circuit system. The switchable chaotic signal source by a memristor circuit and a nonlinear circuit comprises a Chua chaotic circuit post-stage switchable-mode main circuit which is composed of an integrating circuit, a control switch circuit (S) arranged at the post stage of the integrating circuit, an absolute value function circuit (H(.)) disposed at the post stage of the control switch circuit (S), a first multiplying circuit (M1) mounted at the post stage of the absolute value function circuit (H(.)) and a negative resistance circuit arranged at the post stage of the first multiplying circuit (M1). The chaotic analog circuit has characteristics of simple circuit structure and strong implementability. In addition, switching of chaotic signals can be realized by the memristor circuit and the nonlinear circuit. Meanwhile, chaotic systems capable of generating two types of different charotic attractors and complex chaotic scrolls both show complex dynamic characteristics and become a novel chaotic signal source.

A notch filter suitable for attenuating certain frequencies of a radio-frequency signal includes an input for receiving the radio-frequency signal and an output for the output of a portion of the radio-frequency signal, first and second capacitive means, at least one inductor and a negative resistance circuit suitable for compensating the resistive losses of said at least one inductor. The inductor and the first and second capacitive means are placed to produce a resonator and the filter comprises a control device suitable for controlling the negative resistance circuit. The input impedance of the filter comprises a pole and a zero, with the pole depending on the second capacitive means and the zero depending on both the first and second capacitive means. The first and second capacitive means are variable and the control device is suitable for controlling the first and second capacitive means.

A voltage controlled oscillator includes a resonator configured to resonate with an initial oscillation frequency during starting period of oscillation and a steady oscillation frequency during a steady state oscillation. The resonator includes a film bulk acoustic resonator having a series resonance frequency higher than the steady oscillation frequency. A negative resistance circuit configured to drive the resonator, has a positive increment for reactance in the steady state oscillation compared with reactance in the starting period.

The invention discloses a low phase noise voltage-controlled oscillator. The low phase noise voltage-controlled oscillator comprises a negative resistance circuit module, a difference coupling inductor capacitor resonant cavity and a source feedback inductor. The coupling inductance capacitor resonant cavity is used for improving an effective quality factor of the resonant cavity. Magnetic coupling between the source feedback inductor and the resonant cavity inductor is regarded as the feedback for increasing the amplitude of output signals of the resonant cavity, and the negative resistance circuit module adopts a current multiplexing structure to reduce power dissipation and remove deterioration of the phase noise by a second harmonic of a common mode node. The low phase noise voltage-controlled oscillator can effectively reduce phase noise.

A voltage controlled oscillator comprises a parallel resonance circuit including an inductor circuit, a variable capacitance circuit, and a high-frequency switch circuit, a negative resistance circuit and a frequency control section, and a frequency tuning sensitivity control section. The frequency control section shifts a band of an oscillation frequency by controlling ON / OFF of a switching element included in the high-frequency switch circuit. The frequency tuning sensitivity control section adjusts a change rate of a total capacitance of the variable capacitance circuit with respect to a control voltage, depending on a band to be used. The frequency tuning sensitivity control section is connected to a virtual ground point of a differential signal.

The present invention provides a voltage controlled oscillator for changing an oscillating frequency in accordance an input control voltage, including a parallel resonant circuit, a negative resistance circuit connected in parallel to the parallel resonant circuit, a first capacitor connected in parallel to the negative resistance circuit, a first current source connected between one terminal of the first capacitor and the negative resistance circuit, and a second current source connected between the other terminal of the first capacitor and the negative resistance circuit. The capacitance value of the first capacitor is set to a value that suppresses a signal with a frequency twice the oscillating frequency at both the terminals of the first capacitor. Each of the first and the second current sources is constituted by a bipolar transistor.

The invention provides a dual-mode broadband voltage controlled oscillator which comprises two voltage controlled oscillator parts working at a high frequency band and a low frequency band respectively, wherein each voltage controlled oscillator part comprises an inductor, two variable capacitors, a negative resistance circuit, a switch variable capacitor array, a switch capacitor array, and a switch tail current source array. In each voltage controlled oscillator part, the inductor is connected between two output ends of the voltage controlled oscillator part; one end of each variable capacitor is connected with control voltage, and the other end of each variable capacitor is connected with bias voltage through a blocking capacitor and a resistor; the negative resistance circuit is formed by a cross-coupled NMOS (n-channel metal oxide semiconductor) pair and a cross-coupled PMOS (p-channel metal oxide semiconductor) pair; the switch variable capacitor array is controlled by digital control words, and used for controlling the tuning range of each tuning curve; the switch capacitor array is controlled by the digital control words; the maximum capacitance in the switch capacitor array and the switch variable capacitor array codetermines the starting point of each tuning curve; the switch tail current source array is controlled by the digital control words and the control voltage together, and used for generating tail current; and the tail current is in direct proportion to output swing amplitude of the voltage controlled oscillator part. The oscillator is stable in output swing amplitude, and wider in tuning range.

An adaptive negative impedance system for improving power supply rejection (PSR) of a voltage regulator (VR) includes a variable negative impedance circuit with a control input; and a signal adjustment block (SAB), wherein a negative impedance value of the variable negative impedance circuit is dependent on a voltage regulator output current, and wherein the variable negative impedance circuit is a variable negative capacitance circuit and / or a variable negative resistance circuit, and the negative impedance value is a negative capacitance value and / or a negative resistance value.

A voltage controlled oscillator (VCO) includes a voltage controlled current source (VCCS), a negative resistance circuit (NRC), a first transformer, a second transformer, a first transistor and a second transistor. A current terminal of the VCCS receives a control voltage. First terminals of first and second current paths in the NRC are coupled to a current terminal of the VCCS. Primary sides of the first and the second transformers are respectively coupled to second terminals of the first and the second current paths. Secondary sides of the first and the second transformers are first and second output terminals of the VCO, respectively. First terminals of the first and the second transistor are respectively coupled to the secondary sides of the first and the second transformers. Control terminals of the first and the second transformers are respectively coupled to the primary sides of the first and the second transformers.

The present invention provides a voltage controlled oscillator for changing an oscillating frequency in accordance an input control voltage, including a parallel resonant circuit, a negative resistance circuit connected in parallel to the parallel resonant circuit, a first capacitor connected in parallel to the negative resistance circuit, a first current source connected between one terminal of the first capacitor and the negative resistance circuit, and a second current source connected between the other terminal of the first capacitor and the negative resistance circuit. The capacitance value of the first capacitor is set to a value that suppresses a signal with a frequency twice the oscillating frequency at both the terminals of the first capacitor. Each of the first and the second current sources is constituted by a bipolar transistor.

The invention discloses a high-Q active resonator for simultaneously measuring the dielectric constant and the magnetic conductivity of a magnetic medium material. The high-Q active resonator is composed of a passive resonator and a negative resistance circuit. The passive resonator comprises a microstrip line structure, a dielectric layer, a metal sheet and a notched metal CSRR structure. The notched groove metal CSRR structure is composed of a groove ring with an opening. Two right angles opposite to the opening of the groove ring are bent towards the inside of the ring, and the electric field intensity of the above region is the strongest for measuring the dielectric constant. Two right angles which are bent inwards are formed by a U-shaped structure which is horizontally overturned anda connecting plate. The opening of the groove ring respectively extends towards the inside and the outside of the ring, and the magnetic field intensity of the above region is the strongest for measuring the magnetic conductivity. According to the invention, the dielectric constant and the magnetic conductivity can be measured at the same time in different regions of the same sensor. Meanwhile, the measurement accuracy is ensured due to extremely high sensitivity and Q value. Therefore, the high-Q active resonator is very suitable for measuring magnetic medium materials with high dielectric constants and magnetic conductivity.

Provided is a Q-boosting circuit for improving a Q factor in a radio frequency (RF) integrated circuit of a semiconductor device using a transformer instead of an inductor. The Q-boosting circuit couples a negative resistance circuit to a pair of terminals of a transformer to reduce a resistance component of the transformer, thereby increasing a mutual inductance component. Therefore, it is possible to obtain a more improved Q factor than a conventional Q factor through adjustment of an inductance and a resistance component, and to obtain the Q factor having a wide range from several tens to several hundreds according to a frequency range.

An oscillator, comprising an LC tank circuit and a negative resistance circuit. The negative resistance circuit is coupled to the LC tank circuit and comprises a pair of transistors and a pair of voltage drop generators. The transistors have first terminals and second terminals, wherein the first terminals are cross-coupled to the second terminals thereof. The voltage drop generators are respectively coupled between the first and second terminals of the transistors.

A voltage controlled oscillator (VCO) is provided. The VCO may include a first ring oscillation circuit that may have a plurality of delay cells and may output first differential oscillation signals, and a second ring oscillation circuit that may have a plurality of delay cells and may output second differential oscillation signals. The delay cells of the first ring oscillation circuit may be respectively cross-coupled to the corresponding delay cells of the second ring oscillation circuit. Each of the delay cells may include a differential amplification circuit that may output a first differential signal based on a first control signal, and a negative resistance circuit that may be connected in parallel to a pair of output terminals of the differential amplification circuit, may receive a second differential signal, may adjust the phase of the first differential signal based on a second control signal, and may then output the first differential signal.

A voltage-controlled oscillator has: an LC resonant circuit including an inductor and a variable capacitor that are connected in parallel between a pair of output terminals; a plurality of negative resistance circuits provided between a power source and the LC resonant circuit; a plurality of capacitor groups; a first switch circuit selecting an arbitrary number of negative resistance circuit from the plurality of negative resistance circuits; and a second switch circuit selecting an arbitrary number of capacitor group from the plurality of capacitor groups. The LC resonant circuit and the selected capacitor group constitute a resonant circuit. The resonant circuit is electrically connected to the power source through the selected negative resistance circuit, oscillates at an oscillation frequency depending on total capacitance of the resonant circuit, and outputs a differential signal of the oscillation frequency from the pair of output terminals.

The invention discloses a low-power-consumption wideband voltage-controlled oscillator, which comprises a first negative resistance circuit module, a second negative resistance circuit module and a four-order resonant cavity. By using the dual-resonant-frequency characteristic of the four-order resonant cavity and controlling the first negative resistance circuit module or the second negative resistance circuit module to compensate the energy loss of the four-order resonant cavity, the four-order resonant cavity is enabled to alternatively resonate at a high frequency band and a low frequency band which are close to each other, and the two frequency bands are enabled to be partially overlapped to cover a very wide frequency range. In addition, the first negative resistance circuit module and the second negative resistance circuit module adopt a current reuse technique to reduce power consumption and improve phase noise, so that lower power consumption and lower phase noise can be realized at the same time when the circuit of the voltage-controlled oscillator outputs wide-range frequency.

The invention discloses an active inductance type voltage-controlled oscillator, which mainly comprises an LC resonance circuit and a negative resistance circuit; the LC resonance circuit mainly comprises a first active inductor, a second active inductor and a capacitor; the negative resistance circuit comprises a first NMOS (N-channel metal oxide semiconductor) transistor, a second NMOS transistor and a bias current source; the first NMOS transistor and the second NMOS transistor are connected in a crosswise coupling method, the bias current source is adjusted for changing the magnitude of negative resistance, and lost energy of the LC resonance circuit is supplemented; the active inductors and the capacitor form the equivalent LC resonance circuit; by adjusting the inductances of the active inductors, the tuning of center frequency of the oscillator is realized. The active inductance type voltage-controlled oscillator disclosed by the invention has the advantages that tuning bandwidth of the circuits is large, simple and convenient effects are realized, and the chip area is saved.

The invention provides an adjustable negative resistance structure-based multimode multi-channel mixer, which comprises a radio frequency input circuit, an adjustable negative resistance circuit, a digital control capacitor array circuit and a double-balanced differential structure circuit, wherein two input ports of the radio frequency input circuit are connected with radio frequency signals RF+ and RF-, and an output port of the radio frequency input circuit is directly connected with ports RFout+ and RFout-; the negative resistance size of the adjustable negative resistance circuit is controlled by two levels Vctrll and Vctrl, and an output end of the adjustable negative resistance circuit is connected with the RFout+ and the RFout-; an input port of the digital control capacitor array circuit is controlled by a digital signal, and two output ports of the digital control capacitor array circuit are connected with the RFout+ and the RFout-; and radio frequency current signals are input into the double-balanced differential structure circuit through the RFout+ and the RFout-, and are mixed with local oscillation signals LO+ and LO- to output intermediate-frequency signals IF+ and IF- to be then input into a rear-end module. By the adjustable negative resistance circuit, the equivalent parallel resistance of a capacitor array is eliminated, a noise coefficient is reduced, the gain of an active mixer is improved, the working frequency of the mixer can be controlled by a digital end, and the requirements of a broadband multi-channel system are met.

A voltage controlled oscillator (VCO) is provided. The VCO may include a first ring oscillation circuit that may have a plurality of delay cells and may output first differential oscillation signals, and a second ring oscillation circuit that may have a plurality of delay cells and may output second differential oscillation signals. The delay cells of the first ring oscillation circuit may be respectively cross-coupled to the corresponding delay cells of the second ring oscillation circuit. Each of the delay cells may include a differential amplification circuit that may output a first differential signal based on a first control signal, and a negative resistance circuit that may be connected in parallel to a pair of output terminals of the differential amplification circuit, may receive a second differential signal, may adjust the phase of the first differential signal based on a second control signal, and may then output the first differential signal.

A data sampler circuit comprises a transconductance amplifier, a latch circuit, a current-to-voltage converter, and a negative resistance circuit. The transconductance amplifier has an input and an output. The latch circuit is coupled to the output of the transconductance amplifier. The current-to-voltage converter has an input coupled to the output of the transconductance amplifier, and an output for providing a feedback signal to the latch circuit. The negative resistance circuit is coupled to the output of the transconductance amplifier and provides equalization during both a sampling mode and a data latching mode. In one embodiment, the negative resistance circuit comprises a pair of cross-coupled transistors. A gain of the negative resistance circuit can be adjusted based on a pulse width of an input signal.

A differential Colpitts voltage-controlled oscillator according to example embodiments includes a feedback circuit constituting a Colpitts oscillator structure, a negative resistance circuit including a first negative resistance transistor and a second negative resistance transistor cross-coupled to each other and connected to the feedback circuit, a resonance circuit including a first inductor and a variable capacitor connected to both ends of the first inductor to generate differential output signals base on outputs of the feedback circuit, and a phase noise reduction circuit coupled to the feedback circuit to remove phase noise.