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 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 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.

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 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.

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.

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.