1128results about "Amplifier modifications to extend bandwidth" patented technology

A method and apparatus is disclosed for improving high frequency performance of an amplifier, such as for example, a current mirror. In one embodiment, a delay element is introduced in a current mirror signal path to account for signal propagation delay that may exist in one or more alternative signal paths. The delay element maintains desired phase alignment at a cascade node of the current mirror thereby establishing, in one embodiment, the cascode node (V_c) in an AC ground state. To extend current mirror high frequency capability an embodiment is disclosed having cross-coupled capacitors, active elements, or one or more other devices configured to provide positive feedback to one or more current mirror inputs. The positive feedback may be selectively configured to increase the operational bandwidth of the current mirror.

An amplifier arrangement for ultra-wideband, UWB, applications and. a method to amplify a UWB signal are presented. A transistor, whose control input forms an input of the arrangement, is connected to a resonant circuit having a controllable resonator frequency. At the resonator circuit, an output of the arrangement is formed. The resonant circuit includes a frequency determining inductance whose value is controllable. By doing this, it is possible to preselect different frequency bands, while achieving the same gain characteristics in each band.

According to an example embodiment, an amplitude feedback loop may include an RF amplifier, a detector, a comparator, and a Q-enhancement cell. In an example embodiment, the RF amplifier has an output signal, and the detector has an input coupled to the output signal of the RF amplifier and is configured to detect a level of the output signal of the RF amplifier. The comparator circuit may receive as inputs a reference voltage and the output of the detector. Also, the comparator circuit is configured to output a control signal based on a difference between the reference voltage and the output signal of the power detector. The Q-enhancement cell may be coupled to the RF amplifier and have an input coupled to an output of the comparator circuit. A bias current of the Q-enhancement cell may be adjusted based on the control signal output by the comparator circuit.

The present invention provides a wideband active balun LNA topology with narrow-band filtering and noise cancelling. The amplifier includes three transconductance stages, a feedback network, and a load. The first and second transconductance stages are connected in parallel to receive the input signal. The differential output of the first transconductance stage is fed back to voltage input through a differential-to-single-end-end feedback network, while the output of the first transconductance, passing through the third transconductance, is added to the output of the second transconductance stage in proper phase. The present invention accomplish both wideband low-noise amplification and narrow-band filtering without inserting interface stages, thereby improving the linearity and noise performance of the whole circuit. Noise cancellation technique is implemented in differential way to ensure the low noise figure. The present invention also achieves single-end to differential conversion with balanced output and superior second order linearity performance.

The invention belongs to the technical field of analog IC (Integrated Circuit) design, in particular to a high-bandwidth low-power consumption frequency-compensation three-stage operational amplifier. The amplifier comprises an input stage, a second stage, an output stage, a common mode feedback stage, a comprehension circuit, an internal feedforward circuit, wherein the second stage is connectedwith the input stage, the output stage is connected with the second stage and used for amplifying a signal output by the second stage and driving an external load circuit, the common mode feedback stage extracts the common mode level of the differential output stage and stabilizes the common mode level, the comprehension circuit comprises a traditional trsanscondutance comprehension circuit, a miller comprehension circuit and a resistor for separating a high-frequency zero pole, and the internal feedforward circuit is used for comprehending an internal additional pole and forming a push-pull circuit together with the output stage to reduce static power consumption. The three-stage operational amplifier realizes high gain, high bandwidth and high stability under the condition of little DC power consumption and can be used in a high-speed analog-digital conversion circuit, such as a sigma-delta modulator suitable for the bandwidth of an LTE (Line Terminator Equipment) wireless communication protocol.

The disclosure relates to an enhanced Doherty amplifier that provides significant performance improvements over conventional Doherty amplifiers. The enhanced Doherty amplifier includes a power splitter, combining node, a carrier path, and a peaking path. The power splitter is configured to receive an input signal and split the input signal into a carrier signal provided at a carrier splitter output and a peaking signal provided at a peaking splitter output. The carrier path includes carrier power amplifier circuitry, a carrier input network coupled between the carrier splitter output and the carrier power amplifier circuitry, and a carrier output network coupled between the carrier power amplifier circuitry and the Doherty combining node.; The peaking path includes peaking power amplifier circuitry, a peaking input network coupled between the peaking splitter output and the peaking power amplifier circuitry, and a carrier output network coupled between the power amplifier circuitry and the Doherty combining node.

A semiconductor integrated circuit includes a flip-flop circuit, a capacitive element, and a switch circuit. The switch circuit includes a first switch circuit which couples the capacitive element to two nodes of the flip-flop circuit at a first timing, and a second switch circuit which short-circuits ends of the capacitive element connected to the two nodes at a second timing different from the first timing.

The invention relates to a full-difference CMOS ultra wide band low-noise amplifier which can be applied in the ultra wide band of 3.1-4.8GHz and 3.1-10.6GHz or can be applied in cognitive radio frequency front end of 900MHz-6GHz. The amplifier is based on common-source transconductance input and resistance negative feedback structure and is composed of a matching stage, an amplifying stage, a feedback stage and a load stage, wherein, the matching stage uses grid electrode inductance to tune wideband input impedance; the amplifying stage uses a current multiplexing common-source stage NMOS tube and a PMOS tube to serve as the input end, a common-grid electrode NMOS tube which is connected with the drain terminal output thereof is used as a current follower; an NMOS tube between an input NMOS tube grid electrode and a current follower NMOS tube drain electrode and resistance form a voltage-current type negative feedback circuit; the load stage uses resistance to load. The invention hassimple structure, occupies small chip area, has high gain and low power consumption and can satisfy the requirement of radio frequency front end of a wideband communication system.

Provided is a low noise amplifier with a common source and a source degeneration, which has linearity, power gain, noise factor, and lossless input matching. The low noise amplifier includes: a first inductor having one terminal connected to an input terminal receiving a signal; a second inductor having one terminal connected to a ground; a MOS transistor having a gate connected to the first inductor, a source connected to the other terminal of the second inductor, and a drain transmitting a signal; and a variable capacitor connected between the source and gate of the MOS transistor and varying an input matching frequency at the input terminal.

The invention discloses a radio-frequency ultra-wideband low-noise amplifier based on inductance compensation, relating to a radio-frequency integrated circuit technology. The radio-frequency ultra-wideband low-noise amplifier mainly consists of an input amplification-stage circuit, a feedback-stage circuit, a matching-stage circuit, a load-stage circuit, a bias-stage circuit and an output buffering-stage circuit jointly. According to the radio-frequency ultra-wideband low-noise amplifier, both the input matching stage and the load stage are subjected to inductance compensation, and the sensitivity of the low-noise amplifier on the technology is reduced by adopting a current multiplexing technology with independent bias, so that the performance is more stable, the ultra-wideband is also realized, and the working frequency range is 0.1-12GHz; meanwhile, the radio-frequency ultra-wideband low-noise amplifier gets favorable indexes, such as noise, linearity, gain, power consumption and the like and is suitable for an ultra-wideband multi-standard wireless communication receiving system.

The present invention is aimed at realizing an amplifying circuit whose chip size is prevented from being significantly increased even if the number of compatible frequencies increases, and which has a wide dynamic range when it operates under a low voltage. The amplifying circuit includes a plurality of impedance converting circuits connected to each other by a switching circuit of a first type having a signal cutting-off function, a switching circuit of a second type connected to a path branched from an input side of the switching circuit of the first type, the switching circuit of the second type having a signal cutting-off function, amplifiers connected respectively to an output side of one of the impedance converting circuits in a final stage and to an output side of the switching circuit of the second type, and a control signal generating circuit for controlling connection/disconnection between said switching circuit of the first type and said switching circuit of the second type; wherein either one of the paths is selected to input a signal to one of the amplifiers.

A multi-band low noise amplifier (LNA) 105 includes an input stage having at least two inputs, a first input (103) coupled to a first input transistor for receiving signals in a first frequency band and a second input (104) coupled to a second input transistor for receiving signals in a second frequency band. The second frequency band spaced apart from the first frequency band. A bias network (218) having a band select input is coupled to the first and second input transistor, wherein a signal level applied to the band select input turns on one of the input transistors and turns off the other input transistors. The LNA (105) operates in the first frequency band when the first input transistor is on and the second frequency band when the second input transistor is on. A switched resonator (216) having a control input is provided, wherein application of a control signal to the control input tunes a resonant frequency of the LNA, and provides gain select, for operation in either the first or second frequency bands.

A low noise amplifying (LNA) circuit comprising an amplifying section (11, 12) and a feedback means (14) arranged for providing input matching from the output to the input. The LNA circuit further comprises at least one frequency band determining inductor (15) having a predetermined resonance frequency for influencing at least one frequency band in which the amplifying section operates. The at least one inductor is directly connected to the output of the circuit and the feedback means (14) provides a feedback connection for the section (s) to the input. In this way, the at least one frequency band in which the amplifying section operates is substantially completely determined by the at least one frequency band determining inductor (15).

The invention discloses a high-efficiency wideband power amplifier with a band-pass filter response function. The high-efficiency wideband power amplifier comprises a DC biasing circuit, a power amplification transistor, an input match circuit and an output match circuit. A microstrip line band-pass filter with different port impedances and a section of tuning microstrip line are designed to be used as the output match circuit of the power amplifier, the function of the filtering is achieved, meanwhile, the circuits are made to have the band-pass filter response characteristic, and two transmission zeros are generated on the edge of a passband. Compared with a traditional cascade circuit of a power amplifier and a filter, due to the fact that the microstrip line band-pass filter is used as the output match circuit, the entire circuit is small in size, small in loss and wide in working band, and high edge selectivity is achieved due to the two transmission zeros. The high-efficiency wideband power amplifier with the high-pass filter response function is achieved, and testing result validation is provided.

T-coil structures are used in one embodiment to inject programmably-variable amounts of transistor biasing currents into the respective drains of current sinking transistor means of a broadband differential amplifier such that, when the differential amplifier is in common mode, total transistor drain current will exceed total voltage-dropping current passing through corresponding voltage-dropping resistances of the amplifier's transistor means. The T-coil structures keep the parasitic capacitances of the programmable current sources that provide the bias currents de-lumped from capacitances of the amplifier's output nodes and/or capacitances of the amplifier's voltage-dropping resistances (variable resistances) to thereby maintain a wide bandwidth.