Abstract: A charge amplifier includes: an input line thorough which an electric charge signal is propagated; an integration circuit including an input terminal coupled to the input line and an output terminal that outputs the voltage signal; a reset switch configured to reset the voltage signal by closing between the input terminal and the output terminal; a leakage current correction circuit including a first resistance circuit and a first switch coupled in series in this order between a first node, which has a first potential different from a potential of the input line, and the input line; and a control circuit configured to control the first switch based on the voltage signal so as to cancel at least a part of a leakage current flowing through the integration circuit.

Abstract: Examples provide methods and apparatus for controlling a DC bias current in an RF amplifier. In one example where the RF amplifier is implemented on an amplifier die, a reference voltage is produced across a reference resistor implemented on the amplifier die, the DC bias current is measured, and a current controller, which is implemented on a controller die that is separate from the amplifier die, operates a feedback loop using the reference voltage to control a level of the DC bias current.

Abstract: An amplifier has a first amplifying circuit configured to receive a voltage input and to output an amplified current, a second amplifying circuit configured to receive the amplified current and to output an amplified voltage, the second amplifying circuit comprising a pair of feedback resistive elements, each feedback resistive element being coupled to a gate and drain of a corresponding transistor in a pair of output transistors in the second amplifying circuit, and a feedback circuit configured to provide a negative feedback loop between an input and an output of the pair of output transistors, the feedback circuit including a first transconductance amplification circuit and a first equalizing circuit.

Abstract: A tunable impedance multiplier with high multiplication factor is described. A single externally connected resistor is used and the multiplier is free of passive elements. The circuit can realize a positive or a negative impedance multiplier. Applications of the design to low and high pass filters are also presented. The simulation and experimental results show that the new design enjoys a multiplication factor above 400 at 2 Hz-to 7 MHz.

Abstract: A tunable impedance multiplier with high multiplication factor is described. A single externally connected resistor is used and the multiplier is free of passive elements. The circuit can realize a positive or a negative impedance multiplier. Applications of the design to low and high pass filters are also presented. The simulation and experimental results show that the new design enjoys a multiplication factor above 400 at 2 Hz-to 7 MHz.

Abstract: Examples provide methods and apparatus for controlling a DC bias current in an RF amplifier. In one example where the RF amplifier is implemented on an amplifier die, a reference voltage is produced across a reference resistor implemented on the amplifier die, the DC bias current is measured, and a current controller, which is implemented on a controller die that is separate from the amplifier die, operates a feedback loop using the reference voltage to control a level of the DC bias current.

Abstract: A single-stage radio frequency amplifier is provided with a signal amplification stage for a magnetic resonance tomography scanner, for example as a low-noise preamplifier in a local coil. The radio frequency amplifier includes a signal input, a signal amplifier, a signal output of the signal amplifier and a phase shifter. The phase shifter is in signal connection with the signal output and the signal input of the signal amplifier and is configured to couple a predetermined portion of an output signal of the signal amplifier with a predetermined phase shift into the signal input of the signal amplifier.

Abstract: A sensing system that produces a multi-dynamic range output is provided. In an illustrative embodiment, a first channel and a second channel receive an analog output signal from a sensing element. The first channel provides a first digital output signal that has a first dynamic range, and the second channel provides a second digital output signal that has a second narrower dynamic range. In some cases, the second narrower dynamic range falls within the first dynamic range, and the first digital output signal may provide a first resolution and the second digital output signal may provide a second greater resolution. The dynamic range and/or resolution of one or more of the first channel and second channel may be dynamically reconfigurable, if desired.

Abstract: A composite transconductance amplifier is formed using a single transconductance amplifier with its output connected to a load via one or more resistors in series. The single transconductance amplifier has a linear transconductance (gm). As the current through the series resistors is increased, the voltage drops across the nodes of the resistors increase. Control terminals of separate drive circuits are connected to the various nodes and successively turn on as the current from the single transconductance amplifier slews more positive. Thus, the effective gm of the composite transconductance amplifier is based on the gm of the single transconductance amplifier and the currents contributed by the successively enabled drive circuits. Therefore, the gm is nonlinear. Pull-down drive circuits are also connected to the resistor nodes to successively pull down the current as the output from the single transconductance amplifier slews negative. The composite transconductance amplifier has low quiescent current.

Abstract: Embodiments relate to peaking inductor array for a peaking control unit of a transceiver. An aspect includes the peaking inductor array comprising a plurality of cells connected in parallel, each cell comprising a respective active inductor. Another aspect includes each of the plurality of cells further comprising a decoupling capacitor.

Abstract: According to an embodiment, an operational amplifier includes a first amplifier stage coupled between an input node and an intermediate node, a second amplifier stage coupled between the intermediate node and an output node, a compensation capacitor having a first terminal coupled to the intermediate node and a second terminal, and a compensation amplifier coupled between the output node and the second terminal. The compensation amplifier has a positive gain greater than one.

Abstract: Embodiments relate to peaking inductor array for a peaking control unit of a transceiver. An aspect includes the peaking inductor array comprising a plurality of cells connected in parallel, each cell comprising a respective active inductor. Another aspect includes each of the plurality of cells further comprising a decoupling capacitor.

Abstract: Embodiments relate to peaking inductor array for a peaking control unit of a transceiver. An aspect includes the peaking inductor array comprising a plurality of cells connected in parallel, each cell comprising a respective active inductor. Another aspect includes each of the plurality of cells further comprising a decoupling capacitor.

Abstract: Embodiments relate to peaking inductor array for a peaking control unit of a transceiver. An aspect includes the peaking inductor array comprising a plurality of cells connected in parallel, each cell comprising a respective active inductor. Another aspect includes each of the plurality of cells further comprising a decoupling capacitor.

Abstract: An amplifier module comprises an amplifier having an output, a coupler coupled to the output to receive a first signal provided at the output and a power detector to provide a power signal from the first signal. It further comprises an input to receive a second signal. A switch is provided that is disposed to provide the power signal or the second signal to a signal output in dependence of a control signal.

Abstract: A multistage amplifier may include a multistage amplifier circuit and a resistive voltage divider network. The multistage amplifier circuit may have multiple transconductance input stages, each of which may have differential inputs and an adjustable tail current input that controls the amount of the transconductance of the input stage. The resistive voltage divider network may control the closed loop gain of the multistage amplifier circuit and include multiple resistors that provide different voltage divider ratios at different points. Each point may be connected to one of the transconductance input stages. Adjustment of tail currents at the tail current inputs may control the degree to which each point affects the closed loop gain of the multistage amplifier.

Abstract: Apparatuses, methods, computer readable mediums, and systems are described for combined dynamic processing and speaker protection for minimizing distortion in audio playback. In some embodiments, at least one compressed audio signal is received, at least one threshold for a speaker is retrieved, modifications to audio signal compression are determined based on the at least one compressed audio signal and the at least one threshold, information embodying the modifications is transmitted to a dynamic processor, and using the dynamic processor, at least one modified compressed audio signal is produced for the speaker based on the information.

Abstract: An amplifier circuit whose frequency response has almost no soft knee characteristic or no peak when inverting input capacitance Csin varies and when feedback capacitance Cf is a fixed value of small capacitance, and a feedback circuit is provided. The amplifier circuit includes a plurality of amplifiers each of which negative feedback is provided to and which are connected in series, and a feedback means (feedback circuit) which is connected to an output side of an amplifier near output of the amplifier circuit and an input side of an amplifier near input of the amplifier circuit. These amplifiers are ones in the plurality of amplifiers. One or odd numbers of amplifiers in the plurality of amplifiers are inverting amplifiers.

Abstract: An amplifier circuit includes an amplifier circuit that emitter-grounds a first transistor that amplifies an input signal; and an emitter-grounded feedback circuit in which a collector of the first transistor is connected to an output line of the amplifier circuit and a base is wiring-connected only to the output line by using a resistor.

Abstract: Some general aspects of the invention relate to a circuit and to a method for analog computation, for example, using switched capacitor integrated circuits. In some examples, a circuit includes a first group of capacitors and a second group of capacitors that may store charges during circuit operation. The first and/or the second group of capacitors may include multiple disjoint subsets of capacitors. An input circuit is provided for receiving a set of input signals and for inducing a charge on each of some or all capacitors in the first group of capacitors according to a corresponding input signal. Switches, for example, transistors controlled by a sequence of clock signals, are used to couple different sets of capacitors. Different configurations of the switches are used to form different sets of the capacitors among which charge can redistribute.

Abstract: Methods and apparatus are disclosed for processing an audio sound source to create four-dimensional spatialized sound. A virtual sound source may be moved along a path in three-dimensional space over a specified time period to achieve four-dimensional sound localization. The various embodiments described herein provide methods and systems for converting existing mono, 2-channel and/or multi-channel audio signals into spatialized audio signals have two or more audio channels. The incoming audio signals may be down-mixed, up-mixed or otherwise translated into fewer, greater or the same number of audio channels. The various embodiments also describe methods, systems and apparatus for generating low frequency effect and center channel signals from incoming audio signals having one or more channels.

Abstract: A power-supply apparatus according to an aspect includes an inductor, a transistor that supplies, in an on-state, a current to the input side of the inductor, a second transistor that becomes, when the first transistor is in an off-state, an on-state and thereby brings the input side of the inductor to a predetermined potential, a signal generation unit that generates voltage signals corresponding to a current flowing to the inductor, an amplifier that outputs a current according to the voltage signals, a converter that converts the current output from the amplifier into a voltage signal, and a control unit that controls the transistors based on a first feedback signal corresponding to the voltage on the output side of the inductor and the voltage signal, which is used as a second feedback signal.

Abstract: In an embodiment, a circuit includes a variable group delay configured to delay a wideband input signal to obtain a delayed input signal; a wideband operational amplifier configured to determine an error signal based on a difference between the delayed input signal and a linearized power amplifier output; a feedback amplifier configured to amplify the error signal to obtain an amplified error signal; and a directional combiner configured to combine the amplified error signal with the power amplifier output to obtain the linearized power amplifier output.

Abstract: Techniques for monitoring and controlling bias current of amplifiers are described. In an exemplary design, an apparatus may include an amplifier and a bias circuit. The amplifier may include at least one transistor coupled to an inductor. The bias circuit may generate at least one bias voltage for the at least one transistor in the amplifier to obtain a target bias current for the amplifier. The bias circuit may generate the at least one bias voltage based on a voltage across the inductor in the amplifier, or a current through a current mirror formed with one of the at least one transistor in the amplifier, or a gate-to-source voltage of one of the at least one transistor in the amplifier, or a voltage in a replica circuit replicating the amplifier, or a current applied to the amplifier with a switched mode power supply disabled.

Abstract: Improved preamplifier circuits for converting single-ended input current signals to differential output voltage signals, including first and second transimpedance amplifiers with input transistors operating according to bias currents from a biasing circuit, output transistors and adjustable feedback impedances modified using an automatic gain control circuit, as well as a reference circuit controlling the bias currents according to an on-board reference current and the single-ended input or the differential output voltage signals from the transimpedance amplifiers.

Abstract: In one embodiment, an amplifier system has a tap, a delay filter, a linearized amplifier, and a hybrid combiner. The tapped portion of an input signal is amplified by the amplifier, the untapped portion of the input signal is delayed by the delay filter, and the combiner combines the resulting amplified, tapped portion and the delayed, untapped portion to generate an amplified output signal. By re-combining the delayed, untapped portion of the input signal with the amplified, tapped portion, the power of the untapped portion is not lost, and the amplifier does not have to compensate for all of the distortion that would otherwise be associated with the total output power level. Such an amplifier system is applicable, for example, in upgrading an existing GSM cell site to support both GSM communications as well as UMTS communications without degrading GSM operations.

Abstract: According to some embodiments, a trans-capacitance amplifier is exhibiting an input current of the biasing in the range of picoAmperes while allowing large output swings. The trans-capacitance amplifier comprises an operational amplifier, a feedback capacitor, circuitry to DC bias and to AC ground the non-inverting input of the operational amplifier, and circuitry to DC bias the inverting input of the operational amplifier. According to some embodiments, the circuitry to bias the inverting input comprises a cascade of degenerated differential pairs. The first transistor of the first pair and the second transistor of the last pair have an active load. The cascade of differential pairs and the active load create a trans-conductance amplifier with a very low equivalent trans-conductance. According to some embodiments, the same invention applies to a differential trans-capacitance amplifier.

Abstract: In a preamplifier (amplifier) for detecting radiation, an output of the preamplifier is set as an output of the first amplifying circuit, a capacitor is connected in parallel to the first amplifying circuit, and the second amplifying circuit with a positive gain of less than onefold is connected between the output terminal and the input terminal of the first amplifying circuit through a switch. When the switch is closed, the capacitor is discharged and reset. As the gain of the second amplifying circuit is less than onefold, the gain of the preamplifier is less than the loop gain of the first amplifying circuit alone during the reset operation, making it harder for oscillation to occur. Accordingly, the preamplifier can reduce the compensation capacitance compared to a conventional case and can shorten the reset time, while preventing oscillation.

Abstract: An amplifier circuit comprises a measurement path with an amplifier (1) for providing an output voltage (Vout) depending on a measuring current (Ipd) with a first and a second amplifier input (11, 12), and an amplifier output (13). A return path of the amplifier circuit comprises a first filter (2), an auxiliary amplifier (3) and a second filter (4). In this case, the first filter (2) is designed to filter a DC voltage from the output voltage (Vout) and is connected to the amplifier output (13). The auxiliary amplifier (3) serves to convert an input voltage (Vfil) into an output current (Ifil) and has a first and a second auxiliary amplifier input (31, 32) and an auxiliary amplifier output (33). In this case, the first auxiliary amplifier input (31) is connected to the first filter (2). The second filter (4) is designed to filter noise from the output current (Ifil) and couples the auxiliary amplifier output (33) to the first amplifier input (11).

Abstract: A trans-impedance amplifier (TIA) for an optical receiver is disclosed, in which the TIA enhances the dynamic range thereof but suppresses the variation of the input impedance thereof. The TIA enhances the dynamic range by subtracting from the photocurrent input therein, which varies the input impedance. The TIA also provides the variable gain amplifier with a feedback resistor. The variable gain of the amplifier compensates the variation of the input impedance due to the current subtraction.

Abstract: A method including receiving an input signal; amplifying the input signal to generate an output signal using a cascade of a plurality of amplifier stages including a first amplifier stage and a last amplifier stage; generating a voltage signal by sensing the output signal in a noninvasive manner so that the sensing results in substantially no change to the output signal; generating a current signal from the voltage signal using a transconductance amplifier; and injecting the current signal into an output node of the first amplifier stage in a noninvasive manner so that the injecting results in substantially no change to an amplification function of the first amplifier stage.

Abstract: A circuit that includes an amplifier circuit with an input impedance due to an input resistance and an input capacitance of the amplifier circuit. The input impedance of the amplifier circuit may vary with frequency. The amplifier circuit may include an amplifier and a feedback circuit configured to provide feedback to the amplifier and to maintain the input impedance at a specified value at a selected frequency by increasing the input resistance of the amplifier circuit at the selected frequency.

Abstract: A high-frequency signal amplifier includes an amplifier having an input terminal and an output terminal, and amplifying a high-frequency signal; a signal line connected between the output terminal of the amplifier and an antenna; coupled lines arranged in parallel and coupled to the signal line and having different line lengths or differently terminated ends; and phase shifters shifting phase of high-frequency signals applied via the signal line and the coupled lines, supplying the high-frequency signals to the input terminal of the amplifier, and having different amounts of phase change.

Abstract: A transconductance comparator includes a comparator having an output of a detector configured to sense an amplitude of an output of a Variable Gain Amplifier (VGA) of a receiver as a first input and a reference amplitude level as a second input. The comparator generates an error signal based on the first input and the second input. The transconductance comparator also includes a transconductance amplifier having a differential voltage input based on the error signal generated through the comparator and generating an output current. The transconductance amplifier includes current sources associated with programmable current limits thereof and differential pairs associated with the current sources, one or more of which is implemented with a size mismatch between transistors thereof to eliminate an offset error due to a mismatch between the current limits, thereby enabling programmability of an attack time and a decay time during automatic gain control of the VGA.

Abstract: Systems and methods which implement a transconductor replica feedback (TRF) block in a transconductor circuit are shown. In accordance with embodiments, the TRF block comprises a feedback transistor disposed as a replica of a corresponding transconductance transistor of the transconductor circuit. The TRF block provides enhanced looking-in degeneration impedance for the transconductor circuit, thereby allowing for higher linearity and lower power at the same time. TRF transconductors of embodiments can be implemented in, or otherwise applied to, various different circuits such as LNAs, filters, etc.

Abstract: An electronic device comprising an amplifier having at least a first input transistor of a first doping type. A first transistor is coupled with a channel as a feedback path between an output of the amplifier and a control gate of the first input transistor forming an input of the amplifier. A diode-coupled second transistor is coupled with a channel between a first current source and the output of the amplifier wherein a control gate of the first transistor is coupled between the first current source and the diode-coupled second transistor and the first transistor is of a second doping type which is opposite to the first doping type of the first input transistor of the amplifier.

Abstract: Analog peaking amplifiers with enhanced peaking capability are provided. For example, a peaking amplifier circuit includes an input node, output node, a feedback node, a first input amplifier having an input connected to the input node and an output connected to the feedback node, a second input amplifier having an input connected to the input node, a coupling capacitor connected between an output of the second input amplifier and the feedback node, a forward-path gain amplifier having an input connected to the feedback node and an output connected to the output node, and a feedback circuit having an input coupled to the output node and an output connected to the feedback node. A peaking response of the peaking amplifier circuit is realized by capacitively coupling the output of the second input amplifier to the feedback node to suppress negative feedback and increase the peaking gain at higher frequencies.

Abstract: A sensor amplifier arrangement includes an amplifier having a signal input to receive a sensor signal and a signal output to provide an amplified sensor signal, and a feedback path that couples the signal output to the signal input and provides a feedback current that is an attenuated signal of the amplified sensor signal and is inverted with respect to the sensor signal.

Abstract: In accordance with the present disclosure, disadvantages and problems associated with controlling signal transmission of a wireless communication device may be reduced. In accordance with an example embodiment of the present disclosure a method for controlling transmission of a wireless communication signal comprises sensing one or more signals indicative of a power level of a wireless communication signal. The power level of the wireless communication signal is amplified by a power amplifier according to an amplifier control signal. The method further comprises determining a change in the power level based on the one or more signals indicative of the power level. The change is associated with one or more perturbations of the amplifier control signal. The method also comprises adjusting transmission of the wireless communication signal according to the change in the power level.

Abstract: A closed loop power output calibration system for variable power output wireless devices. The wireless device includes a wireless transceiver having a transmit core coupled to a discrete power amplifier. Power detection circuitry formed in the wireless transceiver provides a detected power level of the power amplifier, and a reference power level, both of which are converted to digital signals using existing I and Q signal analog to digital converters in the receiver core. The digital signals are processed to cancel power distortion and temperature effects to provide a resulting power feedback signal. Corrective control signals are generated in response to the power feedback signal relative to a desired power output level. The gain in the transmit core is then adjusted in response to the corrective control signals such that the power amplifier outputs the target output power level.

Abstract: An output circuit of a charge mode sensor includes a second resistor and an operational amplifier. The second resistor connects an output portion of the charge mode sensor and a ground. The operational amplifier is configured to output a detection signal that varies in accordance with an amount of charge kept in the charge mode sensor. The operational amplifier includes an inverting input portion, a non-inverting input portion, and an output portion. The inverting input portion is connected to the output portion of the charge mode sensor via a sensor cable. The non-inverting input portion is connected to a reference voltage. The output portion is connected to the inverting input portion via a first resistor.

Abstract: According to one embodiment, an amplification circuit can be switched between amplifying and calibration modes. During calibration, a preamplifier amplifies a differential input signal and generates a differential output signal. The amplifier circuit includes an input switch unit which sets a differential input signal as the reference voltage signal of the same voltage level at the time of calibration, a PWM conversion unit which carries out Pulse-Width-Modulation of the differential output signal, and generates a differential PWM signal based on the result of comparing the differential output signal with the reference signal, a calibration unit which generates an offset adjustment signal according to the phase difference of differential PWM signals, and an electric amplifier which carries out electric power amplification of the differential PWM signal and generates the differential final output signal.

Abstract: A current balance circuit includes a first branch and a second branch in parallel between a power supply unit and at least one load, which respectively include a switch. The current balance circuit detects and compares currents flowing through the first branch and the second branch. The current balance circuit also generates triangle waves and reversed triangle waves, compares voltage of a control pole of a first switch with the triangle waves, and compares voltage of the control pole of a second switch with the reversed triangle waves. Then the current balance circuit controls if the triangle waves and the reversed triangle waves are input to the first switch and the second switch according to the currents flowing through the first branch and the second branch to adjust impedance of the first switch and the second switch to balance the currents flowing through the first branch and the second branch.

Abstract: There is provided a bias circuit that can operate even at low voltage and control a current reflecting a change in drain voltage. A first current mirror circuit for feeding back a drain terminal current of an FET which receives an output of an operational amplifier at a gate terminal to an input terminal of the operational amplifier and a second current mirror circuit are coupled in parallel. A variable voltage is coupled to the first current mirror circuit, and a fixed voltage is coupled to the second current mirror circuit. Even if the variable voltage becomes lower than the threshold voltage of FETs configuring the first current mirror circuit, the second current mirror circuit feeds back the current to the input terminal of the operational amplifier with reliability.

Abstract: A limiting amplifier and method are provided. In one implementation an apparatus includes a plurality of amplifier stages including a first amplifier stage and a last amplifier stage configured in a cascade arrangement, and a transconductance amplifier, wherein the first amplifier stage is configured to receive an input signal; the last amplifier stage outputs an output signal; the transconductance amplifier is configured receive a voltage signal from the last amplifier stage via a first resistor; and the transconductance amplifier is configured to output a current signal to an output node of the first amplifier stage via a second resistor in a negative feedback manner.

Abstract: Embodiments provide an amplifier and a method for using and manufacturing said amplifier that incorporate an impedance matching stage, a feedback circuit, and a gain stage. The impedance matching stage is coupled to the feedback circuit wherein the feedback circuit provides a compensated second bias voltage for the impedance matching stage. The output of the impedance matching stage is used to set an input bias voltage for both the impedance matching stage and the gain stage. The output of the impedance matching stage is also used, together with the output of the gain stage, to produce an output of the amplifier. A signal reuse stage may be provided between the output of the impedance matching stage and the output of the amplifier.

Abstract: A transconductor for providing an output current that is linear in the input voltage (Vin) comprises a main output transconductor (Ms, Mc) and a model transconductor (Msr1, Msr2, Mcr1, Mcr2) is comprised in a predistortion circuit (A), which measures the output of the model transconductor and the overall voltage input (Vin) to provide a control signal (Vc, Vc?) for the transconductors that compensates for their non-linearity.

Abstract: Embodiments provide an amplifier and a method for using and manufacturing said amplifier that incorporate an impedance matching stage, a feedback circuit, and a gain stage. The impedance matching stage is coupled to the feedback circuit wherein the feedback circuit provides a compensated operating voltage for the impedance matching stage. The output of the impedance matching stage is used to set an input bias voltage for both the impedance matching stage and the gain stage. The output of the impedance matching stage is also used, together with the output of the gain stage, to produce an output of the amplifier.

Abstract: Apparatus and methods reduce the likelihood of amplifier saturation due to propagated DC offsets, and reduce the recover from saturated stated when such saturation occurs. Advantageously, these attributes are beneficial for monitoring of bioelectric signals. A circuit uses an instrumentation amplifier connected as a high pass filter to attenuate large DC offsets and amplify small signals. The circuit can include an instrumentation amplifier electrically coupled with a first feedback circuit including at least one resistor and a second feedback circuit including an op-amp. The feedback circuit can also include a low-pass filter. The op-amp in the second feedback circuit can be configured as a non-inverting amplifier, an inverting amplifier, and/or an integrator circuit. Alternatively, the circuit can include an instrumentation amplifier with one feedback circuit including at least one resistor, and a coupling capacitor electrically coupled with a reference voltage.

Abstract: Active resistive circuitry (10, 10A, 11, 11A 25, 30, 35, or 40) includes a first current divider circuit (11) having an input (15) coupled to a first signal (Vi). The first current divider circuit (11) includes a first amplifier (13) having a first input (?) coupled to the first signal (Vi). A symmetrically bilateral first bidirectional circuit (M1a,M1b; R1) is coupled between the first input (?) of the first amplifier (13) and an output (17) of the first amplifier (13), and functions as a feedback circuit of the first amplifier (13). A symmetrically bilateral second bidirectional circuit (M2a,M2b; R2) is coupled between the output (17) of the first amplifier (13) and an output (18) of the first current divider circuit (11).