Abstract: A radiofrequency power amplifier includes a balun transformer and a plurality of power transistor pairs arranged in a push-pull configuration. The balun transformer has an unbalanced coil extending between a first single-ended signal terminal and a first reference, and a balanced coil extending between a first balanced signal terminal and a second balanced signal terminal. The balun transformer also includes an auxiliary coil electrically isolated from the unbalanced coil and the balanced coil. The auxiliary coil is inductively coupled to the unbalanced coil and extends between a third balanced signal terminal and a fourth balanced signal terminal forming a balanced combiner-divider. An output of a first one of the power transistor pairs is coupled to the first and second balanced signal terminals and an output of a second one of the power transistor pairs is coupled to the third and fourth balanced signal terminals.

Abstract: An integrated circuit transformer (150) is formed with a primary winding (91) located in at least a first winding layer having a first thickness, a secondary winding (92) located in at least the first winding layer and having a first center point at the first side of the transformer and two secondary terminals at a second, opposite side of the transformer, and a first center tap feed line (81) located along a symmetry axis of the transformer in an upper metal layer having a second thickness that is at least equivalent to the first thickness of the first winding layer, wherein the first center tap feed line has a direct electrical connection to the first center point in the secondary winding.

Abstract: A multi-phase switching regulator and a switching regulating method using the multi-phase switching regulator employ an interleaving circuit. The multi-phase switching regulator includes: a first regulating circuit configured to receive an input voltage and generate a first sub-output voltage with a first phase by transforming the input voltage in response to a first set signal; a second regulating circuit configured to receive the input voltage and generate a second sub-output voltage with a second phase by transforming the input voltage in response to a second set signal; and the interleaving circuit configured to repeatedly and sequentially generate the first set signal and the second set signal by comparing a reference voltage with an output voltage generated based on the first sub-output voltage and the second sub-output voltage.

Abstract: An amplifier system including a push-pull power amplifier having an input to receive a radio frequency (RF) input signal and an output, the push-pull power amplifier being configured to amplify the RF input signal and provide at the output an RF output signal that is an amplified version of the RF input signal, a switchable shunt capacitance switchably connected between a load-line connected to the output of the push-pull power amplifier and a reference potential, and a switch configured to selectively connect the switchable shunt capacitance to the reference potential and disconnect the switchable shunt capacitance from the reference potential to vary an impedance of load-line.

Abstract: A multi-phase switching regulator and a switching regulating method using the multi-phase switching regulator employ an interleaving circuit. The multi-phase switching regulator includes: a first regulating circuit configured to receive an input voltage and generate a first sub-output voltage with a first phase by transforming the input voltage in response to a first set signal; a second regulating circuit configured to receive the input voltage and generate a second sub-output voltage with a second phase by transforming the input voltage in response to a second set signal; and the interleaving circuit configured to repeatedly and sequentially generate the first set signal and the second set signal by comparing a reference voltage with an output voltage generated based on the first sub-output voltage and the second sub-output voltage.

Abstract: Bias arrangements for amplifiers are disclosed. An example bias arrangement for an amplifier includes a bias circuit, configured to produce a bias signal for the amplifier; a linearization circuit, configured to improve linearity of the amplifier by modifying the bias signal produced by the bias circuit to produce a modified bias signal to be provided to the amplifier; and a coupling circuit, configured to couple the bias circuit and the linearization circuit. Providing separate bias and linearization circuits coupled to one another by a coupling circuit allows separating a linearization operation from a biasing loop to overcome some drawbacks of prior art bias arrangements that utilize a single biasing loop.

Abstract: A filterless high-efficiency class D power amplifier (HEPA) exploits the phase relationships of even and odd harmonics at transistor drains of a push-pull topology to eliminate output filtering, enabling an ultra-high-efficiency, low harmonic signal. The filterless HEPA relieves the amplifier of a requirement for a power consuming filter by implementing a high-quality operational harmonic block on an output stage without output buffering. The operational harmonic block senses the voltage source radio frequency to the amplifier prior to waveform squaring and employs a harmonic canceling balun to block even harmonics (in-phase) but pass odd harmonics (180° out of phase). The sensed ideal voltage source shunts the odd-harmonic currents to ground, leaving only the fundamental current on its primary to pass to the load.

Abstract: A radio-frequency power converter and a radio-frequency transmission system for magnetic resonance imaging are provided in embodiments of the present invention. The radio-frequency power converter comprises a printed circuit board, the printed circuit board comprises a first circuit layer, a ground layer, and one or a plurality of intermediate layers located between the first circuit layer and the ground layer. A plurality of planar spiral inductors connected in parallel are formed on the first circuit layer. One ends of the plurality of inductors are connected to each other and respectively connected to one end of a first capacitor, the other ends of the plurality of inductors are respectively connected to one ends of a plurality of second capacitors, and the other ends of the plurality of second capacitors are all grounded.

Abstract: A device to reduce distortion in an amplifier includes an input transistor configured to generate a voltage based on an input signal. The device further includes a diode connected transistor that is configured to sink the current. The diode connected transistor includes an output terminal, and a control terminal, where the output terminal is coupled to a control terminal. The device further includes a current source circuit that coupled to the control terminal. The device additionally includes an impedance element that coupled to the output terminal at a first node and to the control terminal and the current source circuit at a second node.

Abstract: A transformer includes: a core having a shaft; primary windings; and secondary windings around the shaft alternately with the primary windings. A first number of turns of a first secondary winding, closest to a first end of the shaft, is less than a second number of turns of a second secondary winding, second closest to the first end. A third number of turns of a third secondary winding, closest to a second end of the shaft, is less than a fourth number of turns of a fourth secondary winding, second closest to the second end. The first and second windings are connected in series. The third and fourth windings are connected in series. The first and second windings are connected in parallel to the third and fourth windings. A total of the first and second numbers is equal to that of the third and fourth numbers.

Abstract: Embodiments of radio frequency (RF) systems include a plurality of power amplifiers having a primary winding and a secondary winding. Each of the power amplifiers may be configured to process signals of different frequency bands. The primary winding for one power amplifier can be detuned while another power amplifier is being used in a transmit mode. By detuning the power amplifier, power coupling from the transmitting power amplifier can be reduced or eliminated.

Abstract: A differential power amplifier is disclosed. The differential power amplifier includes an output transformer having a primary winding with a first primary terminal, a center-tap terminal, and a second primary terminal. The differential power amplifier further includes a positive amplifier having a first signal output terminal coupled to the first primary terminal and a negative amplifier having a second signal output terminal coupled to the second primary terminal. A harmonic tuning network is made up of a common-mode inductor coupled between the center-tap terminal and a tuning node and a first electronically tunable capacitor coupled between the tuning node and a fixed voltage node. A controller is configured to tune the electronically tunable capacitor to resonate with the common-mode inductor at a second harmonic frequency of a signal being amplified by the positive amplifier and the negative amplifier.

Abstract: A semiconductor substrate includes emitter electrodes for multiple high-frequency amplifying transistors. An insulating substrate includes multiple land electrodes, ground electrodes, and multiple inductor electrodes. The land electrodes are formed on the front surface or near the front surface of the insulating substrate, and are joined to the respective emitter electrodes. The ground electrodes are formed inside the insulating substrate. Each of the inductor electrodes couples a corresponding one of the land electrodes to any of the ground electrodes in such a manner that the lengths of the coupling to the ground electrodes are individually determined.

Abstract: A high-frequency amplifier module includes a semiconductor substrate and an insulating substrate. The semiconductor substrate includes multiple emitter electrodes, each of which is coupled to the emitter of a corresponding one of high-frequency amplifying transistors. The insulating substrate includes a common ground electrode, ground terminal electrodes, and thickness-direction coupling electrodes. The common ground electrode is formed on or near the front surface of the insulating substrate, and is joined to the emitter electrodes. The ground terminal electrodes are formed on the back surface of the insulating substrate. The thickness-direction coupling electrodes couple the common ground electrode to the ground terminal electrodes.

Abstract: A multi-mode multi-band power amplifier includes a controller, a wide-band amplifier channel and a fundamental impedance transformer. The controller receives an external signal and outputs a control signal according to the external signal. The wide-band amplifier channel receives single-band or multi-band RF signals through the input terminal, performs power amplification on the RF signals and outputs the RF signals through the output terminal. The fundamental impedance transformer includes a first segment shared by RF signals in all bands, second segments respectively special for RF signals in all bands, and a switching circuit controlled by the controller to separate RF signals subject to power amplification to the second segment in a switchable manner for multiplexed outputs.

Abstract: Improvement in linearity is achieved at low costs in a power amplifier module employing an envelope tracking system. The power amplifier module includes a first power amplifier circuit that amplifies a radio frequency signal and that outputs a first amplified signal, a second power amplifier circuit that amplifies the first amplified signal on the basis of a source voltage varying depending on amplitude of the radio frequency signal and that outputs a second amplified signal, and a matching circuit that includes first and second capacitors connected in series between the first and second power amplifier circuit and an inductor connected between a node between the first and second capacitors and a ground and that decreases a gain of the first power amplifier circuit as the source voltage of the second power amplifier circuit increases.

Abstract: The present invention provides a wireless communication device that can receive a high frequency signal with a high sensitivity by reducing the noise received from a DC-DC converter, as well as a power measurement device equipped with such a wireless communication device. According to an embodiment, a wireless communication device includes: a switching-type DC-DC converter; a balun configured with a coil to output a differential signal based on a wirelessly received high frequency signal; a low noise amplifier driven by an output voltage of the DC-DC converter to process the differential signal output from the balun; and a ground voltage line that couples the low noise amplifier to a ground voltage source. The ground voltage line includes partial ground voltage lines that are arranged to face each other with the balun interposed therebetween.

Abstract: A push-pull amplifier includes a pair of active devices driving the primary side of a double distributed active transformer (DDAT). The primary side of the DDAT includes a cascaded arrangement of primary windings of a first set of transformers with the active devices coupled ends of cascaded arrangement of primary windings. The secondary side of the DDAT includes a cascaded arrangement of secondary windings of a second set of transformers coupled to a load. Secondary windings of the first set of transformers drive inputs of respective active stages. Outputs of the active stages drive respective primary windings of the second set of transformers.

Abstract: The described apparatus and methods may include a receiver configured to receive a control signal, and a controller configured to regulate power consumption of the receiver during intervals of less than one radio frame based on the control signals. The controller may also be configured to regulate power consumption of a transmitter during intervals of less than one radio frame based on the control signal.

Abstract: A transformer of distributed-constant type is provided between an AC power supply with a frequency f and a load with a resistance value R, and includes: a first converter connected to the AC power supply and having a length of ?/4; and a second converter provided between an end of the first converter and the load, and having a length of ?/4, where a wavelength at the frequency f is ?. Such a transformer has a small size and a light weight, and does not need a coil, an iron core, and the like as used in a conventional transformer.

Abstract: A programmable transmitter circuit may be coupled to a controller circuit. The controller circuit may be configured to generate control signals based at least on a signal. The transmitter circuit may include a plurality of unit cells. Each unit cell may include a respective first current source and a respective second current source. Each unit cell may be configured to be set in an activated state or a deactivated state based at least on the control signals. For a unit cell of the plurality of unit cells, when the unit cell is set in the activated state, the respective first current source or the respective second current source may be configured to generate a current to be applied to a load.

Abstract: A circuit includes first and second electronic switches, first and second excitation circuits, and first and second inductors. The first and second electronic switches are electrically coupled in series. The first and second excitation circuits are used for respectively controlling the first and second electronic switches to be turned on and turned off and are configured to synchronously switch the first and second electronic switches. The first inductor is electrically coupled between the first excitation circuit and the first electronic switch, for transmitting the switch control signal of the first excitation circuit to the first electronic switch. The second inductor is electrically coupled between the second excitation circuit and the second electronic switch, for transmitting the switch control signal of the second excitation circuit to the second electronic switch.

Abstract: A circuit includes a de-Qing network coupled in parallel between a first and a second series-coupled reactive network. The de-Qing network is sized to lower the quality factor of the second reactive network. The first reactive network is a low valued inductor, which is sized for modifying high frequency signals. The second reactive network is a high valued inductor, which is sized for modifying low frequency signals. The de-Qing network can be a resistor or combination of resistors, inductors, and capacitors.

Abstract: A device includes a main low noise amplifier (LNA) stage configured to amplify a single-ended communication signal, an auxiliary LNA stage coupled to the main LNA stage, the auxiliary LNA stage configured to cancel non-linear second order products generated by the main LNA stage, and a load circuit configured to receive an output of the main LNA stage and an output of the auxiliary LNA stage, the load circuit configured to convert the single-ended communication signal to a differential signal.

Abstract: A transceiver includes: a power amplifying circuit arranged to generate differential output signals during a transmitting mode of the transceiver; a balance-unbalance circuit arranged to convert the differential output signals into a single-ended output signal; a switchable matching circuit arranged to receive the single-ended output signal on a signal port of the transceiver during the transmitting mode, and to convert a single-ended receiving signal on the signal port into a single-ended input signal during a receiving mode of the transceiver; and a low-noise amplifying circuit arranged to convert the single-ended input signal into a low-noise input signal during the receiving mode. The power amplifying circuit, the Balun, the switchable matching circuit, and the low-noise amplifying circuit are configured as a single chip.

Abstract: Disclosed herein is a transformer including: a primary coil formed of a first conductor having a predetermined length and including a first end and second end for receiving a signal, wherein the first conductor is formed as a first loop; and a secondary coil that is coupled to the primary coil in an electromagnetic coupling, and is formed of a second conductor having a predetermined length and including a first end and a second end for outputting a signal, wherein the second conductor is formed as a second loop, wherein the primary coil and the secondary coil are stacked while crossing each other. Accordingly, power transformer efficiency may be increased.

Abstract: A power amplifier configured to receive an AC input signal and output, based on the AC input signal, an output voltage via a first output voltage terminal and a second output voltage terminal. The power amplifier includes a first transistor and a second transistor connected in a push-pull configuration, a first inductor, a second inductor, and a first capacitor. The first output voltage terminal is located between the first inductor and the first transistor. The second output voltage terminal is located between the second transistor and ground. The first capacitor is configured to provide a first circuit path between the first output voltage terminal and the second output voltage terminal. The first circuit path functions as a short circuit for even harmonics of a fundamental frequency of the AC input signal but does not function as a short circuit for the fundamental frequency of the AC input signal.

Abstract: In order to realize a wider bandwidth of a frequency characteristic of a power amplification circuit, outputs of differential push-pull amplifiers which are matched at respectively different frequencies are combined together by secondary inductors, and the combined signal is outputted.

Abstract: Methods and devices provide for power amplification in a push pull power amplifier. A circuit comprises an input stage, a power amplifier stage and an output stage. The input stage provides a plurality of control voltages based on a control current. The input stage may include a transformer with a primary side and two secondary sides. A power amplifier stage comprises an NMOS transistor and a PMOS transistor arranged in a push-pull configuration to generate a plurality of amplified signals. The transistors may be in a common gate arrangement. The output stage combines the amplified signals and generates an output voltage. The output stage may include a transformer with two primary sides and a secondary side.

Abstract: A differential electronic amplifier including: a first switch connected between a first reference voltage and a first node; a second switch connected between a second reference voltage and a second node; a resonant differential load connected between the first and second nodes and having a centre point connected to a third reference voltage; an output stage constituted by a first side of a transformer; a load impedance connected to a second side of the transformer; a first capacitive element connected between the first side of the transformer and the first node; and a second capacitive element connected between the first side of the transformer and the second node; wherein all inductive elements connected in series between the first and second capacitive elements are inductively coupled to the second side of the transformer.

Abstract: A reduction is achieved in the primary-side input impedance of a transformer (voltage transformer) as an output matching circuit without involving a reduction in Q-factor. An RF power amplifier includes transistors, and a transformer as the output matching circuit. The transformer has a primary coil and a secondary coil which are magnetically coupled to each other. To the input terminals of the transistors, respective input signals are supplied. The primary coil is coupled to each of the output terminals of the transistors. From the secondary coil, an output signal is generated. The primary coil includes a first coil and a second coil which are coupled in parallel between the respective output terminals of the transistors, and each magnetically coupled to the secondary coil. By the parallel coupling of the first and second coils of the primary coil, the input impedance of the primary coil is reduced.

Abstract: A differential power amplifier is provided and includes a first pair of transistors. A first transistor is inductively coupled to a voltage source and is connected to a node at a ground reference potential. A second transistor is inductively coupled to the node and is connected to the voltage source. Gates of the transistors are configured to receive an AC signal with a fundamental frequency. Drain of the first and second transistors are respectively first and second output nodes. The output nodes provide a first differential output. A capacitor is connected between the output nodes and provides a pathway for cancellation of even harmonic signals of the fundamental frequency. A second pair of transistors provides a second differential output. A first inductor is connected between the output nodes. A second inductor is connected between output nodes of the second pair of transistors. A combiner is inductively coupled to the inductors.

Abstract: A radio frequency system includes a first power splitter, a first push-pull power amplifier and a second push-pull power amplifier. The first power splitter is configured to receive a first radio frequency signal and generate a first output signal and a second output signal. The first push-pull power amplifier is configured to amplify the first output signal. The first push-pull power amplifier comprises a first set of transistors including at least two radio frequency power transistors and a first output transformer. The second push-pull power amplifier is configured to amplify the second output signal. The second push-pull power amplifier includes a second set of transistors including at least two radio frequency power transistors and a second output transformer. An output of the first transformer is galvanically and directly connected to an output of the second output transformer.

Abstract: A power amplifier according to the present invention includes: an input-side transformer which has an annular primary coil which is a first metal line and a plurality of linear secondary coils which are second metal lines, and matches input impedance and divides the input signal into a plurality of split signals; push-pull amplifiers each including a pair of transistors for amplifying one of the split signals; and an output-side transformer which has an annular secondary coil which is a third metal line and a plurality of linear primary coils which are fourth metal lines, and combines the amplified split signals and matches output impedance, two input terminals of the pair of transistors being connected to each other via each of the second metal lines and two output terminal of the pair of transistors being connected to each other via each of the fourth metal lines.

Abstract: A reduction is achieved in the primary-side input impedance of a transformer (voltage transformer) as an output matching circuit without involving a reduction in Q-factor. An RF power amplifier includes transistors, and a transformer as the output matching circuit. The transformer has a primary coil and a secondary coil which are magnetically coupled to each other. To the input terminals of the transistors, respective input signals are supplied. The primary coil is coupled to each of the output terminals of the transistors. From the secondary coil, an output signal is generated. The primary coil includes a first coil and a second coil which are coupled in parallel between the respective output terminals of the transistors, and each magnetically coupled to the secondary coil. By the parallel coupling of the first and second coils of the primary coil, the input impedance of the primary coil is reduced.

Abstract: The present invention relates to a large time constant steering circuit for slowly changing a voltage on a node between at least two discrete voltage levels. The present invention further relates to a slow steering current DAC comprising said large time constant steering circuit. The present invention further relates to an instrumentation amplifier device comprising a current balancing instrumentation amplifier for amplifying an input signal to an amplified output signal and a DC servo-loop for removing a DC-component from the input signal. The present invention further relates to an EEG acquisition ASIC comprising said instrumentation amplifier device.

Abstract: In order to realize a wider bandwidth of a frequency characteristic of a power amplification circuit, outputs of differential push-pull amplifiers which are matched at respectively different frequencies are combined together by secondary inductors, and the combined signal is outputted.

Abstract: A power amplifier according to the present invention includes: an input-side transformer which has an annular primary coil which is a first metal line and a plurality of linear secondary coils which are second metal lines, and matches input impedance and divides the input signal into a plurality of split signals; push-pull amplifiers each including a pair of transistors for amplifying one of the split signals; and an output-side transformer which has an annular secondary coil which is a third metal line and a plurality of linear primary coils which are fourth metal lines, and combines the amplified split signals and matches output impedance, two input terminals of the pair of transistors being connected to each other via each of the second metal lines and two output terminal of the pair of transistors being connected to each other via each of the fourth metal lines.

Abstract: A reduction is achieved in the primary-side input impedance of a transformer (voltage transformer) as an output matching circuit without involving a reduction in Q-factor. An RF power amplifier includes transistors, and a transformer as the output matching circuit. The transformer has a primary coil and a secondary coil which are magnetically coupled to each other. To the input terminals of the transistors, respective input signals are supplied. The primary coil is coupled to each of the output terminals of the transistors. From the secondary coil, an output signal is generated. The primary coil includes a first coil and a second coil which are coupled in parallel between the respective output terminals of the transistors, and each magnetically coupled to the secondary coil. By the parallel coupling of the first and second coils of the primary coil, the input impedance of the primary coil is reduced.

Abstract: Methods and apparatus for a switchable balun for combined BLUETOOTH® and WLAN operation. A switchable balun is provided that includes an input circuit for receiving an amplified signal, the input circuit comprising first and second coils connected at a center tap, an output circuit comprising a third coil that is inductively coupled to the first and second coils, the output circuit for outputting an adjusted version of the amplified signal for transmission in a selected transmission mode, and a switch coupled to the center tap, wherein the switch is configured to couple a first voltage to the center tap to select operation in a first transmission mode and to couple a second voltage to the center tap to select operation in a second transmission mode.

Abstract: A power amplifier circuit comprising a scalable power amplifier including an input and an output, and a plurality of activated amplifier elements operative to produce an output signal at the output, and operative to dynamically vary a power output level of the output signal. A variable impedance circuit operatively responsive to dynamically load the output of the scalable power amplifier. Wherein the scalable power amplifier further includes an amplifier configuration circuit operatively responsive to selectively activate the selectively activated amplifier elements by at least reducing power to at least one of the selectively activated amplifier elements.

Abstract: In order to realize a wider bandwidth of a frequency characteristic of a power amplification circuit, outputs of differential push-pull amplifiers which are matched at respectively different frequencies are combined together by secondary inductors, and the combined signal is outputted.

Abstract: A reduction is achieved in the primary-side input impedance of a transformer (voltage transformer) as an output matching circuit without involving a reduction in Q-factor. An RF power amplifier includes transistors, and a transformer as the output matching circuit. The transformer has a primary coil and a secondary coil which are magnetically coupled to each other. To the input terminals of the transistors, respective input signals are supplied. The primary coil is coupled to each of the output terminals of the transistors. From the secondary coil, an output signal is generated. The primary coil includes a first coil and a second coil which are coupled in parallel between the respective output terminals of the transistors, and each magnetically coupled to the secondary coil. By the parallel coupling of the first and second coils of the primary coil, the input impedance of the primary coil is reduced.

Abstract: An amplifier having an input transmission network with a plurality of input transformers having serially coupled primary windings. Each one of the input transformers has a secondary winding magnetically coupled to a corresponding one of the primary windings. The amplifier includes an output transmission network having a plurality of output transformers having serially coupled secondary windings. Each one of the output transformers has a secondary winding magnetically coupled to a corresponding one of the primary windings. The amplifier includes a plurality of amplifier sections, each one the sections having an input connected to a corresponding one of the secondary windings of the input transformers and an output connected to a corresponding one of the primary windings of the output transformers.

Abstract: An output stage (1) for a digital RF transmitter is provided. The output stage comprises: an input adapted to receive an input signal (RFin, b7-b0) to be transmitted; a plurality N of power amplification sections (S1, S2, S3, S4); and an output (A, B) providing an output voltage signal. Each of the N power amplification sections (S1, S2, S3, S4) is arranged to receive the input signal (RFin, b7-b0) and comprises a transformer (T1, T2, T3, T4) adapted to provide a respective output signal. Each transformer comprises a primary stage and a secondary stage; the secondary stages of the transformers (T1, T2, T3, T4) of the N power amplification sections (S1, S2, S3, S4) are combined such that a combined output voltage signal of the output stage is provided. The N power amplification sections (S1, S2, S3, S4) are adapted such that the input signal (RFin, b7-b0) is latched by clock signals (clock1, clock2, clock3, clock4) comprising different phases.

Abstract: A reduction is achieved in the primary-side input impedance of a transformer (voltage transformer) as an output matching circuit without involving a reduction in Q-factor. An RF power amplifier includes transistors, and a transformer as the output matching circuit. The transformer has a primary coil and a secondary coil which are magnetically coupled to each other. To the input terminals of the transistors, respective input signals are supplied. The primary coil is coupled to each of the output terminals of the transistors. From the secondary coil, an output signal is generated. The primary coil includes a first coil and a second coil which are coupled in parallel between the respective output terminals of the transistors, and each magnetically coupled to the secondary coil. By the parallel coupling of the first and second coils of the primary coil, the input impedance of the primary coil is reduced.

Abstract: Embodiments of circuits and systems for a harmonic tuning network coupled with a radio frequency (RF) push-pull power amplifier to terminate both second- and third-harmonic energies are disclosed. Other embodiments may also be described and claimed.

Abstract: A reduction is achieved in the primary-side input impedance of a transformer (voltage transformer) as an output matching circuit without involving a reduction in Q-factor. An RF power amplifier includes transistors, and a transformer as the output matching circuit. The transformer has a primary coil and a secondary coil which are magnetically coupled to each other. To the input terminals of the transistors, respective input signals are supplied. The primary coil is coupled to each of the output terminals of the transistors. From the secondary coil, an output signal is generated. The primary coil includes a first coil and a second coil which are coupled in parallel between the respective output terminals of the transistors, and each magnetically coupled to the secondary coil. By the parallel coupling of the first and second coils of the primary coil, the input impedance of the primary coil is reduced.

Abstract: In order to realize a wider bandwidth of a frequency characteristic of a power amplification circuit, outputs of differential push-pull amplifiers which are matched at respectively different frequencies are combined together by secondary inductors, and the combined signal is outputted.

Abstract: An RF power amplifier includes a first amplifier module comprising a first push-pull amplifier including a first plurality of field effect transistors and a first output transformer. An output impedance of the first amplifier module is 25 ohms. A second amplifier module includes a second push-pull amplifier including a second plurality of field effect transistors and a second output transformer. An output impedance of the second amplifier module is 25 ohms. A combiner is connected to the first amplifier module and the second amplifier module. The combiner combines an output from the first amplifier module and an output from the second amplifier module into a combined signal. An output impedance of the combiner is 50 ohms.