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.

A power management circuit operable to reduce rush current is provided. The power management circuit is configured to provide a time-variant voltage(s) to a power amplifier(s) for amplifying a radio frequency (RF) signal(s). Notably, a variation in the time-variant voltage(s) can cause a rush current that is proportionally related to the variation of the time-variant voltage(s). To reduce the rush current, the power management circuit is configured to maintain the time-variant voltage(s) at a non-zero standby voltage level when the power amplifier(s) is inactive. When the power amplifier(s) becomes active and the time-variant voltage(s) needs to be raised or reduced from the non-zero standby voltage level, the rush current will be smaller as a result of reduced variation in the time-variant voltage(s). As such, it is possible to prolong the battery life in a device employing the power management circuit.

An apparatus is disclosed for processing a signal with a divided amplifier. In example implementations, an apparatus includes a first portion of an amplifier, a first port interface, a second port interface, and a switch matrix. The first port interface includes a first transformer; a second portion of the amplifier, which is coupled to the first transformer; and a first switch component that is coupled to at least one of the first transformer or the second portion of the amplifier. The second port interface includes a second transformer and a second switch component that is coupled to the second transformer. The switch matrix is coupled between the first switch component and the first portion of the amplifier and between the second switch component and the first portion of the amplifier. The switch matrix is also coupled between the second portion of the amplifier and the first portion of the amplifier.

A mixer includes a load portion connected between an input terminal of a first power voltage and an output terminal of the radio frequency transmit signal and configured to adjust a magnitude of the radio frequency transmit signal, a first switching unit connected to an output terminal of the radio frequency transmit signal, and configured to perform a first switching operation in response to a plurality of local oscillation signals, and a second switching unit connected between the first switching unit and an input terminal of a second power voltage, lower than the first power voltage, and configured to perform a second switching operation in response to a plurality of baseband signals, the plurality of local oscillation signals include an I+ baseband signal, an I− baseband signal, a Q+ baseband signal, and a Q− baseband signal, and the second switching unit includes a first branch performing a switching operation under control of the I+ baseband signal and the Q+ baseband signal, a second branch performing a switching operation under control of the I− baseband signal and the Q− baseband signal, a third branch performing a switching operation under control of the Q+ baseband signal and the I− baseband signal, and a fourth branch performing a switching operation under control of the Q− baseband signal and the I+ baseband signal.

A radio-frequency integrated chip (RFIC) is described which provides a number of low noise amplifiers (LNAs) and load circuits. The low noise amplifiers are organized in groups. In some embodiments, a load circuit may be dedicated to a group or shared between groups. The RFIC includes an LNA group including a plurality of LNAs configured to amplify carrier signals related to a plurality of frequency bands, a second LNA group configured to amplify a plurality of second carrier signals, a first load circuit group dedicated to the first LNA group, a second load circuit group dedicated to the second LNA group, and a third load circuit group shared between the first LNA group and the second LNA group. In some embodiments the third load circuit group adaptively performs frequency down-conversion on a carrier signal amplified by at least one of the first LNA group and the second LNA group.

Circuits and methods for use in amplifying amplitude and phase modulated signals. A circuit uses a digital controlled multi stage combiner, a signal phase discrete mapper and a combiner digital control circuit with N parallel signal feeding it. The signals resulting from N power amplifiers have phases with belonging to an alphabet with M discrete phases prior to being fed to the multi stage combiner. The phases of the N input signals are converted in an control signal generator into Ns sets of digital control signals to control N.M sets of switches where the signals are selected according the phase and sent to the corresponding combiner in the M possible combiners. Each one combiner from the set of M combiner then combines these signals. A second stage with digital controlled combiner, combines into two sub-sets of signals the signals resulting from first stage and the resulting outputs of the combiner are then combined by a third combining digital controlled stage into the output signal. The signal amplifiers employed before the combining stage may be Class Dor Class F amplifiers to provide high efficiency amplification of the signals.

Techniques for generating a power tracking supply voltage for a circuit (e.g., a power amplifier) are disclosed. The circuit may process multiple transmit signals being sent simultaneously on multiple carriers at different frequencies. In one exemplary design, an apparatus includes a power tracker and a power supply generator. The power tracker determines a power tracking signal based on inphase (I) and quadrature (Q) components of a plurality of transmit signals being sent simultaneously. The power supply generator generates a power supply voltage based on the power tracking signal. The apparatus may further include a power amplifier (PA) that amplifies a modulated radio frequency (RF) signal based on the power supply voltage and provides an output RF signal.

A transformer device includes a first coil, a second coil, and a third coil. The first coil includes a first ring structure, a second ring structure, a first connecting portion, and a first terminal, in which the first terminal is arranged on the first connecting portion and is located at a central location between the first ring structure and the second ring structure, the first terminal is connected to the first ring structure through the first connecting portion in a first direction, and connected to the second ring structure through the first connecting portion in a second direction, and the first direction is the opposite of the second direction. The second coil is configured to couple the first ring structure. The third coil is configured to couple the second ring structure, in which the second coil and the third coil have the same structure.

Systems and methods related to power amplification and power supply control. A power amplification control system can include an interface configured to receive a transceiver control signal from a transceiver. The power amplification control system can include a power amplifier control component configured to generate a power amplifier control signal based on the transceiver control signal from the transceiver and a power supply control component configured to generate a power supply control signal based on the transceiver control signal from the transceiver and to generate the power supply control signal based on a local control signal from the power amplifier control component.

A bias circuit for a Doherty amplifier, characterized by comprising: an input port with an input impedance, wherein the input port is configured to receive a bias signal from a power supply; a first output port configured to provide a bias signal to an amplifier; a second output port configured to provide a bias signal to an amplifier; a two port impedance transformer with an input connected to the first input port, and an output of the two port impedance transformer having an intermediate impedance; an in-phase N-port dividing impedance transformer with an input connected to the output of the two port impedance transformer, wherein the in-phase N-port dividing impedance transformer comprises: a first output connected to the first output port having a first output impedance; and a second output connected to the second output port having a second output impedance.