There is provided a phase-switch-equipped variable amplification device including a switch including one input port and two output ports and configured to output a single-ended signal input to the one input port into one of the two output ports, a first converter coupled to the two output ports of the switch and configured to convert the single-ended signal output from the switch into a pair of differential signals having phases different from each other by 180-degree and invert phases of the pair of differential signals in response to a switching operation at the switch, a variable amplifier configured to amplify the pair of differential signals in accordance with a control voltage, and a second converter configured to convert the pair of differential signals amplified by the variable amplifier into a single-ended signal.

An illustrative integrated circuit configured for galvanically isolated signaling includes a receiver having: a detector module coupled to receive a differential signal from terminals of a transformer secondary, the detector module responsively presenting an impedance that varies based on a magnitude of the differential signal; a biasing module that converts the detector module impedance to a response signal; and a comparator module that compares the response signal to a reference signal to obtain a detection signal indicative of oscillation in the differential signal. A method of receiving a pulse modulated alternating current (AC) signal from a resonantly-coupled signaling path comprises: supplying balanced quiescent currents from a cross-coupled FET pair in a common gate amplifier configuration thereby obtaining an impedance that varies based on an AC signal magnitude; converting the impedance into a response signal; and comparing the response signal to a reference signal to obtain a detection signal representing pulses in the differential AC signal.

An illustrative integrated circuit configured for galvanically isolated signaling includes a receiver having: a detector module coupled to receive a differential signal from terminals of a transformer secondary, the detector module responsively presenting an impedance that varies based on a magnitude of the differential signal; a biasing module that converts the detector module impedance to a response signal; and a comparator module that compares the response signal to a reference signal to obtain a detection signal indicative of oscillation in the differential signal. A method of receiving a pulse modulated alternating current (AC) signal from a resonantly-coupled signaling path comprises: supplying balanced quiescent currents from a cross-coupled FET pair in a common gate amplifier configuration thereby obtaining an impedance that varies based on an AC signal magnitude; converting the impedance into a response signal; and comparing the response signal to a reference signal to obtain a detection signal representing pulses in the differential AC signal.

An illustrative embodiment of an integrated circuit configured for galvanically isolated signaling includes a transfer conductor carrying a modulated carrier signal. A floating transfer loop is electromagnetically coupled to the transfer conductor to receive the modulated carrier signal. The floating transfer loop includes a primary of a step-up transformer. A receiver is coupled to a secondary of the step-up transformer to receive the modulated carrier signal in an amplified, differential fashion, and to demodulate the modulated carrier signal to obtain a digital receive signal.

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.

A galvanic isolation circuit is formed by a differential transformer having primary and secondary windings for transmission of signals over a carrier between the primary and the secondary windings of the transformer. A galvanic isolation oxide layer is provide between the primary and secondary windings. Each winding includes include a center tap providing a low-impedance paths for dc and low frequency components of common-mode currents through the differential transformer. A pass-band stage is coupled to the secondary winding of the transformer and configured to permit propagation of signals over said carrier through the pass-band amplifier stage while providing for a rejection of common-mode noise.

The disclosed technology includes device, systems, techniques, and methods for amplifying a complex modulated signal with a mixed-signal power amplifier. A mixed-signal power amplifier may include an input network for splitting an input signal to multiple signals with corresponding phase and amplitude offsets, a main power amplification path including at least an analog power amplifier for amplifying a first signal, one or more auxiliary power amplification paths including at least one digitally controlled analog power amplifier in each path for amplifying a second signal, and an output network for combining the two amplified signals. The main power amplification path and the auxiliary power amplification paths can operate together to achieve load modulation to enhance the overall power amplifier efficiency at power back-off mode and the overall power amplifier linearity. The disclosed technology further includes transmission systems incorporating the mixed-signal power amplifier.

A power amplifier system includes a differential power amplifier and a bias circuit. The differential power amplifier is arranged for receiving a differential input pair to generate an output signal. The bias circuit is arranged for generating a bias voltage to bias the differential power amplifier, and the bias circuit comprises a source follower for receiving a reference voltage to generate the bias voltage.

A system includes a first amplifier stage and a second amplifier stage. The first amplifier stage is configured to amplify an input signal and generate first output signals. The first amplifier stage includes a common-source differential amplifier. The common-source differential amplifier includes a plurality of metal-oxide semiconductor field-effect transistors (MOSFETs) having source terminals connected to a common potential. The second amplifier stage includes a first differential amplifier and a second differential amplifier configured to respectively generate first and second differential outputs based on the first output signals. Each of the first and second differential amplifiers includes a plurality of MOSFETs having source terminals connected to the common potential via a respective balun.

A dual operation mode power amplifier is disclosed. In the power amplifier in accordance with an embodiment of the present invention, a bias circuit part can be converted to decrease power consumption. Different from the prior art, performance of the present invention is not reduced in a high power mode, and no additional passive components like inductors or transformers with a large area are necessary to be further added. Furthermore, a tunable impedance matching circuit provides impedances respectively matching impedances of a fully differential amplifier and a single-ended amplifier, thereby improving the performance of the power amplifier.